EVOLUTION OF HAPTOGLOBIN CONCENTRATION IN SERUM DURING THE EARLY PHASE OF ACUTE MYOCARDIAL-INFARCTION

Haptoglobin (Hp) is a haemoglobin-binding acute phase protein with thr ee genetic types: Hp 1-1, Hp 2-1, Hp 2-2. We investigated 45 patients during the first 48 hours of acute myocardial infarction, and studied determinant factors and clinical correlates. Upon hospital admission, serum haptoglobin concentration was increased (1.95 +/- 0.94 g/l, mean +/- SD, P < 0.001) versus the reference population (0.97 +/- 0.46 g/l , n = 107), independent of haptoglobin type: 1.84 +/- 0.64 g/l (Hp 1-1 , n = 11) (P < 0.01), 1.98 +/- 0.79 g/l (Hp 2-1, n = 25) (P < 0.001), 1.98 +/- 1.58 g/l (Hp 2-2, n = 9) (P < 0.001). Moreover, during the fi rst hours of hospitalization, a temporal lowering of haptoglobin was o bserved suggesting acute haemolysis, independent of the haptoglobin ty pe. Minimal serum haptoglobin was reached 9.6 +/- 5.8 hours after admi ssion. The amplitude of the haptoglobin decrease correlated with initi al serum haptoglobin (r = 0.78) and was more pronounced (P < 0.05) in men (0.53 +/- 0.57 gill than in women (0.18 +/- 0.17 g/l). Decrease of serum haptoglobin did not correlate with infarct size (based on creat ine kinase-MB release). Out of the other acute phase proteins measured upon admission, only C-reactive protein was significantly increased ( P < 0.05). During the next 36 hours, haptoglobin increased as a result of the acute phase response to myocardial injury. Our findings sugges t that acute myocardial infarction is also preceded by an acute phase response, characterized by an initial high haptoglobin and followed by a temporal haptoglobin decrease due to haemolysis.