Comparison between light and electron microscopic findings in 30 patients with lupus nephritis

Background: The kidney biopsy specimen is used for initial diagnosis of patients with SLE who at the time of biopsy lack either diagnostic clinical manifestation and or serological markers. Another role is evaluation of renal dysfunction in transplanted patients when lupus has occurred in renal allograft. The aim of this study is correlating the findings of light, immunofluorescent and electron microscopy in thirty patients with lupus nephritis. Methods: The kidney biopsies of thirty patients with SLE were studied for purpose of correlating the findings of light, immunofluorescent and electron microscopy. We studied 30 parameters in light microscopy sections, 5 parameters in semi -thin and EM sections , and IgG, IgM, IgA, C3, C4 and fibrinogen in different structures of specimens by immunofluroscent microscopy. The P value and measurement of agreement of kappa was calculated. Results: In 25 cases LM and EM correlated completely including lupus nephritis class, activity and chronicity indices and presence or absence of immune complex deposition. In 5 cases discrepancy between Light Microscopy and Electron Microscopy diagnosis was found. Three cases were classified as class III according to LM and class II by EM. LM reevaluation of all three cases showed focal and segmental endocapillary cell proliferation with neutrophilic infiltration. We found that LM study is cornerstone in the focal lesions because of the limited inclusion of glomeruli in EM. One case of class IV by LM, in EM shows massive (grade III) sub-epithelial depositions and grade I sub endothelial deposition and was classified it as Class V + VI. In LM, findings cellular crescent in six glomeruli, severe endocapillary cell proliferation with activity index of (16/24) were detected. So the correct diagnosis was Class V + VI. The last case classified as IV in LM classification and revealed moderate mesangial cell proliferation with obliteration of lumens. In EM, we had three glomeruli which all showed mesangial cell proliferation, grade II mesangial deposition, with one focus of small (grade I) sub endothelial deposition. According to the above-mentioned findings the EM class of patient was class II. Conclusion: We found that there is agreement between EM and semi-thin sections for detection of exact site of depositions as well as their grading. Study of semi-thin sections by LM can demonstrate the deposits that are observed on EM.