Peripheral blood lymphocyte subsets and serum immunoglobulins in Sheehan's syndrome and in normal women during the menstrual cycle.

Objective: There has been increasing evidence on the mechanisms underlying the interactions between the neuroendocrine and the immune systems, particularly in animal models with relatively few information in the human. In this study, we evaluate the cellular and humoral immunity in female patients with hypopituitarism and in normal women throughout the menstrual cycle in an attempt to determine the role of pituitary and gonadal hormones on the immune system.

Design: Serum immunoglobulins, peripheral blood lymphocyte subsets, and serum hormones were measured in eight patients with postpartum pituitary necrosis (Sheehan's syndrome) and in six normal women along different phases of the menstrual cycle, taking advantage of the lack of pituitary function and the cyclic variations in serum hormones, respectively.

Results: Patients with Sheehan's syndrome had higher T lymphocytes (CD2), including helper (CD4) and suppressor (CD8) cell subpopulations and B lymphocytes (CD19) when compared with normal menstruating women. An increase of serum IgA concentrations was also observed. Normal women showed little non-statistically different changes along the menstrual cycle in peripheral blood cell parameters and in serum immunoglobulin levels.

Conclusions: a) Hypopituitarism in humans, in contrast with the animal model, may associate with immune up-regulation at both cellular and humoral levels; and b) hormonal changes along the normal menstrual cycle probably do not influence in great extent the immune system.