Antibodies to peptidoglycan in juvenile onset ankylosing spondylitis and pauciarticular onset juvenile arthritis associated with chronic iridocyclitis.

Using an indirect enzyme linked immunosorbent assay, antibodies of the IgG class to Streptococcus pyogenes group A peptidoglycan-polysaccharide polymers (PG-GSP) were measured in the sera of 37 patients with juvenile onset ankylosing spondylitis (JAS), 22 with pauciarticular onset juvenile arthritis associated with chronic iridocyclitis and 20 healthy children. Mean antibody activity, measured in arbitrary units, was of 184 U in JAS and 250 U in chronic iridocyclitis (p = NS). The results in both groups differed significantly from those found in healthy children (p less than 0.001 and p less than 0.01, respectively). This suggests either a possible role of bacterial cell wall products in the pathogenesis of these disorders or a state of immune reactivity to PG-GSP in these children.