Identification of distinct cytokine/chemokine profiles in dermatomyositis with anti-transcriptional intermediary factor 1-γ antibody.

OBJECTIVES

DM and clinically amyopathic DM (CADM) patients with positive expression of anti-transcription intermediary factor 1-γ (anti-TIF1-γ) antibody (Ab) are characterized by distinct clinicopathological features. We aimed to determine the role of cytokine/chemokine profiles in the classification of anti-TIF1-γ positive DM/CADM patients.

METHODS

Serum levels of 24 cytokines/chemokines were measured in 27 anti-TIF1-γ positive DM/CADM patients by a Luminex 200 system. Principal components analysis and unsupervised hierarchical clustering were used to reduce variables and establish patient subgroups. Spearman's correlation coefficient was calculated between cytokine/chemokine levels and disease activity markers.

RESULTS

Among anti-TIF1-γ positive DM/CADM patients, two distinct patient clusters were identified. The diagnosis of CADM was more common in cluster 1 than in cluster 2 (58.3% vs 6.7%, P = 0.008). Skin disease activity was higher in cluster 2 than in cluster 1 as measured by Cutaneous DM Disease Area and Severity Index-Activity [38.6  (10.4) vs 25.3  (10.0), P = 0.003]. Patients within cluster 2 exhibited significant muscle weakness (Medical Research Council scale ≤ 3, 33.3% vs 0.0%, P = 0.047), higher levels of anti-TIF1-γ Ab [92.4  (20.6) vs 66.9  (13.9), P = 0.001] and an increased malignancy rate (73.3% vs 25.0%, P = 0.021). Cluster 2 exhibited higher serum levels of CXCL10 [564.2  (258.8) vs 122.0  (97.8), P < 0.001], CCL2 [1136.6  (545.4) vs 441.6  (163.3), P < 0.001], galectin-9 [38879.6  (20009.3) vs 12612.4  (6640.0), P < 0.001], IL-18 [436.1  (188.9) vs 243.0  (114.5), P = 0.003], TNF-α [9.3  (3.8) vs 5.6  (2.4), P = 0.007] and TNFRI [1385.1  (338.2) vs 2605.6  (928.5), P < 0.001] than cluster 1.

CONCLUSION

In anti-TIF1-γ positive DM/CADM, we identified a 'skin-predominant' cluster and a 'hyperinflammation' cluster based on the cytokine/chemokine profiles.Cytokine/chemokine profiles in anti-TIF1-γ positive DM/CADM can identify discrete clusters of patients with different disease patterns, organ involvements and clinical outcomes.