AIMTo describe the technique of immunofluorescence on paraffin embedded tissue sections and discuss the po-tential pitfalls with an in depth review of literature.METHODSImmunofluorescence is integral to diagnostic ren...AIMTo describe the technique of immunofluorescence on paraffin embedded tissue sections and discuss the po-tential pitfalls with an in depth review of literature.METHODSImmunofluorescence is integral to diagnostic renal pa-thology. Immunofluorescence on paraffin embedded renal biopsies （IF-P） after enzyme treatment has been described in literature, however has not found widespread use in renal pathology laboratories. In our laboratory proteinase K digestion of paraffn embedded renal biopsy material was standardized and applied prospectively in cases where immunofuorescence on fresh frozen tissue was non contributory or not possible. Diagnostic utility was assessed and in a cohort of cases comparison of intensity of staining with routine immunofuorescence was performed.RESULTSOver the 5-year study period, of the 3141 renal biopsies received IF-P was performed on 246 cases （7.7%） and was interpretable with optimal digestion in 214 cases （6.8%）. It was of diagnostic utility in the majority of cases, which predominantly included glomerular disease. Non-diagnostic IF-P was found in membranous nephropathy （2 of 11 cases）, membranoproliferative glomerulonephritis （2 of 32 cases）, lupus nephritis （1 of 25 cases）, post infectious glomerulonephritis （1 of 11 cases） and chronic glomerulonephritis （3 of 8 cases）. Comparing cases with both routine IF and IF-P, 35 of 37 showed either equal intensity or a minor difference in intensity of staining（1＋） for the diagnostic immunoglobulin/complement. Technically assessment of immunofluorescence on the paraffin embedded tissue was found to be easier with clearly observed morphology, however a false positive staining pattern was observed in under-digested tissue. CONCLUSIONAs a “salvage” technique, immunofuorescence on paraffn embedded renal biopsies is of great diagnostic utility, however not without pitfalls.展开更多
文摘AIMTo describe the technique of immunofluorescence on paraffin embedded tissue sections and discuss the po-tential pitfalls with an in depth review of literature.METHODSImmunofluorescence is integral to diagnostic renal pa-thology. Immunofluorescence on paraffin embedded renal biopsies （IF-P） after enzyme treatment has been described in literature, however has not found widespread use in renal pathology laboratories. In our laboratory proteinase K digestion of paraffn embedded renal biopsy material was standardized and applied prospectively in cases where immunofuorescence on fresh frozen tissue was non contributory or not possible. Diagnostic utility was assessed and in a cohort of cases comparison of intensity of staining with routine immunofuorescence was performed.RESULTSOver the 5-year study period, of the 3141 renal biopsies received IF-P was performed on 246 cases （7.7%） and was interpretable with optimal digestion in 214 cases （6.8%）. It was of diagnostic utility in the majority of cases, which predominantly included glomerular disease. Non-diagnostic IF-P was found in membranous nephropathy （2 of 11 cases）, membranoproliferative glomerulonephritis （2 of 32 cases）, lupus nephritis （1 of 25 cases）, post infectious glomerulonephritis （1 of 11 cases） and chronic glomerulonephritis （3 of 8 cases）. Comparing cases with both routine IF and IF-P, 35 of 37 showed either equal intensity or a minor difference in intensity of staining（1＋） for the diagnostic immunoglobulin/complement. Technically assessment of immunofluorescence on the paraffin embedded tissue was found to be easier with clearly observed morphology, however a false positive staining pattern was observed in under-digested tissue. CONCLUSIONAs a “salvage” technique, immunofuorescence on paraffn embedded renal biopsies is of great diagnostic utility, however not without pitfalls.
