Serum chitotriosidase tied to poor prognosis in patients with anti-MDA5–positive DM/CADM-ILD
Serum chitotriosidase levels appear to be useful in predicting a poor prognosis in patients with antimelanoma differentiation-associated gene 5 antibody (anti-MDA5)–positive dermatomyositis (DM)/clinically amyopathic DM-associated interstitial lung disease (DM/CADM-ILD), suggests a study.
Serum chitotriosidase in patients with anti-MDA5–positive DM/CADM-ILD had a median level of 17.3 ng/ml, which was higher compared to that in healthy controls (2.0 ng/ml) and anti-aminoacyl-tRNA synthetase antibody–positive (anti-ARS)-polymyositis (PM)/DM/CADM-ILD (8.9 ng/ml).
Ten of the 30 patients included in the study died of respiratory failure associated with DM/CADM-ILD deterioration. In Cox hazard analysis, higher serum chitotriosidase level and lower partial pressure of oxygen in the alveoli (PaO2) value significantly predicted a poor outcome.
Chitotriosidase ≥23.5 ng/ml, ferritin ≥800 ng/ml and Krebs von den Lungen–6 ≥720 U/ml also significantly predicted a poor prognosis when using optimal cutoff levels according to receiver-operating characteristic curve analyses. Serum chitotriosidase levels showed a negative association with PaO2 and percentage predicted forced vital capacity.
Patients with high chitotriosidase levels (≥23.5 ng/ml) had a significantly poorer survival rate than those with low chitotriosidase levels (<23.5 ng/ml).
This retrospective study evaluated the prognostic factors of anti-MDA5–positive DM/CADM-ILD and the use of serum chitotriosidase, a marker for macrophage activation, as a potential biomarker in anti-MDA5–positive DM/CADM-ILD. Clinical characteristics and laboratory findings at the time of diagnosis were analysed.
The investigators measured serum chitotriosidase levels in 30 patients, in 21 healthy controls and in 25 patients with anti-ARS–PM/DM/CADM-ILD. They also assessed the potential of serum chitotriosidase as a prognostic biomarker in anti-MDA5–positive DM/CADM-ILD.