Predominant Th1 cell infiltration in acute rejection episodes of human kidney grafts

T-cells and their cytokines are thought to play a major role in the genesis of cellular infiltration and rejection in human kidney allografts. Production of Th1 (IFN-gamma) and Th2-type (IL-4 and IL-5) cytokines was assessed in a large series of T-cell clones, derived from core biopsies of kidney grafts in 10 patients with acute interstitial grade I/II rejection (AIR), 6 patients with a histology of "borderline rejection" (BLR) and 3 with cyclosporine A (CsA) toxicity, all receiving standard maintenance immunosuppression. Biopsies were pre-cultured in IL-2 in order to preferentially expand T-cells activated in vivo, and T-cell blasts were cloned with phytohemagglutinin (PHA) and IL-2 using a highly efficient (23 to 98%) cloning technique. A total of 483 T-cell clones obtained from AIR episodes were compared with 346 and 132 clones derived from patients with BLR episodes and CsA toxicity, respectively. In two series of 22 AIR and 77 BLR T-cell clones, alloreactivity against donor cells was shown by 25 and 14% of CD8+ and 21 and 4% of CD4+ clones, respectively. When stimulated by donor-derived EBV B-cells, all these alloreactive clones produced IFN-gamma, but not IL-4 or IL-5 (Th1 clones). Upon stimulation with PHA, the principal qualitative and quantitative differences between AIR- and BLR-derived T-cell clones were that cells derived from AIR patients: (i) showed significantly higher proportions (80 +/- 15 vs. 55 +/- 13%) of Th1 clones in their progeny; (ii) included smaller proportions (3 +/- 4 vs. 20 +/- 17%) of clones incapable of producing IFN-gamma, IL-4 or IL-5 ('null' clones); and (iii) produced significantly higher quantities of IFN-gamma (100 +/- 50 vs. 36 +/- 7 U/10(6) cells/ml), these quantities also being significantly correlated (r = 0.83) with the degree of interstitial graft infiltration (item 'i' in the Banff histological grading). The clones derived from CsA toxicity biopsies exhibited a pattern very similar to that found in BIR cases. These data lead us to conclude that the powerful inflammatory response elicited in acute rejection of a kidney graft recruits and activates both allospecific and non-specific Th1 effector cells, which are primed to high IFN-gamma production. Our results also suggest that IFN-gamma could contribute, at least in part, to the degree of graft infiltration and to the severity of the rejection episode.     

Disruption of the murine IL-4 gene blocks Th2 cytokine responses

Murine T-helper clones are classified into two distinct subsets (Th1 and Th2) on the basis of their patterns of lymphokine secretion. Th1 clones secrete interleukin-2 (IL-2), tumour necrosis factor-beta (TNF-beta) and interferon-gamma (IFN-gamma), whereas Th2 clones secrete IL-4, IL-5 and IL-10 (ref. 1). These subsets are reciprocally regulated by IL-4, IL-10 and IFN-gamma and differentially promote antibody or delayed-type hypersensitivity responses. To evaluate whether IL-4 is required for mounting Th2 responses, we generated IL-4-mutant mice (IL-4-/-) and assessed the cytokine secretion pattern of T cells both from naive and Nippostrongylus brasiliensis infected mice. CD4+ T cells from naive IL-4-/- mice failed to produce Th2-derived cytokines after in vitro stimulation. The levels of Th2 cytokines IL-5, IL-9 and IL-10 from CD4+ T cells obtained after nematode infection were significantly reduced. The reduced IL-5 production in IL-4-/- mice correlated with reduced helminth-induced eosinophilia, which has been shown to be dependent on IL-5 in vivo. We conclude that IL-4 is required for the generation of the Th2-derived cytokines and that immune responses dependent on these cytokines are impaired.     

