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IgG4-related disease (IgG4-RD) is a rare immune-mediated condition with multi-organ involvement and varied clinical presentations. While recognition of IgG4-RD has grown, limited data exist regarding ethnic differences in its manifestation and outcomes. This study examined ethnic disparities in the presentation, management, and clinical outcomes of IgG4-RD.We retrospectively analysed 29 patients diagnosed with IgG4-RD at a tertiary pancreaticobiliary clinic. Data were sourced from King’s College Hospital NHS Foundation Trust electronic patient records. Patients were categorized into three ethnic groups: Black ethnic group (primarily African-Caribbean), White ethnic group, and Asians (including West, East, and Southeast Asians). Comparative analyses were performed between ethnic minority groups (African and Asian groups), which was quite a diverse and heterogenous group, and the White group, on demographics, clinical features, investigations, management, and outcomes.When comparing the ethnic minority groups (n=17) to the White population (n=12), several clinical differences were noted. Jaundice was more common in patients from minority ethnic backgrounds (88.2% vs. 58.3%), as well as weight loss (58.8% vs. 33.3%) and abdominal pain (58.8% vs. 33.3%). Pruritus, submandibular, salivary and lacrimal gland involvement were unique to the patients in the ethnic minority group. Pancreatic involvement was seen in all patients in the ethnic minority group (100%) compared to 83.3% of the White group, and retroperitoneal fibrosis was nearly twice as frequent (17.6% vs. 8.3%). Serum IgG4 levels were elevated more in the ethnic minority group (mean 2.80 g/L) compared to White group (2.15 g/L). However, histological findings were consistent across groups, with similar rates of lymphoplasmacytic infiltrate, storiform fibrosis, and obliterative phlebitis, as well as comparable IgG4+ cell counts and IgG4/IgG+ ratios. In terms of outcome, the remission rate in the ethnic minority group was 88.2%, lower than the 100% observed in the White population. Treatment approaches, including immunosuppressive therapy and surgery, were generally similar, although patients in the Black ethnic group more frequently required multiple agents.In conclusion, the ethnic minority group exhibited more severe clinical symptoms and extensive organ involvement, with lower remission rates than the White group. Despite similar histological patterns and treatment regimens, outcome disparities suggest the need for earlier recognition and potentially tailored management strategies in ethnically diverse populations.Abstract P42 Table 1References Wallace ZS, Zhang Y, Perugino CA, Naden R, Choi HK, Stone JH; ACR/EULAR IgG4-RD Classification Criteria Committee. Clinical phenotypes of IgG4-related disease: an analysis of two international cross-sectional cohorts. Ann Rheum Dis. 2019;78(3):406–412. doi:10.1136/annrheumdis-2018–214603Poo SX, Tham CSW, Smith C, Lee J, Cairns T, Galliford J, et al. IgG4-related disease in a multi-ethnic community: clinical characteristics and association with malignancy. QJM. 2019;112(10):763–769. doi:10.1093/qjmed/hcz149Fong W, Liew I, Tan D, Lim KH, Low A, Leung YY. IgG4-related disease: features and treatment response in a multi-ethnic cohort in Singapore. Int J Rheum Dis. 2018;21(11):1923–1929. doi:10.1111/1756–185X.13447Stone JH, Zen Y, Deshpande V, Carruthers M. IgG4-related disease: what a hematologist needs to know. Haematologica. 2020;105(3):561–572. doi:10.3324/haematol.2019.220947