Fig. 5.24 Lupusnephritis.(A)Focalproliferativeglomerulonephritis,withtwofocalnecrotizinglesionsatthe11o’clockand2o’clockpositions(H&Estain).Extracapillaryproliferationisnotprominentinthiscase.(B)Diffuseproliferativeglomerulonephritis.Notethemarkedincreaseincellularitythroughouttheglomerulus(H&Estain).(C)Lupusnephritisshowingaglomeruluswithseveral“wire-loop”lesionsrepresentingextensivesubendothelialdepositsofimmunecomplexes(periodicacid-Schiffstain).(D)ElectronmicrographofarenalglomerularcapillaryloopfromapatientwithSLEnephritis.Subendothelialdensedeposits(arrowheads) onbasementmembrane(arrow)correspondto“wireloops”seenbylightmicroscopy.(E)DepositionofIgGantibodyinagranularpattern,detectedbyimmunofluorescence.(AtoC,Courtesy of Dr. Helmut Rennke, Department of Pathology, Brigham and Women’s Hospital, Boston, Massachusetts. D,Courtesy of Dr. Edwin Eigenbrodt, Department of Pathology, University of Texas, Southwestern Medical School, Dallas,Texas. E,Courtesy of Dr. Jean Olson, Department of Pathology, University of California, San Francisco, California.) http://ebooksmedicine.net nephritis,halformoreoftheglomeruliareaffected.Involvedglomerulishowproliferationofendothelial,mesangial,andepithelialcells(see
Fig.5.24B ),withthelatterproducingcellularcrescentsthatfillBowman’sspace.Subendothelialimmunecomplexdepositsmaycreateacircumferentialthickeningofthecapillarywall,forming“wire-loop”structuresonlightmicroscopy(see
Fig.5.24C ).Immunecomplexescanbereadilydetectedbyelectronmicroscopy(see
Fig.5.24D
Fig.5.24E ).Lesionsmayprogresstoscarringofglomeruli.Patientswithdiffuseglomerulonephritisareusuallysymptomatic,showinghematuriaaswellasproteinuria.Hypertensionandmildtosevererenalinsufficiencyalsoarecommon.
Membranous lupus nephritis (classV)ischaracterizedbydiffusethickeningofthecapillarywallsduetodepositionofsubepithelialimmunecomplexes,similartoidiopathicmembranousnephropathy,describedinChapter14.Theimmunecomplexesareusuallyaccompaniedbyincreasedproductionofbasementmembrane-likematerial,resultingin“holes”and“spikes”onsilverstain.Thislesionisusuallyaccompaniedbysevereproteinuriaornephroticsyndrome,andmayoccurconcurrentlywithfocalordiffuselupusnephritis.
Advanced sclerosing lupus nephritis (classVI)ischaracterizedbysclerosisofmorethan90%oftheglomeruli,andrepresentsend-stagerenaldisease.
Changesintheinterstitium and tubules arefrequentlypresent.Rarely,tubulointerstitiallesionsmaybethedominantabnormality.Discreteimmunecomplexessimilartothoseinglomeruliarepresentinthetubularorperitubularcapillarybasementmembranesinmanylupusnephritispatients.Sometimes,therearewell-organizedB-cellfolliclesintheinterstitium,associatedwithplasmacellsthatmaybesourcesofautoantibodies.