Immune dysregulation symptoms as a rare manifestation of X-linked lymphoproliferative syndrome type 1

X-linked lymphoproliferative syndrome type 1 (XLP1) is a primary immunodeficiency, the most dramatic manifestations of which are hemophagocytic lymphohistiocytosis (usually associated with Epstein-Barr virus), lymphoma and dysgammaglobulinemia. Immune symptoms like vasculitis, aplastic anemia and others are extremely rare. Specialists awareness and suspicion regarding such complications of XLP1 facilitate correct diagnosis and early curative treatment - hematopoietic stem cell transplantation (HSCT). Here we present two clinical cases of XLP1 with immune dysregulation symptoms where one patient underwent successful HSCT. In each case, the parents gave consent to the use of their child's data, including photographs, for research purposes and in publications.