Background Rituximab is an anti-CD20 monoclonal antibody therapy used widely in the management of paediatric rheumatological conditions. Studies suggest that Rituximab is safe and effective in rheumatic autoimmune diseases, but data on paediatric use remains limited. Although Rituximab spares plasma cells, hypogammaglobulinaemia can still develop, leading to recurrent infections. Frequency of hypogammaglobulinaemia in children receiving Rituximab for rheumatological conditions is unknown.
Objectives To analyse the use of Rituximab in a tertiary Paediatric Rheumatology centre over the last 15 years (2001–2015). The primary aims were to identify the number of patients who received Rituximab, the underlying diagnoses and the response to treatment. Our secondary aims were to identify the incidence of hypogammaglobulinemia associated with Rituximab use and the frequency and severity of infections. Frequency of monitoring of immunoglobulin levels, lymphocyte subsets and functional antibodies to pneumococcus were noted.
Methods Retrospective analysis of case notes, electronic records and laboratory data of patients who received Rituximab in the paediatric rheumatology department from 2001–2015.
Results A total of 22 patients received Rituximab (total of 1500mg/m2 per cycle over 2 – 4 divided doses) during the study period. 3 were excluded due to insufficient data. Median time of commencement of Rituximab from diagnosis was 2 years 8 months. Of these, 12 patients achieved remission within 6 to 12 months. Rituximab was discontinued in the non-responders at 12 months.
8 patients (42%) were noted to have hypogammaglobulinaemia at some point. The role of cyclophosphamide contributing to hypogammaglobulinaemia could not be excluded in 2 and a further patient is currently being investigated for an underlying primary immune deficiency. In the remaining 5 (26%) patients, we believe the low IgG levels are secondary to Rituximab, of which two needed long term Ig replacement. Overall 12 patients reported recurrent/severe infections of which 6 had low immunoglobulin levels.
Conclusions RF+ JIA patients appear to have responded the best to Rituximab and RF- JIA patients the least (0/4), with good results in JDM and SLE subgroups (80–83%). The incidence of hypogammaglobulinaemia secondary to Rituximab in our cohort was 26%, which can be prolonged and worsen with increased number of cycles. Prior treatment with cyclophosphamide may be contributory. We suggest regular monitoring of immunoglobulin levels and lymphocyte markers on all patients prior to commencement of Rituximab and regular intervals subsequently, including further cycles.
Disclosure of Interest None declared