[Immune deficits in hemodialysis patients]

Patients with chronic renal insufficiency under maintenance dialysis present numerous immunological alterations to which renal impairment, nutritional disturbances, blood transfusions and biocompatibility of the dialysis system may contribute. Although presently less frequent, infections still represent an important source of mortality and morbidity. Polynuclear neutrophils chemotactic responses are decreased and bactericidal capacity reduced, especially in polytransfused patients with iron overload. Lymphocyte counts are diminished and T lymphocytes present several alterations, including defective IL-2 synthesis, spontaneous expression of the p55 (CD25) chain of IL-2 receptor with high serum levels of this molecule, and defective T helper function in antibody production. Such alterations may account for the defect of delayed hypersensitivity reactions and the diminished antibody response after vaccination. Complement activation, increased expression of adhesion molecules by leukocytes, production of IL-1 and reduced oxygen molecular species during dialysis might contribute to immunological disorders of these patients.