Poor responses to recombinant HBV vaccination in patients with HIV infection.

ABSTRACT

The study was conducted with an aim to assess the efficacy of recombinant HBV vaccination in untreated HBV seronegative HIV/AIDS subjects as compared to normal controls. The second objective was to identify differences in CD4 and CD8 T cell numbers/kinetics/functions and levels of TH2 cytokines (IL4 and IL10) in different groups during the three-dose vaccination regimen. 40 HIV/AIDS patients were subdivided into groups 1A where patients had a high CD4 (> 200/mm3) count and IB where patients had a low CD4 (< 200/mm3) count. Twenty normal healthy control subjects were also recruited in the study (group II). Patients received 40 micro and controls received 20 micro of recombinant HBV vaccine in each dose. All subjects received 3 doses of the vaccine. Detection of CD4 and CD8 cells was done by flowcytometry. TH2 type of cytokines IL4 and IL10 were estimated in the culture supernatant of PHA stimulated leukocyte rich plasma by sandwich ELISA. Anti-HBs levels were estimated in the serum by ELISA. Anti-HBs response was severely compromised in patients as compared to controls. Groups II, 1A and 1B showed titers of 16906 +/- 21303, 8834 +/- 14136 and 462 +/- 814 m/U/m/ respectively. Both CD4 and CD8 cells increased significantly after vaccination in all the groups irrespective of the disease status. On the other hand, IL4/IL10 responses to PHA stimulation in the HIV-positive groups were much lower than in controls (P< 0.1). Despite a double dose of vaccine in patients, the antibody response was significantly lower which correlated with a lower CD4 count. Cytokines IL4 and IL10 which regulate antibody response, were also lower in-patients and this together with a low CD4 count possibly accounted for the low anti-HBs levels. All patients with high CD4 lymphocyte count were responders while only 47% of patients with low CD4 lymphocyte count responded to immunization. Patients with a CD4 count of less than 50 failed to respond. Thus early immunization is advocated in all HIV patients at a stage when they are still capable of mounting an adequate immune response.