BackgroundThe purpose of this study is to characterize the risk of cancer in a large cohort of patients with primary Sjögren syndrome (SjS).MethodsWe had analyzed the development of cancer in 1300 consecutive patients fulfilling the 2002 SjS classification criteria. The baseline clinical and immunological characteristics and systemic activity (ESSDAI scores) were assessed at diagnosis as predictors of cancer using Cox proportional hazards regression analysis adjusted for age at diagnosis and gender. The sex-and age-specific standardized incidence ratios (SIR) of cancer were estimated from 2012 Spanish mortality data.ResultsAfter a mean follow-up of 91 months, 127 (9.8%) patients developed 133 cancers. The most frequent type of cancer was B-cell lymphoma (including 27 MALT and 19 non-MALT B-cell lymphomas). Systemic activity at diagnosis of primary SjS correlated with the risk of hematological neoplasia and cryoglobulins with a high risk of either B-cell or non-B-cell lymphoma subtypes. Patients with cytopenias had a high risk of non-MALT B-cell and non-B-cell cancer, while those with low C3 levels had a high risk of MALT lymphomas and those with monoclonal gammopathy and low C4 levels had a high risk of non-MALT lymphomas. The estimated SIR for solid cancer was 1.13 and 11.02 for hematological cancer. SIRs for specific cancers were 36.17 for multiple myeloma and immunoproliferative diseases, 19.41 for Hodgkin lymphoma, 6.04 for other non-Hodgkin lymphomas, 5.17 for thyroid cancer, 4.81 for cancers of the lip and oral cavity, and 2.53 for stomach cancer.ConclusionsOne third of cancers developed by patients with primary SjS are B-cell lymphomas. The prognostic factors identified at SjS diagnosis differed according to the subtype of B-cell lymphoma developed. Primary SjS is also associated with the development of some non-hematological cancers (thyroid, oral cavity, and stomach).Electronic supplementary materialThe online version of this article (doi:10.1186/s13045-017-0464-5) contains supplementary material, which is available to authorized users.

Aberrant nucleic acids generated during viral replication are the main trigger for antiviral immunity, and mutations disrupting nucleic acid metabolism can lead to autoinflammatory disorders. Here we investigated the etiology of X-linked reticulate pigmentary disorder (XLPDR), a primary immunodeficiency with autoinflammatory features. We discovered that XLPDR is caused by an intronic mutation that disrupts expression of POLA1, the gene encoding the catalytic subunit of DNA polymerase-α. Unexpectedly, POLA1 deficiency results in increased type I interferon production. This enzyme is necessary for RNA:DNA primer synthesis during DNA replication and strikingly, POLA1 is also required for the synthesis of cytosolic RNA:DNA, which directly modulates interferon activation. Altogether, this work identified POLA1 as a critical regulator of the type I interferon response.

Primary SS is undeniably a systemic disease, with the joints, lungs, skin and peripheral nerves being the most frequently involved organs. Cytopenias, hypocomplementaemia and cryoglobulinaemia at diagnosis strongly correlated with higher cumulated ESSDAI scores in the clinical domains. Clinically the ESSDAI provides a reliable picture of systemic involvement in primary SS.

This study provides the first evidence of a strong influence of geolocation and ethnicity on the phenotype of primary SjS at diagnosis.

Patients with primary SS, who present at diagnosis with high systemic activity (ESSDAI ≥14) and/or predictive immunological markers (especially those with more than one), are at higher risk of death.