Immune ontogeny in childhood-onset systemic lupus erythematosus: effect of immune maturity on disease phenotype and therapeutic responses.

Childhood-onset systemic lupus erythematosus (cSLE) occurs during a period of significant developmental changes in the immune system, when tolerance checkpoints and regulatory networks continue to mature. Compared with adult-onset SLE (aSLE), cSLE more frequently presents with strong type I interferon activity, BAFF-induced B-cell hyperactivation, and increased activity of T follicular helper cells that promote persistent generation of autoantibodies. These changes induce an IFN-BAFF-B-cell-immune complex-complement axis positive feedback loop that can affect developmentally vulnerable organs, thus increasing the risk for early severe lupus nephritis, neuropsychiatric involvement, cytopenias, infection, and drug toxicities. We synthesize evidence for an immune ontogeny-based approach that considers altered molecular pathways, organ development, and responses to different therapeutics, and highlight that a higher genetic burden must be addressed for the effective stratification of patients. Finally, we propose a pragmatic approach to precision care based on developmental stage, immunophenotype, genetics, and long-term safety to enable the earlier onset of steroid-sparing therapy and long-term protection of patients.