Activación y función cooperadora del linfocito T en la inmunodeficiencia variable común

Résumé

Common Variable Immunodeficiency (CVID) is an heterogeneous syndrome characterized by hypogammaglobulinaemia and recurrent infections. Although early works pointed to a primary B lymphocyte defect as a cause of the disease, a failure in T lymphocyte cooperation has also been suggested. We studied T cell properties in order to elucidate whether alterations in T cells could be responsible for a deficient T/B cooperation in CVID patients. We evaluated, in T lymphocytes from CVID patients and healthy controls, the distribution of naïve and memory cells, the proliferative response, the expression of co-stimulatory molecules (CD28, CD40L/CD154 and CTLA-4/CD152), the production of cytokines (IL-2, IL-4, IL-6, IL-10, IFN-γ and TNF-α) and the tyrosine phosphorylation pattern. Peripheral blood mononucleated cells and purified T cells were stimulated with optimal doses of anti-CD3 or suboptimal doses of anti-CD3 and antiCD28. The distribution of naïve and memory T lymphocytes was similar between CVID patients and controls. After stimulation, the proliferative response and the expression of co-stimulatory molecules (CD28, CD40L/CD154 and CTLA-4/CD152) were similar in both groups. Except for higher production of IL-4 after stimulation with anti-CD3, CVID patients T cells produced similar amounts of cytokines compared to controls. Neither alterations in the distribution of T lymphocytes nor imbalance between costimulatory molecules expression and cytokine production by T cells explain a deficient cooperation between T and B cells in our group of CVID patients.