Seroreversion For Rheumatoid Factor is common in those with RA on Biologic Therapy
Khizer Iqbal, Dalal Alkhudair, Trevor Duffy, Carl Orr
Connolly Hospital, Blanchardstown and RCSI
Serology findings in RA have been reported as stable over time. Rheumatoid factor (RF) remains an important in tool in the diagnosis of rheumatoid arthritis. It has been reported that serology for RF is stable over time, and that titres are weakly associated with disease activity.
While the stability of various autoantibodies involved in rheumatoid arthritis have been reported, little has been doe thus far to investigate what factors influence seroreversion. We interrogated the rates, and the likely factors that might determine seroreversion.
Of 89 consecutive rheumatoid arthritis (RA) patients attending clinic, 26 had RF checked on more than one occasion. We compared baseline and the most recently updated serology for RF, in patients with a clinical diagnosis of rheumatoid arthritis, and examined for inconsistency, contingent upon treatment strategies, smoking status, follow-up disease activity, and RF titre.
Seroreversion was observed in a large number of subjects 6/19 (31.6%). Having ever smoked was associated with lower seroreversion rates than non-smokers (p=0.04), and those with an initial moderate or low RF titre were more likely to serorevert (p=0.04). No differences were observed between those who seroreverted and those who did not in respect of age of onset, disease activity (by DAS28-CRP or ESR), disease duration, or time between initial RF test and the most recent. While not statistically significant (p=0.1) all those who seroreverted were all receiving biologic therapy.
We report regular seroreversion for RF in those on biologic therapies who have never smoked. More data is needed to better understand how modern treatments influence disease progression and outcome in RA.