The Utility of Assessing CD68+ Glomerular Macrophages in Assessing Endocapillary Hypercellularity in IgA Nephropathy.

INTRODUCTION

IgA nephropathy (IgAN) is the most common form of glomerulonephritis across the world. Oxford classification defines criteria and effects of endocapillary hypercellularity on E score but the reproducibility of the same is debatable. Hence, there is a need for an objective marker that could establish a gold standard in assessing endocapillary hypercellularity.

METHODS

Forty biopsies of proven IgAN were taken and grouped into two groups based on the presence or absence of endocapillary hypercellularity ( = 20 each). These biopsies were then stained by CD68 immune stain and the glomerular macrophages were quantified. Mean serum creatinine, presence of hypertension, degree of proteinuria and haematuria at the time of biopsy were also recorded and the correlation between these parameters and endocapillary hypercellularity was also studied.

RESULTS

Mean glomerular CD 68+ cell count was significantly higher in glomeruli showing endocapillary hypercellularity. Utilising the objective cutoff values of 0.6 CD68+ per glomerulus, more than 8 glomerular CD68+ cells in the entire biopsy and/or around 4 CD68+ cells in the most inflamed glomerulus, endocapillary hypercellularity can be predicted with a sensitivity of 70-80% and specificity of 70%. After regrouping the biopsies based on the cutoff values obtained from the receiver operating curve analysis the mean urine RBC count per high power field showed a significant correlation with endocapillary hypercellularity.

CONCLUSION

Glomerular CD68+ macrophage count seems to be a promising approach in assessing endocapillary hypercellularity. Further studies with emphasis on correlation with the clinical outcome are needed to validate its utility as an objective tool.