HIV-infected long-term nonprogressors display a unique correlative pattern between the interleukin-7/interleukin-7 receptor circuit and T-cell homeostasis

Background

We hypothesized that there may be a correlation between the interleukin‐7 (IL‐7)/IL‐7 receptor (IL‐7R) regulatory system and parameters of T‐cell homeostasis in HIV‐infected long‐term nonprogressors (LTNPs) as compared with patients with disease progression.

Methods

The possibility of a correlation between T‐cell homeostatic parameters and IL‐7/IL‐7R was investigated in 22 LTNPs (CD4 count ≥500 cells/μL for >10 years) vs. HIV‐positive patients at different disease stages [12 early: CD4 count ≥400 cells/μL; 15 late (AIDS‐presenters): CD4 count ≤150 cells/μL].

Results

Compared with early‐stage HIV‐positive patients, LTNPs displayed a higher circulating IL‐7 concentration (P=0.05), which was positively associated with higher IL‐7Rα expression and a higher T‐cell receptor excision circle (TREC) content specifically within CD4 cells (P<0.05). Compared with late‐stage disease patients, early‐stage disease patients displayed a lower IL‐7 concentration (P<0.01) and higher percentages of IL‐7Rα⁺ CD4 and CD8 cells (P=0.05). IL‐7 was positively correlated with the percentage of TREC⁺ CD4 cells (P<0.01), which translated into a higher percentage of naïve CD4 cells in early‐stage disease patients than in late‐stage disease patients; however, the CD4 cells in early‐stage disease patients were less enriched in recent thymic emigrants (RTEs) compared with LTNPs (P<0.05). In late‐stage AIDS‐developing patients, substantially increased IL‐7 was correlated with a decreased percentage of IL‐7Rα⁺ CD4 cells (P=0.01), which resulted in these patients having a significantly lower percentage of naïve T cells (P<0.01) and a significantly lower content of TREC (P<0.01) than the other patients.

Conclusions

The maintenance of high CD4 cell counts in LTNPs was associated with a specific IL‐7/IL‐7R pattern characterized by increased IL‐7 and highest IL‐7Rα‐expressing CD4 cells relative to other patients. Compared with patients with late‐stage disease, LTNPs displayed a phenotypically naïve, less activated CD4 cell pool highly enriched in RTEs, suggesting the existence of a compensatory IL‐7‐mediated pathway specifically sustaining peripheral CD4 counts.

     

Increased intraarticular interleukin‐7 in rheumatoid arthritis patients stimulates cell contact–dependent activation of CD4+ T cells and macrophages

Objective

To determine the level of intraarticular expression of interleukin‐7 (IL‐7) in patients with rheumatoid arthritis (RA) and to investigate the mechanisms by which IL‐7 facilitates activation of CD4+ T cells and monocyte/macrophages in RA.

Methods

IL‐7 levels were measured in synovial fluid obtained from patients with RA and patients with osteoarthritis (OA). Immunohistologic analysis was used to assess the expression of IL‐7 in synovial tissue from patients with RA. Proliferation and activation markers were determined in order to measure the effect of IL‐7 on mononuclear cells, isolated CD4+ T cells, and monocyte/macrophages from the peripheral blood and synovial fluid. Cocultures of CD4+ T cells and monocytic cells in the absence or presence of a semipermeable membrane were performed to assess the extent to which IL‐7 induces its effects, either contact dependently or via soluble mediators.

Results

IL‐7 levels were increased in synovial fluid from patients with RA compared with the levels in synovial fluid from patients with OA. Macrophages, fibroblasts, and endothelial cells in the joint lining tissue expressed abundant IL‐7. In vitro, synovial fluid CD4+ T cells and macrophages were hyperresponsive to IL‐7 when compared with peripheral blood cells. Furthermore, IL‐7 enhanced cell contact–dependent activation of CD4+ T cells and monocyte/macrophages.

Conclusion

The abundant intraarticular expression of IL‐7 and the stimulation by IL‐7 of contact‐dependent activation of CD4+ T cells and monocytic cells indicate that this cytokine plays an important proinflammatory role in RA synovitis. Further identification of IL‐7–induced pathways may improve understanding of the important interactive role of CD4+ T cells and monocytic cells in RA.

