Fas expression on CD4⁺ and CD8⁺ peripheral T cells from BMT recipients and their normal donors. (A and B) individual values obtained by cytofluorometric analysis. Horizontal bars indicate the median values for each group. (C) Representative histogram profiles generated from the T cells of UPN 324 showing the fluorescence obtained with an anti-Fas or irrelevant isotype matched MoAb (vertical bars).