Analysis of cytokine production by Mycobacterium-reactive T cells. Failure to explain Mycobacterium leprae-specific nonresponsiveness of peripheral blood T cells from lepromatous leprosy patients

Recent analyses of antimycobacterial T cells clones from a small number of individuals indicate that mycobacteria preferentially induce Th cells that produce high levels of IFN-gamma and no or little IL-4 in Mycobacterium leprae-resistant tuberculoid leprosy (TT) patients and healthy subjects, whereas in one study M. leprae-induced Ts clones from polar lepromatous leprosy (LL) patients showed a reciprocal cytokine secretion profile and mediated their suppressive activity via the release of high levels of IL-4. We have evaluated these findings in peripheral blood T cells from a larger panel of TT and LL patients as well as healthy individuals. Mycobacterium-reactive T cell lines generated from the PBMC of these individuals were tested for cytokine secretion and proliferative capacity in response to M. leprae, Mycobacterium tuberculosis, and various individual mycobacterial Ag. The lepromatous pole of the leprosy spectrum was additionally investigated by analyzing the cytokine-secretion profile of M. leprae-induced (suppressor) T cell clones as well as primary ex vivo PBMC. All T cell lines from healthy individuals and TT patients responding to M. leprae, M. tuberculosis, or individual Ag, produced high levels of IFN-gamma and TNF-alpha but little or no IL-4 and IL-6. At the lepromatous pole, T cell lines failed to proliferate upon stimulation with M. leprae but in some cases produced significant levels of IFN-gamma. No IL-4 or IL-6 secretion was observed in response to M. leprae. These lines displayed strong proliferation and Th1-like cytokine production upon stimulation with M. tuberculosis. Similarly, stimulation of primary PBMC from LL patients with M. leprae or M. tuberculosis resulted in the release of IFN-gamma but no detectable IL-4 production. Control tetanus toxoid-reactive T cell lines from the same individuals instead produced large amounts of IL-4 and low levels of IFN-gamma. The analysis of M. leprae-induced T cell clones, including those with known suppressive activity, revealed that all lepromatous T cell clones produced large amounts of IFN-gamma. Most of these clones released no or little IL-4, but some clones produced higher levels of IL-4 in addition to IFN-gamma. Most clones tested produced IL-10 as well. The suppressor activity of suppressor T cell clones could not be inhibited by a neutralizing anti-IL-4 antibody and only in one case by neutralizing anti-IL-10 antibody. Anti-IL-4 and anti-IL-10 could not overcome the M. leprae-specific unresponsiveness observed in primary PBMC from LL patients.(ABSTRACT TRUNCATED AT 400 WORDS)     

Lack of correlation between the reduction of sevoflurane MAC and the cerebellar cyclic GMP concentrations in mice treated with 7-nitroindazole

The clinical spectrum of leishmaniasis and control of the infection are influenced by the parasite-host relationship. The role of cellular immune responses of the Th1 type in the protection against disease in experimental and human leishmaniasis is well established. In humans, production of IFN-gamma is associated with the control of infection in children infected by Leishmania chagasi. In visceral leishmaniasis, an impairment in IFN-gamma production and high IL-4 and IL-10 levels (Th2 cytokines) are observed in antigen-stimulated peripheral blood mononuclear cells (PBMC). Moreover, IL-12 restores IFN-gamma production and enhances the cytotoxic response. IL-10 is the cytokine involved in down-regulation of IFN-gamma production, since anti-IL-10 monoclonal antibody (mAb) restores in vitro IFN-gamma production and lymphoproliferative responses, and IL-10 abrogates the effect of IL-12. In cutaneous and mucosal leishmaniasis, high levels of IFN-gamma are found in L. amazonensis-stimulated PBMC. However, low or absent IFN-gamma levels were observed in antigen-stimulated PBMC from 50% of subjects with less than 60 days of disease (24 +/- 26 pg/ml). This response was restored by IL-12 (308 +/- 342 pg/ml) and anti-IL-10 mAb (380 +/- 245 pg/ml) (P < 0.05). Later during the disease, high levels of IFN-gamma and TNF-alpha are produced both in cutaneous and mucosal leishmaniasis. After treatment there is a decrease in TNF-alpha levels (366 +/- 224 pg/ml before treatment vs 142 +/- 107 pg/ml after treatment, P = 0.02). Although production of IFN-gamma and TNF-alpha might be involved in the control of parasite multiplication in the early phases of Leishmania infection, these cytokines might also be involved in the tissue damage seen in tegumentary leishmaniasis.     

