PTX3 expression confined to macrophages in irradiated versus non-irradiated arteries. Positive staining of PTX3 (red fluorescence) superimposed with cell specific marker CD68 (green fluorescence) indicated that PTX3 co-localizes with CD68/macrophages in irradiated arteries compared to non-irradiated arteries (controls), both from the same patient. Nuclear staining (blue fluorescence) was made with DAPI (C + F). A-C = irradiated vessels. D-F = non-irradiated vessel.