PARATHYROID-HORMONE AND THE CELLULAR IMMUNE-SYSTEM

Parathyroid hormone (PTH) is the main hormone controlling calcium conc entration in the extracellular fluid (ECF) through its biological acti vity on bone, kidney and intestine. However, data published over the l ast two decades indicate that PTH may act as an immunomodulator. The p urpose of the present review is to summarize the effects of PTH on var ious immune functions. Polymorphonuclear leukocytes of patients with c hronic renal failure (CRF) and elevated blood levels of PTH showed imp aired migration, reduced phagocytic and bactericidal activity, and inh ibited granulocyte chemotaxis. Antibody production and T and B lymphoc yte proliferation are affected by PTH, both in vivo and in vitro. Poss ible implications of the involvement of PTH and its fragments in CRF a re discussed.