In 122 patients with the haemolytic uraemic syndrome (HUS), serum proteins were analysed in the acute phase of the disease (n = 122) and 6 weeks (n = 57) and 6 months (n = 84) later. Total serum protein levels were significantly lower on admission than 6 weeks and 6 months later (P < 0.0001). The same was true for median values of serum albumin (P < 0.0001), alpha(2)-globulins (P < 0.0001) and gamma-globulins (P < 0.001). There was no difference in beta-globulins, whereas the alpha(1)-globulins were significantly higher in the acute phase (P < 0.0001). There was a significant positive correlation between age and total protein and gamma-globulin levels. Serum total protein and albumin levels displayed a significant positive correlation with serum sodium levels and a significant negative correlation with urinary protein excretion. Patients with oligoanuria had significantly lower serum albumin and significantly higher alpha(1)-globulin levels than those with preserved urine production. Marked differences were observed between patients with (D+) and patients without (D-) prodromal diarrhoea. In D(-) HUS, only albumin and total protein levels were lower on admission, but to a lesser degree than in D(+) HUS. Serum (1)-globulin levels were significantly higher and alpha(2)-globulin levels significantly lower in D(+) HUS than D(-) HUS. In the D(+) subgroup of patients, by far the largest, there was a significant positive correlation between serum albumin and total protein on the one hand and the duration of the prodrome on the other. Patients with bloody stools had significantly lower serum albumin and total protein levels than those without. Faecal alpha(1)-antitrypsin concentration measured in 12 HUS patients on admission was found to be significantly increased compared with age-matched controls. This study confirms the existence of hypoproteinaemia in childhood HUS and indicates that intestinal protein loss is an important, albeit not the only, physiopathological mechanism.
