Clinical, morphological features and prognostic factors associated with interstitial lung disease in primary Sjӧgren's syndrome: A systematic review from the Italian Society of Rheumatology

Objective: To evaluate the prevalence, clinical presentation, serological and morphological features of, and therapeutic options for Interstitial Lung Disease (ILD) in primary Sjögren's Syndrome (pSS).

Methods: Pubmed was searched between February 1996 and December 2018 using a combination of MESH terms related to pSS and ILD. Selected works were subjected to blind evaluation by two authors and a senior author in case of disagreement. The work followed PRISMA guidelines and was registered on PROSPERO (CRD42018118669).

Results: About 20% of pSS patients have ILD, with a 5-y survival of 84% and a need for supplemental oxygen in the 11-33% range. A significant proportion of ILD patients are seronegative without sicca syndrome. ILD seems to be associated with higher levels of Lactic Dehydrogenases and positivity for Anti-Ro52k. The prevalent pattern in High Resolution Computed Tomography is Nonspecific Interstitial Pneumonia (NSIP), but all other patterns can be present. No difference in mortality was found between patients with NSIP and Usual Interstitial Pneumonia patterns. Amyloidosis and primary lung lymphoma can be observed in about 10% of pSS patients.

Conclusion: The recognition of pSS underlying an ILD can be challenging in seronegative patients with no or mild sicca symptoms. A complete diagnostic assessment, including minor salivary glands and, in some cases, lung biopsy, should be performed on all patients at risk. A better recognition of the clinical or serological markers of ILD progression in these patients is warranted to drive the physicians to an early diagnosis and an effective treatment.