Early-onset and adult periodontitis associated with abnormal cytokine production by activated T lymphocytes

There is growing evidence for an important role of the immune system in the pathogenesis of periodontitis. To further characterize the possible immunoregulatory dysfunction of peripheral blood mononuclear cells (PBMC) in periodontitis patients, we investigated functional aspects of PBMC from patients with early-onset periodontitis (EOP) and adult periodontitis (AP). Compared to controls, we observed decreased proliferative responses of PBMC from patients with EOP following stimulation with a mitogenic stimulus (phytohemagglutinin). To investigate whether this abnormality reflects a modulation in cytokine production, we measured the in vitro production of interleukin (IL)-3, IL-5, granulocyte macrophage colony-stimulating factor (GM-CSF), and interferon-gamma (IFN-gamma) by activated PBMC. PBMC in EOP patients expressed significantly decreased levels of IFN-gamma protein in response to mitogenic stimulation. Reduced IFN-gamma secretion was associated with decreased IFN-gamma and IL-2 mRNA expression in these cells, as well as decreased HLA-DR surface expression on monocytes. On the other hand, we observed significantly higher levels of IL-5 and GM-CSF in the same system using PBMC from AP patients. These were comparable to the levels observed for patients with allergic asthma. These data imply that EOP is associated with decreased Th1-like cytokine expression, and that the PBMC response from patients with AP is predominantly Th2/Th0 in nature.     

Cytokine production at the site of disease in human tuberculosis

Clinical and immunologic evidence suggests that tuberculous pleuritis provides a model to understand protective immune mechanisms against Mycobacterium tuberculosis. We therefore evaluated the pattern of cytokine mRNA expression and cytokine production in pleural fluid and blood of patients with tuberculous pleuritis. RNA was extracted from mononuclear cells, reverse transcribed to cDNA, and amplified by polymerase chain reaction (PCR). After normalization for T-cell cDNA, cDNA from pleural fluid cells and peripheral blood mononuclear cells (PBMC) was amplified with cytokine-specific primers. PCR product was quantified by Southern blot. For the Th1 cytokines gamma interferon (IFN-gamma) and interleukin-2 (IL-2), PCR product was greater in pleural fluid than in blood, whereas PCR product for the Th2 cytokine IL-4 was decreased in pleural fluid compared with blood. Concentrations of IFN-gamma were elevated in pleural fluid compared with serum, but IL-2, IL-4, and IL-5 were not detectable. Mean concentrations of IFN-gamma and IL-2 in supernatants of M. tuberculosis-stimulated pleural fluid cells were significantly greater than corresponding concentrations in supernatants of stimulated PBMC. In situ hybridization showed that increased IFN-gamma production by pleural fluid cells was associated with a 20- to 60-fold increase in the frequency of antigen-reactive IFN-gamma-mRNA-expressing cells. Because IL-10 can be produced by T cells and macrophages, pleural fluid cells and PBMC were normalized for beta-actin cDNA content and then amplified by PCR with IL-10-specific primers. IL-10 mRNA was greater in pleural fluid cells than in PBMC and was expressed predominantly by macrophages. IL-10 concentrations were elevated in pleural fluid versus serum. These data provide strong evidence for compartmentalization of Th1 cytokines and IL-10 at the site of disease in humans with a resistant immune response to mycobacterial infection.     

Cytokine production regulating Th1 and Th2 cytokines in hemophagocytic lymphohistiocytosis

