Type C RNA virus-specific antibody in human systemic lupus erythematosus demonstrated by enzymoimmunoassay.

Abstract

Postmortem study of proliferative glomerulonephritis associated with human systemic lupus demonstrated that an antigen related to mammalian type C RNA viral core (p30) proteins was deposited in the renal glomerular lesions with human immunoglobulins [Ig] in an immune-complex pattern. Human Ig were sequentially eluted from the lupus glomerular immune deposits and were assayed by a sensitive enzymoimmunoassay developed for the measurement of anti-p30 antibody activity against purified viral p30 proteins of mammalian type C viruses. Human Ig showing specific anti-p30 antibody activity, particularly against p30 antigen of feline endogenous virus RD-114 and to a smaller extent against p30 antigen of murine type C virus, were eluted by acid buffer from the glomerular immune deposits in 2 patients with lupus proliferative glomerulonephritis who have deposits of viral p30-related antigen in the same tissue lesions. Expression of type C viral antigen may be involved in the multifactorial pathogenesis of proliferative glomerulonephritis associated with human systemic lupus.