Evaluation of the T helper 17 cell specific genes and the innate lymphoid cells counts in the peripheral blood of patients with the common variable immunodeficiency

Abstract

Background: Common variable immunodeficiency (CVID) is characterized by a deficiency in the immune system with a heterogeneous collection of disorders resulting in antibody deficiency and recurrent infections. T helper 17 (Th17) cells promote B-cell survival and synergize with the B-cell activating factor to induce their differentiation into the plasma cells. A sub-population of innate lymphoid cells (ILCs) also produces interleukin 17 (IL-17). This study aimed to measure the Th17 specific genes and ILCs counts in the CVID patients in comparison with control subjects.

Materials and methods: Total messenger ribonucleic acid (mRNA) was extracted from the whole blood samples of 10 CVID patients and 10 healthy individuals. IL-17, retinoic acid receptor-related orphan receptor C2 (RORC2), IL-23R, and IL-9 gene expression were measured using the quantitative reverse transcriptase-polymerase chain reaction. Count of lineage negative/CD127(+)/CD90(+) ILCs in the blood samples was performed by the flow cytometry method.

Results: The transcript levels of IL-17 and RORC2 in CVID patients was strongly lower than control subjects (P = 0.049 and P = 0.046, respectively), but slight reduction in the IL-23R expression (P = 0.252) have seen in the CVID patients. Accordingly, the number of ILCs decreased significantly (P = 0.04). Interestingly, IL-9 mRNA level was more significantly in the CVID patients (P = 0.001).

Conclusion: The results presented in this study show that the Th17 cell specific genes expression (as the determiner Th17 cells) and ILCs (another lymphoid source of IL-17) are decreased in patients with CVID and this could be an explanation for the defect of their humoral immune response. In addition, elevation of the IL-9 gene expression may shed a new light into the way toward the understanding of the mechanism of autoimmunity in the CVID patients.

Keywords: Common variable immunodeficiency; T helper 17 cells; innate lymphoid cells; interleukin 17; interleukin 23R; interleukin 9.

Figure 1

Flow cytometry analysis of the Lin−/CD127+/CD90+innate lymphoid cells in the peripheral blood of the Common variable immunodeficiency (CVID) patients compared with the healthy individuals. (a) FSC/SSC diagram of peripheral blood cells shows gated area for lymphoid cells. (b) Flow cytometry analysis of the peripheral blood samples in which T cells, B-cells and NK cells are detected as one population using the FITC-conjugated anti-CD3, anti-CD19, and anti-CD56 antibodies. (c) Percentage of the Lin−/CD127+/CD90+ILCs in a CVID patient. No ILCs was found in the studied patients. (d) Percentage of the Lin−/CD127+/CD90+ILCs in a normal control

Figure 2

Comparison of the gene expression of IL-17, RORC2, IL-23R, and IL-9 in the peripheral blood of the CVID patients with the healthy individuals by the quantitative reverse transcriptase-polymerase chain reaction. Black bars represent gene expression of the patients and white bars show gene expression of the healthy individuals. The findings showed a decrease in transcript levels of IL-17, RORC2, and IL-23R (P = 0.049, P = 0.046, and P = 0.252, respectively) and strongly increased in transcript levels of IL-9 (P = 0.001)