Seyed Mohammad Owji - Department of Pathology, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran
Simin Torabi Nezhad - Department of Pathology, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran
Hadi Raeisi Shahraki - Department of Epidemiology and Biostatistics, School of Health, Shahrekord University of Medical Sciences, Shahrekord, Iran
Bahar Bagheri - Student Research Committee, Shiraz University of Medical Sciences, Shiraz, Iran

Systemic lupus erythematosus (SLE) disease is known as a chronic inflammatory disease which is potentially able to involve vital organs. One of the most involved organs is the kidney. In the current study, all kidney biopsy with a diagnosis of lupus nephritis via electron microscopy (EM) were investigated and compared with reports from light and fluorescent microscopes and clinical and paraclinical data.Materials and Methods In this cross-sectional study, we investigated kidney biopsies of patients which were sent to our referral EM unit (affiliated to Shiraz University of Medical Sciences) from 2001 to 2016. The final diagnosis of lupus nephritis was based on the EM study. For each patient, primary light microscopy findings were compared with EM diagnosis. The immunofluorescent study was done for some patients. The available patients’ demographic and clinical data were extracted from the pathology request sheet. All the statistical analysis was performed in SPSS 19.0 and p<0.05 was considered as statistically significant. Results 671 patients diagnosed with lupus nephritis using EM were enrolled in the study. Mean age of the patients was 28.2±11.6 years and most (82.1%) of them were female. Interstitial fibrosis was reported in 42.7% of EM reports. Based on EM diagnosis, 306 (45.6%) patients were categorized in class â…£ of lupus followed by 148(22.1%), 133(19.8%) and 70(10.4%) patients into classes â…¡, â…¢, and â…¤ respectively. Interstitial fibrosis was more predominate in class â…¥(85.7%). Class â…£ and â…¤ showed more positivity of immunoglobulin and complement deposition. The most common cause of misdiagnosis in light microscopy was inadequate kidney tissue with 67(49.7%) followed by glomerulosclerosis with 17.1%. Lower severity of tubular atrophy was significantly (p<0.001) associated with a higher proportion of misdiagnosis in light microscopy. In 20.1% of patients, EM study was essential in diagnosis. Chronic kidney disease was more common in class â…£(34.6%). Proteinuria and hypertension were more common in class â…£. Edema was more dominant in class â…¥. Conclusion: EM study had a notable role to prevent misdiagnosis. Considering the limitations of using EM, the results obtained from this study can help with the appropriate use of EM and physicians clinical suspicion so that this disease can be diagnosed earlier. As the early diagnosis, and consequently, early treatment and classification of the disease will make better the prognosis of lupus nephritis, it will be a significant help to patients, physicians, and even insurance structures.

Microscopy, Electrons, Transmission; light microscopy; glomerulonephritis; proteinuria; lupus nephritis.