Catabolism of haemoglobin-haptoglobin complexes in haemolytic uraemia-like syndromes of different etiologies.

The catabolism of haemoglobin-haptoglobin complexes was studied in four patients with increased vascular haemolysis as part of acute or subacute haemolytic uraemic syndromes. The apparent volumic substance elimination rates for haemoglobin (Fe) bound to haptoglobin in plasma were 1.1 mumol/h/l and 2.9 mumol/h/l in two patients suffering from sublimate and hydrochloric acid poisoning, respectively. This is estimated to correspond to a normal catabolism, when the increased haptoglobin synthesis is taken into account. In the other two patients suffering from serum-sickness there was reduced clearance and thereby an accumulation of haemoglobin-haptoglobin complexes in plasma during penicillin administration. When the offending drug was withdrawn the plasma concentration of haemoglobin bound to haptoglobin remained high for about three days and then fell rapidly (approximately with 3.8 mumol/l/h and 1.9 mumol/l/h). Thus, also in these patients the clearance capacity could be normalized after discontinuation of the drug.