Activation of the alternative pathway of complement during the acute phase of typical hemolytic uremic syndrome

FERRARIS J R; FERRARIS V; ACQUIER A B; SORROCHE P; SAEZ M S; GINACA A; MENDEZ C F

CLINICAL AND EXPERIMENTAL IMMUNOLOGY

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Oxford; Año: 2015 vol. 181 p. 118 - 125

0009-9104

The Hemolytic Uremic Syndrome (HUS) is characterized by hemolytic anemia, thrombocytopenia and acute renal failure. We studied the activation state of classical and alternative pathways of complement during the acute phase of Shiga toxin-associated HUS by performing a prospective study of 18 patients and 17 age-matched healthy controls to evaluate C3, C3c, C4, C4d, Bb, and SC5b-9 levels. SC5b-9 levels were significantly increased in all patients at admission as compared to healthy and to end-stage renal disease controls but were significantly higher in patients presenting with oliguria as compared to those with preserved diuresis. C3 and C4 levels were significantly elevated at admission in the non-oliguric group when compared to controls. No significant differences were found for C4d values, whereas factor Bb was elevated in all patients and significantly higher in oliguric patients when compared to both controls and non-oliguric individuals. A positive and significant association was detected when Bb formation was plotted as a function of plasma SC5b-9 at admission. Bb levels declined rapidly during the first week, with values not significantly different from controls by days 3 and 5 for non-oligurics and oligurics, respectively. Our data demonstrates the activation of the alternative pathway of complement during the acute phase of Stx-associated HUS. This finding suggests that complement activation may represent an important trigger for the cell damage that occurs during the syndrome.