     

The response of T cells to interleukin‐6 is differentially regulated by the microenvironment of the rheumatoid synovial fluid and tissue

Objective

Interleukin‐6 (IL‐6) is a proinflammatory cytokine with regulatory effects on the survival and differentiation of T cells. It exerts its biologic function in 2 ways: by directly binding to the IL‐6 receptor (IL‐6R; CD126) or via trans‐signaling, in which soluble IL‐6R/IL‐6 complexes bind to the signaling component CD130. This study was undertaken to assess the expression and regulation of CD126 and CD130 and determine how these affect the response of CD4+ T cells to IL‐6 in the joints of patients with rheumatoid arthritis (RA).

Methods

Flow cytometry and immunofluorescence microscopy were used to determine the expression, function, and regulation of CD126 and CD130 in CD4+ T cells from the peripheral blood (PB), synovial fluid (SF), and synovial tissue of RA patients.

Results

Compared to the findings in RA PB, CD4+ T cells in the SF and synovial tissue expressed low levels of CD126. In contrast, whereas CD4+ T cell expression of CD130 was minimal in the SF, its level in the synovial tissue was high. Consistent with this phenotype, synovial tissue T cells responded to trans‐signaling by soluble IL‐6R/IL‐6 complexes, whereas no response was evident in CD4+ T cells from the SF. Down‐regulation of both receptor components in SF T cells could be explained by exposure to high levels of IL‐6. Increased levels of CD130 messenger RNA and protein in synovial tissue CD4+ T cells suggested that CD130 is up‐regulated locally. Among a range of cytokines tested, only IL‐10 induced CD130 expression in T cells.

Conclusion

The inflamed microenvironment in the synovial tissue maintains responsiveness to IL‐6 trans‐signaling through the up‐regulation of CD130 expression in CD4+ T cells, and this process may be driven by IL‐10.

     

Blockade of the interleukin‐7 receptor inhibits collagen‐induced arthritis and is associated with reduction of T cell activity and proinflammatory mediators

Objective

To study the effects of interleukin‐7 receptor α‐chain (IL‐7Rα) blockade on collagen‐induced arthritis (CIA) and to investigate the effects on T cell numbers, T cell activity, and levels of proinflammatory mediators.

Methods

We studied the effect of anti–IL‐7Rα antibody treatment on inflammation and joint destruction in CIA in mice. Numbers of thymocytes, splenocytes, T cell subsets, B cells, macrophages, and dendritic cells were assessed. Cytokines indicative of Th1, Th2, and Th17 activity and several proinflammatory mediators were assessed by multianalyte profiling in paw lysates. In addition, T cell–associated cytokines were measured in supernatants of lymph node cell cultures.

Results

Anti–IL‐7Rα treatment significantly reduced clinical arthritis severity in association with reduced radiographic joint damage. Both thymic and splenic cellularity were reduced after treatment with anti–IL‐7Rα. IL‐7Rα blockade specifically reduced the total number of cells as well as numbers of naive, memory, CD4+, and CD8+ T cells from the spleen and significantly reduced T cell–associated cytokines (interferon‐γ, IL‐5, and IL‐17). IL‐7Rα blockade also decreased local levels of proinflammatory cytokines and factors associated with tissue destruction, including tumor necrosis factor α, IL‐1β, IL‐6, matrix metalloproteinase 9, and RANKL. IL‐7Rα blockade did not significantly affect B cells, macrophages, and dendritic cells. B cell activity, indicated by serum anticollagen IgG antibodies, was not significantly altered.

Conclusion

Blockade of IL‐7Rα potently inhibited joint inflammation and destruction in association with specific reductions of T cell numbers, T cell–associated cytokines, and numerous mediators that induce inflammation and tissue destruction. This study demonstrates an important role of IL‐7R–driven immunity in experimental arthritis and indicates the therapeutic potential of IL‐7Rα blockade in human arthritic conditions.

     

Persistence of CCR5 usage among primary human immunodeficiency virus isolates of individuals receiving intermittent interleukin‐2

Objective

To investigate the impact of intermittent interleukin‐2 (IL‐2) plus combination antiretroviral therapy (cART) on HIV‐1 entry co‐receptor use.

Methods

Primary HIV‐1 isolates were obtained from 54 HIV‐1‐positive individuals at baseline and after 12 months using co‐cultivation of peripheral blood mononuclear cells (PBMC) with activated PBMC of HIV‐negative healthy donors. HIV‐1 co‐receptor use was determined on U87‐CD4 cells.

