ABSTRACT
DiscrepanciesbetweenthestrengthofantiglobulinreactionsandtherateofRBCdestruction arecommonlyencountered.TherelationshipofhemolysisinvivotoapositiveDATwith anticomplementalone,orwithanticomplementplusanti-IgG,islessclearthanforRBCshaving onlylgGdetectableontheirsurfaces.AlthoughsomepatientswithaweaklypositiveDATmay havesignificanthemolysis,otherswithstronglypositiveDATduetoRBC-boundC3mayhave nohemolysis.Althoughthesedifferences,inpart,relatetothemechanismbywhichcomplement isfixedtotheRBCs,itmayalsorelatetovariationsintheamountofcomplementfixed. Discrepanciesamongresultsoftestsperformedwithcommerciallyavailablereagents,and apparentdiscrepanciesamongreportsusingantiserainvestigatorsproducedthemselves,may reflectthelackofacceptedcriteriaforreagentstandardizationwithresultantwidevariationin potencyandspecificity.Althoughvirtuallyallcommercialantiglobulinseraweresaidtohave somereactivitywithcomplement,itbecameevidentintheearly1970sthattherewas nonuniformityofthereagentsrelatedtorelativeproportionsofanti-C3candanti-C3dinthe differentreagents(49,141,142).Muchexperimentalworkinthisareawasperformedwith unstandardizedandincompletelycharacterizedreagents,complicatinginterpretationofindividualstudiesandmakingitdifficulttocomparetheresultsfromdifferentlaboratories.
