Antiperinuclear factor in juvenile rheumatoid arthritis.

The serological diagnosis of juvenile rheumatoid arthritis (JRA) is difficult, with only 7-10% of patients 19S IgM rheumatoid factor positive. About 60-70% of patients are positive for hidden 19S IgM rheumatoid factor, but this test requires serum separation and is not available in most laboratories. Antiperinuclear factor has been described in both seropositive and seronegative adult patients with rheumatoid arthritis, but has not been thoroughly evaluated in children with JRA. This study determined the diagnostic sensitivity and specificity of antiperinuclear factor in patients with JRA. Serum samples from 64 children with JRA, 24 with systemic lupus erythematosus (SLE), and 24 control subjects were tested for the presence of antiperinuclear factor. A total of 10 (83%) of seropositive, polyarticular onset and six (37%) of seronegative, polyarticular onset patients with JRA were positive for antiperinuclear factor. The occurrence of antiperinuclear factor in five (19%) with pauciarticular onset and one (10%) with systemic onset (JRA) as well as in four (17%) with SLE was not increased compared with the control subjects (1/24 (4%)). These data show an overall diagnostic sensitivity and specificity of 34 and 90% respectively in this group of patients. Although less sensitive than the hidden rheumatoid factor assay, the antiperinuclear factor assay is easier to perform and may contribute to the serological diagnosis of JRA.

Correlation of antiperinuclear factor with antibodies to streptococcal cell-wall peptidoglycan-polysaccharide polymers and rheumatoid factor.

Antiperinuclear factor (APF) has been noted in most seropositive rheumatoid arthritis (RA) and juvenile rheumatoid arthritis (JRA) patients. The nature of the antigen is unknown; however, there are some suggestions that it might be a glycoprotein or proteoglycan. We studied the correlation of APF with antiproteoglycan antibodies and the reactivity of IgM-rheumatoid factor (RF) with the perinuclear antigen. Ten serum samples were separated to IgG, IgM, and IgM-RF enriched fractions. In seven samples, APF was found in the IgG fraction. Only 4 had APF in their IgM rheumatoid factor (RF)-containing fraction. In two of these, APF activity was present solely in the IgM RF fraction and was inhibited by pre-incubation with IgG. Fifty-five JRA patients' sera were also tested for the presence of antibodies to Streptococcal cell wall peptidoglycan-polysaccharide polymers (PG-PSP). 76% of the APF-positive sera were anti-PG-PSP positive and 59% of the APF-negative sera were also anti-PG-PSP negative. Furthermore, 75% of the APF-positive sera lost their APF activity following adsorption to Streptococcal cell wall PG-PSP. Our results show that in JRA sera APF are polyclonal antibodies of both the IgG and IgM classes. Although the presence of APF correlates with RF positivity, and they sometimes may cross-react, many IgM RF-containing fractions do not show APF activity. However, the presence of APF does correlate with anti-PG-PSP positivity and the data suggest cross-reactivity between these two antibodies. This implies antigenic similarity between Streptococcal cell wall PG-PSP and the perinuclear antigen.

Diflunisal versus naproxen in the management of rheumatoid arthritis.

Diflunisal (500 mg orally, twice daily) and naproxen (375 mg orally, twice daily) were compared for efficacy and tolerability in a 12-week open-label study in 33 patients with active rheumatoid arthritis (RA). Both drugs resulted in marked reduction in the number of swollen, tender, and painful joints and comparable improvement in patients' assessment of disease activity and pain. There were no significant differences between the two medications in the measured indices of disease activity. No adverse experiences were reported by patients in either treatment group. The results indicate that both diflunisal and naproxen were equally effective and that both agents are generally well tolerated in this group of patients with RA.