Expansion of CCR4+ activated T cells is associated with memory B cell reduction in DOCK8-deficient patients

Abstract

Hyper-IgE syndrome (HIES) is a genetic disorder characterized by elevated IgE serum levels, mostly due to mutations in STAT3 or DOCK8. Despite clinical heterogeneity between the two forms of the disease, clinical manifestations may not be conclusive for diagnosis and immunological differences are still unclear. Herein, we performed a detailed characterization of the T- and B-cell compartments by flow cytometry in seven HIES patients with homozygous DOCK8 mutations and six patients presenting heterozygous STAT3 mutations. We observed that DOCK8-deficient patients showed a marked reduction of naive and recent thymic emigrant (RTE) T lymphocytes together with a relative increase of activated T cells, most of which co-expressed the chemokine receptor CCR4, a marker of Th2 polarization. Moreover, an extreme reduction of memory B cells was detected, despite a normal/increased proportion of immunoglobulin-secreting cells. These observations indicate that DOCK8-deficient patients display a distinctive immunophenotype which is characteristic of this form of HIES.

Keywords: DOCK8; Hyper-IgE syndrome; Memory B cells; Recent thymic emigrants; Th2 commitment.