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Objective: For the definitive diagnosis of IgG4-related disease (IgG4-RD), biopsies of local lesions are recommended so as to exclude other diseases, including lymphoma and cancer. However, performing biopsies of underlying organs is technically difficult. In this study, we examined the diagnostic utility of labial salivary gland (LSG) biopsy as a less invasive procedure., Methods: Sixty-six patients with suspected IgG4-RD by clinical findings or high serum IgG4 underwent LSG biopsy. We examined the relationship between the number of IgG4-positive plasma cells in LSG and clinical findings., Results: The final diagnosis was 45 patients with IgG4-RD, 12 with Sjögren's syndrome, four with suspected Sjögren's syndrome, three with malignant lymphoma, one with systemic lupus erythematosus, and one with Warthin's tumor. The sensitivity, specificity, and accuracy of LSG biopsy were 55.6%, 100.0%, and 70.0%, respectively. Forty-five IgG4-RD patients were divided into two groups: 1) 25 with lesions of salivary glands (IgG4-RD S+) and 2) 20 without these lesions (IgG4-RD S-). Seventeen of 25 (68.0%) IgG4-RD S + and 8 of 20 (40.0%) IgG4-RD S - patients were positive for LSG biopsy. In the IgG4-RD S - patients, the mean number of affected organs and serum IgG4 in the positive cases for LSG biopsy were significantly higher than in the negative cases., Conclusion: A solo LSG biopsy is insufficient for the diagnosis of IgG4-RD because of its low sensitivity. However, LSG biopsy combined with clinical findings, including serum IgG4 and number of affected organs, may contribute towards a diagnosis of IgG4-RD patients with affected underlying organs.

In the labial salivary glands (LSGs) of 16 primary and 18 secondary Sjögren's syndrome (SS) patients, infiltrating lymphocytes were histologically and immunohistochemically examined; also, the serum levels of rheumatoid factor, antinuclear antibodies, anti-DNA antibodies, anti-SS-A and anti-SS-B antibodies, and immunoglobulins (including IgG, IgM and IgA) were all assayed. An immunohistochemical analysis of the lymphocyte subsets in LSGs revealed that severe lymphocytic infiltration was frequently accompanied by marked B cell accumulation both in primary and secondary SS patients. Furthermore, local B cell accumulation was also closely associated with elevated levels of anti-SS-A and anti-SS-B antibodies and IgG, and this association was statistically significant in the group with primary SS but not in the group with secondary SS. Thus, local lymphocytic infiltration, especially B cell accumulation, in the salivary glands is suggested to be involved in serological abnormalities in primary SS, while complicated autoimmune diseases other than SS may also be involved in serological abnormalities in secondary SS. [ABSTRACT FROM AUTHOR]