Differential expression of function-related antigens on blood monocytes in children with Hemolytic Uremic Syndrome

FERNANDEZ, GC; RAMOS, MV; GOMEZ, SA; DRAN, GI; EXENI, R; ALDUNCIN, M; GRIMOLDI, I; VALLEJO, G; ELIASCOSTA, C; ISTURIZ, MA; PALERMO, MS

JOURNAL OF LEUKOCYTE BIOLOGY

Society for Leukocyte Biology

Lugar: USA; Año: 2005 vol. 78 p. 853 - 861

0741-5400

Monocytes (Mo) mediate central functions in inflammation and immunity. Different subpopulations of Mo, with distinct phenotype and functional properties, have been described. Here, we investigate the phenotype and function of peripheral Mo from children with Hemolytic Uremic Syndrome (HUS). For this purpose, blood samples from patients in the acute period of HUS (HUS AP) were obtained on admission, before dialysis and/or transfusion. The Mo phenotypic characterization was performed on whole blood by flow cytometry and markers associated to biological functions were selected: CD14 accounting for LPS responsiveness, CD11b for adhesion, FcgRI/CD64 for phagocytosis and cytotoxicity, and HLA-DR for antigen-presentation. Some of these functions were also determined. Moreover, the percentage of CD14+ CD16+ Mo was evaluated. We found that the whole HUS AP Mo population exhibited reduced CD14, CD64 and CD11b expression, and decreased LPS-induced TNF production and Fcg-dependent cytotoxicity. HUS AP showed an increased percentage of CD14+ CD16+ Mo, with higher CD16 and lower CD14 levels compared to the same subset from healthy children. Moreover, the CD14++ CD16- Mo subpopulation of HUS AP had a decreased HLA-DR expression that correlated with severity. In conclusion, the Mo population from HUS AP patients presents phenotypic and functional alterations. The contribution to the pathogenesis and the possible scenarios that led to these changes are discussed.