ABSTRACT
Objective: To investigate the abnormalities in early morning serum melatonin among patients with juvenile rheumatoid arthritis [JRA] and to outline its relation to disease activity and severity
Methodology: Twenty one patients with IRA and twenty health age and sex matched controls were enrolled in the study. Fifteen patients had polyarticular JRA, 3 had oligoarticular JRA and 3 had systemic onset JRA. Evaluation was carried out clinically, functionally and radiologically by using disease activity score, Juvenile Arthritis Functional Assessment Report for Children [JAFAR-C score] and modified Larsen score respectively. Laboratory investigations included CBC, ESR, CRP, classic IgM RF [latex agglutination], ANA [indirect imniunofluorescence] and melatonin estimation by Enzyme Linked Immunosorbent Assay [ ELISA]
Results: The serum levels of melatonin were significantly increased in JRA patients [13.9 +/- 8 pg/ml] as compared to healthy controls [8.1 +/- 2.7 pg/ml] [p<0.01]. A significant positive correlation could link serum melatonin levels to disease activity scores and ESR [r = 0.91, p<0.001 and r = 0.55, p < 0.01 respectively]. No significant correlation was found between melatonin and either Larsen or JAFAR scores [r = 0.19, p>0.05, r = 0.15, p>0.05 respectively]. According to melatonin levels, there was 2 groups of patients: group I with elevated melatonin level [more than 11 pg/ml] [n = 15] and group 2 with normal melatonin level [less than 11 pg/ml] [n = 6]. Patients with elevated melatonin levels had higher ESR [p<0.05], higher disease activity scores [p<0.01] and Larsen scores [p<0.05], than the group of patients with normal serum melatonin. The results of GAFAR scores were comparable between the two groups [p>0.05]
Conclusion: The elevated melatonin levels among JRA patients with active synovitis and its close relation to disease activity rather than disease severity suggests that melatonin may play a promoting role in rheumatoid arthritis. Hence, inhibition of its synthesis and/or action by specific antagonists may be of therapeutic value. Serum Melatonin in Juvenile Rheumatoid Arthritis: Correlation with Disease Activity