Background/Purpose:

IgG4-related disease (IgG4-RD) is an immune-mediated condition which clinical spectrum encompasses single or multiple organ involvement. Enlargement of major and minor salivary glands is one of the main disease features. Whether salivary gland enlargement is associated with systemic involvement has not been previously evaluated. The purpose of this study was to elucidate if salivary gland enlargement is associated with systemic disease. 

Methods:  We included patients with an established diagnosis (definitive: organ involvement, biopsy proven and high IgG4 levels; probable: organ involvement, biopsy proven without high IgG4 levels; possible: organ involvement, high IgG4 levels without histology) of IgG4-RD according to the Comprehensive Diagnostic Criteria, who regularly attend a tertiary referral center in Mexico City (2000-2017). We retrospectively collected demographics, clinical (organ involvement, disease activity and damage assessed by the IgG4-RD Responder Index [IgG4-RD RI] at basal and at 6 months of follow-up, number of relapses, remission and treatment), basal laboratory (C3, C4, ESR, PCR, total eosinophil count, IgG4 levels) as well as imaging and histologic data.

Results:

We included 32 patients, 17 (53.1%) men, mean age 50.2 ± 14.1 years and median disease duration 20.5 months. Seven (21.9%) have a definitive diagnosis, 12 (37.5%) probable and 13 (40.6%) possible. Overall we identified 21 anatomic sites affected, mainly pancreas 56.2%, lymph nodes 56.2%, lacrimal glands 37.5% and bile duct 34.3%. Salivary gland involvement was present in 12 (37.5%) patients (2 parotid, 3 minor salivary gland and 7 both). Among these patients, only 5 (41.6%) referred dry mouth and in 7 patients (58.3%) glandular enlargement was the onset disease feature. Salivary glandular enlargement was identified only radiologically in 5 patients (41.6%) and both clinical and radiologically in 7 (58.3%) patients. When we compared patients with (n=12) vs. without (n=20) salivary gland enlargement, the first group had a higher number of affected organs (6.5 vs. 2, p=0.0001) and absolut eosinophil’s count (348 vs. 137.5/mm³, p=0.05), a higher prevalence of lacrimal glands (75% vs. 15%, p=0.002), lymph nodes (91.7% vs. 35%, p=0.002) and lung involvement (33.3% vs. 0%, p=0.01), azathioprine use (83.3% vs. 30%, p=0.003), as well as a higher basal IgG4-RD RI (12 vs. 6, p=0.001) and a longer delay in diagnosis (64 month vs. 6.5 months, p=0.001). We did not find differences regarding gender, age, IgG4 serum levels, C3, C4, ESR, PCR, antinuclear antibodies, rheumatoid factor, anti-Ro/SSA and anti-La/SSB antibodies (negative in all patients), number of relapses, remission at 6 months and damage. We performed a logistic regression analysis (only including the number of organs, the basal IgG4-RD RI and time of follow-up) and found an association of salivary gland enlargement with the basal IgG4-RD RI (OR 1.63, 95% CI 1.12-2.35, p=0.009).

Conclusion:  Our study highlights the systemic nature of IgG4-RD. Patients with salivary gland enlargement should be routinely screened for systemic involvement.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/salivary-gland-enlargement-in-igg4-related-disease-is-associated-with-multiorgan-involvement-and-higher-basal-disease-activity/