ELISA determined IgM, IgG and IgA rheumatoid factors in rheumatoid arthritis and in other connective tissue diseases.

We used an adaptation of an enzyme-linked immunoadsorbent assay (ELISA) to determine serum levels of IgM, IgG and IgA rheumatoid factors (RF) in 50 patients with classic or definite rheumatoid arthritis (RA) according to the ARA criteria, balanced for positive or negative-routine Latex-RF reaction. A control group of 50 young normal subjects and a reference group of 44 patients with other connective tissue diseases (OCTD) were also studied. We confirmed the high sensibility of the method, together with its good specificity and reproducibility.

IgM, IgG and IgA rheumatoid factors and circulating immune complexes in patients with AIDS and AIDS-related complex with serological abnormalities.

To investigate some humoral aspects which may reflect the involvement of B lymphocytes in the acquired immunodeficiency syndrome (AIDS), we used an enzyme-linked immunoassay (ELISA) to determine the levels of IgM, IgG and IgA rheumatoid factors (RF) in 16 patients suffering from full-blown AIDS and 32 patients with AIDS-related complex (ARC), in the clinical form of lymphoadenopathy syndrome (LAS), compared with 40 healthy, young heterosexual subjects. Both AIDS and ARC patients showed a greater incidence of high IgM RF levels, with mean values significantly higher than controls, but with no differences between the two pathological groups. IgG RF behaviour was similar in the two patient populations and the healthy subjects.

Detection, by an enzyme linked immunoadsorbant assay (ELISA), of IgM, IgG and IgA rheumatoid factors in patients with essential mixed cryoglobulinemia.

In order to investigate on some yet unclear aspects of the relationship between Rheumatoid Factor (RF) activity, cryoprecipitation and clinical features of Essential Mixed Cryoglobulinemia (EMC), we determined, by an ELISA technique, the IgM, IgG and IgA RF in 16 patients with EMC, 16 patients affected with seropositive Rheumatoid Arthritis (AR), taken as a reference, and 16 young, normal controls. For IgM RF a high rate of incidence of positive samples (11/16 = 69%) from the EMC group was found, with mean values significantly higher than controls (p less than 0.001) and quite similar to those of the RA group.