CD8A and systemic lupus erythematosus: As a potential diagnostic marker for active LN, CD8+ TEM cells infiltrate the kidney and can be even detected in the urine.4 5 Elevated CD8+ TEM frequency in patients with juvenile-onset SLE were persistently associated with active disease and a higher LN prevalence.6 Therefore, understanding the skewed phenotype and distribution of T lymphocytes and the memory subsets may potentially benefit clinical management of SLE and LN.