Autoantibodies and Relapse of Systemic Sclerosis After Autologous Hematopoietic Cell Transplantation

Objective Autologous hematopoietic cell transplantation (HCT) is an effective treatment for a subset of systemic sclerosis (SSc) patients. Unfortunately, relapse is a significant problem, with no available tests to predict relapse. We studied whether relapse is associated with pre- or post-HCT serum levels of SSc-related autoantibodies. Methods The cohort comprised 38 consecutive evaluable SSc patients who underwent HCT at a single center, who were followed for median 33 months. Sixteen (42%) patients developed relapse at median 14 months post-HCT. Autoantibody levels were determined by immunoassays. Results Regarding pre-HCT autoantibodies, in univariate analyses, the cumulative incidence of relapse (CIR) was lower in anti-RNA polymerase III (ARA) positive than negative patients (Hazard ratio (HR)=0.2, P=.04). Conversely, there was a non-significant trend towards higher CIR in patients with positive anti-Ro52 (HR=2.9, P=.05). The CIR was similar in patients positive and negative for anti-topoisomerase antibody (ATA, i.e., Scl70) or anti-nuclear antibody (ANA). In bivariate analyses that included older age as a risk factor for relapse, pre-HCT ARA was still associated with relapse (HR=0.2, P=.04). This was not the case for Ro52 (HR=2.21, P=.16) Regarding post-HCT autoantibody level trajectory, there was no significant difference between patients with vs without relapse. Conclusion In conclusion, positive ARA pre-HCT is associated with reduced relapse risk, and post-HCT autoantibodies do not appear to be associated with relapse risk.