[Cytokines and T cell differentiation in systemic sclerosis]. / Cytokines et différenciation lymphocytaire T au cours de la sclérodermie systémique.

The physiopathology of systemic sclerosis remains unclear within a complex interaction between vasculopathy, perivascular inflammatory infiltrate, extensive tissue fibrosis and auto-immune manifestations. Chronology between vascular disease and adjacent inflammatory cell infiltration is still not yet clarified. There is growing evidence that T cell activation and its cytokine expression play a key role in vascular impairment occurrence and collagen dysregulation. Nevertheless, cytokine descriptions are mainly limited to blood and tissue measurement and the T cells differentiation analysis restricted to the Th1/Th2 balance. The purpose of this review is to establish an exhaustive cartography of cytokines involved in T cell differentiation, regarding the recent advance in T lymphocyte differentiation, including Th9, Th17, Th22 and regulatory T cells (Treg) pathways. This review will focus on Th17, Th22 and Treg differentiation, corresponding to the equilibrium between inflammation and tolerance. Finally, regarding published results in systemic sclerosis, T cells participation appears to be more a Th1/Th2 co-expression than an exclusive Th1 or Th2 polarization. Also, a possible Th22/Treg imbalance is suggested, leading to a Th22 overexpression and likely to tissue inflammation genesis.

Analysis of CD16+CD56dim NK cells from CLL patients: evidence supporting a therapeutic strategy with optimized anti-CD20 monoclonal antibodies.

Although anti-CD20 monoclonal antibodies (mAbs) show promise for the treatment of chronic lymphocytic leukemia (CLL), the success of the anti-CD20 mAb rituximab in CLL treatment has been limited. Novel anti-CD20 mAbs with more potent cytotoxic activity have recently been engineered, but so far most have only been tested in vitro with natural killer (NK) cells from healthy donors. Because it is still unclear whether these optimized cytotoxic mAbs will improve NK-cell killing of tumor cells in CLL patients, we characterized the relevant phenotypic and functional features of NK cells from CLL patients in detail. Expression of inhibitory and activating NK-cell receptors and of Fc gamma receptor IIIA (FcγRIIIA) is well preserved in CD16(+)CD56(dim) cytotoxic NK cells from these patients, independently of disease progression. These cells are fully functional following cytokine stimulation. In addition, the FcγRIIIA-optimized LFB-R603 anti-CD20 mAb mediates 100 times greater antibody-dependent cell-mediated cytotoxicity by NK cells from CLL patients and healthy donors than rituximab. Enhanced degranulation against autologous B-CLL cells is observed at lower concentrations of LFB-R603 than rituximab, regardless of CLL prognostic factors. These findings strongly justify further clinical development of anti-CD20 mAbs optimized for FcγR engagement in CLL patients.

Down-regulation of CD8+ T-cell expansions in patients with human immunodeficiency virus infection receiving highly active combination therapy.

Analysis of T-cell receptor (TCR) repertoire usage made by peripheral T lymphocytes during the chronic phase of HIV-1 infection has revealed the presence of clonal expansions of CD8 T cells that are also shown to be largely HIV-specific. Yet, it remains unclear whether the global repertoire perturbation observed during the chronic phase of the infection is also HIV-related and reversible in the long term with the application of highly active antiretroviral therapy. Furthermore, the diversity and the stability of repertoire usage after a relapse of viral replication were never examined. Eight patients were observed longitudinally up to 31 months under triple-association therapy. When viral replication was steadily suppressed, CD8 repertoires were significantly stabilized. Conversely, in situations of incomplete or only transient viral suppression, persistence or rebound in repertoire perturbation was observed. Finally, a T-cell response remarkably different from baseline, as reflected by a repertoire switch, was generated after the discontinuation of highly active therapy. In conclusion, a sustained control of HIV replication correlated with profound modifications of the CD8 repertoire usage. These data also suggested that autovaccination by the withdrawal of antiviral drugs would result in the selection and expansion of T-cell clones that were not necessarily dominant before the onset of treatment.

Apoptosis and expression of soluble Fas mRNA in systemic lupus erythematosus.

