Circulating Helper T-Cell Subsets and Regulatory T Cells in Patients With Common Variable Immunodeficiency Without Known Monogenic Disease.

BACKGROUND

Common variable immunodeficiency (CVID) is the most common symptomatic primary immunodeficiency (PID). It is characterized by heterogeneous clinical manifestations and defects in B cells and T cells. In the present study, we investigated helper T (TH) cell subsets and regulatory T (Treg) cells and their related cytokines and transcription factors in CVID patients with no definitive genetic diagnosis.

METHODS

The study population comprised 13 CVID patients and 13 healthy controls. Mutation analysis was performed using whole exome sequencing in CVID patients to rule out monogenic PIDs. TH subsets and Treg were analyzed using flow cytometry. The expression of determinant cytokines (IFN-γ, IL-17, IL-22, and IL-10) and cell subset specific transcription factors was evaluated before and after stimulation.

RESULTS

The main clinical presentations of these patients were infections only and lymphoproliferative phenotypes. No autoimmune or allergy phenotypes were recorded. The frequencies of CD4+ T cells, TH17, and Treg cells were significantly reduced in CVID patients; however, TH1, TH1-like TH17, and TH22 subsets were normal. After stimulation, expression of retinoic-acid-orphan-receptor-C (RORC), runtrelated transcription factor 1 (RUNX1), IL17, and IL10 was significantly lower in CVID patients than in the healthy controls. Moreover, the concentration of IL-17 and IL-10 in the cell culture supernatants of stimulated CD4+ T cells was lower in CVID patients than in healthy controls.

CONCLUSIONS

Our findings demonstrate that the imbalance of TH17 and Tregs could be associated with infection and the lymphoproliferative phenotype in CVID patients without monogenic disorders.