Skin infiltration of CD56(bright) CD16(-) natural killer cells in a case of X-SCID with Omenn syndrome-like manifestations.

[omenn syndrome]

We observed a patient with X-linked severe combined immunodeficiency (X-SCID ) with Omenn syndrome -like manifestations . X-linked inheritance , absence of CD 132 expression and impaired response to interleukin-2 (IL -2 ) indicated that the case is typical of X-SCID due to gamma (c ) defect . However , this case was unusual in that circulating natural killer (NK ) cells were increased and nearly half of these NK cells exhibited the CD 5 6 (bright ) CD 16 (-) phenotype . A missense mutation was found within exon 5 of the IL 2 RG gene . The identical mutation was detected within NK , CD 4 (+) T and B cells . Engraftment of maternally derived NK cells or gene reversion was ruled out . The erythroderma -like skin lesion was characterized by infiltration of the dermis by CD 5 6 (bright ) NK cells admixed with CD 1 a (+) dendritic cells (DC ). Expression of mRNA for inflammatory cytokines was significantly enhanced within the skin . This may be the first human case to demonstrate that close cell-to -cell contact between DC and NK cells provides an effective alternative pathway for NK cell differentiation /activation in vivo .