[Rapid assessment of the complement system reactivity]

The authors developed a new indicator of humoral immunity, which characterizes the complement system reactivity (CSR). Complement system reactivity has been investigated in haemolytic assay using sheep red blood cells, autologous heterophile antibodies and complement in a "load" as 0.29 M NaCl in the system. There has been made a study of blood sera of 10 healthy donors and 20 patients who undergo screening for chronic infections in clinical-diagnostic centers. Inhibition of complement--0.29 M NaCl at a level of 30-70% in healthy donors is taken as an indicator that characterizes normal complement system reactivity of a human serum. Investigations have revealed in 11 patients (55%) of the 20 examined people high complement system reactivity (lysis degree more than 70%), in 6 patients (30%)--normal complement system reactivity, and in 3 patients (15%)--low complement system reactivity (lysis degree less than 30%). Thus, the study of the complement system reactivity in a "load", in the presence of 0.29 M NaCl in the test sample, detects functional changes, both reinforcing and reducing complement activity.