High Prevalence of Myositis-Specific and Associated Antibodies in Patients with Pulmonary Hypertension

Pulmonary hypertension (PH) is a serious condition linked to immune-system dysfunction. Myositis-specific/associated antibodies (MSAs/MAAs) play a role in idiopathic inflammatory myopathy (IIM) and interstitial lung disease (ILD), but their significance in PH remains unclear. We believe the presence of these antibodies may be underestimated. This study analyzed adult PH patients without pre-existing IIM for MSA/MAA prevalence using a line-blot assay. We compared PH patients with and without ILD signs to a cohort clinically suspected of IIM/ILD (n = 558). Our PH cohort (n = 121) showed a significantly higher prevalence of overall weak positive MSAs/MAAs and positive overlap syndrome-associated MAAs than the suspected IIM/ILD group (p < 0.001). Notably, MSAs/MAAs were found in PH patients both with and without ILD, though more prevalent in those with ILD. Anti-synthetase and anti-overlap syndrome antibodies were the most common. Our study is the first to systematically show a high MSA/MAA prevalence in PH without IIM presentation. This highlights the need to consider PH when diagnosing MSA/MAA-associated conditions. We recommend MSA/MAA screening for newly diagnosed PH, especially in those with ILD, for early detection and potential immunomodulatory treatment. Further research should explore the link between MSAs/MAAs and PH, and the value of monitoring patients with weak MSA/MAA positivity over time.

Corrigendum: Applicability of a serodiagnostic line blot for idiopathic inflammatory myopathy: the muscle biopsy is not all

[This corrects the article DOI: 10.3389/fneur.2024.1504260.].

Predictors of response to intravenous immunoglobulin in patients with dermatomyositis: the ProDERM study

OBJECTIVES

The phase 3 ProDERM study demonstrated intravenous immunoglobulin (IVIg) was safe and effective in patients with dermatomyositis (DM). This analysis assessed clinical and serological predictors of IVIg response in DM patients from ProDERM.

METHODS

ProDERM was a prospective, randomised, placebo-controlled study of DM patients. For Weeks 0-16, patients received 2.0 g/kg IVIg (Octagam, 10%) or placebo every 4 weeks. Eligible patients entered the open-label extension phase, where all received IVIg to week 40. Univariate and multivariate analyses examined associations between baseline variables and total improvement score (TIS), including myositis disease activity assessment tool (MDAAT; assessing different organ involvement), and myositis-specific and myositis-associated autoantibodies.

RESULTS

Ninety-five patients were enrolled. Univariate analyses found no significant association between TIS at week 16 or 40 and age; sex; ethnicity; disease duration/activity; cutaneous, skeletal, gastrointestinal or muscle disease activity; or previous failed or concomitant medications.Multivariate analysis found patients with higher MDAAT cutaneous scores had a better chance of at least minimal TIS improvement. Higher MDAAT pulmonary scores were associated with a lower, but still considerable, chance of improvement. Patients with TIF1-γ antibodies had a better TIS response; however, after controlling for cutaneous disease activity, there was no significant association between antibody classification (including anti-TIF1-γ) and efficacy outcome.

CONCLUSION

IVIg was effective in treating DM patients regardless of demographic features and autoantibody status (for most autoantibodies). Patients with higher cutaneous disease activity and/or anti-TIF1-γ responded best to IVIg, while pulmonary disease activity predicted a lower, but still effective, IVIg response, warranting further investigation.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov, NCT02728752.

Applicability of a serodiagnostic line blot for idiopathic inflammatory myopathy: the muscle biopsy is not all

Introduction

Differential diagnosis of rare idiopathic inflammatory myopathies (IIM) is mainly based on clinical aspects, muscle biopsy analysis, and auxiliary assays that determine myositis-specific and associated autoantibodies (MSA and MAA). While MSAs are considered specific for their respective IIM subclass, MAAs can be present in more than one subclass and in other conditions. This study compares results of a multispecific line blot assay with the final diagnosis of IIM patients based on clinical features and muscle biopsy to draw conclusions for the test's applicability in the diagnostic workflow.

Methods

Samples from patients (n = 50) diagnosed with various forms of IIM, including patients (n = 5) with other myopathies, were analyzed using the EUROLINE Autoimmune Inflammatory Myopathies 16 Ag (IgG), an anti-HMGCR (IgG) line blot, and the Anti-cN-1A ELISA (IgG, all EUROIMMUN).

Results

MSA and MAA were detected in 74.0% (37/50) of sera and were concordant with the final diagnosis in 64.8% (24/37), discordant in 16.2% (6/37) and not evaluable in 18.9% (7/37) of cases. In 100% (5/5) of patients with other myopathies, no MSA was found. MSA/MAA-co-positivity was observed in 18.0% (9/50) of patients. In 30.0% (15/50) of cases, the muscle biopsy analysis was essential to establish the final diagnosis.

Conclusion

The agreement between serodiagnostic results and final diagnosis highlights the applicability of the EUROIMMUN myositis-related diagnostic test as first line diagnostic tool in the IIM diagnosis workflow and suggests morphological analysis in cases of inconclusive or negative serology. However, results of diagnostic assays shall always be interpreted in combination with clinical features.