Hemophagocytic lymphohistiocytosis (HLH) is caused by the hyperactivation of T cells and macrophages. The clinical characteristics associated with this disease result from overproduction of Th1 cytokines including interferon-gamma (IFN-gamma), interleukin-2 (IL-2), and tumor necrosis factor-alpha (TNF-alpha). In this study, we analyzed the production of IL-12 and IL-4, which determine Th1 and Th2 response, respectively, and IL-10, which antagonizes Th1 cytokines, in 11 patients with HLH. IL-12 was detected in plasma in all patients (mean peak value, 30.0 +/- 5.0 pg/mL), while IFN-gamma was massively produced in nine patients (mean peak value, 79.2 +/- 112.0 U/mL). IL-4 was not detected in any of the patients. Plasma IL-10 levels were elevated in all patients (mean peak value, 2,698.0 +/- 3,535.0 pg/mL). There was a positive correlation between the levels of IFN-gamma and IL-10 (P < .01). The plasma concentrations of these cytokines were initially high, before decreasing after the acute phase. However, the decrease in IL-10 levels was slower than that of IFN-gamma. Although the concentration of IL-12 was high at the acute phase, in some patients, a peak in the level was delayed until the chronic phase. Thus, in HLH, production of cytokines that promote development of Th1 cells appears to be predominant over that for Th2 cell development. Overproduction of IL-10 was also observed indicating that a mechanism suppressing hyperactivation of Th1 cells and monocytes/macrophages functions in patients with this disease.     

Down-regulating effects of IL-4 and IL-10 on the IFN-gamma response in atopic dermatitis

Atopic dermatitis (AD) is a chronic allergic disease associated with toxin (superantigen)-producing Staphylococcus aureus skin infections, impaired delayed hypersensitivity responses, and the expansion of IL-4-secreting Th2 cells, as well as diminished IFN-gamma synthesis. IL-12 is known to induce IFN-gamma synthesis and to augment Th1 responses. In this study, therefore, we examined the potential role of IL-12 in the immunopathogenesis of AD. We show that, after stimulation with staphylococcal toxic shock syndrome toxin-1 (TSST-1) or IL-12, PBMC from patients with AD are deficient in their ability to produce IFN-gamma. PBMC from AD patients, however, produced normal quantities of IL-12 and expressed normal levels of IL-12R. Induction of IFN-gamma by TSST-1 was decreased by neutralizing anti-IL-12 Ab in normal donors, but not in AD patients. The latter observation is consistent with a defective response to IL-12 in AD PBMC. Because AD is associated with increased production of IL-4 and IL-10, we examined the effect of IL-4 on IL-12- or TSST-1-induced IFN-gamma production in normal donors. IL-4 inhibited IL-12-induced IFN-gamma production. Furthermore, Ab neutralization of IL-4 caused increased production of IFN-gamma in AD PBMC. However, neutralization of IL-10 activity caused an even greater augmentation of IFN-gamma production. Our data suggest that despite normal levels of IL-12 production and IL-12R expression, PBMC from AD patients are unable to generate normal IL-12-induced IFN-gamma responses. This defective response may be due to the excess production of IL-4 and IL-10 in this common allergic condition.     

Interleukin-12 primes human CD4 and CD8 T cell clones for high production of both interferon-gamma and interleukin-10

Interleukin-12 (IL-12) induces differentiation of T helper 1 (Th1) cells, primarily through its ability to prime T cells for high interferon-gamma (IFN-gamma) production. We now report that the presence of IL-12 during the first several days of in vitro clonal expansion in limiting dilution cultures of polyclonally stimulated human peripheral blood CD4+ and CD8+ T cells also induces stable priming for high IL-10 production. This effect was demonstrated with T cells from both healthy donors and HIV+ patients. Priming for IL-4 production, which requires IL-4, was maximum in cultures containing both IL-12 and IL-4. IL-4 modestly inhibited the IL-12-induced priming for IFN-gamma, but almost completely suppressed the priming for IL-10 production. A proportion of the clones generated from memory CD45RO+ cells, but not those generated from naive CD45RO- CD4+ T cells, produced some combinations of IFN-gamma, IL-10, and IL-4 even in the absence of IL-12 and IL-4, suggesting in vivo cytokine priming; virtually all CD4+ clones generated from either CD45RO(-) or (+) cells, however, produced high levels of both IFN-gamma and IL-10 when IL-12 was present during expansion. These results indicate that each Th1-type (IFN-gamma) and Th2-type (IL-4 and IL-10) cytokine gene is independently regulated in human T cells and that the dichotomy between T cells with the cytokine production pattern of Th1 and Th2 cells is not due to a direct differentiation-inducing effect of immunoregulatory cytokines, but rather to secondary selective mechanisms. Particular combinations of cytokines induce a predominant generation of T cell clones with anomalous patterns of cytokine production (e.g., IFN-gamma and IL-4 or IFN-gamma and IL-10) that can also be found in a proportion of fresh peripheral blood T cells with "memory" phenotype or clones generated from them and that may identify novel Th subsets with immunoregulatory functions.     

