Is Sjogren's (Sjogren's syndrome) syndrome an autoimmune disease?

Sjögren's Syndrome: An Autoimmune Disease

Yes, Sjögren's syndrome is definitively an autoimmune disease characterized by immune-mediated infiltration of the lacrimal and salivary glands with lymphocytes, leading to glandular dysfunction and systemic manifestations. 1

Pathophysiology and Classification

Sjögren's syndrome is characterized by:

• Lymphocytic infiltration of exocrine glands, particularly lacrimal and salivary glands 1
• Production of autoantibodies, with anti-SSA/Ro antibodies being the most specific marker 1, 2
• Immune-mediated inflammation leading to glandular dysfunction 3

The disease is classified as:

1. Primary Sjögren's syndrome: Occurs alone as an independent autoimmune condition
2. Secondary Sjögren's syndrome: Occurs in association with other autoimmune diseases such as rheumatoid arthritis, systemic lupus erythematosus, or scleroderma 1

Clinical Manifestations

Glandular Manifestations

• Xerophthalmia (dry eyes) due to decreased lacrimal gland function
• Xerostomia (dry mouth) due to decreased salivary gland function 1

Systemic Manifestations

• Fatigue, arthralgia, and myalgia (common symptoms) 1
• Pulmonary complications (in approximately 10% of patients) 1
  • Diffuse interstitial pneumonitis
  • Bronchial hyperreactivity
  • Bronchiectasis
• Other organ involvement:
  • Cutaneous manifestations
  • Neurological symptoms
  • Renal involvement
  • Vasculitis 2

Diagnostic Criteria

The latest classification criteria for Sjögren's syndrome are based on a weighted scoring system that includes:

• Anti-SSA/Ro antibody positivity (3 points)
• Focal lymphocytic sialadenitis with focus score ≥1 foci/4 mm² (3 points)
• Abnormal ocular staining score ≥5 (1 point)
• Schirmer's test result ≤5 mm/5 minutes (1 point)
• Unstimulated salivary flow rate ≤0.1 ml/minute (1 point)

A total score of ≥4 meets the criteria for primary Sjögren's syndrome 1

Epidemiology

• Prevalence: Approximately 0.4% of the population 1
• Annual incidence: 3.9-5.3 per 100,000 1
• Female-to-male ratio: 20:1 1
• About 10% of patients with clinically significant dry eye have underlying Sjögren's syndrome 1

Clinical Significance and Complications

Sjögren's syndrome patients are at increased risk for:

• Lymphoproliferative disorders (16-times increased risk compared to general population) 3
• Vasculitic complications 2
• Other ocular manifestations of immune dysfunction (scleritis, sterile keratitis, uveitis) 1
• Decreased quality of life due to chronic symptoms 1

Management Considerations

The European League Against Rheumatism (EULAR) recommends a treatment approach that addresses:

1. The central triplet of symptoms (dryness, fatigue, and pain)
2. Systemic manifestations when present 1

Treatment options include:

• Topical therapies for dry eyes and mouth
• Systemic therapies including hydroxychloroquine, glucocorticoids, immunosuppressants, and biologics for systemic manifestations 1

Important Clinical Considerations

• Patients with Sjögren's syndrome should be co-managed with a rheumatologist due to potential systemic complications 1
• Regular monitoring for development of lymphoma is essential, particularly in patients with decreased C4 levels 1
• Anti-Ro antibody positive women require special monitoring during pregnancy due to risk of congenital heart block in offspring 2

Sjögren's syndrome represents a classic example of an autoimmune disease with both organ-specific manifestations and systemic features, requiring multidisciplinary care and vigilance for potentially serious complications.