Karim Abbed

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.

Prolonged survival without neurological improvement in patients with AIDS-related progressive multifocal leukoencephalopathy on potent combined antiretroviral therapy.

To evaluate the benefit of combined antiretroviral therapy including protease inhibitors (CART) on survival time and neurological progression in patients with AIDS-related progressive multifocal leukoencephalopathy (PML), 81 consecutive PML cases, collected between January 1990 and June 1998, were reviewed. Fifteen patients were neuropathologically proven. JC virus detection in CSF was positive in 59 patients. At PML diagnosis, median CD4 cell count was low (median, 35 cells/microL) and plasma HIV load, determined in 41 patients, was high (median, 4.8 log10 copies/ml). Following PML diagnosis, there was a significant difference (P<10(-4)) in survival between patients who were untreated or treated with nucleoside analogs (n=50, median: 80 days) and patients who were started early on CART (n=23, median: 246 days). A third group of eight patients who received CART late during the course of PML was considered separately. At the study endpoint, 18 of all the CART-treated patients (n=31) were still alive. Plasma HIV load was undetectable in 67% of them. The median increase in CD4 cell count was 112 cells/microL from CART onset. In contrast, no significant improvement in neurological status was observed. Our results demonstrate a benefit of CART on survival of AIDS-related PML patients and suggest the need for an early, specific anti-JC virus treatment to limit the neurological deterioration.

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.

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−CD25hiFoxP3+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.

CD25 Appears Non Essential for Human Peripheral Treg Maintenance In Vivo

Background IL-2 has been reported to be critical for peripheral Treg survival in mouse models. Here, we examined Treg 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 Treg depletion: the proportion of FoxP3+ cells among CD4 T cells and the level of FoxP3 expression were both unchanged. IL-2Rβ expression was enhanced in FoxP3+ cells both before and after basiliximab treatment, while the level of IL-2Rγ expression was similar in Tregs and non-Tregs. No significant change in the weak or absent expression of IL-7Rα and IL-15Rα 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 Treg functionality in vivo in the absence of functional CD25. Conclusions CD25 appears non essential for human Treg peripheral maintenance in vivo. However, our results raise questions as to Treg 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.

THU0107 CCL19, a chemokine involved in B-cell trafficking, is related to the decrease of blood memory B-cells and predicts the clinical response to rituximab in rheumatoid arthritis: Results from the smart study

Background In rheumatoid arthritis (RA), the decrease of peripheral blood memory B-cell may be explained by their migration into the synovium and predicts the response to rituximab (RTX), delineating thus a B-cell-driven RA subtype. Objectives We aimed to investigate whether the serum levels of chemokines involved in B-cell trafficking are correlated with the decrease of blood memory B-cells before RTX and may predict the clinical response to RTX in RA. Methods 208 RA patients all treated with methotrexate but refractory or intolerant (n=194) or with contra-indication (n=14) to anti-TNF have been included in the RTX retreatment dose “SMART” study. All received a 1st course of RTX (1g on days 1 and 15) and EULAR response was evaluated at week 24 (W24). Before the 1st RTX infusion, a blood sample was obtained to assess CD19 B-cells subsets by flow cytometry using CD27 and IgD stainings, serum B-cell activation biomarkers (rheumatoid factor [RF], anti-CCP, free light chains [FLC], IgG, IgA, IgM levels and BAFF) and serum chemokines (CCL19, CXC12, CXCL13) by ELISA. We aimed to determine whether serum chemokines levels were correlated with memory B-cells and/or serum B-cell biomarkers (Spaerman correlation) and whether they may predict subsequent EULAR response at W24 in univariate and multivariate analyses (logistic regression). Results Among the 208 patients (age =56±11 years, 85% of women, initial DAS28-CRP =5.8±0.9), 149 (72%) were responders (44 good [21%] and 105 partial [51%] responders). The 3 chemokines levels were correlated positively with several serum B-cell biomarkers and inversely with blood CD27+ memory B-cell and especially the CD27+ IgD- switched subtype (Table). Univariate analysis showed that logarithm-transformed CCL19 level (logCCL19) was associated to the EULAR response at week 24 (odds ratio [OR]=1.432; 95%confidence interval [95%CI]: 1.08-1.90; p=0.01). In multivariate analysis, after adjustment on DAS28 and memory B-cell frequency, logCCL19 predicted the response to rituximab at week 24 (OR=1.48; 95%CI: 1.06-2.06; p=0.02). However, this association did not persist after adjusting for RF or anti-CCP positivity. Conversely, CXC12 and CXCL13 levels were not predictive of response. Conclusions An increased serum level of the CCL19, CXCL12 and CXCL13 chemokines was related to the decrease of blood memory CD27+ B-cells in RA before RTX and may represent an additional feature of a B-cell-driven RA subtype. We demonstrate for the first time that serum CCL19 may predict the clinical response to RTX in RA, independently of B-cell subsets disturbances. Disclosure of Interest J. Sellam: None Declared, S. Rouanet Employee of: Roche France, H. Hendel-Chavez: None Declared, K. Abbed: None Declared, B. Combe: None Declared, J. Sibilia: None Declared, X. Le Loët: None Declared, J. Tebib: None Declared, R. Jourdan Employee of: Roche France, M. Dougados: None Declared, Y. Taoufik: None Declared, X. Mariette: None Declared