IG‐G, IG‐A AND IG‐M GRANULOCYTE‐REACTIVE ANTINUCLEAR FACTORS IN RHEUMATOID ARTHRITIS

Sera from 84 patients with rheumatoid arthritis were investigated for Ig, Ig-G, Ig-A, Ig-M ANF reactive with nuclei of polymorphonuclear granulocytes, using a two- and three-layer immunofluorescent antibody technique. Granulocyte-reactive ANF were found in 2/3 of the sera. Of the 56 positive sera, 60% contained Ig-G ANF, 62% Ig-A and 67% Ig-M ANF. Sera containing granulocyte-reactive ANF exclusively of high molecular weight (Ig-A and Ig-M) constitute 39% of the positive sera. Granulocyte-reactive ANF were found significantly more frequently in sera from patients 61 years old or older, owing to an increase of Ig-G ANF. No sex difference was demonstrated. There was no statistically significant relationship between gran.-react. ANF of the three human immunoglobulin classes and such clinical parameters as ESR, functional capacity or concentration of haemoglobin. A strict correlation between granulocyte-reactive ANF and the presence of nodules was found, all patients with nodules showing a positive ANF reaction. Half the 56 positive sera reacted exclusively with nuclei of polymorphonuclear granulocytes, while the other half also reacted with other human nuclei. With advancing disease increasing non-specificity of ANF occurred and a significantly higher proportion of sera from patients with long-lasting disease also contained ANF reactive with other human nuclei. This increase in nuclear reactivity was accompanied by a change in the immunoglobulin pattern of granulocyte-reactive ANF, the Ig-G ANF being found significantly more frequently in sera from patients with disease of short duration, while Ig-G ANF were present in a significantly higher proportion of sera from patients with more long-lasting disease.