A group of 25 patients with arthritis after acute respiratory disease (ARD) was followed up, on average for 4.7 years, with regard to the short-term and long-term prognosis. The patients developed arthritis 1-4 weeks after ARD and it affected mainly or exclusively the joints of the lower extremities, in particular the talocrural ones. After a mean period of five weeks the arthritis receded completely. 60% of the patients were HLA B27+, the number of affected joints in these patients was greater than in HLA B27- patients. HLA B27+ subjects are more likely to develop arthritis after ARD than HLA B27- subjects (relative risk = 6.35). In the long-term prognosis articular changes were found in 6/22 patients (5 were HLA B27+): three times sacroileitis was found, twice a relapse of arthritis after repeated ARD and once systemic lupus erythematosus. As to laboratory tests, arthritis after ARD was associated with a transient response of reactants of the acute phase and serum IgG. High values of IgA and immunocomplexes, on the other hand, persisted throughout the investigation in 41% and 28% of the patients resp.

Keywords: Acute Disease; Adolescent; Adult; Arthritis /etiology/; Female; HLA-B27 Antigen /analysis/; Humans; Male; Middle Aged; Prognosis; Respiratory Tract Diseases /complications/