Allogeneic bone marrow transplantation

Allogeneic bone marrow transplantation (BMT) after high-dose, marrow-ablative chemoradiotherapy has been established as the treatment of choice for various hematologic, neoplastic, and congenital disorders. The most common type of marrow graft is an allogeneic one from a sibling donor who has compatible human leukocyte antigen (HLA). Only 30% of patients requiring allogeneic BMT have an HLA-compatible sibling donor. Over the past few years, marrows from unrelated HLA-compatible donors have been used with increasing frequency and promising outcome in certain hematologic malignancies. Despite the morbidity and mortality associated with this treatment modality, allogeneic BMT may provide a 20% to 90% chance of long-term, disease-free survival to patients with a wide variety of neoplastic and abnormal marrow disorders.     

Endothelium and bone marrow transplantation

Thrombotic complications may occur early after marrow transplantation and many data suggest that endothelial injury plays a pivotal role in their pathogenesis. Since plasma thrombomodulin and P-selectin are thought to be of value as markers of vascular endothelial cell membrane injury, we investigated their plasma concentration in bone marrow transplant patients aiming better to clarify the degree of endothelial involvement. Plasma thrombomodulin and P-selectin were monitored in 25 patients without thrombotic complications before transplant, on day 0 and weekly for 1 month thereafter, while in three patients who developed VOD monitoring continued until day +52. These proteins were in the normal range in all the uncomplicated patients and in two with reversible VOD, while they were always very high in the only patient who developed very severe and lethal VOD. In conclusion, we suggest that endothelial activation/damage occurs rarely in the course of BMT for hematological malignancies; we were able to document endothelial injury in only one patient with very severe thrombotic complication.     

52Fe for additional marrow ablation before bone marrow transplantation

The effectiveness of bone marrow transplantation (BMT) for malignant blood diseases remains limited by the inability of the preparative regimen to eliminate the disease without causing toxicity to normal organs. We have used 52Fe to deliver radiotherapy selectively to the BM. Fourteen patients with hematologic malignancies received 52Fe before a conventional BMT conditioning regimen. The median 52Fe dose was 58 mCi (range, 32 to 85 mCi). As evaluated by quantitative scanning, the median percentage of 52Fe taken up by the BM was 82% (range, 36% to 90%). This resulted in a median radiation-absorbed dose to the BM of 632 rad (range, 151 to 1,144 rad). The median uptake of 52Fe by the liver was 18% (range, 10% to 64%) and the median radiation-absorbed dose to the liver was 239 rad (range, 82 to 526 rad). The median whole body radiation-absorbed dose was 46 rad (range, 22 to 68 rad). No untoward effects were noted after the injections of 52Fe. The patients recovered hematopoiesis without toxicity in excess of that expected with conventional conditioning alone. The median follow-up was 8 months and three patients have relapsed. 52Fe should provide a way to boost the radiation dose to marrow-based diseases before marrow transplantation without increasing toxicity.     

Lymphoid follicles in bone marrow aspirates

Lymphoid follicles were observed in 260 of 1,450 consecutive bone marrow aspirates (17.9%). As expected, the incidence of lymphoid follicles was less than those reported from autopsies (26.1-62.3%), but was twice as great as those in previous reports based upon study of aspirations (3.3-9.1%). The number of lymphoid follicles is also related to age and sex of the patient: they are rare in childhood and common after the fourth decade of life, particularly in women. Lymphoid follicles are found in higher incidence in bone marrow aspirates with plasma-cytosis and/or lipid granulomas than in those without these reactive changes. This relationship has not been described previously and suggests that the frequent occurrence of lymphoid follicles in the older age group may be a minifestation of a response to chronic immunologic stimulation.     

A mouse bone marrow dosimetry model

Bone marrow is the primary dose-limiting organ in radioimmunotherapy. Athymic nude mouse models are used to guide radioimmunotherapy in humans. In the mouse, the dimensions of the marrow are comparable to the mean range of the beta particles for a wide variety of beta-emitting radionuclides, so local beta energy deposition cannot be assumed. METHODS: We have developed a computer simulation model in which slab, spherical and cylindrical geometries of the bone marrow of the mouse were incorporated. The energy deposition within the marrow was estimated using beta dose point kernels for several beta-emitting radionuclides. RESULTS: The calculated percentages of energy deposited in the mouse marrow using the full geometry were 46%, 24% and 10% for 131I-, 186Re- and 90Y-radiolabeled antibodies, respectively. Assuming a concentration of activity in the marrow of 0.36 times the blood activity concentration, the percentages of energy deposition in the marrow from marrow and whole-body sources were 61%, 40% and 29% for 131I, 186Re and 90Y, respectively. CONCLUSION: This work shows that, even for the lower mean beta energy-emitting radionuclide, such as 131I, accurate computation of the mouse bone marrow dose involves including both the energy loss from beta decays within the marrow and dose contributions from tissue surrounding the marrow.     

