Antibody to streptococcal cell wall peptidoglycan-polysaccharide polymers in sera of patients with juvenile rheumatoid arthritis but absent in isolated immune complexes.

Sera of 88 children with juvenile rheumatoid arthritis (JRA) (10 seropositive, polyarticular onset, 29 seronegative, polyarticular onset, 32 pauciarticular onset, and 17 systemic onset) were evaluated for the presence of serum antibodies to streptococcal cell wall peptidoglycan-polysaccharide polymers (PG-PSP). Immune complexes (IC) isolated by the antihuman IgM (HIgM) affinity column method were also evaluated for the presence of antibodies to PG-PSP. Forty-one of 88 patients with JRA (7 of 10 seropositive, polyarticular onset, 11 of 29 seronegative, polyarticular onset, 16 of 32 pauciarticular onset, and 7 of 17 systemic onset) showed elevated levels of antibodies to PG-PSP in their sera. IgM rheumatoid factors (RF) were demonstrated in 70/88 isolated IC fractions of patients with JRA and IgG RF in 7; however, none of the patients demonstrated the presence of antibodies to PG-PSP in their isolated IC fractions from the anti-HIgM affinity column. These data indicate that antibodies are produced to PG-PSP in all JRA onset types, but they are not constituents of isolated IC by the anti-HIgM affinity column method.