Immune complexes in ovarian cancer: association between IgM class complexes and antinuclear autoantibodies in ascitic fluid.

Samples of ascitic fluid from patients with ovarian cancer were analyzed for autoantibodies to nuclear and cytoplasmic antigens and for immune complexes (ICs) detectable by the Clq deviation and polyethylene glycol (PEG) precipitation (either IgG or IgM class) assays. The predominant autoantibody was antinuclear (ANA); this was detected in 29 of 58 samples (59% showing the homogeneous and 41% the speckled pattern). The antibody was not reactive to saline extractable nuclear antigens. A strong association between this autoantibody and the PEG-precipitated IgM class ICs was shown, suggesting the possible participation of this autoantibody in IgM class ICs formation. The lack of association between C1q-reactive and IgG class ICs and the autoantibodies indicates that the IgG class ICs may be more related to the tumor.