(A) Direct in situ RT-PCR to amplify 5′-NC region of HCV genome in CD34⁺ cells. Note the complete absence of reaction in an adjoining cell. Immunocytochemistry to detect core (B) and E2/NS1 (C) antigens in CD34⁺ cells. In both cases a cytoplasmic appearance of immune reactants was found. Note adhesion of the core antigen to the nuclear membrane and accumulation of E2/NS1 antigen in cytoplasmic submembrane spaces. In (D) core reactivity was blocked by preadsorption of antibody with recombinant HCV core antigen. (E) Staining of CD34⁺ cells with FITC-conjugated anti-E2/NS1 protein. Specific signal outlining nonfluorescent nuclei is demonstrated. (F) The same cell as described in (E) was shown to coexpress CD34 antigen, stained with PE-labeled antibody.