IgA Nephropathy Associated With Infliximab Treatment in Patients With Crohn's Disease: Study of IgA1 and IgA2 Expression in Glomeruli

Background/Aim: It is well known that infliximab is an anti-tumor necrosis factor chimeric factor that is effective in treating inflammatory bowel diseases, such as Crohn's disease. Recently, there have been reports of new onset or flare- ups of immunoglobulin A (IgA) nephropathy during infliximab therapy for Crohn's disease. Inflammatory bowel disease-associated IgA nephropathy has been associated with IgA2; However, its activation by infliximab is still unknown. Case Report: We report our experience with two patients who experienced acute exacerbations of pre-existing abnormal urinalysis and renal dysfunction 1-18 years following infliximab treatment for Crohn's disease. Renal biopsies at the time of renal disease flare-up revealed IgA nephropathy in one patient and mesangial proliferative nephropathy in the other. Immunostaining results showed no clear predominance of intraglomerular expression of IgA2, and the patient diagnosed with IgA nephropathy entered remission with high dose methylprednisolone pulse therapy and oral corticosteroids, without the need for tonsillectomy. In contrast, the patient with mesangial proliferative nephritis had many devastated glomeruli, thus corticosteroids were not administrated, and the patient was followed up. Conclusion: The clinical course of our patients, along with similar cases reported in the literature, indicates that infliximab therapy for Crohn's disease is linked to a relatively high risk of new-onset IgA nephropathy or disease relapse. This report is notable because it is the first to compare the expression of IgA1 and IgA2 in glomeruli in nephritis associated with infliximab therapy.