Glomerular Expression of Monocyte Chemoattractant Protein-1 is Predictive of Poor Renal Prognosis in Pediatric Lupus Nephritis

Background: Monocyte chemoattractant protein-1 (MCP-1) is upregulated and it recruits and activates inflammatory cells in murine lupus nephritis (LN).

Methods: Clinical outcomes of children with LN were examined in relation to glomerular expression of MCP-1 and macrophage infiltration, as determined by immunohistochemical staining of renal biopsy sections with MCP-1 and CD68. Sections were analysed using a modified histological score (H-score; maximum of 300) based on both percentage of positively stained cells and intensity of staining.

Results: Renal biopsies were examined from 34 children [27 (79%) female] aged 7.7-17.3 (median 13.7) years with 50% ISN/RPS Class IV LN. Renal dysfunction and proteinuria at follow-up of 2.2-15.4 (median 6.5) years were analysed with estimated glomerular filtration rates (eGFR) of 11.2-124.1 (median 93.6) ml/min/1.73 m(2) and urine albumin:creatinine ratios of 1-535 (median 63) mg/mmol. There was a correlation between glomerular expression of MCP-1 and CD68 (r = 0.98, P = 0.04; median modified H-score of 219.7 and 230.8, respectively). Patients with Class III and IV LN had increased glomerular expression of both MCP-1 and PGM1 compared to the other classes (P = 0.01) with Class IV-G LN patients having the most glomerular expression of MCP-1 (median of 227.3) and PGM1 (median of 237.5) and the worst renal prognosis (with proteinuria and reduced eGFR).

Conclusions: There is a correlation between glomerular expression of MCP-1 and PGM1 and worsening renal prognosis in paediatric LN. Larger prospective studies of paediatric LN are required to further evaluate MCP-1 and other markers of disease progression.