Pulmonary aspergillosis in patients with leukaemia.

appearance of anti-HBc IgM antibody. Larger studies indeed confirm that "e" antigen to "e" antibody seroconversion occurs one to two months after the onset of symptoms, when acute HBV infection resolves'; the disappearance of anti-HBc IgM antibody (even when assayed in a 1/1000 serum dilution) occurs only three to four months after this event.23 Assay of "e" antigen and "e" antibody responses therefore permits earlier confirmation of the diagnosis of acute HBV infection than does assay of anti-HBc IgM antibody responses. Assay of anti-HBc IgM antibody therefore has a major role in the diagnosis of acute hepatitis B only when hepatitis B surface antigen is absent from the serum.' In surface antigen positive cases the diagnosis is best made by detection of "e" antigen to "e" antibody seroconversion in serial serum specimens. DJ MORRIS North Manchester Regional Virus Laboratory, Booth Hall Children's Hospital, Charlestown Road, Manchester M9 2AA