In Journal of internal medicine
OBJECTIVE : To explore the role of peripheral lymphocyte count in phenotyping and prognosis prediction in dermatomyositis (DM) patients with anti-MDA5 antibodies.
METHODS : In total, 1669 patients with idiopathic inflammatory myopathy (IIM) were retrospectively enrolled. Clinical characteristics and prognosis of patients with anti-MDA5+ DM were analyzed in association with peripheral lymphocyte counts and clusters determined by unsupervised machine learning.
RESULTS : The peripheral lymphocyte count was significantly lower in the anti-MDA5+ DM group (N = 421) than in the other IIM serotype groups. The anti-MDA5+ DM patients were divided into three groups; the severe lymphopenia group had skin ulcers and rapidly progressive interstitial lung disease (RP-ILD); patients with a normal lymphocyte count had a younger age of onset, more frequent arthritis, and normal serum ferritin levels; whereas mild lymphopenia group showed a moderate increase of serum ferritin and intermediate incidence of RP-ILD. Survival analysis revealed that the 3- and 6-month mortality rates were significantly higher in the severe lymphopenia group (29.0% and 42.1%, respectively) than in the mild lymphopenia group and normal lymphocyte count group (P all< 0.001). Consistently, unsupervised machine learning identified three similar groups; the arthritis cluster shows the highest lymphocyte counts and best prognosis; the RP-ILD cluster presents the lowest peripheral lymphocyte, high incidence of RP-ILD, and poor prognosis; the typical DM rash cluster had a moderate peripheral lymphocyte count and an intermediate prognosis.
CONCLUSIONS : Lymphopenia is a unique manifestation of anti-MDA5+ DM. Peripheral lymphocyte count can define clinical phenotypes and predict prognosis in anti-MDA5+ DM. This article is protected by copyright. All rights reserved.
Jin Qiwen, Fu Lijun, Yang Hongxia, Chen Xixia, Lin Sang, Huang Zhenguo, Gao Baoxiang, Tian Xiaolan, Jiang Wei, Shu Xiaoming, Lu Xin, Wang Guochun, Peng Qinglin
2023-Jan-22
anti-MDA5 antibody, dermatomyositis, lymphopenia, phenotype, prognosis