Results

Fourteen out of the 21 (67%) IL‐2‐treated individuals harbouring a primary CCR5‐dependent (R5) HIV‐1 isolate at baseline confirmed an R5 virus isolation after 12 months in contrast to 3 out of 7 (43%) of those receiving cART only. After 12 months, only 1 R5X4 HIV‐1 isolate was obtained from 21 cART+IL‐2‐treated individuals infected with an R5 virus at entry (5%) vs. 2/7 (29%) patients receiving cART alone, as confirmed by a 5‐year follow‐up on some individuals.

Conclusions

Intermittent IL‐2 administration plus cART may prevent evolution towards CXCR4 usage in individuals infected with R5 HIV‐1.

     

Important role of interleukin‐3 in the early phase of collagen‐induced arthritis

Objective

Activation of basophils contributes to memory immune responses and results in exacerbation of collagen‐induced arthritis (CIA). We undertook the present study to analyze the production and biologic effects of interleukin‐3 (IL‐3), a strong activator of basophils, in CIA.

Methods

Arthritis was induced by immunization with type II collagen. Mice were treated with blocking monoclonal antibodies against IL‐3 or with recombinant IL‐3. Clinical scoring, histologic analysis, fluorescence‐activated cell sorter analysis, enzyme‐linked immunosorbent assay, and cell culturing were performed to assess disease activity and IL‐3 production.

Results

IL‐3 was produced in large quantities by collagen‐specific CD4+ T cells in the spleen and was present in the synovial tissue during onset of arthritis, but was down‐regulated in paws with severe inflammation. Blockade of IL‐3 during the time of arthritis onset resulted in profound improvement of the disease, with reductions in synovial leukocyte and cytokine levels, peripheral blood basophil levels, and anticollagen antibody titers. Blockade of IL‐3 during the late phase of arthritis had no beneficial effect. Administration of recombinant IL‐3 during onset of arthritis induced a marked exacerbation of the disease, with increased peripheral blood basophil and plasma IL‐6 levels and increased titers of anticollagen antibody. In studies of the regulation of IL‐3 expression in CD4+ T cells, IL‐6 and IL‐4 suppressed the release of IL‐3 by activated CD4+ T cells, whereas lipopolysaccharide and CpG DNA up‐regulated IL‐3 secretion in activated CD4+ T cells by acting on costimulatory cells.

Conclusion

Taken together, the present results demonstrate for the first time that IL‐3 has an important role in the early phase of CIA.

     

Antiretroviral effects on HIV-1 RNA, CD4 cell count and progression to AIDS or death: a meta-regression analysis

Objective

Governments, clinicians and drug‐licensing bodies have adopted changes in CD4 cell counts and HIV‐1 RNA levels as evidence of effectiveness for new therapeutic interventions. We aimed to determine the strength of the association between the magnitude of the effect of changes in CD4 cell count and HIV‐1 RNA and progression to AIDS or death in the highly active antiretroviral therapy (HAART) era.

Methods

We identified all randomized clinical trials (RCTs) evaluating the effect of HAART on both clinical and surrogate endpoints (1994 to September 2006). We performed a meta‐regression and weighted linear regression. We additionally estimated potential RCT sample sizes that would be required to assess the effectiveness of new interventions in terms of clinical endpoints.

Results

We included data from 178 RCTs. We were unable to demonstrate a strong relationship at any time‐point. Specifically, this was the case when CD4 T‐cell change and clinical outcomes were examined at week 24 [coefficient ?0.01, 95% confidence interval (CI) ?0.03 to 0.001, P=0.54], week 48 (coefficient ?0.01, 95% CI ?0.02 to 0.001, P=0.83) and week 96 (coefficient 0.00, 95% CI ?0.03 to 0.04, P=0.76). This was also the case when viral load was examined as a surrogate marker. Given the small number of clinical events occurring in new interventional RCTs, any RCT aiming to evaluate clinical endpoints within these time‐points would require an exceptionally large sample size.

Conclusions

Our findings indicate that, within short‐term clinical trial settings, it is not possible to estimate the proportion of treatment effect associated with surrogate endpoints.

     

A polymorphism within IL21R confers risk for systemic lupus erythematosus

Objective

Interleukin‐21 (IL‐21) is a member of the type I cytokine superfamily that has a variety of effects on the immune system, including B cell activation, plasma cell differentiation, and immunoglobulin production. The expression of IL‐21 receptor (IL‐21R) is reduced in the B cells of patients with systemic lupus erythematosus (SLE), while serum IL‐21 levels are increased both in lupus patients and in some murine lupus models. We recently reported that polymorphisms within the IL21 gene are associated with increased susceptibility to SLE. The aim of this study was to examine the genetic association between single‐nucleotide polymorphisms (SNPs) within IL21R and SLE.

