The clinical and physiological aspects of tuftsin deficiency syndromes exhibiting defective phagocytosis.

The tetrapeptide tuftsin (Thr-Lys-Pro-Arg) stimulates phagocytosis by blood neutrophilic granulocytes and tissue macrophages in a highly specific manner. Tuftsin is cleaved off the carrier gamma-globulin molecule as the free active form by two enzymes. One of these is in the spleen and the other on the outer membrane of the phagocyte. Congenital tuftsin deficiency usually arises when the peptide is mutated to an inactive peptide. The acquired type occurs if the spleen function is curtailed by removal or disease. Tuftsin deficiency is manifested by severe recurrent infections involving primarily the skin, lymph nodes and lungs. Therapy is limited to gamma-globulin injection along with appropriate chemotherapy.