ABSTRACT. We investigated the effect of age on the expression of immune molecules [ANA, C4, double stranded DNA (dsDNA), CD16/32, CD19, CD3, and CD64], urine protein, and pathology in mice with chronic graft-versus-host disease (cGVHD) lupus nephritis (LN), and their relationship with reactivity index score. Mouse models of cGVHD LN were established, and mice were randomly divided into four aged-based groups of nine mice each. Serum levels of ANA, C4, and dsDNA were determined, the urine protein levels were assessed, and expression levels of CD16/32, CD19, CD3, and CD64 were measured.