Post-SARS-CoV-2 Atypical Inflammatory Syndrome in a Toddler with X-Linked Inhibitor of Apoptosis Deficiency After Stem Cell Transplant.

A 10-month-old boy was diagnosed with X-linked lymphoproliferative syndrome type 2 due to X-linked inhibitor of apoptosis deficiency after presenting with failure to thrive and refractory inflammatory bowel disease. He underwent a matched unrelated donor stem cell transplant with reduced intensity conditioning at 16 months. At 27 months, he presented with an atypical inflammatory syndrome in the setting of recent COVID-19 infection, Epstein-Barr viremia, and low chimerism (7.3%). He recovered after treatment with intravenous immunoglobulin and steroids.