Monitoring of polymorphonuclear leukocyte functions in diabetes mellitus— a comparative study of conventional radiometric function tests and low‐light imaging systems

Abstract

In this study neutrophil (PMN) phagocytic capacity was investigated using a conventional radiometric ingestion assay (IN) in comparison with PMN respiratory burst activity assessed by luminol‐enhanced chemiluminescence (LCL) in response to phorbolesters and LCL induction during phagocytosis of opsonized Staphylococous aureus (STLCL) in diabetes mellitus and healthy controls. PMN ingestion was measured with ³H‐thymidine‐labelled S. aureus in a kinetic radiometric assay. LCL and STLCL were assessed in a parallel detecting microtitre‐plate luminometer (MTP‐Reader). PMN of diabetic subjects showed a highly significant reduction of peak LCL in response to PMA as well as during phagocytosis of S. aureus (STLCL) compared to non‐diabetic controls (ppin vitro data displayed impaired PMN oxidative burst activity at glucose concentrations ⩾ 13.8mmol/L, whereas PMN IN was significantly reduced at glucose levels ⩾27.75mmol/L. The control group showed a positive correlation of peak LCL response and IN (pex vivo and in vitro as measured by LCL and by ingestion of ³H‐thymidine‐labelled S. aureus suggesting inhibitory effects of elevated glucose concentrations on various PMN‐functions, which might be of clinical importance concerning altered host defence.