Enhanced monocyte generation of reactive oxygen species in primary systemic vasculitis.
OBJECTIVE
Little is known about the role of mononuclear phagocytes in systemic vasculitis. We examined the hypothesis that monocytes from patients with primary systemic vasculitis have increased capacity to generate reactive oxygen species.


METHODS
We studied patients with primary systemic vasculitis (n = 24) and compared them with patients with autoimmune related vasculitis (20), peripheral vascular disease (12), and postrenal transplantation (8). Healthy controls were also studied (56). Peripheral blood monocytes were stimulated using phorbol myristate acetate (PMA). We measured the generation of superoxide by cytochrome c reduction and myeloperoxidase (MPO) dependent products using peak luminol chemiluminescence.


RESULTS
Patients with primary systemic vasculitis generated significantly more superoxide than all 3 non-vasculitis groups. Superoxide generation in the autoimmune vasculitis group was also higher than other groups but failed to reach significance versus controls (p = 0.07). Generation of MPO dependent products was also significantly higher in patients with primary vasculitis compared to all other groups. Subgroup analysis within the primary vasculitis group showed no correlation of these findings with disease activity, antineutrophil cytoplasmic antibodies, or American College of Rheumatology classification.


CONCLUSIONS
Mononuclear phagocytes act as a source of reactive oxygen species in primary systemic vasculitis. Further study is required to determine if the reactive oxygen species generated act as a mechanism to promote vessel wall injury, or healing in this condition.
Bruce
I
I
Department of Rheumatology, Musgrave Park Hospital, School of Clinical Medicine, The Queen's University of Belfast, UK.
McNally
J
J
Bell
A
A
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019268:Antibodies, Antineutrophil Cytoplasmic / Q000097:blood; D001327:Autoimmune Diseases / Q000276:immunology / Q000378:metabolism / Q000473:pathology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009000:Monocytes / Q000201:enzymology* / Q000276:immunology; D009336:Necrosis; D009195:Peroxidase / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism*; D016897:Respiratory Burst; D014657:Vasculitis / Q000276:immunology* / Q000378:metabolism* / Q000473:pathology
D019268:Antibodies, Antineutrophil Cytoplasmic; D017382:Reactive Oxygen Species; D009195:Peroxidase