The role of therapeutic plasma exchange in clinically amyopathic dermatomyositis with MDA-5 antibody: A case report and review of the literature

[Increasing dyspnoea and intermittent joint suffering]

In rheumatic diseases the possibility of pulmonary manifestation must always be considered and checked. Interstitial lung disease can often be fatal in these cases. In the presented case, the link between progressive dyspnea and newly occurring skin irritation is to be seen as particularly important. A good outcome can be achieved by immediate therapy with immunosuppression and plasmapheresis.

Plasma exchange for anti-MDA5 antibody-positive dermatomyositis-associated rapidly progressive interstitial lung disease: A case report and literature review

The prognosis of anti-MDA5-positive dermatomyositis (DM)-associated rapidly progressive interstitial lung disease (RPILD) is extremely poor and effective treatment options are limited. In addition, the risk of infection during immunosuppressive treatment is a major challenge. We report here, a case of RPILD in a 31-year-old man with anti-MDA5 antibody-positive DM. Despite treatment with methylprednisolone and human immunoglobulin, his lung condition worsened and his serum ferritin levels increased. Six cycles of plasma exchange (PE) adjuvant treatment significantly mitigated his symptoms and he was discharged from hospital two months later. We suggest that PE may be a promising therapeutic option for patients with anti-MDA5-positive DM-associated RPILD. However, randomized, controlled studies are required to confirm our findings.

Therapeutic plasma exchange for steroid refractory idiopathic inflammatory myopathies with interstitial lung disease

BACKGROUND

Idiopathic inflammatory myopathies (IIMs) encompass many rheumatologic diseases characterized by inflammatory muscle disease, typically unified by proximal muscle weakness. A subset of patients with IIM present with interstitial lung disease (ILD) with identifiable antibodies such as in anti-synthetase syndrome (AS) with antibodies to aminoacyl-tRNA synthetases, and clinically amyopathic dermatomyositis (CADM) with anti-melanoma differentiation-associated protein 5 (MDA5). Recent case reports demonstrate response to therapeutic plasma exchange (TPE) or column filtration plasmapheresis in IIM with ILD resistant to medical management. We present our experience with eight patients with IIM with ILD undergoing TPE at a large US-based hospital system.

PATIENT CHARACTERISTICS

Eight patients with IIM with ILD were treated with TPE over the last 10 years. The therapy consisted of 5-7 one plasma volume exchanges every other day to daily. Seven of eight patients had identifiable antibodies.

RESULTS

Following completion of TPE, seven of eight demonstrated improvement in pulmonary function despite lack of improvement of pulmonary function with standard therapy.

CONCLUSION

In antibody-mediated, treatment refractory IIM with ILD, TPE may be a viable intervention. This is a disease for which the role of apheresis is evolving.

CLINICAL TRIAL REGISTRATION

Not application.

Mortality Risk Stratification Using Cluster Analysis in Patients With Myositis-Associated Interstitial Lung Disease Receiving Initial Triple-Combination Therapy

Objective

To stratify patients with polymyositis/dermatomyositis-associated interstitial lung disease (ILD) who were initially treated with an intensive regimen consisting of high-dose corticosteroids, a calcineurin inhibitor, and intravenous cyclophosphamide (triple-combo therapy) into subgroups based on mortality outcomes by a cluster analysis using a large-scale multicenter retrospective cohort of Japanese patients with myositis-associated ILD (JAMI).

Methods

Two-step cluster analysis of preclustering and subsequent hierarchical clustering was conducted in 185 patients who received triple-combo therapy in an unbiased manner. Initial predictors for mortality previously reported in patients with myositis-associated ILD were used as variables and included age, sex, disease duration, classification of myositis, requirement of supplemental oxygen, anti-aminoacyl tRNA synthetase (ARS) antibody, anti-melanoma differentiation-associated gene 5 (MDA5) antibody, and serum levels of C-reactive protein (CRP) and Krebs von den Lungen-6 (KL-6). The cluster model was further applied to 283 patients who received conventional regimens consisting of corticosteroids with or without a single immunosuppressive agent (dual-combo therapy or monotherapy). Cumulative survival rates were compared using Kaplan-Meier analysis, and the log-rank test was used to test for significant differences between two groups.

Results

We developed a cluster model consisting of 6 clusters, which were categorized by age at onset, clinically amyopathic dermatomyositis, CRP, KL-6, requirement of supplemental oxygen, anti-ARS antibody, and anti-MDA5 antibody. This model was judged to be of good quality based on the silhouette measure of cohesion and separation of 0.6. These clusters were regrouped into three subsets based on low (<10%), moderate (10-50%), and high (>50%) mortality rates. The performance of the clustering was generally replicated in patients who received initial dual-combo therapy or monotherapy. Survival benefits of triple-combo therapy over dual-combo therapy or monotherapy were not observed in any of the clusters.

Conclusion

We successfully developed a cluster model that stratified patients with myositis-associated ILD who were treated with initial triple-combo therapy into subgroups with different prognoses, although this model failed to identify a patient subgroup that showed survival benefits from triple-combo therapy over dual-combo therapy or monotherapy.