Correct Answer: A. Lymphocytic infiltration and destruction of salivary and lacrimal glands ✅
Sjögren syndrome is a systemic autoimmune disorder characterized by lymphocytic infiltration and destruction of exocrine glands, particularly the salivary and lacrimal glands. The presence of anti-Ro (SSA) and anti-La (SSB) antibodies is pathognomonic for primary Sjögren syndrome. These autoantibodies target intracellular antigens (Ro52, Ro60, and La proteins) present in epithelial cells of the affected glands. The pathological mechanism involves CD4+ and CD8+ T lymphocytes infiltrating the glands, forming lymphoid aggregates and germinal centers, leading to progressive destruction of acinar tissue. This results in the classic presentation of xerophthalmia (dry eyes) and xerostomia (dry mouth). The anti-La antibody is highly specific for Sjögren syndrome and is almost always accompanied by anti-Ro positivity. The lymphocytic infiltration causes loss of secretory function, explaining the clinical symptoms. This is a Type IV hypersensitivity reaction (cell-mediated immunity) rather than antibody-mediated destruction, though autoantibodies serve as markers of the disease. Indian prevalence is significant, particularly in women aged 40–60 years, and diagnosis relies on the combination of clinical features, positive serology, and characteristic histopathology showing lymphocytic infiltration with focus score ≥1.
Why the other options are wrong
B. Destruction of exocrine glands by neutrophils — This is wrong because Sjögren syndrome is fundamentally a lymphocyte-mediated (T cell and B cell) autoimmune disease, not a neutrophil-driven process. While neutrophils may be present in inflammatory infiltrates, they are not the primary destructive cells. Neutrophil-mediated gland destruction is characteristic of other conditions like granulomatosis with polyangiitis (GPA), not Sjögren syndrome. This option represents a misunderstanding of the cellular immunology underlying the disease. C. Deposition of amyloid in salivary glands — This is wrong because amyloid deposition is not the pathological hallmark of Sjögren syndrome. While amyloidosis can occur in chronic inflammatory conditions, it is not the primary mechanism of gland destruction in Sjögren syndrome. Amyloid deposition is more characteristic of systemic amyloidosis (AL or AA type) or light-chain disease. The histopathology of Sjögren syndrome shows lymphocytic infiltration and acinar atrophy, not amyloid deposits. This is an NBE distractor exploiting knowledge of chronic inflammation. D. IgE-mediated hypersensitivity reaction — This is wrong because Sjögren syndrome is not an IgE-mediated (Type I) hypersensitivity reaction. IgE-mediated reactions are immediate, allergic responses (e.g., anaphylaxis, allergic rhinitis). Sjögren syndrome is a Type IV hypersensitivity reaction involving T cell-mediated immunity and B cell autoantibody production (IgG, not IgE). The presence of anti-Ro and anti-La antibodies (IgG class) indicates a chronic autoimmune process, not acute allergic sensitization. This option confuses the type of immune response involved.
High-Yield Facts
- Anti-La (SSB) antibody is highly specific for primary Sjögren syndrome and is almost always accompanied by anti-Ro (SSA) positivity.
- Sjögren syndrome pathology is Type IV hypersensitivity (cell-mediated) with CD4+ and CD8+ T lymphocyte infiltration forming lymphoid aggregates in salivary and lacrimal glands.
- Focus score ≥1 (≥50 lymphocytes per 4 mm² of gland tissue) on minor salivary gland biopsy is diagnostic for Sjögren syndrome.
- Sjögren syndrome predominantly affects middle-aged to older women (female:male ratio ~9:1) in Indian populations.
- Xerostomia and xerophthalmia result from progressive loss of acinar tissue due to lymphocytic infiltration, not from antibody-mediated blockade of secretion.
Mnemonics
SSA/SSB = Sjögren Specific Antibodies Anti-Ro (SSA) and anti-La (SSB) are the hallmark serological markers of Sjögren syndrome. La is more specific; Ro is more sensitive. Both indicate lymphocytic autoimmunity against exocrine glands. SICCA Syndrome Sjögren's = Inflammatory Chronic Autoimmune disease. Presents with Sicca symptoms (dry eyes, dry mouth) due to lymphocytic destruction of lacrimal and salivary glands, not antibody blockade.
NBE Trap
NBE pairs Sjögren syndrome with "antibody-mediated destruction" or "neutrophil-driven inflammation" to lure students who confuse it with other autoimmune conditions (e.g., GPA with neutrophils, or myasthenia gravis with antibody blockade). The key discriminator is that Sjögren is fundamentally a lymphocytic infiltration disease with secondary autoantibody production.
Clinical Pearl
In Indian clinical practice, Sjögren syndrome often presents insidiously in middle-aged women with complaints of "dry mouth" and "gritty eyes," frequently misdiagnosed as simple xerosis or allergic conjunctivitis. Serology (anti-Ro/SSA and anti-La/SSB) combined with minor salivary gland biopsy showing lymphocytic infiltration clinches the diagnosis and guides immunosuppressive therapy to prevent further gland destruction.
_Reference: Robbins and Cotran Pathologic Basis of Disease, Ch. 6 (Diseases of Immunity); Harrison's Principles of Internal Medicine, Ch. 330 (Sjögren Syndrome)_