Hyposplenism in systemic lupus erythematosus: biological and radiological characteristics and its association with increased risk of infection

Objective This study aimed to evaluate the prevalence of hyposplenism in patients with systemic lupus erythematosus (SLE) and its association with an increased risk of infection. Methods This single-centre study included patients with SLE who underwent a systematic evaluation for Howell-Jolly bodies (HJB) on peripheral blood smear, a marker of hyposplenism. Patients exhibiting HJB were classified as having hyposplenism (cases), whereas those without such inclusions were considered to have normal splenic function (controls). We collected radiological data to assess spleen morphology. The prevalence of infections and thrombosis was recorded. Results In a tertiary care cohort of 245 patients, 23 (9.4%) demonstrated HJB on peripheral smear, after exclusion of those with a history of splenectomy or intrinsic haemolytic anaemia. In multivariable analysis, three factors were independently associated with hyposplenism: paediatric-onset SLE (OR 5.2, 95% CI 1.3 to 21.2, p=0.02), antiphospholipid syndrome (OR 6.8, 95% CI 2.2 to 20.8, p=0.001) and history of constitutional symptoms of SLE (OR 3.9, 95% CI 1.2 to 12.4, p=0.02). Patients with HJB had a higher risk of infection-related hospitalisation (OR 7.3, 95% CI 2.4 to 21.8, p<0.001), particularly pneumococcal infections (5/23 cases (21.7%) vs 1/222 controls (0.5%), p<0.001), but no increased risk of thrombosis (OR 1.6, 95% CI 0.3 to 7.8, p=0.57). Hyposplenism was associated with splenic hypoplasia identified on abdominal CT scan (6/23 assessed cases (26%) vs 0/166 assessed controls (0%), p<0.001), but not with splenic calcifications. Hyposplenism was also associated with eosinophilia, neutrophilia, monocytosis and thrombocytosis. Conclusion Hyposplenism was observed in 9.4% of patients with SLE in a tertiary care cohort and was significantly associated with an increased risk of infection and radiological splenic hypoplasia. These findings highlight the importance of preventive measures for impaired splenic function, including patient and physician education, vaccination and infection surveillance in this population.