Our objective was to measure the relative proportions of messenger RNAs coding for soluble and membrane-bound Fas in peripheral blood mononuclear cells (PBMCs) and to quantify lymphocyte apoptosis in vitro in systemic lupus erythematosus (SLE). A RT-PCR (soluble/membrane Fas mRNA) ratio was calculated in 16 SLE, 11 RA and 16 healthy subjects' PBMCs. Apoptosis was quantitated in vitro using nick-end labeling and flow-cytometry analysis immediately and after overnight T cell activation. The mean soluble/membrane Fas ratio was 1.219+/-0.424 in the SLE group, significantly higher than in healthy subjects, 0.516+/-0.180 (P = 0.0001). There was no significant difference between inactive and active SLE groups whereas Fas ratio was higher in SLE patients with nephritis (1.460+/-0.365) compared to those without nephritis (1.031+/-0.380) (P=0.039). Mean soluble/ membrane Fas ratio in RA patients (0.975 +/- 0.37) was higher than in healthy subjects (P = 0.0003) and lower than lupus nephritis patients (P=0.015). A significantly higher proportion of mononuclear cells engaged apoptosis after T cell activation in active lupus patients, compared to control subjects. In comparison with healthy subjects, Fas alternative splicing was skewed toward the soluble form of Fas in SLE and RA. Apoptosis after T cell activation in vitro was increased in active SLE patients.

Oligoclonal expansion of HIV-specific cytotoxic CD8 T lymphocytes in the skin of HIV-1-infected patients with cutaneous pseudolymphoma.

A massive infiltration of the skin by activated CD8+ T lymphocytes involving both the dermis and the epidermis has been found in HIV-1-infected patients presenting with a chronic skin rash. We characterized the T cell receptor (TCR) BV-BJ junctional diversity of the skin-infiltrating lymphocytes (SILs) in four patients. The SILs expressed a limited set of TCRBV gene segments. Complementarity determining region 3 length analysis further emphasized their oligoclonality, suggesting that antigen stimulation might be responsible for the cutaneous T cell expansion. Furthermore, independent skin biopsies obtained from the same individual were shown to harbor distinct T cell repertoires, possibly reflecting the spatial heterogeneity of the antigenic stimuli. The CD8+ cytotoxic T lymphocyte (CTL) lines isolated from the skin rash in one patient exhibited a specific, class I MHC-restricted cytotoxic activity against HIV-1 Gag- and Pol-expressing target cells, whereas CTL lines derived from the skin lesions of a second patient were shown to be predominantly Env-specific. Taken together, these data demonstrate the infiltration of HIV-specific CTLs in the skin of HIV-infected patients, and suggest that in addition to their known role in controlling the retroviral infection, these CTLs may also be involved in the pathogenesis of cutaneous inflammatory disorders occurring during the course of HIV infection.

Susceptibility of peripheral blood mononuclear cells to apoptosis is correlated to plasma HIV load.

OBJECTIVES: To quantify spontaneous and activation-induced apoptosis in peripheral blood mononuclear cells (PBMC) of HIV-infected patients and to look for correlations between PBMC apoptosis levels, stages of HIV disease, CD4 count, and plasma viral load. STUDY POPULATIONS: 75 consecutive inpatients and outpatients infected with HIV (mean CD4 count, 202 +/- 182 x 10(6)/L; mean plasma viral load, 4 +/- 1.29 log10 RNA copies/ml) and a control group composed of 18 healthy, HIV-negative adults. METHODS: Spontaneous apoptosis was detected at the single-cell level by direct incorporation of fluorescein-deoxyuridine triphosphate (dUTP) in PBMC DNA strand breaks. Activation-induced apoptosis was determined after in vitro stimulation with anti-CD3 antibodies and interleukin-2 (IL-2). RESULTS: Spontaneous apoptosis was low in patients and controls, whereas activation-induced apoptosis was significantly higher in HIV-infected patients (5.22 +/- 4.32% versus 2.46 +/- 1.77%, respectively; p = .009). The degree of activation-induced apoptosis was positively correlated with the plasma viral load (r = 0.29; p = .029) and negatively correlated with the CD4 count (r = -0.37; p = .0009). Although activation-induced apoptosis was significantly higher in patients fulfilling AIDS criteria, it did not differ significantly between patients with an acute AIDS-defining event and those with stable disease. CONCLUSION: Susceptibility of PBMC to apoptosis in HIV-1-infected patients is correlated to the plasma viral load and the stage of the disease.

Perturbation of CD4+ and CD8+ T-cell repertoires during progression to AIDS and regulation of the CD4+ repertoire during antiviral therapy.

The T-cell antigen receptor (TCR) repertoire was studied longitudinally by analyzing the varying lengths of the beta chain CDR3 hypervariable region during the course of HIV-1 infection and following combination antiretroviral therapy. Drastic restrictions in CD8+ T-cell repertoire usage were found at all stages of natural progression and persisted during the first six months of treatment. In contrast, significant CD4+ T-cell repertoire perturbations were not found in early stages of infection but correlated with progression to AIDS. Out of ten patients presenting with pretreatment perturbations, normalization of the CD4+ repertoire was observed in eight good responders, but not in two cases of unsuccessful therapy. These results indicate that, besides CD4+ cell count rise, an efficient control of HIV replication may allow qualitative modifications of the CD4+ repertoire balance.