An ex vivo study of T lymphocytes recovered from the lungs of I/St mice infected with and susceptible to Mycobacterium tuberculosis

I/St mice, previously characterized as susceptible to Mycobacterium tuberculosis H37Rv, were given 10(3) or 10(5) CFU intravenously. At two time points postinoculation, the cell suspensions that resulted from enzymatic digestion of lungs were enumerated and further characterized phenotypically and functionally. Regarding the T-cell populations recovered at 2 and 5 weeks postinfection, two main results were obtained: (i) the population of CD44(-) CD45RB+ cells disappeared within 2 weeks postinfection, while the number of CD44(+) CD45RB-/low cells slowly increased between weeks 2 and 5; (ii) when cocultured with irradiated syngeneic splenocytes, these lung T cells proliferated in the presence of H37Rv sonicate. Using H37Rv sonicate and irradiated syngeneic splenocytes to reactivate lung T cells, we selected five CD3(+) CD4(+) CD8(-) T-cell clones. In addition to the H37Rv sonicate, the five clones react to both a short-term culture filtrate and an affinity-purified 15- to 18-kDa mycobacterial molecule as assessed by the proliferative assay. However, there was a clear difference between T-cell clones with respect to cytokine (gamma interferon [IFN-gamma] and interleukin-4 [IL-4] and IL-10) profiles: besides one Th1-like (IFN-gamma+ IL-4(-)) clone and one Th0-like (IFN-gamma+ IL-4(+) IL-10(+)) clone, three clones produced predominantly IL-10, with only marginal or no IL-4 and IFN-gamma responses. Inhibition of mycobacterial growth by macrophages in the presence of T cells was studied in a coculture in vitro system. It was found that the capacity to enhance antimycobacterial activity of macrophages fully correlated with INF-gamma production by individual T-cell clones following genetically restricted recognition of infected macrophages. The possible functional significance of cytokine diversity among T-cell clones is discussed.     

Analysis of cytokine and specific antibody profiles in hydatid patients with primary infection and relapse of disease

We studied in vitro cytokine production by peripheral blood mononuclear cells (PBMC) from patients with primary and recurrent hydatid disease when cells were incubated with mitogen (PHA) and antigen from hydatid cyst fluid (HCFAg); levels of specific IgE, IgG4 and eosinophil counts were also measured in sera. When specifically stimulated, PBMC from patients produced higher levels of IL-2 (P < 0.02), IFN-gamma (P < 0.0028) and IL-5 (P < 0.01) than those from uninfected donors, whereas IL-10 levels were comparable. Notably, IL-5 was also produced in higher levels (P < 0.01) by PBMC from patients when incubated with PHA. The IL-5:IFN-gamma ratio was significantly greater (P < 0.02) when measured in response to specific stimulation than it was for PHA-stimulated cultures. These cytokine data suggest a bias towards a Th2-response which is in agreement with the high levels of IgG4 and IgE observed. The polarized response appears to be related to clinical status, as differences between patients with primary infection and those with relapse of disease were demonstrated, with significantly higher levels of IgE (P < 0.003), IgG4 (P < 0.04) titres and eosinophil counts (P < 0.04) in the latter; in addition a tendency to an increased production of IL-5 buy lower IFN-gamma was also observed in this group. These results merit further study as they are suggestive of a putative role of Th2-like responses in susceptibility to reinfection by E. granulosus.     

