Decreased number of regulatory T lymphocytes is related to inflammation and number of CD8+ T cells expressing programmed cell death protein-1 in common variable immunodeficiency

Common variable immunodeficiency (CVID) is a primary immunodeficiency disorder related to recurrent infections, as well as a range of non-infectious manifestations including autoimmune and inflammatory disorders. We hypothesized that patients with CVID and different clinical phenotypes would demonstrate alterations in lymphocyte T subsets, including T lymphocytes expressing programmed cell death protein 1 (PD-1), and regulatory T lymphocytes. We performed flow cytometry in two CVID groups: group 1 with infections only, and group 2 with infections and concomitant noninfectious manifestations. Patients were 18-59 years old (mean 35.8 years of age). Increased proportions of CD8+PD-1+ T cells and reduced regulatory T cells were associated with lymphadenopathy. Amount of regulatory T cells correlated with CD8+PD-1+ T lymphocytes (r = 0.54; p = 0.013), and with CRP (r = -0.64; p = 0.004). Forty percent of patients expressed manifestations in addition to infections (group 2), and they had reduction in number of regulatory T cells [8 (3-12) vs. 24 (11-26)/μl; p = 0.034), naive CD4+ T lymphocytes [36 (27-106) vs. 149 (81-283)/μl; p = 0.034], and elevated C-reactive protein (CRP) [5.33 (3.15-8.82) vs. 1 (1-2.16) mg/l; p = 0.003] in comparison to group 1. In conclusion, the amount of CD8+ T cells expressing PD-1 is associated with lymphadenopathy and number of regulatory T cells in patients with CVID. Patients with CVID and non-infectious complications have increased level of inflammation and alterations in regulatory T cells.