Rituximab-associated hypogammaglobulinemia: incidence, predictors and outcomes in patients with multi-system autoimmune disease.

Rituximab is a B cell depleting monoclonal antibody used to treat lymphoma and autoimmune disease. Hypogammaglobulinemia has occurred after rituximab for lymphoma and rheumatoid arthritis but data are scarce for other autoimmune indications. This study describes the incidence and severity of hypogammaglobulinemia in patients receiving rituximab for small vessel vasculitis and other multi-system autoimmune diseases. Predictors for and clinical outcomes of hypogammaglobulinemia were explored. We conducted a retrospective study in a tertiary referral specialist clinic. The severity of hypogammaglobulinemia was categorized by the nadir serum IgG concentration measured during clinical care. We identified 288 patients who received rituximab; 243 were eligible for inclusion with median follow up of 42 months. 26% were IgG hypogammaglobulinemic at the time that rituximab was initiated and 56% had IgG hypogammaglobulinemia during follow-up (5-6.9 g/L in 30%, 3-4.9 g/L in 22% and <3 g/L in 4%); IgM ≤0.3 g/L in 58%. The nadir IgG was non-sustained in 50% of cases with moderate/severe hypogammaglobulinemia. A weak association was noted between prior cyclophosphamide exposure and nadir IgG concentration, but not cumulative rituximab dose. IgG concentrations prior to and at the time of rituximab correlated with the nadir IgG post rituximab. IgG replacement was initiated because of recurrent infection in 12 (4.2%) patients and a lower IgG increased the odds ratio of receiving IgG replacement. Rituximab is associated with an increased risk of hypogammaglobulinemia but recovery of IgG level can occur. IgG monitoring may be useful for patients receiving rituximab.

Immunoglobulin G replacement for the treatment of infective complications of rituximab-associated hypogammaglobulinemia in autoimmune disease: a case series.

The anti-CD20 B cell depleting monoclonal antibody rituximab is being used increasingly for autoimmune diseases, including patients with refractory disease with extensive prior exposure to immunosuppressive treatments. Rituximab, in this context, may be associated with increased risk of adverse effects, in particular hypogammaglobulinemia which predisposes to recurrent infections necessitating Immunoglobulin G replacement. Outcome data following Immunoglobulin G replacement after rituximab in patients with autoimmune disease are limited. We conducted a retrospective study in a tertiary referral lupus and vasculitis clinic of 288 patients who received rituximab. Clinical details of patients prescribed IgG replacement therapy following rituximab treatment were reviewed. We identified 12 patients with autoimmune disease, 10/12 with systemic vasculitis, received IgG replacement for the treatment of recurrent infections in the context of persistent moderate or severe hypogammaglobulinemia following rituximab. We observed a range of ages (16-67 years), rituximab dosages (2-15.8 g), previous immunosuppression (median 3.5 non-glucocorticoid agents) and duration of disease (2-228 months). Six continued to receive rituximab alongside IgG replacement therapy to maintain disease control. IgG replacement appeared to decrease the incidence and severity of infections, and recovery of IgG concentrations allowed cessation of IgG replacement in two patients after 4 and 7.5 years of treatment. IgG monitoring is useful for patients receiving rituximab. IgG replacement for sustained hypogammaglobulinemia with recurrent infections appeared to be useful in this series. The IgG replacement course is prolonged in most patients, but IgG recovery is reported.

The effect of rituximab therapy on immunoglobulin levels in patients with multisystem autoimmune disease.

BACKGROUND: Rituximab is a B cell depleting anti-CD20 monoclonal antibody. CD20 is not expressed on mature plasma cells and accordingly rituximab does not have immediate effects on immunoglobulin levels. However, after rituximab some patients develop hypogammaglobulinaemia. METHODS: We performed a single centre retrospective review of 177 patients with multisystem autoimmune disease receiving rituximab between 2002 and 2010. The incidence, severity and complications of hypogammaglobulinaemia were investigated. RESULTS: Median rituximab dose was 6 g (1-20.2) and total follow-up was 8012 patient-months. At first rituximab, the proportion of patients with IgG <6 g/L was 13% and remained stable at 17% at 24 months and 14% at 60 months. Following rituximab, 61/177 patients (34%) had IgG <6 g/L for at least three consecutive months, of whom 7/177 (4%) had IgG <3 g/L. Low immunoglobulin levels were associated with higher glucocorticoid doses during follow up and there was a trend for median IgG levels to fall after ≥ 6 g rituximab. 45/115 (39%) with IgG ≥ 6 g/L versus 26/62 (42%) with IgG <6 g/L experienced severe infections (p=0.750). 6/177 patients (3%) received intravenous immunoglobulin replacement therapy, all with IgG <5 g/L and recurrent infection. CONCLUSIONS: In multi-system autoimmune disease, prior cyclophosphamide exposure and glucocorticoid therapy but not cumulative rituximab dose was associated with an increased incidence of hypogammaglobulinaemia. Severe infections were common but were not associated with immunoglobulin levels. Repeat dose rituximab therapy appears safe with judicious monitoring.

Evidence-Based Guideline for the diagnosis and management of eosinophilic granulomatosis with polyangiitis.

Eosinophilic granulomatosis with polyangiitis (EGPA) is a rare anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis, characterized by asthma, eosinophilia and granulomatous or vasculitic involvement of several organs. The diagnosis and management of EGPA are often challenging and require an integrated, multidisciplinary approach. Current practice relies on recommendations and guidelines addressing the management of ANCA-associated vasculitis and not specifically developed for EGPA. Here, we present evidence-based, cross-discipline guidelines for the diagnosis and management of EGPA that reflect the substantial advances that have been made in the past few years in understanding the pathogenesis, clinical subphenotypes and differential diagnosis of the disease, as well as the availability of new treatment options. Developed by a panel of European experts on the basis of literature reviews and, where appropriate, expert opinion, the 16 statements and five overarching principles cover the diagnosis and staging, treatment, outcome and follow-up of EGPA. These recommendations are primarily intended to be used by healthcare professionals, pharmaceutical industries and drug regulatory authorities, to guide clinical practice and decision-making in EGPA. These guidelines are not intended to limit access to medications by healthcare agencies, nor to impose a fixed order on medication use.