Antiglobulin factor in sera from patients with liver disease.

(1) An antiglobulin factor, non-neutralizable by human gamma-globulin, was demonstrated in sera of two patients with liver disease. (2) By absorption and elution techniques, two fractions were differentiated in a serum: one is reactive to rabbit antibody and the other seems cross-reactive to rabbit and human antibodies. (3) In double immunodiffusion test, the antiglobulin factor formed a precipitation band with heat-aggregated human IgG as did rheumatoid arthritis serum. (4) While the antiglobulin activity to rabbit antibody was demonstrated in both the IgM and IgG fractions, the reactivity to human antibody was localized in the IgM fraction. (5) From its selective reactivity to individual anti-D sera (sensitizers), at least a part of the specificity of the antiglobulin factor must be related to anti-Gm (1), and consequently can be regarded as auto-reactive.