Soluble Tyro-3 and Axl may reflect the current activity and renal involvement in patients with microscopic polyangiitis and granulomatosis with polyangiitis

Abstract

Objective

This study investigated whether soluble Tyro-3 (sTyro-3), sAxl, and sMer could reflect the current activity in patients

with microscopic polyangiitis (MPA) and granulomatosis with polyangiitis (GPA).

Methods

This study retrospectively reviewed the medical records of 76 patients with MPA and GPA, and measure the serum

concentrations of sTyro-3, sAxl, and sMer using the stored serum at AAV diagnosis. Antineutrophil cytoplasmic antibody

(ANCA)-associated vasculitis (AAV)-specific indices included Birmingham vasculitis activity index (BVAS), five-factor

score, the short-form 36-item health survey, and vasculitis damage index. High AAV activity was defined as the

highest tertile of BVAS.

Results

The median age of the 47 MPA and 29 GPA patients was 66.0 years and 43.4% were men. The serum concentrations

of sTyro-3 and sAxl were significantly correlated with BVAS and the total score of renal manifestation. The serum

concentrations of sTyro-3 and sAxl were independently correlated with BVAS (β=0.343 and β=0.310, respectively).

In addition, the serum concentrations of sTyro-3 and sAxl were independently associated with the renal involvement

of MPA and GPA (OR 1.003 and OR 1.055, respectively).

Conclusion

This study demonstrated the potential of the serum concentrations of sTyro-3 and sAx