Systemic lupus erythematosus (SLE) is a chronic multisystem autoimmune disease with varied clinical manifestations and complex pathogenesis. SLE has a significant impact on morbidity, mortality and quality of life. Several multi-ethnic studies conducted outside sub-Saharan Africa identify black Africans as the group most at risk for morbidity and mortality among the 5,000,000 people affected by lupus worldwide. The few studies specifically focusing on SLE in sub-Saharan Africa have highlighted a non-rare incidence of the disease across the continent, use of corticosteroids and antimalarials as standard treatment as well as a high mortality rate (around 10%). France, due to its colonial history, has numerous so-called overseas territories housing a significant proportion of inhabitants of sub-Saharan African descent. The island of Mayotte, belonging to the Comoros archipelago in the Indian Ocean, is a French department since 2011 after being a French territory since 1841. To date, no study has evaluated SLE in Mayotte. The objective of this work is to describe the epidemiological and clinical aspects of systemic lupus erythematosus in Mayotte, in the Indian Ocean.

The authors evaluated all patients with SLE, diagnosed at the Mayotte Hospital Center (CHM), from 2015 to 2023. Over this 8-year period, 57 patients were diagnosed with SLE, an incidence estimated at 4 to 7 new cases per year. The age at diagnosis ranged from 17 to 33 years, a single pediatric case was reported. Within the study population, 6 patients had severe neurological damage at diagnosis (neurolupus), 29 had renal damage (nephrolupus). Concerning non-severe SLE involvement: 28 had hematological involvement, 29 had rheumatic involvement and 42 had skin involvement, including 4 with a pure discoid form. The basic treatment systematically included hydroxychloroquine as well as corticosteroid therapy. Treatments for severe forms followed the recommendations when they were updated: 14 patients received cyclophosphamide, 27 mycophenolate mofetil (MMF), 7 methotrexate, 5 azathioprine and 4 patients were on belimumab. Mortality in the study population was 2%. Complete remission of the disease was obtained for 17 patients (33%), 6 patients (11%) benefited from medical evacuation, follow-up data remained unknown for 10 patients (18%). The main complications are infectious in the foreground with cases of neuromeningeal cryptococcosis, severe bacterial endocarditis (S.aureus secreting Panton Valentine toxin), pulmonary nocardiosis and shingles. Then follow the complications of the disease: obstetric APS, deterioration of renal function then iatrogenic complications (aplasia due to azathioprin).

The uniqueness of the Mahorese cohort relies on the high prevalence of severe forms of SLE (especially kidney involvement) although non-severe forms are probably insufficiently diagnosed in the territory. The occurrence of opportunistic infection in this dysimmune status with immunosuppressive treatment is also a particularity of the Mahorean lupus population. To our knowledge, this is the first study describing the epidemiology of SLE in Mayotte. Additional studies are nevertheless necessary to evaluate the immunological and histological profile of Mahorais patients.