Hantavirus antigen detection in kidney biopsies from patients with nephropathia epidemica

Renal biopsies collected from ten patients with serologically confirmed Puumalavirus (PUUV) infection in the acute stage with renal dysfunction who lived in the same PUUV endemic area in The Netherlands, were studied histologically, immuno-histochemically and subsequently examined for the presence of viral antigen by immunoperoxidase staining. Interstitial hemorrhages and deposition of IgM, complement component C3 and fibrin along the basal side of the tubular epithelial cells, were found in PUUV seropositive patients. In six of these patients viral antigen was detected in the cytoplasm of renal tubular epithelial cells with focal distribution in the cortical and medullary areas of the kidneys. Surprisingly, also in two of the ten renal biopsies from PUUV seronegative patients, PUUV antigen was demonstrated, with essentially the same localization. Comparison of severity and extent of the lesions in the seropositive group with those of these two patients showed no significant differences between tubular and interstitial abnormalities. These findings indicate that the demonstration of certain histopathological alterations and the detection of viral antigen by immunoperoxidase techniques in kidney biopsies, may be useful as additional tools for the diagnosis of PUUV infection.