Clinical significance of CMV-specific T helper responses in lung transplant recipients

BACKGROUND: Cytomegalovirus (CMV) disease continues to be a major problem for lung transplant patients who generate an inefficient immune response to control this viral infection. Both T helper and cytotoxic T cells are thought to play an important role in prevention and control of CMV disease. We investigated the clinical significance of CMV-specific memory responses in lung transplant recipients. METHOD: Peripheral blood samples (140) were collected from 99 lung transplant recipients. Patients were grouped according to their pre-transplant CMV serological status as recipient/donor (R-/D+, 25 patients), 28 R+/D+ patients, 35 R+/D- patients and 11 R-/D- patients. Memory responses to CMV whole antigen, 5 CMV proteins, and tetanus toxoid (TT) were measured in a 6-day proliferative assay. Results were expressed as the stimulation index (SI = experimental cpm/background cpm), and were considered positive if the SI was >3 and the cpm values were over 1,000. RESULTS: The frequency of positive CMV memory responses was similar in three groups: 64% for R-/D+, 63% for R+/D+ and 56% for R+/D- except for R-/D- (21%). The memory response to TT was similar for all four groups (70% of samples were positive). The level of responsiveness to individual CMV proteins was much higher in R+/D+ group (65%) than the other two groups (35% for R+/D-, and 31% for R-/D+). We determined the temporal relationship between the presence of CMV-specific memory responses and the diagnosis of CMV disease. In the R-/D+ group, 16 of 17 patients who had CMV disease eventually developed CMV-specific memory. In those patients (n = 3) who failed to develop CMV-specific T helper response for a prolonged time, all had recurrent CMV disease. In the R+/D+ group, 4 of 8 patients with CMV disease exhibited CMV-specific memory responses. Three of 4 patients in whom we observed a persistent absence of CMV-specific memory had multiple episodes of CMV pneumonitis. In the R+/D- group, only one of 4 patients with CMV disease had suppressed CMV-specific memory response after first episode of CMV pneumonitis and had recurrent disease. CONCLUSION: In lung transplant recipients, the loss or persistent lack of CMV-specific memory following infection was associated with chronic CMV disease. These data suggest that monitoring T helper memory responses following primary CMV infection or after augmented immunosuppression for treatment of rejection may identify those patients at risk for morbidity associated with recurrent CMV disease.     

Dysgerminoma in an Arabian filly

Late onset cytomegalovirus (CMV) disease (occurring more than 1 year post-transplant] was documented in two liver transplant recipients with recurrent hepatitis C virus hepatitis in the absence of factors known to precipitate CMV disease, i.e., primary acquisition of CMV, allograft rejection, augmented immunosuppression, concomitant infections, or blood transfusions. Both patients had CMV enteritis (with CMV adrenalitis in one case]; however, other symptoms and signs of overt CMV infection, i.e., fever, leukopenia, or atypical lymphocytes, were lacking. Hepatitis C virus is an immunomodulatory virus; impaired CMV-specific T-cell responses may have accounted for the predisposition of our patients to unprovoked, late onset CMV disease. Given the high incidence of hepatitis C virus recurrence after liver transplantation, awareness of the occurrence and recognition of the unusual presentation of CMV disease in this setting is both clinically relevant and significant, particularly since CMV is treatable if recognized promptly.     

Strategies for the prevention of cytomegalovirus disease after marrow transplantation

The purposes of this review are to examine the epidemiology of disease due to cytomegalovirus (CMV) in recipients of autologous and allogeneic marrow transplants and to compare different antiviral regimens used for the prevention of such disease in recipients of allogeneic marrow transplants, with an emphasis on ganciclovir. In seven studies, ganciclovir reduced the incidence of CMV infection and disease after allogeneic marrow transplantation. In one study mortality after transplantation was reduced because of a decreased rate of CMV-related death among ganciclovir-treated patients. Ganciclovir was effective when given to all CMV-seropositive patients (prophylaxis) or to patients who were considered at high risk for CMV disease on the basis of a positive surveillance culture (early treatment). The effectiveness of ganciclovir for the prevention of CMV infection and disease is limited by drug-induced neutropenia. Experience with other antiviral agents, such as foscarnet, has been limited. Initial studies of the adoptive transfer of CMV-specific CD8+ cytotoxic T cells have been conducted. In short, ganciclovir is currently effective for the prevention of CMV disease in allogeneic marrow transplant recipients, but its usefulness is limited by neutropenia. Future studies must be aimed at confining the toxicity of ganciclovir to patients at the highest risk for CMV disease.     

