Evidence of impaired polymorphonuclear leucocyte phagocytic functions and chemiluminescence response in rheumatoid arthritis

Summary In this study, the phagocytic uptake of ³H-thymidine-labelled Staphylococcus aureus and bacterial killing (Bk) by polymorphonuclear leucocytes (PMN) from patients with rheumatoids arthritis (RA) were investigated and compared to the luminol-enhanced chemiluminescence response (LCL) to phorbolmyristic acetate (PMA), a receptor and second message-independent activator of respiratory burst activity in definite or classical rheumatoid arthritis (RA), with regard to the inflammatory activity of the disease process, and compared to patients with osteoarthritis (OA) and healthy controls. PMN of RA patients showed a significant reduction in uptake (57.8±4.4%) and less Bk capacity (27.3±4.2%) compared to OA patients (uptake 71.4±4.3%, Bk 20.6±2.9%; P<0.001) and controls (uptake 73.2±5.2%, Bk19.3±4.2%;P<0.001). In contrast, PMN LCL response was markedly enhanced in RA patients compared to OA patients (P<0.001) and controls (P<0.001). There was no significant influence of inflammatory activity on various PMN functions in RA and no difference was found between OA and control subjects. These data clearly demonstrated impaired PMN phagocytic functions (uptake, Bk) and enhanced LCL in RA, suggesting priming and/or activated peripheral blood PMN, which might be of clinical importance concerning altered host defence in these patients.