JAK3 and immune system disorder: In this regard, it is of interest that although severe combined immunodeficiency (SCID) patients with RAG1 or RAG2 deficiency do not develop verrucosis after hematopoietic stem cell transplantation, those with IL2RG or JAK3 deficiencies might instead develop diffused HPV infections despite successful hematopoietic stem cell transplantation [61–63], possibly reflecting a keratinocytic intrinsic defect [57].