- Increase in urinary eosinophils and IL-5 in lupus nephritis patients. - Eosinophil level showed correlation with renal function and SLE disease activity. - Patients with eosinophiluria and tissue eosinophil infiltration were more likely to progress to end-stage kidney disease. - Blood eosinophil levels between SLE patients and healthy controls were comparable. Here, IL5 is linked to systemic lupus erythematosus.