Deficiency of T helper cells in transient hypogammaglobulinemia of infancy.

We studied 17 patients with transient hypogammaglobulinemia of infancy to define the immunologic defect responsible for this disorder. The number of circulating B cells in these patients was normal, as was the ability of the B cells to synthesize immunoglobulins when stimulated with Epstein-Barr virus, a direct B-cell activator. However, the capacity of the B cells to synthesize IgG in response to pokeweed mitogen, a T-cell-dependent B-cell activator, was depressed. Experiments with cultured lymphocytes indicated that excess suppressor-cell activity was not present in these patients, but that their T cells were deficient in providing help to B cells from their normal parents. A numerical deficiency in T4-positive (T4+) helper cells was found. Patients who had recovered from the disorder had a normal number of T4+ helper cells. Our results indicate that a numerical, as well as a functional, deficiency in helper T cells underlies the deficiency in IgG production in transient hypogammaglobulinemia of infancy.