Background: Common variable immunodeficiency (CVID) is a heterogeneous group of disorders, characterized by decreased immunoglobulin levels in serum and increased susceptibility to recurrent infections, autoimmunity, and malignancy. The pathogenesis of CVID is still unknown.

Objectives: This study was performed to investigate T-helper (TH) 1 and 2 cytokine levels in patients with CVID.

Material and Methods: Twenty-four cases of CVID were studied. Cytokine levels of interleukin (IL)-2, IL-4, IL-10, and interferon gamma were measured in the serum of the patients and compared with those of healthy controls.

Results: TH2 cytokine levels (IL-4 and IL-10) were significantly higher in the patient group than in the controls (median: 64.5 vs 0.0 pg/mL, P = .016 for IL-4 and 321.1 vs 0.0 pg/mL, P = .001 for IL-10). However, there were no significant differences in TH1 cytokines between the 2 groups (median, 116.5 vs 104.5 pg/mL, P = .22 for IL-2 and 50.5 vs 42.3 pg/mL, P = .32 for IFN-γ).

Conclusions: Increased levels of IL-4 and IL-10 could indicate high activation of TH2 lymphocytes in this group of patients and consequently supports the concept of a bias towards TH2-type responses.

Key words: Common variable immunodeficiency. Cytokine. Interleukin 4. Interleukin 10.