58. DIFFERING EXPRESSION OF ANTIBODIES TO DOUBLE STRANDED DNA IN AUTOIMMUNE CHRONIC ACTIVE HEPATITIS (aCAH) & PRIMARY SCLEROSING CHOLANGITIS (PSC)

摘要

Non organ-specific autoantibodies, in particular antinuclear antibody(ANA) are present in both aCAH and PSC of childhood, suggesting an imbalance in immune-regulation akin to that observed in systemic lupus erythematosus(SLE). The aim of this study was to investigate whether an increase in antibody to double-stranded DNA (dsDNA), typical of SLE, is present in these two conditions. Binding to dsDNA was determined by RIA in 8 ANA positive children with PSC [4 male, median age 7yrs, range 3-14yrs] and in 20 patients with aCAH[5 male, median age 12.5yrs, range 8-21yrs], 6 of whom are ANA positive, the remainder being positive for antibodies to smooth muscle (SMA), liver/kidney microsomes(LKM) and/or gastric parietal cells(GPC). Anti-dsDNA antibodies in the range diagnostic for SLE (>25 U/ml) were found in 5 children with aCAH[2 ANA positive, 2 LKM positive, 1 SMA positive] but in none of the PSC group. The mean dsDNA binding in children with aCAH was 15.0 IU/ml ± SD 10.63 compared to 7.78 U/ml ± SD 1.7 in those with PSC (p < 0.05). Anti-dsDNA antibodies of more than 25 U/ml in aCAH occurred in the absence of ANA. In the PSC group where ANA is commoner & generally of higher titre, anti-dsDNA antibodies did not correlate with ANA titre. This is a further demonstration of different immune dysfunction in these two chronic liver disorders.