Successful engraftment of haploidentical stem cell transplant for familial haemophagocytic lymphohistiocytosis using both bone marrow and peripheral blood stem cells

Familial haemophagocytic lymphohistiocytosis (HLH) is a disease with a very poor prognosis unless patients receive a bone marrow transplant. It is often difficult to find an HLA-matched donor and haploidentical familial donors may be considered. The main complication of this type of transplant is graft rejection. We describe a patient with familial HLH who received a haploidentical transplant using both mobilized peripheral blood and bone marrow stem cells in an attempt to overcome graft rejection by increasing the stem cell dose. The peripheral blood stem cell inoculum was CD34 enriched using a Cellpro column and T-cell depleted by Campath-1M, the patient received conditioning for a matched sibling donor transplant with the addition of Campath 1G. There was rapid and full engraftment and the patient remains disease free at 5 months. This technique may be applicable for other fatal inborn errors in the absence of an HLA-matched donor.     

Impact of high-dose oral acyclovir prophylaxis on cytomegalovirus (CMV) disease in CMV high-risk renal transplant recipients

Recent studies showed contradictory results concerning the efficacy of oral acyclovir in the prevention or amelioration of cytomegalovirus (CMV) disease after renal transplantation (TX). This study evaluated the incidence and severity of CMV disease within the first year after TX in high-risk renal transplant recipients (CMV-seropositive donor, seronegative recipient) treated prophylactically with oral acyclovir (800 to 3200 mg/day) over a period of 12 wk (ACY, N = 22), compared with high-risk patients randomly assigned as controls (CO, N = 10). Follow-up for CMV infection included serological determination of CMV-specific immunoglobulin G and immunoglobulin M antibodies, antigen detection in peripheral blood leukocytes (PP 65), shell vial culture (blood), and virus isolation/early antigen detection (urine). Severity of CMV disease was quantified by a scoring system for CMV-related symptoms. Nine patients (40.1%) in the acyclovir group and four patients (40%) in the control group developed CMV disease. Neither severity (ACY, 11.4 versus CO; 12.5 points score), nor duration of disease (ACY, 21 days; CO, 22 days), nor transplant function at the end of the observation period differed significantly. The onst of CMV disease was not delayed significantly in acyclovir-treated patients compared with controls (ACY, 47 +/- 34 days versus CO, 27 +/- 14 days after TX, not significant). Our results show no beneficial effect of oral acyclovir prophylaxis in CMV high-risk renal transplant recipients.     

An in vitro model of T cell activation by autologous cytomegalovirus (CMV)-infected human adult endothelial cells: contribution of CMV-enhanced endothelial ICAM-1

Cellular immunity is strongly implicated in control of CMV disease; however, many mechanistic details remain unresolved. We previously demonstrated T cell activation responses to CMV-infected allogeneic endothelial cells (EC), suggesting EC as a mediator of CMV response in the transplant recipient. We now test the hypothesis that CMV-specific T cell responses can be directly stimulated by infected EC in an environment free of potentially confounding allogeneic factors. By isolating splenic T cells and gonadal vein endothelial cells (GVEC) from individual cadaveric organ donors, we have developed an in vitro model of T cell interaction with autologous CMV-infected EC. Proliferation assays demonstrated significantly enhanced responses by CMV-seropositive donor-derived T cells cocultured with CMV-infected GVEC, as compared with those elicited by uninfected cells. Similarly, as determined by limiting dilution analysis of IL-2-producing cells, T cell response frequencies to infected GVEC were significantly greater than to uninfected EC. In contrast, responses of CMV-seronegative donor-derived T cells were minimal, regardless of CMV status of stimulator GVEC. Intriguingly, CD4 responses were observed in spite of the fact that CMV-infected EC express no HLA class II. Finally, attenuation of CMV-stimulated T cell proliferation observed in the presence of blocking Ab specific for ICAM-1 suggests a contributing role for CMV-enhanced endothelial ICAM-1 expression in the activation response. These studies demonstrate that EC can stimulate autologous T cell responses to CMV in the absence of accessory APC and suggest potentially novel mechanisms of immune activation.     