Methods

We genotyped 17 SNPs in the IL21R gene in 2 large cohorts of lupus patients (a European‐derived cohort and a Hispanic cohort) and in ethnically matched healthy controls.

Results

We identified and confirmed the association between rs3093301 within the IL21R gene and SLE in the 2 cohorts (meta‐analysis odds ratio 1.16 [95% confidence interval 1.08–1.25], P = 1.0 × 10⁻⁴).

Conclusion

Our findings indicate that IL21R is a novel susceptibility gene for SLE.

     

Treatment outcomes amongst previously antiretroviral-naïve HIV-infected patients starting lopinavir/ritonavir-containing antiretroviral regimens at the Royal Free Hospital

Objective

To describe outcomes in patients starting first‐line antiretroviral regimens including lopinavir/ritonavir (LPV/r) in a routine clinic setting.

Methods

Previously naïve patients starting LPV/r‐containing antiretroviral therapy were included in the study. Virological failure was defined as the first of two viral loads >500 HIV‐1 RNA copies/mL more than 6 months after starting LPV/r. Cumulative percentages experiencing virological failure were calculated using Kaplan–Meier methods.

Results

A total of 195 individuals had a median follow‐up time of 1.7 years. At 48 weeks, 87.9, 77.4 and 71.6% of patients with pretreatment CD4 counts of <50, 50–200 and >200 cells/μL, respectively, remained on LPV/r. By 48, 72 and 96 weeks, 2.2, 3.0 and 5.0% of patients, respectively, had experienced virological failure, ignoring treatment changes but censoring follow‐up at discontinuation of all antiretrovirals; these percentages became 24.0, 33.7 and 42.3% when LPV/r discontinuation was considered as virological failure. Censoring those who stopped LPV/r with a viral load <50 copies/mL and considering as virological failures those who stopped LPV/r with a viral load >50 copies/mL gave 12.1, 14.6 and 17.0% virological failure at 48, 72 and 96 weeks, respectively. Median CD4 count increases at 24, 48 and 72 weeks were 167, 230 and 253 cells/μL, respectively.

Conclusions

Few patients experienced virological failure whilst on a LPV/r‐based regimen, although it was not uncommon for patients in our clinic with higher baseline CD4 counts to discontinue LPV/r.

     

Elevated expression of interleukin‐7 receptor in inflamed joints mediates interleukin‐7–induced immune activation in rheumatoid arthritis

Objective

To evaluate the expression and functional ability of the high‐affinity interleukin‐7 receptor (IL‐7Rα) in patients with rheumatoid arthritis (RA).

Methods

Expression of IL‐7Rα and IL‐7 was determined in synovial tissue from RA patients and was compared with that in synovial tissue from patients with undifferentiated arthritis (UA) and osteoarthritis (OA). IL‐7Rα expression on CD4 T cells, CD19 B cells, and CD14 monocyte/macrophages from RA synovial tissue, synovial fluid, and peripheral blood was also assessed. The proliferative capacity of IL‐7Rα^bright and IL‐7Rα^dim/− T cells was measured. In addition, we examined IL‐7R blockade with soluble human IL‐7Rα (hIL‐7Rα) in the prevention of immune activation of peripheral blood mononuclear cells.

Results

We found significantly higher IL‐7Rα expression in RA and UA synovial tissue than in OA synovial tissue, and the level of IL‐7Rα expression correlated significantly with the levels of CD3 and IL‐7 expression. CD4 T cells from RA synovial fluid and synovial tissue strongly expressed IL‐7Rα. A substantial percentage of B cells and macrophages from RA synovial fluid and synovial tissue also expressed IL‐7Rα, although less prominently than T cells. We found that peripheral blood IL‐7Rα^bright T cells that did not express FoxP3 were highly proliferative as compared with IL‐7Rα^dim/− T cells that did express high levels of FoxP3. Soluble hIL‐7Rα inhibited IL‐7–induced proliferation and interferon‐γ production by mononuclear cells from RA patients.

