Prolymphocytoid transformation in TCL1 transgenic mice lacking TIR8. (A) Histopathologic examination of spleen of TCL1^tg/tgTIR8^wt/w and TCL1^tg/tgTIR8^−/− (1 representative animal 9 months old of 6 analyzed): microscopic evaluation 40×. Small and large black arrows indicate small-size and large-size cells, respectively. (B) Histopathologic examination of extranodal localizations of TCL1^tg/tgTIR8^−/− mice (1 representative animal 9 months of 6 analyzed). Liver (i-v) and lung (vi-x) were analyzed by H&E staining or immunohistochemical stains for B220, p27 and Ki-67 as indicated. Microscopic evaluation: 40× (i,iii-vi,viii,ix, xii) and 100× (ii,vii). Small and large black arrows indicate small-size and large-size cells, respectively.