Long-term low-dose IL-2 enhances immune function in common variable immunodeficiency

Common variable immunodeficiency (CVID) is a primary immunodeficiency disea se characterized by hypogammaglobulinemia and lack of antibody production. Numerous T cell defects have been described, including reduced gene express ion and production of IL-2. Since some of the T cell defects could be expla ined by lack of IL-2, we have been investigating the effects of in vivo IL- 2 treatment. Here, a long-acting form of IL-2, PEG-IL-2, was given for 12-1 8 months to 15 randomly chosen CVID subjects, in comparison to 39 CVID subj ects who served as controls. After 6 to 12 months of treatment, T cell prol iferative responses to mitogens and to IL-2 were significantly enhanced; pr oliferative responses to tetanus and candida antigens increased up to 50-fo ld. Four of eight subjects immunized with the neoantigen bacteriophage phiX 174 displayed increased antibody responses after treatment. Treated subjec ts recorded reduced, but not overall statistically significant, days of bro nchitis, diarrhea, and joint pain. These data indicate that IL-2 might serv e as an adjuvant to therapy in some subjects with CVID, enhancing T cell fu nctions and reversing T cell anergy in most. (C) 2001 Academic Press.