Phospholipase A2 in juvenile rheumatoid arthritis: correlation to disease type and activity
Pruzanski, W.; Albin-Cook, K.; Laxer, R.M.; MacMillan, J.; Stefanski, E.; Vadas, P.; Silverman, E.D.
Journal of Rheumatology 21(10): 1951-1954
1994
ISSN/ISBN: 0315-162X PMID: 7837165 Document Number: 436575
Objective: Secretory nonpancreatic phospholipase A-2 (snpPLA-2) is a proinflammatory enzyme and its activity in serum correlates with disease activity in adults with rheumatoid arthritis. Juvenile rheumatoid arthritis (JRA) may be stratified into 3 clinical types with differing degrees of disease activity. Since in JRA there are no reliable indices of disease activity, our objective was to find whether the level of circulating snpPLA-2 correlates with the severity of inflammation and with JRA activity. Methods: PLA-2 enzymatic activity was assayed using E. coli membranes labelled with (14C)-oleic acid. SnpPLA-2 immunoreactivity was tested by ELISA technique using monoclonal antibodies against recombinant human (rh) snpPLA2-2. SnpPLA-2 activity was determined in sera of 127 children including 25 with systemic (S-JRA), 50 with polyarticular (Po-JRA) and 52 with pauciarticular (Pa-JRA) types of JRA. Twenty-five patients with active disease, were subsequently restudied in an inactive phase. Results: Markedly increased snpPLA-2 ( gt mean + 2 SD of normal mean, i.e., gt 575 U/ml) was found during the active disease in 100% S-JRA, 57% Po-JRA and 25% Pa-JRA patients. The differences in the mean and median PLA-2 activity among these 3 subtypes of JRA were highly significant (p lt 0.001) with the highest levels found in S-JRA and the lowest in Pa-JRA. Presence of rheumatoid factor and/or of antinuclear antibody had no relation to the level of snpPLA-2. SnpPLA-2 activity became markedly lower when active inflammation became quiescent. In the whole group' snpPLA-2 activity correlated highly with the Lansbury index, number of involved joints and number of effusions. A significant positive correlation was also found between snpPLA, and erythrocyte sedimentation rate (ESR) and neutrophil count, while a significant negative correlation was noted with the level of albumin and hemoglobin. With the exception of snpPLA-2, other laboratory variables did not correlate with the number of effusions or the number of active joints. However a negative correlation was noted between both hemoglobin and albumin, and Lansbury index. Conclusion: Circulating snpPLA-2 significantly correlates with JRA activity and may serve as an index of activity in JRA especially in patients with systemic type of disease.