Elevated serum elastase and alpha-1-antitrypsin levels in hemolytic uremic syndrome.

Clinical observations and experimental studies have pointed to a role for leukocytes in the pathogenesis of the typical or epidemic form of the hemolytic uremic syndrome. As a result of these observations we measured serum elastase levels and the levels of two protease inhibitors, alpha-1-antitrypsin and alpha-2-macroglobulin in 12 patients with this syndrome. The serum elastase levels were significantly elevated in patients compared with normal individuals (421 +/- 278 vs 91 +/- 27 mg/dl, p less than 0.005) and patients with renal diseases not caused by hemolytic uremic syndrome (191 +/- 254 mg/dl, p less than 0.025). The serum alpha-1-antitrypsin levels were also significantly elevated: hemolytic uremic syndrome vs normals (774 +/- 260 vs 285 +/- 98 ng/ml, p less than 0.0001); and in hemolytic syndrome compared with patients with renal diseases not caused by hemolytic uremic syndrome (774 +/- 260 vs 335 +/- 131 ng/ml, p less than 0.0001). There were no significant differences in the alpha-2-macroglobulin levels among the three groups. There was a significant correlation between the serum elastase levels and the total white cell counts as well as between the elastase and the polymorphonuclear cell counts but not among any of these values and the serum creatinine concentrations. These results provide additional evidence favoring the possibility that leukocytes are activated in patients with hemolytic uremic syndrome.