The lantibiotic mersacidin inhibits peptidoglycan biosynthesis at the level of transglycosylation

BACKGROUND & AIMS: The cytokine pattern secreted by T cells at the site of viral replication may influence the final outcome of hepatitis B virus (HBV) and hepatitis C virus (HCV) infections. The aim of this study was to assess whether a cytokine imbalance oriented toward T helper (Th) 1 or Th2-type responses may play a role in chronic hepatitis B or C. METHODS: Production of interferon (IFN)-gamma, interleukin (IL)-4, and IL-5 by wide series of T-cell clones derived from the liver of 6 patients with chronic hepatitis B (291 clones) and 9 patients with chronic hepatitis C (260 clones) was studied. T-cell clones were generated by limiting dilution from freshly isolated mononuclear cells derived from liver tissue to give a reliable representation of the intrahepatic inflammatory infiltrates. RESULTS: The majority of liver-infiltrating T cells in chronic hepatitis C were Th1 cells able to secrete IFN-gamma but unable to secrete IL-4 or IL-5, whereas in hepatitis B, most CD4+ and CD8+ liver T cells were ThO-like cells able to produce not only IFN-gamma but also IL-4 and IL-5. CONCLUSIONS: The different cytokine profiles of T cells within the liver in chronic HBV and HCV infections illustrate a different behavior of the local immune response in these two infections that may have pathogenetic implications.     

Lactobacilli and streptococci induce interleukin-12 (IL-12), IL-18, and gamma interferon production in human peripheral blood mononuclear cells

Human peripheral blood mononuclear cells (PBMC) were stimulated with three nonpathogenic Lactobacillus strains and with one pathogenic Streptococcus pyogenes strain, and cytokine gene expression and protein production were analyzed. All bacteria strongly induced interleukin-1beta (IL-1beta), IL-6, and tumor necrosis factor alpha mRNA expression and protein production. S. pyogenes was the most potent inducer of secretion of IL-12 and gamma interferon (IFN-gamma), and two of three Lactobacillus strains induced IL-12 and IFN-gamma production. All strains induced IL-18 protein production. IL-10 and IL-4 production was induced weakly and not at all, respectively. Our data show that nonpathogenic lactobacilli and pathogenic streptococci can induce Th1 type cytokines IL-12, IL-18, and IFN-gamma in human PBMC.     

IL-17 is produced by some proinflammatory Th1/Th0 cells but not by Th2 cells

IL-17 is defined as a proinflammatory cytokine and produced by activated CD4+ T cells. In rheumatoid arthritis synovial tissue, high levels of IL-17 contribute to IL-6 production by synoviocytes. The present study was performed to see whether Th cells that produce IL-17 are associated with the Th1, Th2, or Th0 subset. Thirty-three CD4+, alphabeta+ T cell clones were developed from synovial membranes and synovial fluid of rheumatoid arthritis patients. Thirteen clones were defined as Th1 since they produced IFN-gamma but not IL-4, and four clones were defined as Th0 type that produced both IL-4 and IFN-gamma. Sixteen clones were defined as Th2 since they produced high levels of IL-4 and/or IL-10 but not IFN-gamma. IL-17 was measured in a bioassay, where IL-6 production from synoviocytes was a measurement for IL-17 activity in the presence and absence of blocking anti-IL-17 mAb. Three Th1 clones and two Th0 clones produced IL-17. In contrast, none of the sixteen Th2 clones analyzed produced IL-17. In addition, six Th2 clones were further cultured in conditions that induced a switch to Th1 type. Induction of this Th1 phenotype also led to production of IL-17 in two of these clones. The results demonstrate that some cells of the Th1/Th0 phenotype produce IL-17 but not cells of the Th2 phenotype. Thus, IL-17 may define a new subset of T cells, and IL-17 production appears to be a mechanism for Th1/Th0 cells, the most frequent Th subtype present in the rheumatoid synovium, to contribute to the local inflammatory reactions.     

