EVIDENCE OF INNATE LYMPHOID CELL REDUNDANCY IN HUMANS

Abstract

Innate lymphoid cells (ILCs) have potent immunological functions in a experimental conditions in mice, but their contributions to immunity in a natural conditions in humans have remained unclear. We investigated the a presence of ILCs in a cohort of patients with severe combined a immunodeficiency (SCID). All ILC subsets were absent in patients with a SCID who had mutation of the gene encoding the common gamma-chain a cytokine receptor subunit IL-2R gamma or the gene encoding the tyrosine a kinase JAK3. T cell reconstitution was observed in patients with SCID a after hematopoietic stem cell transplantation (HSCT), but the patients a still had considerably fewer ILCs in the absence of myeloablation than a did healthy control subjects, with the exception of rare cases of a reconstitution of the ILC1 subset of ILCs. Notably, the ILC deficiencies a observed were not associated with any particular susceptibility to a disease, with follow-up extending from 7 years to 39 years after HSCT. a We thus report here selective ILC deficiency in humans and show that a ILCs might be dispensable in natural conditions, if T cells are present a and B cell function is preserved.