Rituximab in IgG4 Related Disease: A Retrospective Study from a Single Tertiary Care Centre

Background: IgG4-related disease (IgG4-RD) is a multi-organ, fibro-inflammatory disorder characterised by tumefactive lesions. Corticosteroids are the first line of treatment. Rituximab (RTX) has been reported to be effective in IgG4-RD. It is reserved as a second-line agent and is a useful treatment option for those with intolerance to corticosteroids or have steroid and immunomodulator refractory disease. Objectives: To assess the response to treatment with RTX in patients with IgG4-related disease at the end of 6 months. Methods: A total of 27 patients diagnosed with IgG4-RD and treated with at least 1g of RTX were included. Patient demographics, clinical data and investigations were noted. Response to RTX was noted at the end of 6 months in terms of clinical improvement, decrease in or normalisation of serum IgG4 levels, withdrawal of steroids or disease-modifying antirheumatic drugs (DMARDs) and the calculation of the IgG4RD responder index (RI). Results: Out of the 27 patients treated with RTX, one patient expired and two were lost to follow-up. Of the remaining 24 patients, nine are off steroids; four patients are off treatment. Among the nine who are off steroids, eight patients had orbital and periorbital involvement. Fourteen patients had elevated IgG4 levels. Post RTX, normalisation of IgG4 levels was achieved in six patients. The average RI before and after RTX was 4.79 (2–10) and 1.33 (0–4), respectively. Conclusions: Patients with IgG4-RD who were intolerant or refractory to steroids and other DMARDs showed significant improvement after RTX infusion, especially in orbital and periorbital involvement. It suggests that RTX may be beneficial in the management of IgG4-RD.