The activity on human serum-chicken red blood cell (RBC) bioassays, which have been reported to measure an abnormal lipoprotein in the serum of some schizophrenics, is not associated with low-density serum lipoproteins upon serum fractionation, but is complement-dependent and can be eliminated from at least some samples by passage through antihuman IgM affinity chromatography columns.
Sera with high bioassay activity can be produced by immunizing rabbits with chicken RBCs and there is a strong correlation between hemolysis and bioassay activity (lactate stimulation and tryptophan uptake).
It is concluded that hemolysins present in human sera produce high scores on the bioassays. High bioassay activity was not correlated with the diagnosis of schizophrenia among psychiatric patients at the Minneapolis Veterans Administration Hospital.