Childhood-onset systemic lupus erythematosus in Singapore: clinical phenotypes, disease activity, damage, and autoantibody profiles

Childhood-onset systemic lupus erythematosus (cSLE) is a multisystem autoimmune disease characterized by immune dysregulation affecting patients less than 18 years old. One-fifth of SLE cases are diagnosed during childhood. cSLE presents differently from adults and has a more severe and aggressive course. We describe the clinical and antibody profiles in our cSLE Singapore cohort. All cSLE patients who satisfied the 1997 American College of Rheumatology diagnostic criteria were captured in our lupus registry from January 2009 to January 2014. Data including demographic, cumulative clinical, serologic data, and damage indices were collected. Adjusted mean SLEDAI-2K (AMS) was used to summarize disease activity over multiple visits. Cluster analysis using non-hierarchical K-means procedure was performed on eight selected antibodies. The 64 patients (female:male ratio 5:1; Chinese 45.3%, Malay 28.1%, Indian 9.4%, and other races 17.2%) had a mean onset age of 11.5 years (range 2.1-16.7) and mean age at diagnosis was 11.9 years (range 2.6-18.0). Our study demonstrated differences in clinical manifestations for which hematologic involvement was the most common manifestation with less renal disease and uncommon neurologic manifestation as compared to other cSLE cohorts reported in our region. Antibody clusters were identified in our cohort but their clinical association/discrimination and outcome prediction required further validation study. Outcomes of our cohort in regard to disease activity after therapy and organ damages were comparable if not better to other cSLE cohorts elsewhere. Steroid-related damage, including symptomatic multifocal avascular necrosis and cataract, were not uncommon locally. Infection remains the major cause of death for the continent. Nevertheless, the five year survival rate of our cohort (98.4%) was high.