Background: Common variable immunodeficiency (CVID) is the most prevalent primary immunodeficiencies characterized by impaired antibody responses, defect in T-cell proliferation and secretion of cytokines, especially IL-2. This study aimed to evaluate the function of cellular immune system in CVID patients based on Il-2 level, as a cell-mediated immune index, as well as the clinical and paraclinical evaluation of such patients.

Materials and Methods: This case-control study was conducted on 20 CVID and 10 healthy participants referred to the Immunology and Allergy Department at Children Medical Center in Kashan. The clinical and paraclinical findings of the patients were collected using the questionnaire. The peripheral blood mononuclear cells were cultured with PHA in both groups and then the supernatants were collected for quantification of IL-2 secretion using the ELISA method.

Results: CVID was seen in 85% of the cases hospitalized with infection. The most common infection was respiratory tract infection the opportunistic infections and autoimmunity were seen in 5-10% and 40% of the cases, respectively. Delayed-type hypersensitivity response was negative in 65% of the patients. Moreover, IL-2 level was zero in15 patients and lower than that of the control group in 5 patients (P<0.05).

Conclusion: All patients showed deficiency in T-cell function with decreased IL-2 production. The manifestations of this deficiency are a high incidence of autoimmunity, granulomatosis, bronchiectasis and recurrent infections in the patients in spite of monthly IVIG injections.