Pulmonary manifestations of primary Sjögren's syndrome.

Sjögren's syndrome (SS) is a complex autoimmune exocrinopathy with multifactorial pathogenesis and multisystem manifestation. It is called primary Sjögren's syndrome (PSS) when the manifestations are seen without any other co-existent rheumatic diseases. The incidence of respiratory system involvement varies widely in the reported medical literature, partly due to lack of a universal agreement over the diagnostic criteria of the disease and the type of study methods employed. Respiratory system manifestations are protean; upper airway symptoms are very common and so is the complaint of dry cough. The PSS patients may develop interstitial lung diseases (ILDs) such as usual interstitial pneumonia (UIP), non-specific interstitial pneumonia (NSIP), lymphocytic interstitial pneumonia (LIP), bronchiolitis obliterans and organising pneumonia (BOOP), etc. They may also develop the whole spectrum of lymphoproliferative disorders of the lung ranging from LIP to follicular bronchiolitis, nodular lymphoid hyperplasia and low-grade lymphomas. Therapeutic options include symptomatic and supportive measures and corticosteroids as the mainstay of the treatment for ILDs occurring in these patients. In recent years, rituximab (anti-CD20) has emerged as a promising treatment for this disease, though data from controlled trials are still lacking. Pulmonary involvement may be a source of significant morbidity in these patients, though only rarely, it is the cause of death.