Hemagglutination study of serum factors related to L.E. cell formation

Abstract
Lupus factor as detected by tannic acidtreated sheep erythrocytes coated with a saline extract of nucleoprotein was found in the sera of 10 patients with systemic lupus erythrematosus and positive L.E. cell preparations. Nucleoprotein and the nucleoprotein extract (NP‐E) were capable of inhibiting the NP‐E hemagglutination as well as L.E. cell formation. Gamma globulin and DNA were not capable of inhibiting the NP‐E hemagglutination test.