Expression and function of CTLA-4 in Th1 and Th2 cells

CTLA-4 is expressed on T cells after activation and shares homology with the CD28 costimulatory receptor. In contrast to CD28, CTLA-4 is thought to be a negative regulator of T cell activation. Cross-linking of CTLA-4 during activation of peripheral T cells reduces IL-2 production and arrests T cells in G1. Much less is known about the function of CTLA-4 in differentiated T cells. We have investigated the expression and function of CTLA-4 in established Th1 and Th2 clones and in bulk populations of Th1 and Th2 cells freshly derived in vitro from TCR transgenic splenocytes. We found that CTLA-4 was induced under similar conditions and with similar kinetics following activation of both Th1 and Th2 clones. However, CTLA-4 expression was much higher in Th2 than Th1 clones and lines. This was confirmed by flow cytometry, confocal microscopy, and Northern blot analysis. The ratio of surface to intracellular expression of CTLA-4 and its rate of endocytosis were similar in Th1 and Th2 clones. Inhibition of binding of CTLA-4 to its ligands using soluble anti-CTLA-4 mAb during stimulation with Ag increased the production not only of IL-2 by Th1 clones, but also that of IL-3 and IFN-gamma by Th1 clones and of IL-3, IL-4, IL-5, and IL-10 by Th2 clones. In contrast, when anti-CTLA-4 was coimmobilized with anti-CD3 and anti-CD28 mAbs, a decrease in the production of multiple cytokines was observed. We conclude that CTLA-4 can function to suppress the production of cytokines produced by both Th1 and Th2 cells.     

In vivo relevance of CD30 in atopic dermatitis

CD30 expression was evaluated by immunohistochemistry in lesional skin biopsies of eight patients with active atopic dermatitis (AD) and three patients with allergic contact (nickel-induced) dermatitis (ACD). CD30 expression was also assessed in a large panel of CD4+ and CD8+ T-cell clones generated from the skin biopsies of four patients with AD. Finally, the levels of soluble CD30 (sCD30) were measured in the serum of 41 patients with AD, 19 patients with ACD, and 60 healthy controls. In all specimens of lesional AD skin, where the great majority of infiltrating cells were CD4+ T cells, remarkable numbers of cells were CD30+, whereas virtually no CD30+ cells were found in the skin of patients with ACD. In CD4+ T-cell clones generated from the lesional AD skin, most of which produced both interleukin (IL)-4 and interferon-gamma (IFN-gamma) (Th0-like cells) or IL-4 and IL-5, but not IFN-gamma (Th2-like cells), CD30 expression directly correlated with the ability to produce IL-4 and IL-5, but was inversely related to IFN-gamma production. High levels of sCD30 (correlated with disease activity: r = 0.618) were detected in the serum of most AD patients, whereas there was no increase of sCD30 levels in the serum of patients with ACD. These data support the view that Th0/Th2-type responses predominate in the skin of patients with AD and suggest that the presence of CD30+ T cells in tissues and/or increased levels of sCD30 in biologic fluids are indicative of Th2-dominated responses.     

A common factor regulates both Th1- and Th2-specific cytokine gene expression

Murine T helper cell clones are classified into two distinct subsets, T helper 1 (Th1) and T helper 2 (Th2), on the basis of cytokine secretion patterns. Th1 clones produce interleukin-2 (IL-2), tumor necrosis factor-beta (TNF-beta) and interferon-gamma (IFN-gamma), while Th2 clones produce IL-4, IL-5, IL-6 and IL-10. These subsets differentially promote delayed-type hypersensitivity or antibody responses, respectively. The nuclear factor NF-AT is induced in Th1 clones stimulated through the T cell receptor-CD3 complex, and is required for IL-2 gene induction. The NF-AT complex consists of two components: NF-ATp, which pre-exists in the cytosol and whose appearance in the nucleus is induced by an increase of intracellular calcium, and a nuclear AP-1 component whose induction is dependent upon activation of protein kinase C (PKC). Here we report that the induction of the Th2-specific IL-4 gene in an activated Th2 clone involves an NF-AT complex that consists only of NF-ATp, and not the AP-1 component. On the basis of binding experiments we show that this 'AP-1-less' NF-AT complex is specific for the IL-4 promoter and does not reflect the inability of activated Th2 cells to induce the AP-1 component. We propose that NF-ATp is a common regulatory factor for both Th1 and Th2 cytokine genes, and that the involvement of PKC-dependent factors, such as AP-1, may help determine Th1-/Th2-specific patterns of gene expression.