LAUSR

Immunoglobulin A vasculitis (IgAV), formerly called Henoch–Schönlein purpura (HSP), predominantly affects small vessels, with deposition of immunoglobulin A complexes. The clinical manifestations include cutaneous purpura, arthralgia, gastrointestinal involvement, and glomerulonephritis (1). Childhood IgAV usually has a benign course; however, the optimal treatment for adult IgAV remains highly controversial (2). Rituximab (RTX), an anti-CD20 monoclonal antibody, has become a standard treatment for antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis. Some reports also showed the potential of RTX in the treatment of IgAV, especially in those with nephritis, but there have been few studies on its efficacy in IgAV with gastrointestinal involvement (3–6). Here, we describe the case of a young man with multiple relapses and steroid-dependent IgAV, which successfully improved with RTX. A 20-year-old man was diagnosed with IgAV with remittent purpura and abdominal pain 5 years ago. There was no evidence of nephritis or other organ involvement. At the first diagnosis in 2017, his recovery was quick and complete, with methylprednisolone 40 mg/day and some supportive care. Glucocorticoid was tapered and discontinued eventually in a year. He had four relapses in the next 2 years. He responded to high-dose methylprednisolone each time, but during steroid tapering to prednisone 15 mg/day, purpura and abdominal pain returned. Azathioprine 100 mg/day was administered in 2019, but when prednisone was reduced to 12.5 mg/day, he complained of intermittent purpura and abdominal discomfort. In July 2021, he was admitted to the ward because of aggravated purpura and abdominal pain with nausea and vomiting. Gastrointestinal endoscopy showed a gastric antral ulcer and proctitis (Figure 1). He received two RTX 500 mg infusions, 2 weeks apart. He quickly improved, with the peripheral CD19 B-lymphocyte count decreasing from 149 cells/mm before RTX infusion to 0 cells/mm. Prednisone was reduced to 5 mg daily and azathioprine was discontinued. He was stable without any discomfort for almost 6 months. In January 2022, he again complained of purpura, abdominal pain, and vomiting. The peripheral CD19 B cells had rebounded to 1.15 cells/mm. Two doses of 1000 mg RTX, 2 weeks apart, were administered. He improved rapidly, with nil CD19 B lymphocytes in circulation. In July 2022, a minor relapse of IgAV occurred, with the same symptoms but not as serious as before. The peripheral CD19 B-lymphocyte count was 0.59 cells/mm. Another dose of RTX 500 mg was administered. Again, his symptoms gradually disappeared and the B-lymphocyte count dropped to 0 cells/mm. Importantly, only low-dose prednisone, at 5 mg/day, had been maintained throughout the past year. The treatment of IgAV is still a matter of debate. In organ-threatening cases, glucocorticoids alone or combined with immunosuppressive agents are routinely used, but the efficacy of these therapeutic regimens remains controversial (2). Previous studies have shown the possible roles of B cells in the pathogenesis of IgAV (7). Upregulation of both the number and function of B lymphocytes was observed in children with IgAV. Moreover, the rise in the peripheral B-lymphocyte count was correlated with IgAV relapse in some cases (8). RTX may decrease the production of IgA–immune complexes by eliminating B lymphocytes and consequently reducing disease activity and flare. A couple of studies have reported the effectiveness of RTX in the treatment of IgAV, but mostly in patients with nephritis. To our knowledge, only five reported cases with predominantly abdominal involvement have been successfully treated with RTX so far. Donnithorne et al reported a 14-year-old Caucasian boy presenting with abdominal pain and palpable purpura who initially responded to high-dose methylprednisolone, but worsened with steroid tapering. He received four doses of RTX (375 mg/m) at weekly intervals and was persistently symptom free during the subsequent 33 months of follow-up, without any steroids or immunosuppressants (9). Wang et al reported on four Chinese IgAV children (aged 4–8 years) with severe abdominal manifestations (gastrointestinal bleeding or perforation), who quickly 324 Scand J Rheumatol 2023;52:324–325