Cytospin specimens of PBMCs and exfoliated oropharyngeal cells from a human affected by IM. Isotopic EBER ISH (silver grains) was combined with immunocytochemistry (red membrane staining). (A) Two EBER- positive peripheral blood lymphocytes (arrows) expressing the CD45RA antigen detected by MoAb Ki-B3. Original magnification × 630. (B) A single EBER-positive peripheral B lymphocyte (arrow) expressing the CD20 antigen (MoAb L26) and two EBER-positive PBMCs lacking CD20 expression. Original magnification × 250. (C and D) Simultaneous labeling for EBER and CD45RA shows single EBV-infected lymphocytes (arrows) among multiple unlabeled epithelial cells characterized by their broad cytoplasm. Original magnification × 630.