[Levels of serum interleukin-15 and the expression of T-helper lymphocyte subsets in peripheral blood of children with juvenile rheumatoid arthritis].
OBJECTIVE
To study the changes of serum interleukin-15 (IL-15) levels and the expression of CD4(+)T (T-helper lymphocyte) subsets CD4(+)CD45RA(+) and CD4(+)CD45RO(+) in peripheral blood of children with juvenile rheumatoid arthritis (JRA).


METHODS
The serum concentration of IL-15 was detected using ELISA in 39 children with JRA. The expressions of CD4(+)CD45RA(+)T and CD4(+)CD45RO(+)T in peripheral blood were detected by flow cytometry in 24 out of the 39 patients with JRA. Twenty-six age and sex-matched healthy children were used as the Control group.


RESULTS
The mean serum IL-15 level in JRA patients was significantly higher than that in controls (1.37 +/- 0.98 pg/mL vs 0.96 +/- 0.41 pg/mL, P <0.05). Among the 39 JRA patients, the serum IL-15 level in 17 patients with systemic JRA increased remarkably (P < 0.01), but not in patients with the other two types of JRA, the oligoarthritis and polyarthritis (n=13, n=9, respectively), compared with that in controls. The mean serum IL-15 level of the JRA patients was significantly reduced after conventional treatment (P < 0.01). The serum IL-15 level in JRA patients positively correlated with white blood cell count (r=0.347, P <0.05) and C reactive protein (r=0.452, P < 0.01) but not with the erythrocyte sedimentation rate. The patients with high serum IL-15 levels (> or = medium level 1.73 pg/mL) had higher expression of CD4(+)CD45RO(+)T than those with low serum IL-15 levels (< medium level) (16.29 +/- 5.46% vs 11.75 +/- 3.15 %, P < 0.05).


CONCLUSIONS
The serum IL-15 levels in JRA patients increased significantly. An increased IL-15 level can transform CD45RA into CD45RO in peripheral blood of patients with JRA, and then result in T lymphocyte activation and mediate the immunopathological impairment. IL-15 may be used a marker for the evaluation of severity of JRA.
Cao
Lan-Fang
LF
Department of Pediatrics, Renji Hospital, Shanghai Second Medical University, Shanghai 200001, China. clf530417@yahoo.com.cn
Lu
Yan-Ming
YM
Ma
Min
M
Xue
Hai-Yan
HY
Zhao
Yu
Y
Yu
Han-Qing
HQ
Mao
Hai-Ying
HY
Gu
Yue-Ying
YY
D000293:Adolescent; D001171:Arthritis, Juvenile / Q000276:immunology*; D015704:CD4 Antigens / Q000032:analysis*; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D019409:Interleukin-15 / Q000097:blood*; D017493:Leukocyte Common Antigens / Q000032:analysis*; D008297:Male; D006377:T-Lymphocytes, Helper-Inducer / Q000276:immunology*
D015704:CD4 Antigens; D019409:Interleukin-15; D017493:Leukocyte Common Antigens