Peripheral blood T-cell subset and its clinical significance in lupus nephritis patients

Objectives Lupus nephritis (LN) is a common and severe manifestation of SLE. Memory T (TM) cells have been implicated in the pathogenesis of SLE. This study aimed to investigate the clinical significance of T-cell subsets in a cohort of patients with LN. Method The peripheral blood T cells of 24 patients with LN and 13 patients with idiopathic membranous nephropathy (iMN) were analysed by flow cytometry. SLE disease activity was evaluated by SLE Disease Activity Index-2000 (SLEDAI-2K). Patients with LN were followed up for >6 months. Results Patients with LN presented lower frequency of CD4 + cells and higher percentage of CD8 + cells than patients with iMN, which was primarily due to lower CD4 + cell count. Interestingly, patients with LN under immunosuppressants had lower CD8 + CD45RO + TM frequency (p=0.007), fewer regulatory CD4 + T cells (p=0.04) than those without immunosuppressants. Most CD4 + and CD8 + TM cells in patients with LN showed an effector memory (CD45RO + CCR7 + ) phenotype. The frequency of CD8 + CD45RO + TM cells among the CD8 + T cells was negatively correlated with white blood cell count, haemoglobin, platelet and serum levels of complements C3 and C4, but was positively correlated with serum IgG, erythrocyte sedimentation rate and SLEDAI score (p<0.05 each). Consistently, the frequency of CD8 + CD45RO + TM cells was higher in patients with LN with positive antidouble-stranded DNA antibody, active renal disease, extrarenal manifestations and with sclerotic glomeruli or moderate-to-severe mesangial hypercellularity in renal pathology (p<0.05). Additionally, CD8 + CD45RO + TM cell frequency was significantly lower in patients with LN with renal complete remission than that in non-remission LN (18.7% vs 31.2%, p<0.05). None of these significant correlations was observed in CD4 + TM cells. Conclusion The frequency of CD8 + TM cells correlates with disease activity and treatment response to immunosuppressant in patients with LN. CD8 + TM monitoring in patients with LN could provide more helpful indices for the monitoring and management of this disease.