PHAGOCYTE RESPIRATORY BURST ACTIVITY IN PATIENTS WITH TYPE 2 DIABETES, USING PMA AND FMLP STIMULI

Diabetes is a hidden epidemic and the most common metabolic disorder in the world. Immune dysfunction (cellular and humoural) is one of the consequences of diabetes, including defects of phagocyte function, notably in chemotaxis, phagocytosis, and killing. Results of studies on phagocyte respiratory burst activity, however, have been contradictory. We studied the respiratory burst of peripheral blood neutrophils and monocytes separately in response to formyl-met-leu-phe (fmlp) and phorbol-12,13-myristate acetate (PMA). 36 patients with type 2 diabetes (mean age 53±7 years) and 20 healthy controls (mean age 50±5 years) each provided a 15ml blood sample. Peripheral blood neutrophils and monocytes were separated and purified (>95%) using specific density gradients and short-term culture. We then separately assessed respiratory burst activity in response to fmlp and PMA by the semi-quantitative nitroblue tetrazolium (NBT) test. Following stimulation with PMA, diabetic neutrophils showed reduced respiratory burst activity compared with normal neutrophils (p=0.097). Following stimulation with fmlp, too, diabetic neutrophils showed reduced respiratory burst activity compared with normal neutrophils, which this time was statistically significant (p=0.027). There was no difference between diabetic and normal subjects with regards to monocyte response to either fmlp or PMA. It appears that the diminished response and reduced effectiveness of the phagocyte system in people with diabetes can facilitate the onset, exacerbation, and persistence of infection.