Clinical and immunological characteristics and prognosis of patients with autoantibody negative dermatomyositis: a case control study.

OBJECTIVES: Myositis-specific antibodies (MSAs) and myositis-associated antibodies (MAAs) are associated with distinctive dermatomyositis (DM) clinical phenotypes. The aim of this study is to explicate the clinical and immunological features of MSAs-negative DM patients. METHODS: A total of 515 individuals diagnosed with DM was screened from 2013 to 2022 and 220 DM patients were enrolled in this retrospective cohort. Clinical and laboratory data of these patients were analyzed. RESULTS: MSAs-negative DM patients were categorized into two groups: MAAs-negative (MSAs (-)/MAAs (-)) group and MAAs-positive (MSAs (-)/MAAs (+)) group. The percentage of Raynaud's phenomenon (P=0.026) was higher in the MSAs (-)/MAAs (+) DM patients than the MSAs-positive DM patients and MSAs (-)/MAAs (-) DM patients. The proportion of rapidly progressive interstitial lung disease (RP-ILD) in the MSAs-negative DM patients was lower than that in the MSAs-positive group. The MSAs (-)/MAAs (+) group had a higher proportion of organizing pneumonia and usual interstitial pneumonia (P=0.011), and elevated eosinophils in their bronchoalveolar lavage fluid (P=0.008). Counts of lymphocytes (P=0.001) and CD16+CD56+ natural killer (NK) cells (P=0.012) were higher in the MSAs-negative group. Additionally, the percentage of CD4+TNFα+ (P=0.040), CD4+IFNγ+ (P=0.037), and CD4+IL-2+ (P=0.018) cells among total CD4+ T cells were higher in the MSA-negative DM patients compared with the MSAs-positive DM patients. Besides, MSAs-negative patients demonstrated a more favorable prognosis than MSAs-positive patients. Multivariable regression analysis identified advanced onset age, higher level of carcinoembryonic antigen (CEA), and RP-ILD as risk factors for mortality in DM patients. CONCLUSIONS: Compared with MSAs-positive group, MSAs-negative DM patients suffered less from organ involvement compared with MSAs-positive group and tend to have better prognosis. Key Points MSAs-negative DM patients exhibited distinct characteristics in comparison with MSAs-positive DM patients:   • The MSAs (-)/MAAs (+) DM patients demonstrated a higher prevalence of organizing pneumonia (OP) and usual interstitial pneumonia (UIP), and elevated eosinophil counts in bronchoalveolar lavage fluid.   • CEA levels were lower in MSAs-negative patients compared with MSAs-positive patients.   • Elevated counts of lymphocytes and CD16+CD56+ NK cells were identified in the MSAs-negative patients. Additionally, proportions of CD4+TNFα+, CD4+IFNγ+, and CD4+IL-2+ cells among total CD4+ T cells were higher in the MSAs-negative DM patients compared with DM MSAs-positive DM patients.   • MSAs-negative DM patients had a more favorable prognosis than MSAs-positive DM patients. A multivariable regression analysis revealed the advanced onset age, high CEA levels, and RP-ILD were risk factors for mortality in DM patients.

Anti-melanoma differentiation-associated gene-5 antibody-positive dermatomyositis with liver dysfunction: a warning sign of higher death risk.

This study aimed to investigate and analyze the clinical and immunological features of patients with anti-melanoma differentiation-associated gene-5 antibody-positive dermatomyositis (MDA5 + DM) complicated with clinical liver dysfunction. A cohort of 85 patients diagnosed with MDA5 + DM admitted into Peking University People's Hospital from 2006 to 2023 were retrospectively enrolled in this study. Clinical characteristics and survival status were collected and analyzed. Clinical liver dysfunction occurred in 28% (24/85) of MDA5 + DM patients. Patients with clinical liver dysfunction were more likely to have muscle impairment (83.3% vs. 52.5%, P = 0.009) and rapidly progressive ILD (72.7% vs. 47.4%, P = 0.027). Lactate dehydrogenase (LDH) (378.5 (296.0,453.8) U/L vs. 280.0 (218.0,355.0) U/L, P = 0.002) and ferritin (FER) (883.0 (279.8,2100.5) ng/mL vs. 293.5.0 (84.0,862.7) ng/mL, P = 0.040) were significantly elevated and total numbers of lymphocytes (827.2 ± 517.2 /µL vs. 1301.8 ± 720.9 /µL, P = 0.042), and CD4 + T cells (403.8 ± 315.9 /µL vs. 548.6 ± 257.7 /µL, P = 0.045) were significantly decreased in patients with clinical liver function. Muscle weakness (OR 5.184, 95% CI 1.305, 20.595, P = 0.019) was identified as an independent risk factor for clinical liver dysfunction. Clinical liver dysfunction was identified as an independent risk factor for poor prognosis in patients with MDA5 + DM (HR = 4.030, 95% Cl 1.233, 13.176, P = 0.021), with an 18-month survival rate of 69%. Liver dysfunction is one of the extramuscular manifestations in patients with MDA5 + DM and might be associated with a poor prognosis.