Sequential analysis of early hematopoietic reconstitution following allogeneic bone marrow transplantation with fluorescence in situ hybridization (FISH)

Using in situ hybridization with an X and Y chromosome probe mixture, we have sequentially studied peripheral blood samples from 10 patients (four males/six females) in an HLA-matched allogeneic setting in order to monitor the kinetics of early hematopoietic reconstitution. Interphase cells from smears consisting of purified granulocytic and lymphocytic populations respectively were studied in three patients at 24, 48, 72 and 96 h post-transplant. This period was arbitrarily defined as the immediate post-transplant period. These three patients plus seven others were studied sequentially at days 5, 10, 15, 20, 25 and 50 post-transplant, defined as the intermediate post-transplant period. The X and Y probes were indirectly labelled with rhodamine and fluoresceine isothiocyanate, respectively. Donor neutrophils were detected as early as 24 h post marrow infusion followed by a significant expansion at 48 h. At 96 h post-transplant, the median percentage of donor neutrophils was > 90%. In the immediate post-transplant period, most of the lymphocytes were of recipient origin. However, we have documented a significant expansion in donor lymphocytes, starting at day 5 post-transplant in most patients. Almost complete chimerism for the myeloid and lymphoid lineages was established at days 10 and 25 post-transplant, respectively. All patients engrafted normally according to standard clinical criteria. Follow-up data for those surviving > or = 100 days (eight patients), showed persistence of this pattern of hematopoietic reconstitution in all but one patient. Molecular monitoring of early engraftment has enabled us to unravel a distinct biphasic pattern of myeloid and lymphoid engraftment.     

Nonmitogenic anti-CD3F(ab')2 fragments inhibit lethal murine graft-versus-host disease induced across the major histocompatibility barrier

We have investigated the in vivo administration of nonmitogenic anti-CD3F(ab')2 fragments for the prevention of lethal graft-vs-host disease (GVHD) in irradiated recipients of fully allogeneic bone marrow cells plus splenocyte (BMS) inocula. Recipients of anti-CD3F(ab')2 fragments administered for 1 mo post-bone marrow transplantation (BMT) had 100% survival without clinical or histopathological evidence of GVHD. Controls given saline injections succumbed by 39 days post-BMT. Similar results were obtained in groups of recipient mice given BMS in which T cells were depleted by in vitro anti-Thy-1.2 plus C' treatment. Further studies were undertaken to define mechanistic differences in the two approaches. Using Ly-5 congenic sources of donor bone marrow and spleen, we determined that anti-CD3F(ab')2 fragments induced TCR modulation and T cell depletion. Mature splenic-derived CD4+ cells were depleted to a greater extent than CD8+ cells. Early post-BMT, recipients receiving injections with control saline had the highest number of CD4+ and CD8+ cells (which may cause GVHD) followed by recipients of anti-CD3F(ab')2 fragments, with the fewest CD8+ cells observed in the anti-Thy-1.2 + C' treated group. CD3+CD4-CD8- cells (which may suppress GVHD generation) were present in higher numbers early post-BMT in recipients given anti-CD3F(ab')2 fragments as compared to recipients given anti-Thy-1.2 + C'-treated BMS. In long term survivors, a mononuclear T cell containing infiltrate without evidence of destruction was observed in sites of GVHD (lung and liver), consistent with a "Quilty" effect, which was not observed in either of the other two groups. Although survivors were tolerant of donor skin grafts and rejected third party grafts, recipients given anti-CD3F(ab')2 fragments but not anti-Thy-1.2 + C'-treated BMS had vigorous anti-host proliferative responses. These results demonstrate that although in vitro anti-Thy-1.2 + C' treatment of BMS (which is highly depletionary) and in vivo administration of anti-CD3F(ab')2 fragments (which is modulatory and less depletionary) are both effective strategies for GVHD, the cellular events involved in achieving GVHD prevention are indeed different.     

