Frequency and clinical relevance of anti-Mi-2 autoantibody in adult Brazilian patients with dermatomyositis

Abstract

Background: To analyze the frequency and clinical relevance of anti-Mi-2 autoantibody in a representative sample of patients with dermatomyositis. Methods: This longitudinal inception cohort study, from 2001 to 2017, included 87 definite adult dermatomyositis. Anti-Mi-2 analysis was performed using a commercial kit. Results: Seventeen patients (19.5%) had anti-Mi-2 and 70 (80.5%) did not have this autoantibody. The following parameters were equally distributed between the patients with versus without anti-Mi-2: mean age at the disease diagnosis onset, median follow-up time, constitutional symptoms (baseline), cutaneous cumulative lesions, dysphagia, joint and pulmonary involvement. There was also no difference between the groups in relation to follow-up time, disease relapsing, treatment, disease status, deaths and occurrence of neoplasia. In contrast, patients with anti-Mi2 antibodies had higher frequency of elevated serum levels of muscle enzymes at disease onset (median: creatine phosphokinase 6240 [3800-9148] U/L and aldolase 60.0 [35.0-138.0] U/L), lower frequency of pulmonary involvement at disease onset (5.9%), less current glucocorticoid dose (median: 0 [0-10] mg/day), and higher frequency of disease remission during follow-up (58.8%) in comparison with patients without anti-Mi-2 autoantibody (484 [115-4880] and 12.1 [6.3-70.0] U/L, 40.0%, 0 [0-10] mg/day, 27.1%, respectively). Conclusion: The anti-Mi-2 autoantibody was found in one fifth of patients with dermatomyositis. This autoantibody was associated with a lower occurrence of pulmonary involvement, a higher frequency of disease in remission, and elevated levels of muscle enzymes. There was also no correlation regarding the frequency of disease relapsing or neoplasia development.

NanoString technology distinguishes anti‐TIF‐1γ+ from anti‐Mi‐2+ dermatomyositis patients

“…The correlation of cancer and Mi‐2 autoantibodies, however, remains debated. While some groups reported no increased risk of cancer development in anti‐Mi‐2 + patients (38‐40), other more recent studies on larger patients cohorts demonstrated a correlation of Mi‐2 antibody and CAM (41, 42). In our cohort, CAM was detected in 60% of anti‐TIF‐1γ‐ and 20% of anti‐Mi‐2‐associated DM patients, which (i) basically reflects results from other larger patient series (43, 44) and (ii) emphasized the need for personalized risk‐stratified cancer follow‐up for both DM subgroups.…”

A Man With Recurrent Pneumonitis: A Rare Case of Interstitial Lung Disease Associated With Anti-Mi-2 Beta-Specific Dermatomyositis

“…The prognosis of ILD related to dermatomyositis depends on myositis-specific antibodies and the pattern of interstitial changes. Anti-Mi-2 antibody dermatomyositis has favorable outcomes with a low occurrence of pulmonary involvement [ 10 ]. Dermatomyositis, in general, is strongly associated with a wide range of cancers, but anti-Mi-2 antibody DM has a rare association with malignancy [ 10 ].…”

“…Anti-Mi-2 antibody dermatomyositis has favorable outcomes with a low occurrence of pulmonary involvement [10]. Dermatomyositis, in general, is strongly associated with a wide range of cancers, but anti-Mi-2 antibody DM has a rare association with malignancy [10].…”

Dermatomyositis autoantibodies: how can we maximize utility?

“…Anti-SAE-positive patients appear to have a high percentage of ILD (64-71%) in Asia, but a much lower percentage (around 18%) in Europe (90,100,104). Other MSAs have very low levels of ILD: anti-Mi-2 (0% in Asia and 6% in Brazil), anti-NXP-2 (0% in Japan and 7% in USA), and anti-TIF-1γ (0-20% in Japan and 0-5% in Europe and USA) (42,46,70,86,91,96,97,99,116,118,126,127). Although many groups have a relatively lower risk of ILD, it is still possible that their risk of ILD is much higher than healthy comparators.…”

“…Anti-SAE-1/2: low report: 18% (UK, IP, high resolution CT scan) (100); high report: 71% (Japan, IP, method of evaluating ILD unspecified)(90). Anti-Mi-2: low report: 0% (India, LIA, high-resolution CT) (91); high report: 6% (Brazil, LIA, high-resolution CT)(127).Anti-Jo-1: low report: 56% (Japan, IP, chest radiograph and high-resolution CT)(114); high report: 86% (USA, ELISA, abnormalities on chest radiograph or high-resolution CT or biopsy)(128). ILD, interstitial lung disease; IP, immunoprecipitation; CT, computed tomography; LIA, line immunoblot assay.…”