Quantitative determinations of immunoglobulins and complement components in human aortic atherosclerotic wall

Saline and acid eluates of intima with only fatty streaks, fibrous plaque and intima surrounding the fibrous plaque were obtained from 42 human aortae. IgG, IgA, IgM, C1q, C3c, C4, C9, C3A, C-reactive protein, alpha-1-antitrypsin, alpha-2-macroglobulin, albumin, transferrin and fibrinogen were quantitatively determined in these eluates using the radial immunodiffusion technique. Saline extracted IgG and IgA were significantly higher in the fibrous plaque and adjacent tissue than in the fatty streak intima, where IgM was the highest. IgG and IgA were only present in acid eluates. The complement components were present in all saline eluates, but only traces of C3c and C1q in some acid eluates. Statistically significant differences were found for C1q and C9. C-reactive protein was present in 23 samples. The results could suggest an involvement of immune mechanisms in the progression of the atherosclerotic lesion.