Hematologic Manifestations and Predictors of Lymphoma Development in Primary Sjögren Syndrome

The diverse hematologic manifestations of primary Sjögren syndrome (pSS) have not been systematically investigated, and their prognostic relevance remains unclear. We conducted a retrospective study of 536 consecutive patients followed in our institution to assess the prevalence of hematologic abnormalities and their associations with various disease manifestations in pSS. We also aimed to identify risk factors for the development of non-Hodgkin lymphoma (NHL) overall and by subtype. Anemia of chronic disease and hypergammaglobulinemia were the most prevalent hematologic manifestations encountered at diagnosis and during the course of pSS. Univariate analysis between cytopenias and glandular manifestations revealed a statistically significant correlation between lymphocytopenia and parotid gland enlargement (p = 0.002), as well as between neutropenia and xerostomia (p = 0.019). Anemia, lymphocytopenia, thrombocytopenia, hypergammaglobulinemia, the presence of monoclonal serum proteins, and cryoglobulinemia correlated significantly with the presence of extraglandular symptoms such as palpable purpura, lymphadenopathy, and splenomegaly. Lymphoma was diagnosed in 7.5% (95% confidence interval [CI], 5.4%-10%) of patients. Marginal zone B-cell lymphomas (MZBCLs) were the predominant histologic type (65%; 95% CI, 48.3%-79.4%), while diffuse large B-cell lymphomas (DLBCLs) accounted for 17.5% (95% CI, 7.3%-32.8%) of all cases. The development of NHL in patients with pSS could be predicted by the presence of simple clinical and laboratory factors at diagnosis: neutropenia (p = 0.041), cryoglobulinemia (p = 0.008), splenomegaly (p = 0.006), lymphadenopathy (p = 0.021), and low C4 levels (p = 0.009). Patients carrying any of these factors had a more than 5-fold increased risk of NHL compared to patients with no risk factors at all. The above set of disease characteristics could predict subsequent development of MZBCL; the presence of lymphocytopenia (p = 0.044) at diagnosis served as a risk factor for the development of a non-MZBCL, most commonly DLBCL. Anemia of chronic disease and hypergammaglobulinemia are common hematologic manifestations at diagnosis and during the course of pSS. Neutropenia and cryoglobulinemia at diagnosis are significantly associated with an increased risk of lymphoma development. Abbreviations: AECC = American-European Consensus Classification, CI = confidence interval, DLBCL= diffuse large B-cell lymphoma, HR = hazard ratio, MALT = mucosa-associated lymphoid tissue, MZBCL = marginal zone B-cell lymphoma, NHL = non-Hodgkin lymphoma, NPV = negative predictive value, PPV = positive predictive value, pSS = primary Sjögren syndrome.