[Assay of rheumatoid factors by the indirect immunofluorescence method]. / Determinazione dei fattori reumatoidi con il metodo della immunofluorescenza indiretta.

Sera from 69 patients affected with rheumatoid arthritis were examined for IgM, IgG and IgA rheumatoid factors (RF) by a indirect immunofluorescence method. The results were compared with those obtained from the classical rheumatoid factor latex test. By this technique we have demonstrated antigammaglobulin activity in a high proportion (23%) of sera from latex test seronegative rheumatoid patients. Moreover, by fractionated antisera it was possible to detect also IgG and IgA factors. Indirect immunofluorescence results to be a simple and available technique for detection of RF, also in many "seronegative" patients.

[Rheumatoid factors: value of their determination in patients with rheumatoid arthritis]. / I fattori reumatoidi: valore della loro ricerca nei pazienti affetti da artrite reumatoide.

IgM, IgA, IgG rheumatoid factors were investigated by a indirect immunofluorescence method in three groups of patients affected with rheumatoid arthritis of various picture: 30 patients with mild articular disease, 20 with severe joint involvement and 19 with articular and systemic symptoms. Rheumatoid factors occurred more frequently in patients with articular and extraarticular severe rheumatoid arthritis; moreover these patients showed higher titres and higher incidence of different immunoglobulin class rheumatoid factors in comparison with rheumatoid patients having mild joint disease.