Enhanced Humoral Immunity in Common Variable Immunodeficiency after Long-Term Treatment with Polyethylene Glycol-Conjugated Interleukin-2

Common variable immunodeficiency is a primary immunodeficiency disease characterized by low serum concentrations of IgG, IgA, and usually IgM1,2. Although some patients appear to have only intrinsic B-cell defects, more than half also have abnormalities of T-cell activation and deficient secretion of interferon-γ and interleukin-2, -4, and -53–7. Most patients also have deficient production of a B-cell differentiation factor, a 34-kd protein that has been purified and lacks interleukin-2, -4, -6, and -10 activity8. We and others hypothesized that the B cells in this disease may be defective because of a lack of essential cytokines . . .