Altered interleukin-2 (IL-2) production and responsiveness after hyposensitization to house dust.

Interleukin-2 (IL-2 or T cell growth factor, TCGF) is a lymphokine absolutely required for clonal expansion of activated T-lymphocytes with specific cytotoxic, helper, and suppressor functions. The capability of production of and responsiveness to IL-2 in 15 normal children, 28 newly diagnosed, and 22 hyposensitized (greater than 1 yr) children with asthma was studied. The results demonstrated (1) The lymphocytes from newly diagnosed patients produced a much greater amount of IL-2 when they were stimulated with specific allergen (house dust) but not with phytohemagglutinin (PHA) than did those from both hyposensitized patients and normal subjects. (2) The responsiveness to IL-2 of activated lymphocytes from hyposensitized patients was much more vigorous than those from both new patients and normal subjects, whether the responder lymphocytes were pretreated with PHA or house dust. Thus, hyposensitization is able to modulate the immunobiologic functions of T cells with respect to production of and responsiveness to IL-2, and such alterations may contribute to the immunologic changes occurring in patients receiving long-term hyposensitization.