Primary Sj?gren's syndrome followed by chronic myelogenous leukemia: a case report with a ten year history

We describe a female patient with primary Sj?gren's syndrome who subsequently developed chronic myelogenous leukemia. The patient received a bone marrow transplant (BMT) from a genotypically HLA-identical brother after pre-transplant preparation with busulfan and cyclophosphamide. Eighteen weeks later, cutaneous and mucosal chronic graft-versus-host disease developed, followed by death 11 months after transplantation. Anti-Ro/SS-A antibodies disappeared within 6 months post-BMT, but antinuclear antibodies remained positive through the post-transplant course.     

Epstein-Barr virus-associated post-transplant lympho-proliferative disease of donor origin in liver transplant recipients

BACKGROUND/AIMS: Post-transplant lymphoproliferative disease, a potential complication of solid organ transplantation, occurs in about 3% of orthotopic liver transplant recipients. We report the genetic and virological characterization of two cases of post-transplant lymphoproliferative disease that occurred early (4 and 6 months) after orthotopic liver transplant as large-cell non-Hodgkin's lymphomas located at the hepatic hilum. METHODS: Lymphomatous tissues were analyzed for clonality and presence of Epstein-Barr virus (EBV) sequences by Southern blot, polymerase chain reaction, and in situ hybridization techniques. RESULTS: The tumors in both cases were sustained by a clonal proliferation of B lymphocytes containing type A EBV DNA. Moreover, in situ hybridization with a digoxigenin-labeled EBV-specific probe evidenced a strong nuclear signal in most of the neoplastic cells. DNA microsatellite analysis at three different loci detected alleles of donor origin in both tumor samples, suggesting that the neoplastic B cells were of donor origin. CONCLUSIONS: EBV-infected donor B lymphocytes might be responsible for intragraft post-transplant lymphoproliferative disease in orthotopic liver transplant recipients. As 20 to 30% of post-transplant lymphomas involve the graft itself, donor-derived post-transplant lymphoproliferative disease might be more frequent than presently appreciated. Prospective studies are needed to assess its real incidence and identify possible risk factors.     

Enhanced lymphoid cell recovery after bone marrow transplantation: correlation with the presence of costimulatory antibodies in serum

We describe a patient with T cell deficiency who underwent bone marrow transplantation (BMT) from an HLA-identical brother. The patient's white blood cell count recovered with exceptional rapidity post-BMT: after 7 to 9 days it rose sharply to 98x10(9) cells/L, 76% of which were mononuclear leukocytes. It then decreased, and a second peak was observed 250 days post-BMT. Lymphocytes from both peaks displayed a phenotype of mature T cells together with characteristics of a constitutively activated state; that is, they 1) exhibited high levels of tyrosine-phosphorylated T cell receptor (TCR) zeta chain, 2) spontaneously secreted IL-2, 3) expressed activation specific cell surface markers, and 4) were unresponsive to in vitro stimuli. The increased cell counts in both peaks correlated with the presence of anti-lymphocytic antibodies in the patient's serum, which reacted with peripheral blood lymphocytes (PBLs) both from the donor and from unrelated individuals. These antibodies were present before BMT and reappeared post-BMT. Variable number tandem repeats analysis revealed that the patient's PBLs were chimeras for up to 2 years post-BMT. This finding could explain the newly synthesized post-BMT anti-lymphocytic antibodies and the appearance of the second WBC peak during that period. The patient's anti-lymphocytic antibodies displayed costimulatory activity, enhancing the in vitro proliferation of normal T cells suboptimally activated via the TCR. The unique characteristics of these antibodies could explain the enhanced T cell recovery observed post-BMT as well as the constitutive activation state of these cells. Furthermore, such antibodies may eventually facilitate development of a therapeutic method for inducing enhanced post-BMT recovery.     

