en Immunology Immunology Original Research Original Research In this survey, opsonization activity of sera in 110 patients with meningitis, sepsis and recurrent infection 12 patients after healing and 50 normal adults has been studied. Opsonization activity was measured by an assay depending on electronic particle counting to measure yeast uptake (alternative pathway activator) which was modified in our laboratory. Three classes of immunoglobulins (lgG, lgM, lgA) and C3 levels were also studied depending on single radial immunodiffusion by using Behring kit in our patients. 54 pathological sera with defective opsonization showed low C3 levels, two with lower than normal opsonization activity showed low C3 levels, 11 defective opsonization cases showed normal C3 levels, 3 of which were related to diabetic patients. 22 instances of decreased 19G, 14 cases of decreased 19M and 18 cases of decreased lgA were observed in 110 patients. The opsonization activity, C3 and immunoglobulin levels in 12 patients have become normal after healing. 125 129 http://mjiri.iums.ac.ir/browse.php?a_code=A-10-298-818&slc_lang=en&sid=1 S NEZAM DIBA 20031947532846006740 20031947532846006740 Yes From the Department of Immunology, the Children's Hospital Medical Center, Tehran university of Medical Sciences, Tehran, Islamic Republic of Iran. A FARHOUDI 20031947532846006741 20031947532846006741 No