Delta infection among patients with chronic hepatitis B in the Stockholm region

The prevalence, epidemiology and consequences of delta infection were analysed in 60 patients attending the Roslagstull Hospital for Infectious Diseases, Stockholm, Sweden, between 1972 and 1982. All of the patients had biopsy-documented chronic hepatitis B. Using radioimmunoassay techniques, sera from all patients were tested for antibodies to hepatitis A virus, for hepatitis B surface antigen and the corresponding antibody, for antibodies to hepatitis B core antigen, for hepatitis B e antigen and the corresponding antibody and for antibodies to delta antigen. All 60 patients underwent a liver biopsy which was repeated in 28 patients. 32% of the patients (19/60) were found to be anti-delta positive. The majority of the anti-delta positive patients were either immigrants from non-European countries or addicts (both 9/19 or 47%). Infections with delta agent were found to have already occurred in the Stockholm region in the early 1970s. During the study period, four of the patients developed clinical and laboratory signs of acute hepatitis in association with a delta infection. Among the anti-delta positive patients, 63% (12/19) were classified as having chronic active hepatitis, with or without cirrhosis, as against 39% (16/41) of the anti-delta negative patients. Histological progression to cirrhosis was observed in two of the four anti-delta positive patients with initial chronic active or chronic persistent hepatitis.