Sjögren’s syndrome is a chronic, immune-mediated, condition of unknown aetiology characterized by focal lymphocytic infiltration of exocrine glands associated with dry mouth and eyes. It occurs in its own right (primary Sjögren’s syndrome, pSS), or as a late feature of other rheumatic diseases such as rheumatoid arthritis, systemic lupus erythematosus or scleroderma (secondary Sjögren’s syndrome).
There is a strong female bias. pSS typically affects women in their middle years with an estimated prevalence of 0.1–0.6%. 75% of patients have anti-Ro and/or anti-La antibodies, often with raised immunoglobulin levels (hypergammaglobulinaemia). In patients without these antibodies the diagnosis can be confirmed by salivary gland biopsy.
Treatment is generally symptomatic using artificial tears, saliva replacements/stimulants and good dental hygiene. Three-quarters of patients with pSS report significant fatigue with a negative impact on quality of life. This can be the most disabling symptom. Approximately 20% of patients develop systemic features including persistent salivary gland swelling, cutaneous vasculitis, peripheral neuropathy, interstitial lung disease, autoimmune cytopenias or renal tubular acidosis. Hydroxychloroquine and corticosteroids are the most widely used therapies for systemic features.
There is a 44fold increased risk of mucosa-associated lymphoid tissue (MALT) B-cell lymphoma in pSS, typically affecting the salivary glands. On account of abnormalities in the B-cell system in pSS there is current interest in the use of anti-B-cell directed monoclonal antibodies to treat pSS and a number of clinical trials are in progress. This approach is already successfully in use for treating MALT lymphoma in pSS.