The study objective was to determine the relationship, if any, between the levels of arachidonic and linoleic acids in erythrocyte membrane phosphatidylcholine (PCH), serum interleukin 6 (IL-6) and TNFalpha levels and C-reactive protein (CRP) in juvenile idiopathic arthritis (JIA).
The study involved 49 children with JIA, aged 3-18 years (mean 11.3 +/- 3.9), and 29 healthy subjects. The JIA children were divided into 2 groups: group I--24 children (in exacerbation period) with mean CRP level of 15.6 mg/L +/- 13.3 and group II--25 children (in remission period--joint swelling-free) with CRP of 7.8 mg/L +/- 5.8 on average. Lipids were extracted according to a modified Folch's method. Fatty acids in erythrocyte membrane PCH were identified using gas chromatography (Hewlett-Packard 5890). The levels of IL-6 and TNFalpha were determined by ELISA, using Quantikine sets: R&D System (USA), while CRP was measured by nephelometric method on a BN II apparatus (Behring).
We found a significant decrease in the level of linoleic acid (p < 0.05) and a statistically insignificant reduction in arachidonic acid in JIA patients as compared to the controls. The decrease in linoleic acid was more pronounced in the active phase of JIA (p < 0.001. The higher serum CRP level was accompanied by a significantly elevated level of IL 6 (p < 0.05). The concentration of TNFa was elevated, but the difference had no statistical significance.
The levels of linoleic and arachidonic acids in erythrocyte PCH decreased and the concentrations of IL-6 and TNF-alpha increased in JIA children in the active phase of the disease. The differences intensified with a rise in CRP.