Characterization of the hyperprocalcitoninemia of inflammatory/infectious disorders
Journal of Investigative Medicine
Patients with severe inflammatory/infectious disorders have markedly increased serum levels of precursors of the hormone calcitonin (e.g., bacterial pneumonia, aspiration pneumonitis, burns, pancreatitis, pyelonephritis, sepsis, heat stroke), frequently with prognostic significance. Elevations of these precursors are preceded and perhaps induced by increased levels of cytokines (e.g. tumor necrosis factor-α, interleukins 1 and 6). We have been defining the distribution of the calcitonin precursors in the sera of these patients using two-antibody rapid assays for procalcitonin (ProCT;∼2.5 hrs) and mature (amidated) calcitonin (mCT, ∼20 hrs), (BRAHMS, Berlin); single-antibody radioimmunoassays for the aminoterminus of ProCT (nProCT), katacalcin (KT), and the midportion of the CT molecule (total CT); and gel filtration and HPLC. Although ProCT usually elutes with a Kav of 0.2 on G-75 Sephadex, it appears to be associated with other high molecular mass species in the sera of some patients (e.g., burns and heat stroke). Mature calcitonin is not significantly elevated except in some cases of heat stroke. Within patient groups there is substantial variation in the proportions of ProCT and the CT-KT moiety, although ProCT usually is the predominant component. The levels of nProCT are also enormously elevated in these patients. Levels of hormone determined by the ProCT, nProCT, and total CT assays are very highly correlated (r >0.9, P<0.0001). In contrast, none of these assays yield hormonal levels which correlate significantly with mCT levels. Interestingly, although neuroendocrine tumors (e.g. medullary thyroid cancer and small cell lung cancer) have increased levels of mCT as well as of the precursors, the mCT usually remains within the normal range for patients having inflammatory/infectious disorders. The physiologic origin and significance of this disordered secretion remains to be determined.
Snider, R., Nylén, E., Thompson, K., Alzeer, A., & Becker, K. (1996). Characterization of the hyperprocalcitoninemia of inflammatory/infectious disorders. Journal of Investigative Medicine, 44 (1). Retrieved from https://hsrc.himmelfarb.gwu.edu/smhs_medicine_facpubs/4990