Conclusion

Our data suggest that enhanced expression of IL‐7Rα and IL‐7 in RA patients contributes significantly to the joint inflammation by activating T cells, B cells, and macrophages. The inhibition of IL‐7R–mediated immune activation by soluble hIL‐7Rα further indicates an important role of IL‐7Rα in inflammatory responses in RA, suggesting IL‐7Rα as a therapeutic target for immunotherapy in RA.

     

The value of serum albumin in pretreatment assessment and monitoring of therapy in HIV/AIDS patients

Objectives

We sought to examine the utility of serum albumin measurement in staging AIDS and monitoring patients' response to therapy.

Methods

The possible importance of serum albumin measurement in assessing AIDS stage and in monitoring the response to highly active antiretroviral therapy using CD4 cell count and body weight as parameters was examined in 185 consecutive HIV‐infected, therapy‐naïve individuals who were recruited for antiretroviral therapy at the university of Ilorin Teaching Hospital. The regimen included lamivudine, stavudine and nevirapine. The diagnosis of AIDS was established through a combination of clinical features and HIV seropositivity using two different enzyme‐linked immunosorbent assay techniques. Serum albumin level was determined by the Bromocresol green method, while the CD4 lymphocyte count was obtained using the Dynal T4 count method. Body weight was measured in kilograms with light clothes on.

Results

There were significant positive correlations between pretreatment albumin and both pretreatment CD4 cell count and pretreatment weight, and between post‐treatment albumin and both post‐treatment weight and post‐treatment CD4 cell count up to a count of 700 cells/μL. There were also significant positive correlations between increase in serum albumin and both increase in body weight and duration of treatment.

Conclusions

We conclude that, in developing countries where many patients may not be able to afford to pay for CD4 cell counts and viral load tests, which are the traditional markers for HIV disease, serum albumin would be a very useful surrogate test for predicting severity of HIV infection and for clinical monitoring of response to antiretroviral therapy.

     

CD28‐dependent differentiation into the effector/memory phenotype is essential for induction of arthritis in interleukin‐1 receptor antagonist–deficient mice

Objective

Interleukin‐1 receptor antagonist (IL‐1Ra)–deficient mice on a BALB/c background spontaneously develop a chronic inflammatory polyarthropathy closely resembling that of rheumatoid arthritis in humans. To elucidate the role of CD28 costimulatory signals in the development of this disease, we studied IL‐1Ra/CD28–double‐deficient mice.

Methods

We crossed IL‐1Ra–deficient mice with CD28–deficient mice and observed the incidence and severity of arthritis. To investigate functions of IL‐1Ra/CD28–double‐deficient T cells, cells were stimulated with CD3 monoclonal antibody or allogeneic antigen‐presenting cells (APCs) and their proliferative responses and levels of cytokine production were measured.

Results

Disease severity was lower in IL‐1Ra/CD28–double‐deficient mice than in mice that were deficient only in IL‐1Ra, although incidence of arthritis was not affected by the presence or absence of CD28. When pathogenic IL‐1Ra–KO T cells were transferred into nude mice, severe arthritis developed. Even though T cells from double‐deficient mice showed the same diminished proliferative capacity as was seen in T cells from CD28–single‐deficient animals, nude mice into which double‐deficient T cells were transferred never developed arthritis.

Conclusion

These findings indicate that IL‐1Ra/CD28–double‐deficient T cells can be activated by IL‐1Ra–deficient activated APCs, resulting in induction of arthritis; however, these T cells did not induce the disease under normal conditions, because they did not differentiate into effector/memory phenotype.

     

Effect of simplification from protease inhibitors to boosted atazanavir‐based regimens in real‐life conditions

Background

Atazanavir (ATV) boosted with ritonavir (ATV/r) is a potent, well‐tolerated, once‐daily protease inhibitor (PI). Few data are available on this agent as a treatment simplification option for patients taking other PIs.

Objective

The aim of the study was to determine the effectiveness and safety of ATV‐containing regimens in patients who have simplified their antiretroviral treatment.

Methods

SIMPATAZ was a multicentre, prospective, noninterventional study in patients who had undetectable HIV RNA on their current PI‐containing therapy and who were switched to an ATV/r‐based regimen. Patients underwent a routine physical examination, and data were collected on HIV RNA levels, CD4 cell counts, liver function, lipid parameters, adverse reactions, adherence to treatment and patient satisfaction.

