Repertoire of V_α and V_β regions of T cell antigen receptors on CD4⁺ and CD8⁺ peripheral blood T cells in a novel X‐linked combined immunodeficiency disease

The repertoire of V regions of α/β⁺ T cell receptor (TcR) on CD4⁺ and CD8⁺ T cells from the peripheral blood of six patients with a novel X‐linked combined immunodeficiency was investigated by flow cytometry. The relative frequencies of V region subfamilies V_α2a on CD4⁺ T lymphocytes and V_β5b and V_β12a on CD8⁺ T lymphocytes from the peripheral blood from the affected males were decreased significantly. Also, the relative frequencies of certain other V region subfamilies on CD4⁺ or CD8⁺ T cells from the peripheral blood of some patients were either considerably below or above the ranges found in normal subjects. Although there may be other explanations including an extrathymic event, we suggest that the abnormalities in the TcR repertoire of peripheral blood T cells are consistent with a dysregulation of the intrathymic maturation/selection of T cells that leads to deficiencies in T cell populations in the peripheral blood of males with this disease.