Neutrophil-to-lymphocyte ratio as a biomarker for clinical response after autologous haematopoietic stem cell transplantation in systemic sclerosis.

OBJECTIVE

SSc is a complex disease that affects various target organs, making it difficult to assess response and determine remission or relapse. A baseline neutrophil-to-lymphocyte ratio (NLR) >2.95 is associated with severe progressive skin and lung disease and decreased 5-year survival in SSc. However, it is unknown whether NLR changes in response to treatment. To retrospectively evaluate NLR changes as a biomarker for treatment response in SSc.

METHODS

Progressive diffuse SSc patients who were treated with autologous haematopoietic stem cell transplantation (AHSCT group), with combination therapy of rituximab and MMF (combination group) or chimeric antigen receptor-T-cell (CAR-T) therapy group, were recruited along with healthy controls (HC group). NLR, modified Rodnan Skin Score (mRSS) and forced vital capacity (FVC)% predicted were repeatedly assessed over 2 years.

RESULTS

Fifteen patients were recruited in the AHSCT group, 15 in the combination group and 6 patients in the CAR-T group. Baseline mean NLR was high (>2.95) in AHSCT, combination groups and CAR-T compared with HC. All treatment arms showed a statistically significant decrease in mRSS values and an increase in FVC% at each time point up to 12 months. In a linear mixed model, NLR significantly decreased up to 24 months only in the AHSCT group. NLR correlated with mRSS and FVC exclusively in the AHSCT group. NLR increased above 3 in two patients who experienced a relapse after AHSCT.

CONCLUSION

NLR is a simple biomarker that correlated with outcome measures in SSc following AHSCT but not with conventional therapy or CAR-T therapy. It is suggested that a decrease in NLR following AHSCT may indicate remission, whereas an increase may be associated with exacerbation. Further research is needed to validate these novel findings.