Immune-complex nephritis in bacterial endocarditis.

Glomerulonephritis developed in a 42-year-old man with subacute bacterial endocarditis caused by an alpha-hemolytic Streptococcus. The patient showed hypocomplementemia and an elevated serum rheumatoid factor titer. Immunofluorescence microscopy of a renal biopsy specimen demonstrated granular deposits of IgM and C3 in all glomeruli studied. With the indirect immunofluores(ence technique and specific antiserum, the antigen in glomerular deposits was observed to correspond to the organism found in the blood cultures. These findings can be taken as further evidence that the glomerulonephritis of subacute bacterial enoocarditis represent an immune-complex disease.