IgG4-related disease is a newly recognized fibro-inflammatory condition characterized by several features: a tendency to form tumefactive lesions in multiple sites; a characteristic histopathological appearance; andoften but not always-elevated serum IgG4 concentrations. An international symposium on IgG4-related The histopathology of IgG4-related disease was a specific focus of the international symposium. The primary purpose of this statement is to provide practicing pathologists with a set of guidelines for the diagnosis of IgG4-related disease. The diagnosis of IgG4-related disease rests on the combined presence of the characteristic histopathological appearance and increased numbers of IgG4 þ plasma cells. The critical histopathological features are a dense lymphoplasmacytic infiltrate, a storiform pattern of fibrosis, and obliterative phlebitis. We propose a terminology scheme for the diagnosis of IgG4-related disease that is based primarily on the morphological appearance on biopsy. Tissue IgG4 counts and IgG4:IgG ratios are secondary in importance. The guidelines proposed in this statement do not supplant careful clinicopathological correlation and sound clinical judgment. As the spectrum of this disease continues to expand, we advocate the use of strict criteria for accepting newly proposed entities or sites as components of the IgG4-related disease spectrum.

Our comprehensive diagnostic criteria for IgG4-RD are practically useful for general physicians and nonspecialists.

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Objectives We propose new classification criteria for Sjögren’s Syndrome (SS), which are needed considering the emergence of biological agents as potential treatments and their associated co-morbidity. These criteria target individuals with signs/symptoms suggestive of SS. Methods Criteria are based on expert opinion elicited using the Nominal Group Technique, and analyses of data from the Sjögren’s International Collaborative Clinical Alliance. Preliminary criteria validation included comparisons with classifications based on the American-European-Consensus-Group (AECG) criteria, a model-based “gold standard” obtained from Latent Class Analysis (LCA) of data from a range of diagnostic tests, and a comparison with cases and controls collected from sources external to the population used for criteria development Results Validation results indicate high levels of sensitivity and specificity for the criteria. Case definition requires at least 2 out of the following 3: Positive serum anti-SSA and/or anti-SSB or [positive rheumatoid factor and ANA ≥ 1:320]; Ocular staining score ≥ 3; Presence of focal lymphocytic sialadenitis with focus score ≥ 1 focus/4mm2 in labial salivary gland biopsies. Observed agreement with the AECG criteria is high when these are applied using all objective tests. However, AECG classification based on allowable substitutions of symptoms for objective tests results in poor agreement with the proposed and LCA-derived classifications. Conclusion These classification criteria developed from registry data collected using standardized measures are based on objective tests. Validation indicates improved classification performance relative to existing alternatives, making them more suitable for application in situations where misclassification may present health risks.

Our comprehensive diagnostic criteria for IgG4-RD are practically useful for general physicians and nonspecialists.