Clinical features of patients with connective tissue disease with anti-human upstream binding factor antibodies: A single-center retrospective study.

Anti-human upstream-binding factor (anti-hUBF) antibodies have been reported predominantly in patients with connective tissue diseases (CTDs); these have also been reported in patients without CTDs such as hepatocellular carcinoma. Because of the low frequency of expression and few case reports, there is no consensus on the clinical significance of these antibodies. Thus, we aimed to examine the clinical features of patients with anti-hUBF antibodies and analyzed 1042 patients with clinically suspected CTDs. The presence of anti-hUBF antibodies was screened using immunoprecipitation assays. Of the 1042 patients, 19 (1.82%) tested positive for anti-hUBF antibodies; among them, 10 (56%) were diagnosed with undifferentiated CTD (UCTD), six with systemic sclerosis (SSc) and three with other diseases. Five of the 10 patients with UCTD were referred to our hospital with suspected SSc. None of the five patients fulfilled the 2013 American College of Rheumatology/European League Against Rheumatism classification criteria, but three scored seven points, a relatively high score. Six anti-hUBF-positive patients with SSc had a significantly lower modified Rodnan skin score (mRSS) than that of anti-hUBF-negative patients with SSc (2 [0-2] vs 7 [0-49], p < 0.01). Compared with anti-topoisomerase I-positive patients, anti-hUBF-positive patients had a significantly lower mRSS (2 [0-2] vs 13 [0-42], p < 0.01) and lower incidence of scleroderma renal crisis (0 of 6 vs 8 of 184, p < 0.01). Compared with anti-centromere-positive patients, anti-hUBF-positive patients had a higher incidence of interstitial lung disease (ILD), but the difference was not statistically significant (4 of 6 vs 19 of 239). In conclusion, anti-hUBF antibodies were predominantly detected in patients with CTDs and UCTD. In patients with CTDs, SSc exhibited a high ratio, displaying a lower mRSS and higher incidence of ILD. In patients with UCTD, careful follow-up is recommended as they may develop CTDs in the future.