In response to the valuable views ofyourcorrespondent, we have the following comments:
1. The higher frequency ofHBV and HCV seromarkers in controls as compared with health care workers (HCW) was indeed a surprising finding for us,as tests were performed by the same set of workers of the same time. Although our controls were not strictly matched, they were all prospective blood donors drawn fmm the same community. While careful history was elicited, it is possible that some high risk groups i.e., professional donors, might have crept in to introduce a bias in a relatively small saipple. However, the point we wish to highlight is that taking the community as a whole, multiple, yet ill defined sources of infection are probably more frequent than the direct blood contact as in the care of HCW’s. However, the need for more work with possible use of other confirmatory tests such as HCV-RNA is stressed.
2. The lack of detection of anti-HBc inHBsAg positive patients is certainly unusual but still possible as shown in a study quoted by Hoofnagle and Di Bisceglie1. In our experience, a classical response to HBV infection is not always observed. In one of our recent studies2 on seromarkers in patients with past or chronic HBV infection, anti-HBc was detected in 74%. A majority of HBe Ag negative patients did not elicit anti-HBe response and anti HBs was negative in 40% of those negative for HBV antigens. The reasons may be multiple, such as low titre, altered immune response, technical reasons etc.
3. The positivity forHbeAg in the absence ofotherHBV markers cannot be explained under the present state of knowledge. We observed this finding in two different studies done two years apart. This suggest the possibility of false positivity which needs to be documented.
Khalil Ur Rehman
Allama Iqbal Medical College, Lahore.
1. Hoofnagle, JR and Di Bisceglie, AM. Serodiagnosis of acute and chronic viral hepatitis. Seminars in liverdisease, Rothschild, MA.. Vol. II. New York, Thieme Medical Publisher, 1991,73-83.
2. Haider, Z., Khan, A.A., Rehman, KU. et al. Seromarkers for chronic and past hepatitis B virus infection in patients with acute hepatitis due to non B Hepatitis viruses (In Press).