Is the level of C reactive protein (CRP), so widely discussed as a cardiac marker, increased by chronic inflammatory conditions, such as chronic prostatitis, periodontal disease, or chronic synovitis?
—Robert Frank, MD, Forest Hills, N.Y.
CRP, like serum amyloid A (SAA), is known as an acute phase protein. By definition, acute phase proteins exhibit a change in plasma concentration of at least 25% during most inflammatory states and are thus useful as a marker of inflammation, albeit a nonspecific one.
These changes are thought to result largely from hepatic production triggered by cytokines, such as tumor necrosis factor-α and interleukin-6. Despite the terminology, the “acute phase” response occurs with both acute and chronic inflammatory states, including the chronic inflammatory conditions mentioned by Dr. Frank. In the case of chronic prostatitis, some older studies in the urologic literature suggest that CRP levels in the semen may be a better marker than levels in the plasma (Andrologia. 1983;15:151-154).
—Daniel G. Tobin, MD (113-17)