From the Guidelines
For patients with Mixed Connective Tissue Disease (MCTD), mycophenolate is conditionally recommended over other therapies for the treatment of interstitial lung disease (ILD) due to its preferred status in the hierarchy of treatments 1. When considering treatment options for MCTD, it's essential to take into account the specific symptoms and organ involvement.
- For ILD associated with MCTD, the initial treatment options include mycophenolate, tocilizumab, rituximab, and azathioprine, with mycophenolate being the preferred choice 1.
- Additional options for ILD treatment in MCTD include cyclophosphamide and JAK inhibitors, which can be considered based on specific patient factors and disease severity 1.
- Glucocorticoids are generally not recommended as first-line treatment for ILD in MCTD, particularly in patients with a systemic sclerosis (SSc) phenotype, due to the risk of renal crisis 1. Key considerations in the treatment of MCTD include:
- Regular monitoring of disease activity, medication side effects, and organ function
- Symptom-specific treatments, such as NSAIDs for arthralgia and proton pump inhibitors for esophageal reflux
- The use of immunosuppressive medications, such as methotrexate, mycophenolate mofetil, and azathioprine, for maintenance therapy or steroid-sparing effects 1.
From the Research
Definition and Characteristics of MCTD
- Mixed Connective Tissue Disease (MCTD) is a rare autoimmune condition that shares features of other autoimmune diseases, such as systemic lupus erythematosus (SLE), systemic sclerosis, inflammatory myopathy, rheumatoid arthritis, and Sjogren's syndrome 2.
- MCTD is characterized by the presence of anti-Ribonucleoprotein antibodies directed against the U1 complex (anti-U1RNP) 3.
- The disease has a heterogeneous clinical presentation, making diagnosis difficult due to its rarity and the lack of validated classification criteria 3.
Clinical Features and Complications
- Clinical features of MCTD include Raynaud's phenomenon, inflammatory arthritis, puffy fingers, myalgia and/or myositis, and rarely, trigeminal neuropathy 3.
- Longstanding disease is generally associated with the development of Pulmonary Hypertension and Interstitial Lung Disease, which are the two main causes of mortality in MCTD 3.
- MCTD can also involve musculoskeletal, skin, and vascular changes, as well as internal organ complications 4.
Diagnosis and Treatment
- Diagnosis of MCTD is arrived at by the association of clinical, serological, and instrumental evaluation, with anti-U1RNP being a specific autoantibody present in all commercial kits for Extractable Nuclear Antigens 3.
- Treatment of MCTD often involves immunosuppressive therapies, with hydroxychloroquine (HCQ) and glucocorticoids (GC) being the cornerstones of treatment 5.
- Disease-modifying antirheumatic drugs (DMARDs) and immunosuppressants (IS) are used for musculoskeletal involvement, pulmonary arterial hypertension (PAH), and interstitial lung disease (ILD) 5.
- Methotrexate therapy has been used in the treatment of MCTD, although evidence from clinical trials is limited 4.