Impaired T8 lymphocyte-mediated suppressive activity in patients with partial Di George syndrome.

We have studied the in vitro B-cell maturation induced by pokeweed mitogen of lymphocytes from seventeen patients with partial Di George syndrome. These patients were characterized by a low number of T8(+) lymphocytes. They had normal immune functions with an increased level of serum IgE for most of them. These patients were investigated before the age of 1 month. In contrast to age-matched subjects, their lymphocytes were able to produce in vitro immunoglobulins, although the level of immunoglobulin production was lower than in adults. These data were explained by a lack of T-cell mediated suppressor activity normally found in newborns. There was a strong correlation between the low number of T8(+) lymphocytes and the magnitude of the in vitro immunoglobulin production by patients' cells. This was further demonstrated by the ability of residual T8(+) lymphocytes isolated from patients to normally suppress the PWM driven B cell maturation on a per cell basis. The defective T-cell mediated suppression progressively disappears within 5 months. It is possible that this phenomenon is secondary to a delayed differentiation of suppressor T-cells in patients with partial Di George syndrome.