Circulating B-cell, Drug and Anti-drug Antibodies Monitoring in Patients Treated With Rituximab for Autoimmune Disorders

Circulating B-cell, Drug and Anti-drug Antibodies Monitoring in Patients Treated With Rituximab for Autoimmune Disorders : the MONIRITUX Study

The MONIRITUX study aimed to evaluate whether monitoring (i) circulating B-cell reconstitution or (ii) serum rituximab levels could help identify relapse of autoimmune diseases in patients treated with rituximab. Retrospective data suggest that B-cell reconstitution or the appearance of anti-drug antibodies are associated with rituximab's failure to prevent relapses (i.e. rheumatoid arthritis, systemic lupus erythematosus, autoimmune cytopenia...). According to the routine care provided by our institution, patients undergoing rituximab therapy are monitored every three months during the first year after treatment induction and every six months thereafter. At each clinical visit, a blood test is performed to quantify total gammaglobulins, IgG and CD19+ cells (along with other tests depending on the disease). This study will use the remaining blood in the tubes from routine care to quantify CD27+ and CD38+ B cells, as well as serum rituximab and anti-rituximab antibodies, during the first year of follow-up. The primary outcome will be to identify risk factors for clinical relapse according to circulating B-cell or rituximab status.

Inclusion Criteria:

• Patient who undergo rituximab treatment according to routine care and having one of the following disorder:
• primary immune thrombocytopenia
• primary autoimmune hemolytic anemia
• systmic lupus erythematous
• systemic sclerosis
• rheumatoid arthritis
• inflammatory myopathy
• ANCA associated vasculitis
• Cryoglobulinemic vasculitis

Exclusion Criteria:

• Patients undergoing multiple immunosuppressive drugs because of refractory disease or concomitant hemopathy or malignancy