IgA nephropathy and IgA vasculitis in a pediatric Crohn's disease patient with early IgA deposition in vascular walls of intestines.

Patients with inflammatory bowel disease may present with extraintestinal manifestations. Crohn's disease complicated with IgA nephropathy or IgA vasculitis is relatively rare. In this case, an 11-year-old girl was diagnosed with Crohn's disease and infliximab was administered. 1 year after treatment, she presented with asymptomatic but persistent microscopic hematuria. The child was diagnosed with IgA vasculitis and IgA nephropathy at the fourth year of follow-up. To explore the association between Crohn's disease and IgA associated diseases, immunostaining for IgA and GdIgA1 deposition was retrospectively conducted in intestinal biopsy tissues obtained at the time of initiation and relapse of Crohn's disease. GdIgA1 deposition in intestinal tissues was found not only at the time of relapse of Crohn's disease, but also at the beginning of Crohn's disease when patient had neither exposure to any drug nor any symptom of IgA vasculitis or IgA nephropathy. The early appearance of GdIgA1 deposition indicated that Crohn's disease played a greater role in its formation than infliximab induction and the child might be prone to IgA associated diseases. Patients with Crohn's disease, especially those who receive tumor necrosis factor-alpha inhibitors are recommended to receive regular kidney examinations.