C-reactive protein immunohistochemical localization in normal and atherosclerotic human aortas.

We examined immunohistochemically 104 formaldehyde-fixed, paraffin-embedded, human autopsy aortic specimens for C-reactive protein (CRP) presence and localization. In addition, we correlated immunoreactivity with a spectrum of the following histologic categories: normal aorta, fatty streak, atheromatous plaque, and fibrous plaque. Using appropriate controls, we confirmed CRP immunoreactivity in 3.3% of normal specimens, 75% of fatty streaks, 90.2% of atheromatous plaques, and 64.6% of fibrous plaques. Immunoreactivity in fatty streaks was located around collections of foam cells. Immunoreactivity in atheromatous plaques was in a bandlike distribution corresponding to the pale-staining insudative zone frequently seen in such lesions. The correlation and localization of CRP immunoreactivity in atherosclerotic lesions presented here suggests a functional role for CRP in the pathogenesis of atherosclerosis. Our results encourage efforts to determine more precisely the physiologic contributions of CRP to the development and exacerbation of atherosclerosis.