Leukocyte microbicidal activity assessed by chemiluminescence in elderly non-insulin dependent diabetes mellitus

Leukocyte dysfunction may contribute to infection in the elderly diabetic. Leukocyte oxidative metabolism assessed by chemiluminescence, correlates with microbicidal activity, and may be impaired with hyperglycaemia and ageing. The leukocyte chemiluminescence response to zymosan +/- luminol was assessed in 12 healthy controls (3M, 9F), aged 69 +/- 5 (mean +/- SD) years and in 23 non-insulin dependent diabetics, aged 68 +/- 5 years, before and after improving glycaemic control with sulphonylureas, when the glycosylated haemoglobin fell from 11.2 +/- 2.3 to 7.9 +/- 1.4% (p less than 0.001). The onset of maximal chemiluminescence with zymosan was similar in controls and diabetics, although the actual counts after improved glycaemic control were less in diabetic patients at all time points than initially (p range less than 0.025-less than 0.001) or when compared to the controls (p range less than 0.05-less than 0.005). Following luminal enhancement the onset and magnitude of maximum chemiluminescence was similar in all groups although an increase early response was observed in diabetics initially. We suggest that sulphonylureas may modify chemiluminescence by suppressing superoxide radical generation. Hyperglycaemic elderly non-insulin dependent diabetics may have subtle disturbances of the leukocyte oxidative burst but in general behave in a similar fashion to healthy elderly controls.