Autoimmune diseases occur when the body’s immune system mistakenly attacks its own healthy tissues instead of foreign invaders. This misdirected response causes inflammation and damage throughout the body. While autoimmune diseases can affect nearly any organ or system, including joints, skin, and blood vessels, the lungs are also susceptible to involvement. The impact on lung tissue can vary depending on how the immune system’s attack manifests within the respiratory system.
How Autoimmunity Impacts Lungs
Autoimmune processes damage lung tissue through several mechanisms. The immune system’s attack often initiates inflammation within the lungs. This chronic inflammation can lead to scar tissue formation, known as fibrosis. Scarring stiffens lung tissue, reducing its ability to expand and efficiently exchange oxygen.
The immune system may target small blood vessels, causing pulmonary hypertension, which is increased pressure in the lung arteries that strains the heart. Alternatively, airways can become inflamed, leading to conditions similar to asthma or bronchitis. The specific lung pathology, whether interstitial lung disease, pulmonary hypertension, or airway inflammation, depends on the targeted lung area.
The immune system’s attack involves specific immune cells like macrophages and lymphocytes. In autoimmune lung disease, these cells and autoantibodies contribute to ongoing inflammation and damage. This persistent immune activity can lead to progressive, sometimes irreversible, changes in lung structure and function.
Common Autoimmune Conditions Affecting the Lungs
Several autoimmune diseases can affect the lungs, each with characteristic manifestations.
Rheumatoid Arthritis (RA)
RA, primarily known for joint inflammation, can also involve the lungs. Lung complications include interstitial lung disease (ILD), which causes scarring of lung tissue, pleurisy (inflammation of the lung lining), and rheumatoid nodules (inflammatory tissue lumps).
Systemic Lupus Erythematosus (SLE)
Lupus is a systemic autoimmune disease that frequently impacts multiple organs, including the lungs. Pleurisy and lupus pneumonitis (acute lung inflammation) are common complications. Lupus can also lead to ILD and pulmonary hypertension.
Systemic Sclerosis (Scleroderma)
Scleroderma is characterized by skin and connective tissue hardening. Lung involvement is a concern, with ILD affecting up to 50% of patients. Pulmonary hypertension is also a frequent complication, impacting lung blood vessels.
Sjögren’s Syndrome
Sjögren’s syndrome primarily affects moisture-producing glands but can also cause lung issues. Patients may develop ILD, particularly lymphocytic interstitial pneumonitis (lymphocyte accumulation in lung tissue). Airway diseases like chronic bronchitis can also occur.
Vasculitis
Vasculitis involves inflammation of blood vessels. Specific forms, such as granulomatosis with polyangiitis, can affect the lungs. Manifestations include lung nodules (inflammatory masses) and alveolar hemorrhage (bleeding into lung air sacs). These conditions can damage lung structure.
Identifying Lung Involvement
Lung involvement in autoimmune conditions often presents with symptoms. These include shortness of breath, especially during physical activity, a persistent dry cough, and chest pain, particularly if the pleura (lung lining) is inflamed. Fatigue, a general autoimmune symptom, can worsen with reduced lung function.
Diagnostic methods confirm lung involvement and assess its extent. Imaging techniques like chest X-rays provide initial views. High-resolution computed tomography (HRCT) scans offer detailed images, revealing subtle changes such as scarring or inflammation. These scans identify patterns consistent with specific lung damage.
Lung function tests measure lung performance. Spirometry assesses inhaled and exhaled air volume. Lung volume measurements determine total lung capacity. The diffusion capacity of the lung for carbon monoxide (DLCO) evaluates oxygen transfer from lungs to bloodstream.
Blood tests aid diagnosis by detecting specific autoantibodies, such as antinuclear antibodies (ANA), rheumatoid factor (RF), anti-cyclic citrullinated peptide (anti-CCP) antibodies, and antineutrophil cytoplasmic antibody (ANCA) patterns. Inflammatory markers like C-reactive protein indicate general inflammation. In some cases, a bronchoscopy or lung biopsy may be necessary for diagnosis.
Managing Lung-Related Autoimmune Conditions
Managing autoimmune diseases affecting the lungs focuses on suppressing the immune system and alleviating respiratory symptoms. Immunosuppressive medications are a primary treatment. These include corticosteroids, which quickly reduce inflammation, and conventional disease-modifying antirheumatic drugs (DMARDs) that slow disease progression. Biologic therapies target specific immune components to dampen activity. The goal is to calm the immune response, reducing inflammation and preventing further lung damage.
Symptom management is also important. Oxygen therapy provides supplemental oxygen for significant shortness of breath. Pulmonary rehabilitation programs offer exercises and education to improve lung function and quality of life. Medications for cough or other respiratory symptoms may also be prescribed.
Lifestyle considerations support lung health. Avoiding lung irritants, such as cigarette smoke, helps prevent further damage. Vaccinations for influenza and pneumonia are important to prevent infections that could compromise lung function. Maintaining general health through a balanced diet and regular physical activity supports overall well-being.
Care for lung-related autoimmune conditions often involves a multidisciplinary team. Rheumatologists, specializing in autoimmune diseases, collaborate with pulmonologists, who focus on lung conditions. Other specialists, such as physical and occupational therapists, may also be involved to provide comprehensive care.