Prominent dermal Langerhans cells in an Omenn syndrome patient with a novel mutation in the IL 2 RG gene

Prominent dermal infiltration by Langerhans cells ( LC ) is a rare finding in patients with Omenn syndrome ( OS ). Here, we report the case study of a 7‐month‐old boy with OS and with prominent dermal infiltration by LC , which is a rare histological manifestation of the skin. Striking erythroderma appeared in the patient 2 weeks after birth. We also noted alopecia, lymphadenopathy, hepatosplenomegaly, eosinophilia and an elevated serum immunoglobulin E level with hypogammaglobulinemia. Peripheral blood flow cytometry showed the T low NK + B + immunophenotype and genetic analysis, a novel mutation in the IL 2 RG gene (c.337_339del TCT , p.Ser113del). The final diagnosis was that of OS . He responded well to an allograft umbilical cord blood transplantation that was performed when the patient was 8 months of age. We speculate that the LC accumulated in the dermis will eventually migrate to the regional lymph node, then stimulate autoreactive T cells by overpresenting antigens, thus causing OS ‐specific skin symptoms.