Inappropriate responses to Mycobacterium leprae infections--C reactive protein in man and serum amyloid P in mice.

In a study of C-reactive protein (CRP) levels in the sera of 77 patients with leprosy, it was found that in the majority of newly diagnosed patients, the level was within the normal range for a healthy Malaysian population. Elevated levels did occur, but were usually found in patients with complications, and were more likely to occur in patients who had been receiving drug treatment for some time. This suggested that Mycobacterium leprae infection by itself does not stimulate CRP synthesis and could reflect a failure of synthesis by macrophages of interleukin-1, or related molecules. This was supported by the study of an analogous acute phase protein, serum amyloid P (SAP) in mice bearing M. leprae from human sources in their hind footpads. Such mice showed no significant difference in SAP levels from control mice.