Abstract:
Unresponsiveness to hepatitis B surface antigen (HBsAg) has been shown to be associated with dysfunction of the presenting cells (APC) and defect in the specific B-lymphocyte and/or T-lymphocyte repertoires. Direct determination of the frequency of specific T-lymphocytes together with complementary analysis of the naive circulating immune cells could provide valuable information about the cellular basis of unresponsiveness to HBsAg. In this study, the phenotypic characteristics of peripheral blood mononuclear cells (PBMC) from healthy adult high-responders (n = 19), intermediate-responders (n = 11), low-responders (n = 9) and non-responders (n = 6) to recombinant hepatitis B vaccine were investigated and compared. The proportions of circulating B-lymphocytes (CD19+ cells), T-lymphocytes (CD3+ cells) and monocytes (CD14+) were similar in all groups of responder individuals (14%, 55-60% and 11-13%, respectively) compared to non-responders (16%, 64% and 9%, respectively). These results suggest that the cellular basis for the lack of response to HBsAg is not associated to a generalized deficiency of immune cells in the non-responder subjects, rather it may reflect a defect in HBsAg-specific B or T cells.