Detection of anticardiolipin and antinuclear antibodies in juvenile idiopathic arthritis and their relation to disease activity

ABSTRACT

Juvenile Idiopathic Arthritis [JIA] is an autoimmune disorder. The American College of Rheumatology defined juvenile arthritis as a chronic condition that causes inflammation in one or more joints and begins before the age of sixteen. Juvenile arthritis may be difficult to diagnose because children often compensate well for loss of function and may not complain of pain. Observations of limping, stiffness when awakening, reluctance to use a limb or reduced activity level may be clues. Anticardiolipin antibodies [aCL] have been demonstrated in a large spectrum of autoimmune diseases. However, its occurrence in childhood, in particular in JIA, is not well established. The present study addressed the frequency and clinical significance of aCL and to find an association of aCL and antinuclear antibodies [ANA] with JIA and their correlation to clinical picture, functional capacity and disease activity. Thirty five children were included in this study. The patients group consisted of 20 children [6 boys and 14 girls] with JIA according to the American College of Rheumatology [ACR] 1987 criteria and fulfilling the criteria for diagnosis of JIA [Cassidy and Pretty, 1990]. Their mean age was 12.0 years [yr] +/- 2.6 SD, ranged from 8.3 to 16 yr, with a mean of disease duration 3.4 yr +/- 1.1SD, ranged from 1.4 to 5.0 yr. The control group consisted of 15 healthy children [6 boys and 9 girls] with a mean age of 11.9 [yr] +/- 2.2 SD, their ages ranged from 7.3 to 15.3 yr. The JIA patients group was further classified into two subgroups according to the onset of the disease into systemic onset [no.= 7] and polyarticular-pauciarticular [P-P] [no.= 13]. All groups were subjected to complete history taking and physical assessment of local articular and systemic manifestations. Assessment of the degree of disease activity for JIA patients was performed according to Mallya and Mace scale [1981]. The functional capacity in all subjects was assessed according to Juvenile Arthritis Function Assessment Scale [JAFAS]; this scale ranged from 0 to 20. Blood samples were collected and subjected to the following tests Complete blood count [CBC], ESR, C- reactive protein, Latex agglutination slide test for RF, and assessment of aCL [IgG and IgM] antibodies and ANA using ELISA method. There was increased incidence of disease in females rather than males [nearly double] and the P-P in patients represented 65%. There was a significant increase of ESR and serum levels of ANAs, aCL [IgG and IgM] autoantibodies and JAFAS [p<0.05] in the JIA patient groups as compared to the control group. There was a significant increase of ESR, AI and activity grade in systemic onset group as compared to P-P patients group [p<0.05]. The correlation study in P-P patients group determined a significant negative correlation between aCL- IgG with patient's age of onset and morning stiffness [p<0.05]. A significant positive correlation was found between disease duration with age [p=0.03] and no. of swollen joints [p=0.009]. In the systemic onset patients group, there was a non-significant correlation of aCL-IgG with any clinical or laboratory data [p>0.05], while significant negative correlations was found between aCL-IgM with age, age of onset, JAFAS and ANAs [p<0.05]. There was a positive significant correlation between ANAs and no. of swollen joint [r=0.79, p=0.04] and JAFAS [r=0.78, p=0.04]. We encountered two JIA female patients having positive aCL and ANA antibodies who manifested as P-P onset of the disease. They should have clinical follow up and regular ophthalmologic examination as they are highly susceptible for uveitis. The presence of aCL was not associated with ANA. The relation of aCL with the clinical parameters, could not be established. Age of disease onset, sex, disease activity, and JAFAS could be a prognostic indicator rather than immunological profile tests