C4d Expression in the Lupus Nephritis Is Higher in the Class V Lupus Nephritis and Not Correlated with Activity or Renal Function

초록

Background: Systemic lupus erythematous (SLE) is immune complex mediated disease and lupus nephritis (LN) is found in 60% of SLE patients. The glomerular expression of C4d in LN can be correlated with microthrombosis or disease activity. However, these results are controversial. Our aim is to evaluate that the glomerular C4d expression can be a marker of activity or renal dysfunction of LN. Methods: Biopsyproven 87 LN were evaluated with following factors: age, amount of proteinuria, estimated glomerular filtration rate (eGFR), serum C3 and C4, serum antinuclear antibody (ANA) level, World Health Organization (WHO) class, activity and chronicity. Immunohistochemistry of the C4d was performed and scored with semi-quantitive method. Results: The score of glomerular C4d (GC4d) is the highest in the WHO class V (class II, 0.56±0.56; class III, 0.56±0.60; class IV, 0.75±0.74; class V, 1.15±0.89; p<0.05). The GC4d scores showed positive correlation with proteinuria, serum C3 and C4 level and negative correlation with ANA titer (p<0.05). Serum creatinine level, eGFR, activity, and chronicity revealed no correlation with GC4d scores (p>0.05). Conclusions: Class V LN showed higher GC4d scores than other WHO group. Proteinuria, serum C3 and C4 levels had positive correlation with GC4d scores. Class V LN is the membranous LN and revealed large amount of proteinuria like membranous nephropathy (MN) which shows glomerular C4d deposition in almost 100% cases. Our results suggest that the pathogenesis of class V LN is similar to MN and in situ classic complement activation can be involved in the pathogenetic mechanisms. There was no correlation between GC4d expression and activity or renal function