IL2 and common variable immunodeficiency: It has been reported that high serum levels of endotoxins were found in the patients suffering from common variable immunodeficiency (CVID), which suggest that CD4+ T-lymphocytes dysfunction was restricted to bacteria-specific and not virus-specific CD4+ T-lymphocytes, including the reduced capacity to proliferate and to produce IFN-γ and IL-2 [32].