A 34-year-old accountant returns home after a trip to Calcutta, complaining of malaise, fatigue, and loss of appetite. Three months after initial diagnosis, the results of serological tests reveal: HBcAb, positive; HBeAb, positive; HBeAg, negative; HBsAg, negative; HBsAb, negative. The absence of HBsAg and HBsAb from the serum of this patient is reflective of which of the following?
Correct Answer: The patient is in the equivalence zone of antibody production
Description: The patient has clearly returned from Calcutta with an active infection of Hepatitis B, since his serum is positive for antibody against the core antigen of Hepatitis B. This is the standard diagnostic for this infection. The absence of HBsAg and HBsAb from the serum reflects that the patient has entered the "window period," a good prognostic indicator, because it demonstrates that antibodies to the surface antigen are being made in enough concentration to precipitate the corresponding antigen out of the circulation. This is the in vivo demonstration of the equivalence zone in the antibody/antigen precipitation titration. Successful vaccination against Hepatitis B would be reflected by a positive titer of HBsAb only. The presence of antibody against the c core antigen reflects the existence of an active infection. Anergy to Hepatitis B is not correct, because a person who is anergic is selectively unresponsive or tolerant to the antigen in question. Clearly, the presence of antibodies to several of these viral antigens in the serum demonstrates that the person is not anergic. Although the person is beginning to mount a protective immune response (antibody to HBsAg), it has not yet reached a protective level. Ref: Ray C.G., Ryan K.J. (2010). Chapter 13. Hepatitis Viruses. In C.G. Ray, K.J. Ryan (Eds), Sherris Medical Microbiology, 5e.
Category:
Microbiology
Get More
Subject Mock Tests
Practice with over 200,000 questions from various medical subjects and improve your knowledge.
Attempt a mock test nowMock Exam
Take an exam with 100 random questions selected from all subjects to test your knowledge.
Coming SoonGet More
Subject Mock Tests
Try practicing mock tests with over 200,000 questions from various medical subjects.
Attempt a mock test now