Background: Lupus nephritis (LN) is more common and more severe is
pediatric systemic lupus erythematosus (pSLE). Endothelial protein C
receptor (EPCR) is an inducer of anti-apoptotic pathways in endothelial
cells. Recent studies have taken elevated anti-injury biomarkers as EPCR
into consideration regarding their roles to antagonize LN. Objectives: to
evaluate the membrane expression of endothelial protein C receptor
(mEPCR) in the renal microvasculature in pediatric patients with LN.
Methods This study was conducted on 25 patients with pSLE following up at
the Allergy and Immunology Clinic, Children's Hospital, Ain Shams
University. The 25 patients have LN proved by a previous renal biopsy.
Medical history, clinical examination and routine laboratory investigations
for assessment of disease activity were done for all patients. Paraffin blocks
of patients' renal biopsies were subjected to immunohistochemistry staining
for the frequency of mEPCR. Results: mEPCR was mainly expressed in the
endothelium of the peritubular capillaries. Our results showed that an equal
number of patients had nil and mild marker expression (8 patients each,
32%) while 9 patients (36%) showed moderate/strong marker expression.
We found that 9 out of 10 (90%) of patients with class II had nil/mild
marker expression, 5 patients out of 9 (55.5%) with class III had
mild/moderate marker expression, while 5 patients 0ut of 6 (83.3%) with
class IV and V had moderate/strong marker expression. We only found a
significant statistical difference between the different degrees of mEPCR
expression regarding 24 hours urinary proteins. No statistical significance
was found between the different degrees of mEPCR expression and different
immuno-suppressive therapy dose/kg or renal outcome using the renal
British Isles Lupus Assessment Group (BILAG) score; in spite that most of
the patients who got improved had nil/mild marker expression. Conclusion:
mEPCR -bearing a statistically significant difference in relation to different
LN classes- showed more expression in the more aggressive classes; a
finding which might suggest a contribution of the endothelium of the renal
parenchyma to the pathophysiology of more progressive LN. Hence the
tissue marker might emerge as a potential new therapeutic target in the
search for more selective treatment for SLE.