Results

A total of 183 patients were enrolled in the study and included in the analysis (80% were male, 29% had AIDS, and 52% were coinfected with HIV and hepatitis B virus or hepatitis C virus). The median baseline CD4 count was 514 cells/μL. Median exposure to previous HIV therapy was 8 years, and 32% of patients had a history of PI failures. Lopinavir boosted with ritonavir was the most frequent PI replaced (62%) and tenofovir+lamivudine /emtricitabine the backbone most used during the study (29%). The study drug was discontinued early by 25 patients (14%), two of whom discontinued as a result of adverse events (Hodgkin lymphoma and vomiting). Two patients died (lung cancer and myocardial infarction). At month 12, 93% of the study population had an undetectable HIV RNA viral load. Hyperbilirubinaemia >3 mg/dL and increased alanine aminotransferase levels>200 IU/L were observed in 38.5% and 4.4% of patients, respectively. Median changes from baseline to month 12 in total cholesterol, triglycerides and low‐density lipoprotein cholesterol were ?13 mg/dL (?7%; P<0.0001), ?19 mg/dL (?13%; P<0.0001) and ?7 mg/dL (?6%; P=0.021), respectively.

Conclusions

In a real‐world setting, switching from other PIs to ATV/r is a well‐tolerated and safe option for improving the lipid profile and for retaining virological response in controlled pretreated patients.

     

Serum lipid profile in highly active antiretroviral therapy‐naïve HIV‐infected patients in Cameroon: a case–control study

Background

HIV status has commonly been found to affect the serum lipid profile.

Objectives

The aim of this study was to determine the effect of HIV infection on lipid metabolism; such information may be used to improve the management of HIV‐infected patients.

Methods

Samples were collected from December 2005 to May 2006 at Yaounde University Teaching Hospital, Yaounde, Cameroon. Lipid parameters were obtained using colorimetric enzyme assays, while low‐density lipoprotein cholesterol (LDLC) values were calculated using the formula of Friedewald et al. (1972) and atherogenicity index by total cholesterol (TC)/high‐density lipoprotein cholesterol (HDLC) and LDLC/HDLC ratios.

Results

HIV infection was most prevalent in subjects aged 31 to 49 years. Most of the HIV‐positive patients belonged to Centers for Disease Control and Prevention categories B (43.0%) and C (30.23%). Compared with control subjects, patients with CD4 counts<50 cells/μL had significantly lower TC (P<0.0001) and LDLC (P<0.0001) but significantly higher triglyceride (TG) values (P<0.001) and a higher atherogenicity index for TC/HDLC (P<0.01) and HDLC/LDLC (P=0.02); patients with CD4 counts of 50–199 cells/μL had significantly lower TC (P<0.001) and significantly higher TG values (P<0.001); patients with CD4 counts of 200–350 cells/μL had significantly higher TG (P=0.003) and a higher atherogenicity index for TC/HDLC (P<0.0002) and HDLC/LDLC (P=0.04); and those with CD4 counts >350 cells/μL had a higher atherogenicity index for TC/HDLC (P<0.0001) and HDLC/LDLC (P<0.001). HDLC was significantly lower in HIV‐positive patients irrespective of the CD4 cell count. Lipid parameters were also influenced by the presence of opportunistic infections (OIs).

Conclusion

HIV infection is associated with dyslipidaemia, and becomes increasingly debilitating as immunodeficiency progresses. HDLC was found to be lower than in controls in the early stages of HIV infection, while TG and the atherogenicity index increased and TC and LDLC decreased in the advanced stages of immunodeficiency.

     

T-lymphocyte populations in hepatitis C and HIV co-infected patients treated with interferon-alfa-2a and ribavirin

Objective

The effects on T‐lymphocyte populations of two interferon‐alfa‐2a (IFN) regimens associated with ribavirin were evaluated in 36 HCV‐HIV co‐infected patients with chronic hepatitis C, T‐CD4 cell count > 250 cells/µL and a plasma viral load of < 10 000 HIV RNA copies/mL.

Methods

Patients were given IFN for 48 weeks. Group A (18 patients) received 6 mega units (MU) subcutaneously three times a week for 24 weeks, then 3 MU three times a week for the last 24 weeks. Group B (18 patients) received 9 MU daily for 2 weeks, 3 MU daily for 22 weeks, then 3 MU three times a week for the last 24 weeks. Serum HCV RNA was evaluated at weeks 12 and 72. Ribavirin was added at week 16 for virologic nonresponders at week 12. CD3, CD3 CD4, CD3 CD8, CD3 CD4 human leucocyte antigen (HLA)‐DR and CD3 CD8 HLA‐DR lymphocyte subsets were evaluated before, during and after treatment by cytofluorometry. Controls were healthy and HCV mono‐infected patients.

