B cell activation biomarkers as predictive factors for the response to rituximab in rheumatoid arthritis: a six-month, national, multicenter, open-label study.

OBJECTIVE: To examine whether serum B cell markers can predict response to rituximab, a B cell-depleting monoclonal antibody, in patients with refractory rheumatoid arthritis (RA). METHODS: This rituximab re-treatment dose study (SMART [eSsai MAbthera sur la dose de Re-Traitement]) involved 208 patients with refractory RA. Serum markers of B cell activation (anti-cyclic citrullinated peptide [anti-CCP] antibodies, rheumatoid factor [RF], serum IgG, IgA, and IgM levels, serum κ and λ free light chains, and serum BAFF) were assessed before the first rituximab cycle (1,000 mg on days 1 and 15). Univariate and multivariate analyses were performed to identify factors associated with a European League Against Rheumatism (EULAR) response at 24 weeks. RESULTS: There were 149 responders (72%). Two baseline factors were associated with a EULAR response at 24 weeks in multivariate analysis: the presence of anti-CCP antibodies or RF (odds ratio 3.5 [95% confidence interval 1.6-7.6]) and a serum IgG concentration above normal (odds ratio 2.11 [95% confidence interval 1.02-4.33]), with synergy between them (odds ratio 6.0 [95% confidence interval 2.2-16.2]). CONCLUSION: The presence of RF or anti-CCP antibodies and elevated IgG are 2 simple biomarkers that can be used routinely before therapy to predict response to rituximab in patients with refractory RA.

Blood memory B cells are disturbed and predict the response to rituximab in patients with rheumatoid arthritis.

OBJECTIVE: To examine blood B cell subsets in patients with rheumatoid arthritis (RA) prior to B cell depletion therapy and to assess their potential as predictors of clinical response to rituximab (RTX). METHODS: Blood B cell subsets were assessed by flow cytometry in 208 RA patients included in an RTX retreatment study (assessed prior to RTX treatment) and in 47 age-matched controls. Expression of BAFF receptor (BAFF-R) on B cells and serum B cell biomarkers was also measured. B cell subsets and BAFF-R expression were compared between RA patient and control populations. Univariate and multivariate analyses were performed to identify baseline factors associated with a European League Against Rheumatism response 24 weeks after 1 cycle of RTX. RESULTS: Mean ± SD counts of both CD27- naive and CD27+ memory B cells were decreased in RA patients (188.6 ± 121.4/mm(3)) compared with controls (257.3 ± 154.1/mm(3)) (P = 0.001) and were partially restored in patients treated with methotrexate (MTX) plus anti-tumor necrosis factor compared with patients treated with MTX alone. Within the CD27+ memory B cells, the CD27+IgD- switched memory subtype was selectively decreased, irrespective of treatment. The frequency of CD27+ memory B cells correlated inversely with levels of several B cell activation biomarkers in RA. Serum BAFF level and BAFF-R expression was comparable in RA patients and controls. A low baseline CD27+ memory B cell frequency was associated with a greater clinical response to RTX (odds ratio 0.97 [95% confidence interval 0.95-0.99], P = 0.0015). CONCLUSION: In B cell depletion therapy-naive RA patients, a low frequency of CD27+ memory B cells correlated with levels of serum B cell activation biomarkers and may predict response to RTX. These results suggest that low memory B cell frequency may be indicative of a B cell-driven RA subtype that is more sensitive to B cell depletion therapy.

CD25 appears non essential for human peripheral T(reg) maintenance in vivo.

BACKGROUND: IL-2 has been reported to be critical for peripheral T(reg) survival in mouse models. Here, we examined T(reg) maintenance in a series of paediatric liver transplant recipients who received basiliximab, a therapeutic anti-CD25 monoclonal antibody. METHODOLOGY/PRINCIPAL FINDINGS: FoxP3+ CD4 T cells were analyzed by flow cytometry before liver grafting and more than 9 months later. We found that in vivo CD25 blockade did not lead to T(reg) depletion: the proportion of FoxP3+ cells among CD4 T cells and the level of FoxP3 expression were both unchanged. IL-2Rbeta expression was enhanced in FoxP3+ cells both before and after basiliximab treatment, while the level of IL-2Rgamma expression was similar in T(regs) and non-T(regs). No significant change in the weak or absent expression of IL-7Ralpha and IL-15Ralpha expression on FoxP3+ cells was observed. Although the proportion of FoxP3+ cells among CD4 T cells did not vary, food allergies occurred more rapidly after liver grafting in patients who received basiliximab, raising questions as to T(reg) functionality in vivo in the absence of functional CD25. CONCLUSIONS: CD25 appears non essential for human T(reg) peripheral maintenance in vivo. However, our results raise questions as to T(reg) functionality after therapeutic CD25 targeting.

