ABSTRACT
Chronicity and arthritis are the main complications of brucellosis. To clarify the causes of these complications, 80 patients with brucellosis, acute and chronic with or without arthritis and 20 normal control subjects were studied. The mean value of rheumatoid factor [RF], alpha-1 - antitrypsin [alpha 1-AT], C3, C4 and fibrinogen did not show significant changes between different groups of patients and normal control, while anti-Fc-receptor antibodies showed significant increased levels in all groups of patients. This increase was more significant in patients with chronic brucellosis who had arthritis. The absence of acute reactive phase proteins with the presence of anti-receptor peptide could be attributed to the disease chronicity. Immune complexes [ICs] also showed significant increased levels in the all groups of patients compared with normal control. Evidence of activation of C3 and C4 was observed in patients who had increased IC levels and who had arthritis. Arthritis did not develop in some patients with high IC levels probably due to decreased level of anti-Fc-R antibodies. Also there was no evidence of complement activation in this group of patients