Toxoplasma gondii infection in marrow transplant recipients: a 20 year experience

Twelve of 3803 consecutive marrow allograft patients treated at this center over the past 20 years have had a post-transplant tissue diagnosis of toxoplasmosis: 10 at autopsy and 2 by brain biopsy. This infection was identified in none of 509 autologous marrow recipients. Occurrence of toxoplasmosis was 0.31 cases per 100 allogeneic transplants and 1.0 per 100 autopsies. An estimated 15% of allogeneic transplant recipients were seropositive for Toxoplasma gondii and 2% of seropositive patients developed toxoplasmosis. Pre-transplant serology was positive by both dye and agglutination tests in 11 infected patients tested. Sequential IgG, IgM, IgA, IgE antibody titers to T. gondii and the differential agglutination ratio were not helpful in diagnosing toxoplasmosis. Median day of clinical presentation was day 59 post-transplant (35-97 days) and of diagnosis, day 62 after transplant (37-143 days). Eleven patients had graft-versus-host disease (GVHD) of grades II-IV. All 12 patients died. Infection was diagnosed prior to death in only 16% of patients and contributed to death in at least 40%. Histopathology revealed tachyzoites of T. gondii most prevalent in brain (100%), heart (67%) and lungs (33%), and toxoplasma cysts alone in heart (33%) and lungs (22%). Toxoplasma infection was diagnosed in two patients receiving trimethoprim-sulfamethoxazole for Pneumocystis carinii pneumonia prophylaxis suggesting this was insufficient prophylaxis for toxoplasmosis. Toxoplasmosis appeared to occur by reactivation within the first 6 months after marrow transplant. Infection developed in patients who were seropositive for T. gondii pre-transplant, had received allogeneic marrow and had severe GVHD.     

Long-term engraftment following in utero T cell-depleted parental marrow transplantation into fetal rhesus monkeys

A major concern with allogeneic BMT for treating most inherited diseases is the need to overcome graft rejection with conditioning chemotherapy which is associated with a relatively high morbidity and mortality. This can be eliminated if the transplant is done in utero when the fetus is unable to reject donor hematopoietic stem cells (HSC). We studied the efficacy of T cell-depleted (TCD) parental bone marrow as a source of HSC for transplantation into early gestation non-defective fetal rhesus monkeys. Thirteen opposite sexed TCD transplants were done into 44 day fetal recipients and 12 into 61 day recipients (165 day total gestation). The procedure-related mortality was 8%, all in the earlier age group. The overall survival was 60% at birth with a projected survival of 44 +/- 10% at 1.5 years with no difference between the two age groups. We used a PCR assay for the rhesus Y chromosome to detect male donor cells in female recipients (six animals transplanted at 44 days and five at 63 days). The overall engraftment rate was 73% with no difference as a function of gestational age at transplant. In six long-term surviving engrafted females we detected donor cells in the peripheral blood and bone marrow up to 3 years of age. We found a delay in the appearance of donor cells in the peripheral blood in engrafted animals, in some cases for up to 6 months post-BMT. In vitro mixed lymphocyte reaction and cell-mediated lymphocytotoxicity studies between the recipient and donor cells indicate that tolerance was induced to donor cells. Individual and pooled erythroid and myeloid marrow colonies grown in methyl cellulose were collected and analyzed for donor origin by PCR. The amount of donor cells in marrows from long-term engrafted animals was < 0.1%. In a fetal recipient studied at 35 days post-BMT, donor cells were detected in bone marrow and liver in both erythroid and myeloid lineages. These results indicate that TCD parental marrow can durably engraft in utero. While the engraftment rate is similar to that seen with fetal liver as the source of HSC, the degree of peripheral blood engraftment (percent donor cells) in this non-defective primate model is low. It will require increasing the percent pre-or postnatally for this approach to be clinically relevant in those disorders in which there is no selective survival advantage for normal engrafted donor cells.     

Lungs are a major organ site of cytomegalovirus latency and recurrence

Recurrence of infectious virus from the latent viral genomes is the initiating event in the pathogenesis of cytomegalovirus (CMV) disease during states of immunodeficiency. Interstitial pneumonia is a frequent manifestation of posttransplantation CMV disease, in particular after bone marrow transplantation and heart and lung transplantations. Recurrence can occur within the transplant derived from a latent infected donor as well as within latently infected organs of the transplant recipient. The reason for a predilection of the lungs as a site of CMV pathology is so far unknown. In a murine model of CMV latency, the lungs were identified as an authentic site of latent infection, since the viral genome remained detectable in lung tissue even after it was cleared to an undetectable level in blood and bone marrow. A comparison between the lungs and the spleen, the previously most thoroughly investigated site of murine CMV latency, revealed a 10-fold-higher burden of latent viral genome for the lungs. Most important, the organ-specific risk of in vivo recurrence was found to correlate with the organ-specific viral genomic load. This new finding thus characterizes the lungs as a high-risk organ for CMV recurrence, and this fact may explain in part why interstitial pneumonia is a frequent manifestation of recurrent CMV infection.     

