Immune deposit nephritis in infectious mononucleosis.

A 22-year-old white male (L.V.) died of gram-negative septicemia complicating infectious mononucleosis (IM) that was associated with jaundice and oliguric renal failure. The kidney showed mesangial granular deposits of IgM and C3, mesangial electrondense deposits, and interstitial infiltrates of infiltrates of mononuclear cells, including atypical lymphocytes. Eluates obtained from kidney, spleen and liver contained Paul--Bunnell (PB) antibodies. Presence of PB antigens in these tissues was indicated by absorption of PB antibodies from IM sera, with the sediments resulting from tissue elutions. The IgM mesangial deposits were partially eluted with acid buffer at 56 degrees C and then reconstituted by incubation with IM sera or with immunoglobulins eluted from tissues of patient L.V. The presence in renal structures of PB antigens, IgM heterophile antibody, C3 and electron-dense deposits is consistent with the hypothesis that heterophile immune complexes were localized in the kidney and that they contribute in the pathogenisis of IM nephritis.