A delayed type hypersensitivity (DTH) skin reaction to hepatitis B surface antigen (HBsAg) and intradermal hepatitis...

The significance of a delayed type hypersensitivity skin reaction to hepatitis B surface antigen (HBsAg) (HBs-DTH) in type B viral hepatitis (VHB) and in intradermal hepatitis B (HB) vaccination is reviewed. HBs-DTH could be developed by the intradermal injection of HB vaccine in anti-HBs positive people and also in persons immunized with HB vaccine. Thus, HBs-DTH could serve as a useful marker for the acquisition of an active Th1 type immunoreactivity to HBsAg. HBs-DTH was absent in patients with chronic VHB. In contrast, HBs-DTH developed early in the convalescent phase of the acute VHB, whereas the production of anti-HBs was significantly delayed, thus suggesting that HBs-DTH may be involved in the recovery mechanisms of acute VHB. Intradermal HB vaccination is useful not only in lowering the cost, but also in the rapid development of anti-HBs, reversing non-responsiveness, improving postexposure prophylaxis and in immunizing immunosuppressed people. A similar vaccination strategy should prove to be useful in prevention and control of not only other infectious diseases but also malignant neoplasms.