Haemopoietic cell transplantation in children with juvenile myelomonocytic leukaemia

Seven children, 11 months to 5.9 years of age, with juvenile myelomonocytic leukaemia (JMML) underwent allogeneic haemopoietic cell transplantation (HCT) using related or unrelated donor bone marrow or umbilical cord blood. All patients had active disease at time of transplant despite chemotherapy in five patients and chemotherapy and splenectomy in one patient prior to HCT conditioning. All patients received cyclophosphamide and TBI, with the addition of busulphan in two cases. Engraftment was documented in all cases. Notably, six of seven patients relapsed after allogeneic HCT with one achieving a return to full donor chimaerism after cyclosporin A (CSA) withdrawal. Two patients are alive in remission, 23+ and 30+ months after transplant. The role of allogeneic HCT in patients with JMML is discussed. A cooperative multicentre trial is needed to establish the optimal therapy for these patients.     

Allogeneic transplantation combining mobilized blood and bone marrow in patients with refractory hematologic malignancies

BACKGROUND: Mobilized blood stem cells have been used successfully in autologous transplant recipients to reduce the complications of pancytopenia due to dose-intensive chemotherapy. Reports of cytokine-mobilized blood progenitor cells in allogeneic transplant recipients are rare. STUDY DESIGN AND METHODS: This is a pilot trial of six patients. Patients with advanced hematologic malignancy received bone marrow (median total 2.6 x 10(8) mononuclear cells/kg) followed by four daily transfusions of blood (median total 9.5 x 10(8) mononuclear cells/kg) from HLA-matched sibling donors who were mobilized with recombinant human granulocyte-colony-stimulating factor (5 micrograms/kg/day subcutaneously for 5 days). All patients received cyclosporine and prednisone for graft-versus-host disease (GVHD) prophylaxis. RESULTS: An absolute neutrophil count greater than 500 per mm3 was achieved on Day 12, and platelet transfusion independence was achieved on Day 16. The median day of hospital discharge was Day 23 after transplant. All patients achieved 100-percent donor cell engraftment. Acute > or = Grade III GVHD did not develop in any patients, but all patients developed Grade I (n = 4) or Grade II (n = 2) acute GVHD. Chronic extensive GVHD developed in four of six patients. One patient died of pneumonia 263 days after transplant while undergoing immune-suppressive therapy for chronic GVHD. CONCLUSION: The transfusion of blood stem cells in patients undergoing allogeneic bone marrow transplant is well tolerated soon after transplant, but the development of chronic GVHD may limit the general usage of unmanipulated blood stem cells.     

Control of cytomegalovirus in bone marrow transplantation chimeras lacking the prevailing antigen-presenting molecule in recipient tissues rests primarily on recipient-derived CD8 T cells

Cytomegalovirus (CMV) infection during the transient immunodeficiency after bone marrow transplantation (BMT) develops into disease unless antiviral CD8 T cells are restored in due course. Histoincompatibility between donor and recipient is associated with increased risk. Complications may include a rejection response against the foreign major histocompatibility complex (MHC) antigens and a lack of antiviral control resulting from a misfit between donor-derived T cells and the antigenic viral peptides presented in recipient tissues. Here we have established a murine model of CMV disease after experimental BMT performed across a single MHC class I disparity. Specifically, BALB/c bone marrow cells expressing the prevailing antigen-presenting molecule Ld were transplanted into the Ld gene deletion mutant BALB/c-H-2(dm2), an experimental setting that entails a selective risk of host-versus-graft but not graft-versus-host response. The reconstituted T-cell population proved to be chimeric in that it consisted of Ld-positive donor-derived and Ld-negative recipient-derived cells. Pulmonary infiltrates did not include cytolytic T cells directed against Ld. This finding implies that the infection did not trigger a host-versus-graft response. Notably, upon adoptive transfer, donor-derived CD8 T cells preferentially protected tissues of donor genotype, whereas recipient-derived CD8 T cells protected tissues of either genotype. We infer from these data that the focus on immunodominant antigens presented by Ld within the donor cell population distracted the donor T cells from protecting recipient tissues and that protection in the chimeras was therefore primarily based on recipient T cells. As a consequence, T-cell chimerism after BMT should give a positive prognosis with respect to control of CMV.     

