The defective gene in X-linked severe combined immunodeficiency encodes a shared interleukin receptor subunit: implications for cytokine pleiotropy and redundancy.

The interleukin-2 receptor plays a pivotal role in the regulation of the normal T cell immune response to foreign antigen. The IL-2 receptor gamma-chain is one component of this receptor, and is encoded by the gene that is defective in X-linked severe combined immunodeficiency. The clinical manifestations of this disease led to the hypothesis and subsequent confirmation that the gamma-chain was in fact a subunit shared by multiple cytokine receptors, including those for IL-2, IL-4, and IL-7.