Paediatric autoimmune diseases with ELANE mutations associated with neutropenia

OBJECTIVE: To explore the clinical characteristics of autoimmune diseases in children with ELANE mutations. METHODS: Three cases of children with ELANE mutations manifesting as autoimmune diseases, who were under treatment from April 2020 to May 2021, were retrospectively analysed. RESULTS: Among the three children, two were boys aged 15 years and 22 months (cases 1 and 3) respectively, and the other one was a 22-month-old girl (case 2). All the cases had recurrent infections. Case 1 presented with cyclic neutropenia and systemic lupus erythematosus (SLE). Case 2 presented with severe neutropenia and autoimmune haemolytic anaemia (AHIA). Case 3 presented with severe neutropenia and anti-neutrophil cytoplasm antibodies (ANCA)-associated small vasculitis. Genetic tests showed that they all had heterozygous mutations in the ELANE gene. Case 1 was treated with methylprednisolone and hydroxychloroquine sulphate for 2 years, making neutrophil level return to normal. Case 2 received allogeneic hematopoietic stem cell transplantation and has stopped taking antibiotics, steroids and all the immunosuppressors. Case 3 received subcutaneous injections of granulocyte colony-stimulating factor, oral prednisone and cyclophosphamide. The boy in case 3 has been followed up for one year, and his absolute neutrophil count has increased to 1.56 × 10(9)/L. CONCLUSION: Patients with ELANE mutations, combined with autoimmune diseases, may have recurrent infections. Disease-modifying antirheumatic drugs (DMARDs) are effective for autoimmune diseases. Autoimmune diseases with ELANE mutations associated with neutropenia can be cured through allogeneic hematopoietic stem cell transplantation.