Figure 2.

Y chromosome detection in the human small intestine. (A) Male control duodenum showing indirect immunodetection of the Y chromosome also immunostained for α smooth muscle actin (αSMA). (B) Female duodenal control showing absence of signal for the Y chromosome also immunostained for αSMA. (C–E) Human duodenal biopsies from female patients who received a bone marrow transplant from a male donor, showing myofibroblasts immunostained with αSMA and positive for the Y chromosome probe (arrows).