SAT0528 IgG4-Related Disease: Baseline Clinical and Laboratory Features in 125 Patients
Authors: Z. Wallace, J. Stone, V. Deshpande, H. Mattoo, V. Mahajan, M. Kulikova, S. Pillai
Journal: Annals of the Rheumatic Diseases (2015)

<h3>Background</h3> IgG4-related disease (IgG4-RD) is an immune-mediated fibroinflammatory condition that can affect nearly any organ (1). No detailed clinical and laboratory assessments have been reported in large numbers of patients with IgG4-RD diagnoses established by strict clinicopathological correlation (2-4). <h3>Objectives</h3> To describe a single center cohort of 125 patients with biopsy-proven disease. <h3>Methods</h3> We reviewed the baseline features of 125 patients with biopsy-proven disease. The diagnosis was confirmed by pathology review according to consensus diagnostic criteria (5). Disease activity and damage were assessed by the IgG4-RD Responder Index (RI) (6). Flow cytometry was used to assess levels of circulating plasmablasts (7, 8). <h3>Results</h3> Of the 125 patients, 103 had active disease and 86 were on no treatment. Only 51% of the patients with active disease had elevated serum IgG4 concentrations. However, patients with active disease and elevated serum IgG4 concentrations were older, had a higher RI, a greater number of organs involved, lower complement levels, a higher absolute eosinophil count, and higher IgE levels compared to those with active disease but normal serum IgG4 (P&lt;0.01 for all comparisons). The correlation between IgG4+ plasmablast level and RI (R=0.45, P=0.003) was stronger than that of total plasmablasts and RI. Seventy-six (61%) of the patients were male, but no significant differences according to gender were observed with regard to disease severity, organ involvement, or serum IgG4 concentrations. Glucocorticoids failed to produce sustained remission in the majority of patients. <h3>Conclusions</h3> Nearly 50% of this patient cohort with biopsy-proven, clinically-active IgG4-RD had normal serum IgG4 concentrations. Serum IgG4 elevation identify a subset with more inflammatory features. IgG4+ plasmablasts correlate well with disease activity. <h3>References</h3> Stone JH, Zen Y, Deshpande V. IgG4-related disease. NEJM 2012; Feb 9;366(6):539-51. Zen Y, Nakanuma Y. IgG4-related disease: a cross-sectional study of 114 cases. Am J Surg Pathol 2010; Dec;34(12):1812-9. Ebbo M, Daniel L, Pavic M, Seve P, Hamidou M, Andres E, et al. IgG4-related systemic disease: features and treatment response in a French cohort: results of a multicenter registry. Medicine (Baltimore) 2012; Jan;91(1):49-56. Chen H, Lin W, Wang Q, Wu Q, Wang L, Fei Y, et al. IgG4-related disease in a Chinese cohort: a prospective study. Scand J Rheumatol 2014;43(1):70-4. Deshpande V. Consensus Statement on IgG4-RD Diagnosis. Modern Pathology 2012; 25(9):1181. Carruthers MN, Stone JH, Deshpande V, Khosroshahi A. Development of an IgG4-RD Responder Index. Int J Rheumatol 2012;2012:259408. Wallace ZS, Mattoo H, Carruthers M, Mahajan VS, Della Torre E, Lee H, et al. Plasmablasts as a biomarker for IgG4-related disease, independent of serum IgG4 concentrations. Ann Rheum Dis 2015; 74(1):190. Mattoo H, Mahajan VS, Della-Torre E, Sekigami Y, Carruthers M, Wallace ZS, et al. De novo oligoclonal expansions of circulating plasmablasts in active and relapsing IgG-related disease. J Allergy Clin Immunol 2014;134(3):679. <h3>Disclosure of Interest</h3> None declared