Results

CD3 CD4 and CD3 CD8 T‐cells counts were both impaired during anti‐HCV therapy, but returned to baseline value after treatment completion. Lymphopenia concerned mainly CD8 T‐cells, the percentage of which decreased, whereas that of CD4 increased. Three patients displayed reversible CD4 lymphopenia < 200 cells/µL. HIV infection at inclusion was responsible for higher CD3 CD8 HLA‐DR T‐cell percentages in co‐infected patients than in healthy and HCV mono‐infected subjects. T‐cell sequestration in lymphoid tissues and enhanced apoptosis may account for lymphopenia.

Conclusion

High‐dosed IFN anti‐HCV therapy induced only moderate and transient CD4 lymphopenia in HIV co‐infected patients.

     

Elevated interleukin‐4 and interleukin‐13 production by T cell lines from patients with Churg‐Strauss syndrome

Objective

To investigate cytokine production patterns of T cell lines (TCL) from patients with Churg‐Strauss syndrome (CSS).

Methods

Short‐term polyclonal TCL were generated from peripheral blood of patients with CSS or Wegener's granulomatosis (WG) and healthy controls (HC). TCL were established in the presence of interleukin‐2 (IL‐2) and phytohemagglutinin and were phenotypically characterized by flow cytometry. Th1/Th2 cytokine production by stimulated TCL (72 hours) was analyzed by enzyme‐linked immunosorbent assay.

Results

TCL that represented the progeny of in vivo–activated T cells from CSS patients displayed a heterogeneous immunophenotype, with a predominance of CD4+ T cells when compared with WG TCL, which were predominantly CD8+. All CSS TCL shared the ability to produce large amounts of interferon‐γ (IFNγ), IL‐4, and IL‐13 compared with HC (P = 0.014 for all 3). Production of IL‐4 and IL‐13 was higher in CSS TCL than in WG TCL (P = 0.014 for both). IL‐5 production was up‐regulated in WG TCL compared with CSS TCL (P = 0.014). Compared with HC, WG TCL showed increased production of IFNγ (P = 0.021), IL‐5 (P = 0.043), and IL‐13 (P = 0.021).

Conclusion

Our results indicate that, while there is evidence for both a type 1 and a type 2 response in CSS, type 2 cytokine production pattern appears to predominate in this disease when compared with WG and HC.

     

Impact of the CTLA‐4/CD28 axis on the processes of joint inflammation in rheumatoid arthritis

Objective

The importance of the costimulatory molecules CD28 and CTLA‐4 in the pathologic mechanism of rheumatoid arthritis (RA) has been demonstrated by genetic associations and the successful clinical application of CTLA‐4Ig for the treatment of RA. This study was undertaken to investigate the role of the CTLA‐4/CD28 axis in the local application of CTLA‐4Ig in the synovial fluid (SF) of RA patients.

Methods

Quantitative polymerase chain reaction was used to analyze the expression of proinflammatory and antiinflammatory cytokines in ex vivo fluorescence‐activated cell sorted CTLA‐4+ and CTLA‐4− T helper cells from the peripheral blood and SF of RA patients. T helper cells were also analyzed for cytokine expression in vitro after the blockade of CTLA‐4 by anti–CTLA‐4 Fab fragments or of B7 (CD80/CD86) molecules by CTLA‐4Ig.

Results

CTLA‐4+ T helper cells were unambiguously present in the SF of all RA patients examined, and they expressed increased amounts of interferon‐γ (IFNγ), interleukin‐17 (IL‐17), and IL‐10 as compared to CTLA‐4− T helper cells. The selective blockade of CTLA‐4 in T helper cells from the SF in vitro led to increased levels of IFNγ, IL‐2, and IL‐17. The concomitant blockade of CD28 and CTLA‐4 in T helper cells from RA SF by CTLA‐4Ig in vitro resulted in reduced levels of the proinflammatory cytokines IFNγ and IL‐2 and increased levels of the antiinflammatory cytokines IL‐10 and transforming growth factor β.

Conclusion

Our ex vivo and in vitro results demonstrate that the CTLA‐4/CD28 axis constitutes a drug target for not only the systemic, but potentially also the local, application of the costimulation blocking agent CTLA‐4Ig for the treatment of RA.