The bone marrow in murine AIDS

In order to increase the understanding of blood cytopenias in HIV infection we have investigated the bone marrow in murine AIDS. C57BL/6 mice infected with the LP-BM5 retrovirus show a decrease in cellularity, numerous haemophagocytic histiocytes, a reduction of all erythroid precursor cells, an increase in eosinophil number and an increase in lymphocytes. Immunostaining with an anti-Pr60gag antibody shows that the majority of bone marrow cells express the viral protein. Thus, the bone marrow in MAIDS has many similarities with the bone marrow from patients with advanced AIDS and may prove useful as a model for therapy aimed at treating blood cytopenias.     

Allogeneic bone marrow transplantation in Japan

Allogeneic bone marrow transplantation (BMT) is being used increasingly to treat diverse diseases in Japan. The distinctive aspects of allogeneic BMT in Japan include the lower incidence of acute graft-versus-host disease, which may be attributable to less disparity in histocompatibility antigens in Japanese. Research in the field of allogeneic BMT in Japan has covered the use of recombinant hemopoietic growth factors, especially granulocyte colony-stimulating factor, and novel immunosuppressive agents.     

Worldwide Web of bone marrow donors

The first successful Bone Marrow Transplant (BMT) was performed in the 1960s. Initially, patients had to have a sibling donor which limited BMT to approximately 30% of patients. The development of regional donor registries and subsequently the establishment of the National Marrow Donor Program (NMDP) in 1986 has expanded the availability of BMT so that the majority of patients in need of a BMT have access to a donor. Physicians need to be aware of the donor registry to encourage their patients to be donors and to know when to refer a patient for consideration for BMT.     

Reimmunization after allogeneic bone marrow transplantation

BACKGROUND/AIMS: Patients with cirrhosis and ascites show high plasma concentrations of endothelin. The aim of the current study was to investigate whether this feature is a compensatory response to effective hypovolemia or a consequence of systemic endotoxemia. METHODS: Protocols 1 and 2 assess the effect of acute changes in effective blood volume on plasma endothelin, and protocol 3 investigates the relationship between plasma endotoxin and endothelin in patients with cirrhosis and ascites. Protocol 1 included nine healthy subjects and 26 patients with cirrhosis studied during supine rest, upright tilt (which decreases effective blood volume) and cycloergometric exercise (which activates vasoactive systems by a baroreceptor independent mechanism). Protocol 2 included six patients studied before and 1 and 3 h after the intravenous administration of a plasma expander. In protocol 3, the plasma levels of endothelin and endotoxin were measured in 17 non-infected patients with cirrhosis and also in four patients with spontaneous bacterial peritonitis at diagnosis and following resolution of infection. RESULTS: Plasma endothelin was 3-5 times higher in patients with cirrhosis than in healthy volunteers. In healthy subjects, upright tilt and exercise were associated with a significant activation of the renin-aldosterone and sympathetic nervous systems and an increase in plasma endothelin. In patients with cirrhosis, upright tilt and exercise were associated with a significant increase and plasma volume expansion with a marked suppression of the renin-aldosterone and sympathetic nervous systems. However, in these patients none of these maneuvers affected plasma endothelin levels. In the patients with cirrhosis in protocol 3, there was no correlation between plasma endotoxin and endothelin. Resolution of peritonitis was associated with a marked fall in plasma endotoxin and no changes in plasma endothelin. CONCLUSIONS: These findings suggest that mechanisms other than effective hypovolemia or systemic endotoxemia are involved in the increased plasma endothelin of cirrhosis with ascites.     

Invasive aspergillosis and bone marrow allograft

Invasive aspergillosis is the most frequent cause of infectious death after allogeneic bone marrow transplantation. Risk factors include the patient's condition (granulocytopenia, immunosuppression) and his environment (air spores count). Pulmonary infections are prominent. Other infections usually occur in the setting of disseminated disease via hematogenous spread. Cerebral aspergillosis appears to be especially frequent and of very poor prognosis. Infections of the paranasal sinuses occur less often and are associated or not with pneumonitis. Mycologically confirmed diagnosis is difficult to obtain: treatment will often have to be instored on clinical findings alone or even on an empiric basis. However, the prognosis remains extremely poor explaining the actual physicians' concern in finding a better prophylaxis of this infection.