Idiopathic late-onset immunoglobulin deficiency with functional T-cell deficiency.

The common features in our two patients were late onset of infections that are known to complicate both T-cell and B-cell deficiencies, decreased numbers of circulating B-cells with low serum immunoglobulin levels, and normal numbers of circulating T-cells, which were, however, defective in the response to delayed hypersensitivity skin test antigens and to mitogens in vitro. The composite of clinical and immunologic aberrations is consistent with the presence of an immune deficiency involving the B-cell system quantitatively and the T-cell system qualitatively.