Correlations between CD10, CD31, and CD40 stromal expression and clinical features. (A) Immunohistochemical analysis of CD31, CD10, and CD40 expression (brown signal) on BMB of SMZL patients. The density of CD10⁺ SCs, the microvascular density, and the expression of CD40 in SMZL BM infiltrates varied consistently among different cases. Representative micrographs of SMZL BM infiltrates characterized by either low (left) or high (right) expression of the 3 markers are shown. Micrographs are relative to 6 of 66 evaluated cases. Immunohistochemistry, STREPTavidin-biotin-peroxidase complex method; original magnification ×400. (B) Double-marker immunofluorescence analysis highlighting the expression of the activation marker CD40 (green signal) by spindle-shaped or stellate BM mesenchymal elements expressing CD146 or CD271 (red signal). The micrographs are relative to a case with high (score 3) CD40 stromal expression. Immunofluorescence with Alexa-488, Alexa-568, and 4,6 diamidino-2-phenylindole fluorochromes; original magnification ×630. (C) Kaplan–Meier curves showing the time to disease progression in SMZL cases subdivided according to CD31, CD10, and CD40 stromal expression.