Increased Susceptibility to Infection Associated with Abnormalities of Complement-Mediated Functions and of the Third Component of Complement (C3)

摘要: Abstract In a patient with Klinefelter's syndrome and lifelong increased susceptibility to infection, no abnormalities were found in humoral antibody production, cellular immunity or leukocyte function. contrast, the patient's serum complement-mediated functions grossly deficient. The concentrations of complement components normal except for that C3 (β1C-globulin), which was less than one-third normal. bulk this form inactive conversion product, C3b, at all times plasma examined over two-year period. Addition small amounts serum, but not purified C3, improved vitro. This disorder, may represent an inborn deficiency protein necessary stability vivo vitro, is detected by lowered concentration positive non-gamma (C3) Coombs antiglobulin test.