Background/Purpose: Our objective was to identify the clinical significance of serum interferon-alpha levels in patients with established rheumatoid arthritis (RA).

Methods: Serum samples and clinical data including demographic information, body mass index measured in kg/m², seropositivity, medications were obtained for 173 RA patients who were enrolled in the University of Pittsburgh Rheumatoid Arthritis Comparative Effectiveness Registry (RACER). Patients who underwent clinical evaluations and completed three self-report questionnaires (PainDETECT, Patient-Reported Outcomes Measurement Information System (PROMIS) 29, Widespread Pain Index/Symptom Severity Scale) were included. Serum cytokines including interleukin (IL)-1 beta, IL-6, and interferon (IFN)-alpha were measured on serum samples using enzyme-linked immunosorbent assay.

Results: Among those patients (N=18) who had detectable IFN-alpha, there were significant differences observed for physician global assessment, physical function, depression, and abilities to participate in social roles, compared with patients who did not have IFN-alpha detected. (Table 1) Those who had detectable IFN-alpha had a poorer physical function and impaired abilities to participate in social roles. (Figure 1) Although there was no statistically significant difference, those who have detectable IFN-α tend to have a higher number of swollen joints, higher seropositivity, and higher pain interference. Interestingly, inflammatory cytokines such as IL-1 beta, IL-6, and C-reactive protein (CRP), pain levels, and RA disease activity scores such as disease activity score 28-CRP and clinical disease activity index were not different between the patients with detectable IFN-alpha and without. (Table 1)

Conclusion: This study highlights the potential roles of serum IFN alpha as a biomarker in identifying a distinct subgroup of patients among those who have similar RA disease activity scores.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/serum-interferon-alpha-levels-could-help-identify-a-subgroup-of-rheumatoid-arthritis-with-poorer-physical-function-and-higher-physician-global-assessment/