Clinical and immunophenotypic features of atypical complete DiGeorge syndrome

DiGeorge syndrome is a congenital malformation characterized by variable defects of the thymus, heart and parathyroid glands. Athymic patients are classified as exhibiting complete DiGeorge syndrome. Some of these patients may also exhibit oligoclonal T-cell expansion, generalized rash and lymphadenopathy at some point after birth. This rare condition is known as atypical complete DiGeorge syndrome, resembles Omenn syndrome, and has not been fully characterized.

The clinical and immunophenotypic features of atypical complete DiGeorge syndrome were assessed in two affected Japanese infants. T-cell receptor (TCR) Vβ repertoire was analyzed on flow cytometry and complementarity-determining region 3 spectratyping.

Both patients had no detectable thymus tissue and profound T-cell lymphopenia soon after birth. Progressive increase of activated T cells, however, as well as eosinophilia, high serum IgE level, generalized rash, and lymphadenopathy were observed during early infancy. A highly restricted TCR Vβ repertoire was demonstrated both in CD4(+) and CD8(+) T cells.

The Omenn syndrome-like manifestations might be associated with the oligoclonal proliferation of activated T cells. Analysis of the immunophenotype and TCR Vβ repertoire is helpful to establish the early diagnosis of atypical complete DiGeorge syndrome.