Predictive Values of Blood Type I and Type II Interferon Production for Disease Activity and Clinical Response to TNF-α Blocking Therapy in Patients with Ankylosing Spondylitis

Tumor necrosis factor-α (TNF-α) blocking therapy is recommended to treat ankylosing spondylitis for patients who fail to respond to nonsteroidal anti-inflammatory drugs (NSAIDs). Herein, we attempt to dissect whether blood type I and II interferon (IFN) production can be predictive of ankylosing spondylitis progression and treatment response to the tumor necrosis factor inhibitor (TNFi). A total of 50 ankylosing spondylitis patients receiving originator TNFi with a 6-month period were retrospectively analyzed. The patients who reached the Assessment of SpondyloArthritis international Society 40 (ASAS40) response at the 6-month interval were classified as responders (n = 29) to TNFi treatment, otherwise as non-responders (n = 21). The serum type I IFN activity, and the serum levels of IFN-α and IFN-γ in the patients at baseline were notably greater than the healthy controls. Pearson correlation analysis showed positive correlations in the patients between the serum type I IFN activity or the serum levels of IFN-α and IFN-γ, and BASDAI scores, ASDASCRP or pro-inflammatory factor production. The responders were demonstrated with reduced serum type I IFN activity concomitant with lower serum levels of IFN-α and IFN-γ compared to the non-responders after anti-TNF treatment. The serum type I IFN activity, and the serum levels of IFN-α and IFN-γ used as a test to predict responders and non-responders to anti-TNF treatment produced an area under the curve (AUC) of 0.837, 0.814, and 0.787, respectively. In conclusion, the study demonstrates that blood type I and II IFN production may be correlated with disease activity, inflammatory cytokine production, and indicative of unsatisfying response to TNFi treatment in ankylosing spondylitis patients.