An updated review of anti-Ro52 (TRIM21) antibodies impact in connective tissue diseases clinical management

Anti-Ro52 (or anti-TRIM21) antibodies are part of the family of anti-Ro/SSA antibodies, historically markers of Sjögren syndrome and systemic lupus erythematosus. Anti-Ro52 antibodies represent one the most frequently encountered autoantibodies in patients with connective tissue disease (primary Sjögren syndrome, systemic lupus erythematosus, systemic sclerosis and idiopathic inflammatory myopathies). Because of their lack of specificity and detection in patients with non-autoimmune disorders, the usefulness of anti-Ro52 testing in connective tissue diseases is still matter of debate among clinicians and immunologists. Autoantibodies are mainly diagnostic markers for autoimmune diseases but some of them can also be directly involved in the generation of tissue damage. Over the past decade several authors reported associations of anti-Ro52 antibodies with some clinical features - especially interstitial lung disease - and survival in patients with connective tissue diseases. There is also a growing evidence of the role of anti-Ro52 antibodies in the pathogenesis of connective tissue diseases. In this review, we comprehensively discuss the clinical associations of anti-Ro52 antibodies in the different connective tissue diseases and the recent advances on their potential role in the inflammatory response.

Clinical significance of anti-Ro52 (TRIM21) antibodies in adult patients with connective tissue diseases

OBJECTIVES

Clinical significance of anti-Ro52 antibodies in connective tissue diseases (CTD) is controversial. Anti-Ro52 antibodies might be associated with a more severe CTD phenotype, especially interstitial lung disease (ILD). The aims of this study were to evaluate ILD prevalence and severity, the prevalence of micro- or macroangiopathy and CTD-associated cancers in CTD with anti-Ro52 antibodies.

METHODS

CTD patients with anti-Ro52 antibody screening by immunoblot at diagnosis were enrolled. Two groups were retrospectively formed according to the presence of anti-Ro52 antibodies with an unbiased 1:1 matching on CTD types. Unsupervised multiple correspondence analysis and hierarchical clustering analysis were used to aggregate anti-Ro52 positive patients in subgroups.

RESULTS

408 CTD patients were included. Anti-Ro52 antibodies were detected in 33 % of CTD patients. Anti-Ro52 antibodies were associated with ILD at CTD diagnosis (47.8% vs. 23.0%, OR 3.3 95% IC 1.4 to 8.0, p = 0.008), even after adjusting for the presence of anti-Ro60 antibodies, especially in patients with antisynthetase syndrome, primary Sjögren syndrome and systemic sclerosis. Micro- or macroangiopathy was more frequent in anti-Ro52 positive CTD patients (18.6% vs. 9.7%, p = 0.02) and CTD patients with anti-Ro52 antibodies experienced more frequent relapses and required more immunosuppressive drugs. Clusters 4 and 5 identified anti-Ro52 positive CTD patients with severe ILD and with clinical features of systemic sclerosis or antisynthetase syndrome respectively.

CONCLUSIONS

We found that anti-Ro52 antibodies were independently associated with ILD in CTD patients irrespective of CTD type. Anti-Ro52 antibodies could be associated with severity and a more relapsing disease course in CTD patients.

Predictive Features and Clinical Presentation of Interstitial Lung Disease in Inflammatory Myositis

Interstitial lung disease (ILD) represents one of the most severe extra-muscular features of idiopathic inflammatory myositis (IIM). We aimed to identify any clinical and serological predictors of ILD in a monocentric cohort of 165 IIM patients.

ILD+ patients were defined as having restrictive impairment in lung function tests and signs of ILD at chest high-resolution computed tomography (HRCT). Available HRCT images were centralized and classified in different ILD patterns: non-specific interstitial pneumonia (NSIP), organizing pneumonia (OP), usual interstitial pneumonia-like (UIP), indeterminate for UIP, and interstitial lung abnormalities (ILA). Lung function test data were recorded at onset, at 1 and 5 years after ILD diagnosis.

ILD was found in 52 IIM patients (31.5%): 46.2% was affected by anti-synthetase syndrome (ARS), 21% by polymyositis (PM), 19% by dermatomyositis (DM), and 13.5% by overlap myositis. Most of ILD+ showed NSIP (31.9%), OP (19%), indeterminate for UIP (19%), and UIP (12.8%) patterns. At multivariate analysis, ILD was predicted by anti-Ro52 (p: 0.0026) and dyspnea (p: 0.015) at IIM onset. Most of ILD onset within is 12 months after IIM. In five cases, ILD occurs after 12 months since IIM diagnosis: these patients more frequently show dry cough and anti-Ku antibodies. Anti-Ro52 + ILD patients showed a significant increase of DLCO at 1 and 5 years of follow-up, compared with anti-Ro52 negative cases.

ILD occurs in about one third of IIM and was predicted by dyspnea at onset and anti-Ro52 antibodies. Anti-Ro52 defines a subgroup of ILD showing a significant improvement of DLCO during follow-up.

This retrospective study has been approved by local ethic committee (ASST-Spedali Civili of Brescia, Italy); protocol number: NP3511