Activity of Childhood Lupus Nephritis is Linked to Altered T Cell and Cytokine Homeostasis

Purpose Standard therapy for lupus nephritis is based on non-specific immunosuppression. We aimed to identify specific alterations in T cell and cytokine homeostasis and possible associations with disease activity in children with lupus nephritis (LN). Methods The phenotype of circulating T cells from children with LN and healthy controls (HC) was analyzed by flow cytometry. Intracellular expression of IL-17 and INF-γ was assessed after stimulation with anti-CD3 and anti-CD28. Serum concentrations of IP10, CCL2, TGF-β, IL-17, and IL-23 were measured by ELISA. Disease activity was determined using the Systemic Lupus Erythematosus Disease Activity Index 2000 update (SLEDAI-2K). Results Children with active LN displayed increased frequencies of effector memory CD4 + CD45RO + CCR7 − and terminal differentiated CD4 + CD45RA + CCR7 − T cells and reduced naive CD4 + CD45RA + CCR7 + T cells compared to those with inactive LN or HC. Circulating CD4 + CXCR3 + and CD4 + CCR2 + T cells correlated inversely with the renal SLEDAI-2K, whereas IP10 and CCL2 showed a positive correlation. Reduced CD4 + Foxp3 + T cells and serum TFG-β levels in active LN were associated with high serum IL-17 and IL-23 levels and correlated inversely with the renal SLEDAI-2K ( r = −0.5855, p = 0.0013 and r = −0.6246, p = 0.0005, respectively), whereas IL-17 and IL-23 correlated positively ( r = 0.5516, p = 0.0029 and r = 0.6116, p = 0.0007, respectively). Expansion of Th17 and Th1/Th17 cells in children with LN was significantly greater than in HC ( p = 0.0304 and p = 0.0067, respectively). Conclusion Children with active LN display high levels of pro-inflammatory cytokines associated with an increase in effector T cells and reduction of regulatory T cells. Therapeutic regulation of the aberrant cytokine profile might specifically interrupt pathogenic mechanisms.