Μελέτη της βιοσυμβατότητας μεμβρανών αιμοκάθαρσης μέσω της κινητικής των μονοκυττάρων με κυτταρομετρία ροής (CD 14+, CD 16+) και της δοκιμασίας ελέγχου αναπνευστικής έκρηξης και φαγοκυτταρικής λειτουργίας

Abstract

Since the early observation of a transient leukopenia in the first minutes of haemodialysis (HD) by Kaplow et al in 1968, this issue has undergone extensive investigation. Ten years later, Graddock et al correlated this transient leukopenia with complement activation during HD. Since then, most studies have focused on the pathophysiology of granulocytes during HD. However, it has been recently suggested that the HD process influences monocytes as well. Peripheral blood monocytes are not a homogenous population and can be subdivided into discrete subpopulations by virtue of their surface antigen expression. A minor subset of circulating monocytes express the FcA receptor III (CD 16) together with low levels of the lipopolysaccharide (LPS ) receptor antigen (CD 14). These cells are described as the CD14+ CD16+ monocyte subpopulation. In normal health subjects CD14+ CD16+ subset accounts for about 7-10% of all circulating blood monocytes. However, during infectious or inflammatory diseases CD14+ CD16+ monocyte numbers are markedly expanded. Blood-membrane contact leads to an increased cellular activation and sequestration into the capillary bed of the lung. On the other hand, patients with chronic renal failure have increased susceptibility to various pathogens, especially to bacterial infection. This has been related to alterations in immune response and to disturbances of polymorphonuclear leukocytes (PMN) and monocytes (MO), which include chemotaxis, adherence and phagocytic and bacterial activity, especially as the consequence of blood-membrane contact. During ingestion of microorganisms, PMN generate highly reactive oxygen species with increased oxygen consumption, the so-called ‘respiratory burst’. The influence of the sequestration on the number of mature monocytes was studied by analyzing the fate of monocytes and particularly of the CD14+CD16+ subpopulation during haemodialysis (HD) treatment. The present study was aimed at examining also the effects of blood-membrane contact on PMN and MO, with two dialysis membrane groups. In particular, we studied phagocytosis activation due to contact with the dialysis membrane during extracorporeal sessions. We also evaluated respiratory burst both in PMN and MO.