Figure 1.

In immunohistological comparison of patient (Left) and normal age-matched (Right) thymus sections, hematoxylin and eosin (H&E) staining revealed fibrous septa separating lobules of lymphoid tissue as seen in normal thymus. However, although cortex and medulla are present in the patient thymus, there is a loss of the normally distinct demarcation between the two areas. Immunohistochemical analysis clearly showed lack of expression of CD1 (second row) but normal staining for CD3 (bottom row), while control samples stained strongly for all three markers. bcl-2 expression in the normal thymus is restricted to the medulla, with few positive cells present within the cortex, whereas the patient’s sample displays a uniformly high level of bcl-2 expression (third row). (Figure is printed at 74% of original magnification.)