Strong correlations of anti-viral capsid antigen antibody levels in first-degree relatives from families with Epstein-Barr virus-related lymphomas.

BACKGROUND: Markers of Epstein-Barr virus (EBV) infection include anti-viral capsid antigen (VCA) immunoglobulin (Ig) G. High anti-VCA titers are associated with EBV-related lymphoproliferation, such as Burkitt lymphoma (BL) and Hodgkin lymphoma (HL). METHODS: Intrafamilial correlations of anti-VCA IgG levels were studied in 3 settings: 127 families recruited through patients with HL in France (population A), 31 families recruited through patients with BL in Uganda (population B), and 74 large families from a general population in Cameroon (population C). Titers were determined by enzyme-linked immunosorbent assay (populations A and C) or by immunofluorescence analysis (population B). RESULTS: In populations A and B, the anti-VCA IgG titers of the relatives of patients with HL or BL increased significantly (P = .01 and P < .001, respectively) with those of the index case patient. In all 3 populations, anti-VCA IgG titers were significantly correlated (P < .001 for A, P = .002 for B, and P < .001 for C) between genetically related individuals (father-offspring, mother-offspring, and sibling-sibling) but not between spouses. Similar results were obtained for population A after adjustment for total IgG levels. In all cases, the pattern of correlations was consistent with a polygenic model, with heritability ranging from 0.32 to 0.48. CONCLUSION: These results provide evidence for the genetic control of anti-VCA IgG titers and pave the way for identification of the loci involved.

Resting regulatory CD4 T cells: a site of HIV persistence in patients on long-term effective antiretroviral therapy.

BACKGROUND: In HIV-infected patients on long-term HAART, virus persistence in resting long-lived CD4 T cells is a major barrier to curing the infection. Cell quiescence, by favouring HIV latency, reduces the risk of recognition and cell destruction by cytotoxic lymphocytes. Several cell-activation-based approaches have been proposed to disrupt cell quiescence and then virus latency, but these approaches have not eradicated the virus. CD4+CD25+ regulatory T cells (Tregs) are a CD4+ T-cell subset with particular activation properties. We investigated the role of these cells in virus persistence in patients on long-term HAART. METHODOLOGY/PRINCIPAL FINDINGS: We found evidence of infection of resting Tregs (HLADR(-)CD69(-)CD25(hi)FoxP3+CD4+ T cells) purified from patients on prolonged HAART. HIV DNA harbouring cells appear more abundant in the Treg subset than in non-Tregs. The half-life of the Treg reservoir was estimated at 20 months. Since Tregs from patients on prolonged HAART showed hyporesponsiveness to cell activation and inhibition of HIV-specific cytotoxic T lymphocyte-related functions upon activation, therapeutics targeting cell quiescence to induce virus expression may not be appropriate for purging the Treg reservoir. CONCLUSIONS: Our results identify Tregs as a particular compartment within the latent reservoir that may require a specific approach for its purging.

CD4 CD25high regulatory T cells are not impaired in patients with primary Sjögren's syndrome.

In animal models of autoimmunity, CD4 CD25high T cells play a key role in the control of the autoimmune process. Few studies have investigated the role of these cells in human autoimmune diseases. We aimed to investigate CD4 CD25high T cells in the peripheral blood of patients with primary Sjogren's syndrome (pSS). The proportion of blood CD4 CD25high T cells was determined by flow cytometry in 21 patients with pSS as determined by the American-European consensus group criteria and two groups of controls (18 patients with lumbar back pain of mechanical origin and 15 healthy blood donors). The suppressive function of CD4 CD25 cells was assessed using co-culture assays. The Vbeta repertoire of CD4 CD25 T cells was examined by flow cytometry. The proportion of CD4 CD25 T cells depended on age in patients and controls. In an age-matched comparison, no significant difference was observed in the proportion of total CD4 CD25low T cells between patients with pSS and controls (P=0.36). In contrast, the pool of CD4 CD25high was significantly increased in patients with pSS (8.5% vs 4.1% in controls, P=0.04). There was a slight but not significant higher proportion of CD4 CD25high cells in patients with a more active disease. CD4 CD25 T cells in patients with pSS effectively suppressed the proliferation of CD4 CD25- autologous responder T cells. The Vbeta repertoire of regulatory T cells from patients with pSS was polyclonal and was not significantly restricted as compared with that in controls. Functional CD4 CD25high regulatory cells are increased in patients with established pSS, through a reactive feedback, despite ongoing autoimmunity. These results suggest that pSS does not occur as a result of reduced level of CD4 CD25high regulatory T cells, nor as a defect of inhibition of proliferation of responder cells.