Severe pancytopenia triggered by recombinant hepatitis B vaccine

We describe the case of a teenager who developed fever, arthritis, cutaneou s vasculitis and severe pancytopenia 3 weeks after the third vaccination bo ost with a recombinant hepatitis B vaccine. Bone marrow examination showed paucity of late myeloid elements and, subsequently, maturation arrest. Inte rferon-gamma (IFN-gamma) production by peripheral blood mononuclear cells f rom the patient was dramatically increased, An underlying immune predisposi tion (HLA-DR3) may have indirectly enabled the vaccine to trigger a hepatit is B virus-specific cytotoxic T-lymphocyte response. It is therefore possib le that the pancytopenia was induced by a dysregulation of the CD8(+) T-cel l compartment via increased IFN-gamma production.