Clinical applications of registration and fusion of multimodality brain images from PET, SPECT, CT, and MRI

The aim was to assess the specificity and functional significance of liver-infiltrating and peripheral blood T cells in chronic hepatitis C. Peripheral blood mononuclear cells hepatitis C virus from 50 of 58 (86.2%) patients with chronic hepatitis C virus infection and 6 of 28 (21.4%) controls showed a proliferative T cell response to at least one of 16 synthetic peptides covering highly conserved regions of the core, envelope (El) and non-structural regions (NS4) of hepatitis C virus. However, six immunodominant peptides were exclusively recognized by the proliferating blood mononuclear cells from 46 patients with chronic hepatitis C virus infection (79.3%). Fine specificity and HLA-restriction were studied with 15 peptide-specific CD4+ T cell lines and 23 T cell clones isolated from liver tissue and peripheral blood of 12 patients with chronic hepatitis C. It was demonstrated that the peptide-specific response of CD4+ T cells was restricted to the presence of autologous accessory cells and HLA-DR and -DP molecules. Eight peptide-specific T cell lines and five T cell clones derived from liver tissue and peripheral blood, released interferon-gamma (200-6600 pg/ml) and tumor necrosis factor-alpha (100-400 pg/ml) and no or little interleukin-4 (< 140 pg/ml) after peptide-specific or mitogeneic stimulation, thus resembling a Th1-like cytokine profile. Patients with active liver disease showed significantly higher proliferative responses to hepatitis C virus core peptides than asymptomatic hepatitis C virus carriers or complete responders to interferon therapy. In conclusion, class II-restricted CD4+ T cell responses to some immunodominant epitopes within the hepatitis core region correlated with disease activity in chronic hepatitis C virus infection. Functionally, liver-infiltrating and peripheral blood T cells released Th1-like cytokines in response to the specific stimulus. Thus, it can be suggested that CD4+ T cells can mediate the pathogenesis of chronic hepatitis C virus induced liver disease.     

Bone marrow transplants from unrelated donors for patients with chronic myeloid leukemia

BACKGROUND: Chronic myeloid leukemia can be cured by marrow transplantation from an HLA-identical sibling donor. The use of transplants from unrelated donors is an option for the 70 percent of patients without an HLA-identical sibling, but the morbidity and mortality associated with such transplants have been cause for concern. We analyzed the safety and efficacy of transplants from unrelated donors for the treatment of chronic myeloid leukemia and identified variables that predict a favorable outcome. METHODS: Between May 1985 and December 1994, 196 patients with Philadelphia chromosome-positive chronic myeloid leukemia in chronic phase received marrow transplants from unrelated donors. RESULTS: The median follow-up was 5 years (range, 1.2 to 10.1). Graft failure occurred in 5 percent of patients who could be evaluated. Acute graft-versus-host disease of grade III or IV severity was observed in 35 percent of patients who received HLA-matched transplants, and the estimated cumulative incidence of relapse at five years was 10 percent. The Kaplan-Meier estimate of survival at five years was 57 percent. Survival was adversely affected by an interval from diagnosis to transplantation of one year or more, an HLA-DRB1 mismatch, a high body-weight index, and an age of more than 50 years. Survival was improved by the prophylactic use of fluconazole and ganciclovir. The Kaplan-Meier estimate of survival at five years was 74 percent (95 percent confidence interval, 62 to 86 percent) for patients who were 50 years of age or younger who received a transplant from an HLA-matched donor within one year after diagnosis. CONCLUSIONS: Transplantation of marrow from an HLA-matched, unrelated donor is safe and effective therapy for selected patients with chronic myeloid leukemia.