FRI0599 A retrospective overview of clinical features, serology and histology of IGG4 related disease in hong kong: a dataset of 108 patients from four regional hospitals

Background IgG4 related disease (IgG4RD) is a spectrum of immune mediated disease with multiple organs involvement characterized by organ enlargement, function loss or obstructive symptoms (1, 2). Objectives In this retrospective study, clinical, serological and histological features of IgG4RD patients over the past ten years from four regional hopsitals were reviewed. Methods Four regional hospitals participated with study period from 1/1/2006 to 30/6/2016. IgG4RD patients were classifed into definite, probable and possible IgG4RD according to Japanese Comprehensive Diagnostic Criteria for IgG4RD (3). Statistical analysis: Association between the individual categorical covariates and the different organ involvement were analyzed by Fisher9s exact test. Results 108 patients were included. There were 81 male patients and 27 female patients and the male to female ratio is 3:1. The mean age of diagnosis was 62.8 year old. 57 patients were diagnosed as definite IgG4RD (53%), 14 patients as probable IgG4RD (13%) and 37 patients as possible IgG4RD (34%). Salivary glands involvement was the commonest, (M=45.7% vs F=33.3%), followed by pancreas (M=28.4% vs F=18.5%) and biliary system in male (M=24.7% vs F=11.1%) and orbital in female (M=23.5% vs F=18.5%). 53% patients also had multi organ involvement. 104 patients had serum IgG4 level checked and it was raised in 94 patients (90.4%). 77 patients (74.0%) had IgG4 level above twice upper limit of normal. IgG4 level was normal in 10 patients. 98% and 86.3% patients with multi organ involvement had IgG4 level >135mg/dL (p=0.016) and >270mg/dL (p=0.007) respectively. In the hepatobiliary group (n=36), 30 patients had blood checked for Ca19.9 level and it was raised in 17 patients (56.7%), with the highest level 14127 U/ml. 71 histological reports were available. Lymphoplasmacytic infiltration was a consistent features in all specimens (100%). Eosinophilic infiltration was seen in 19 specimen (27%). Fibrosis was seen in 44 specimens (63%). Sialadenitis and dacryoadenitis were associated with dense fibrosis. Obliterative phlebitis was seen in 7 specimens (10%). IgG4/IgG ratio was reported in 61 specimens. 53 specimens had IgG4/IgG ratio greater than 40% per high power field which accounted for 86.9% of the specimens. Conclusions Most patients were male with the peak diagnosis at age 50 to 70. Salivary gland and pancreas were the most common organ involved. Most patients had a raised IgG4 level and most histological specimens showed a raised IgG4/IgG ratio on immunostaining. IgG4 level twice the upper limit of normal was quite specific for the disease and was associated with multi organ involvement. References Pieringer H, et al. IgG4- related disease: an orphan disease with many faces. Orphanet journal of rare diseases. 2014;9:110. Haitao Du YW et al. IgG4-related disease and the curreny status of diagnostic approaches. EXCLI. 2012;11:651–8. Umehara H, et al. Comprehensive diagnostic criteria for IgG4-related disease (IgG4-RD), 2011. Modern Rheumatology. 2012;22(1):21–30. Disclosure of Interest None declared