[Heterogeneity of antinuclear antibodies (ANA), immunoglobulin- and complement levels in sera of patients with rheumatoid arthritis (RA) (author's transl)].

ANA typing of RA patients according to the heavy- and light chains, complement fixing ability and immunofluorescent staining pattern was performed by the immunofluorescence technique and partially by qualitative immunoelectrophoresis. In the corresponding sera the immunoglobulins and complement components were quantiatively determined. Dependent on the ANA-immunoglobulin classes we found the following distribution: IgG-ANA; 40/93 (43%), IgM-ANA: 19/93 (20%), IgA-ANA: 2/93 (2%), and Ig-comb.-ANA:17/93 (18%). ANA only positive for polyspecific antimmunoglobulin serum: 15/93 (16%). After L-chain typing we found within a given ANA-Ig-class positivity for both L-chain subclasses (kappa and lambda): IgG-ANA: 19/40 (48%), IgM-ANA: 3/19 (16%), IgA-ANA:1/1 and Ig-comb.-ANA: 14/17 (82%). ANA cases within a given Ig-class only positive for the L-chain/type kappa:IgM-ANA:6/19 (32%), IgG-ANA: 9/40 (23%), Ig-comb.-ANA:2/12 (12%). ANA cases within a given Ig-class only positive for the L-chain type lambda: IgM-ANA: 7/19 (37%), IgG-ANA: 3/40 (8%), Ig-comb.-ANA:1/17 (6%) and IgA-ANA:1/1. In all cases of restricted ANA-positivity (only positive by use of polyspecific anti-immunoglobulin serum) no light chains were detected. In total we found approximatively 25% of complement fixing ANA, predominantly IgG-ANA (70%). Concerning the immunofluorescent nuclear staining we stated the following patterns: homogenous: 34/93 (36.6%), speckled: 29/93 (31.2%), mixed pattern : 22/93 (23.6%) peripheral: 5/93 (5.4%) and nucleolar: 3/93 (3.2%). The quantitative Ig-determination reveals a significant increase of IgG in ANA (single type) positive sera. IgG + IGM + IGA-ANA and IgG + IgM-ANA are found together with a significantly increased IgG- and IgM-serum levels, in the case of IgG + IgM-ANA we could demonstrate an additional relative decrease of the complement component C4. Sera with positive complement fixing ANA compared with non complement fixing ANA are characterized by an absolute increase of IgG and relative decrease of the complement component C4. No differences in serum-immunoglobulin- and -complement concentrations were registered dependent on ANA-immunofluorescent staining patterns.