ABSTRACT
Autoimmunehemolyticanemia(AIHA)wasthefirstautoimmunediseasetobedescribedin whichtheautoantibodywasclearlyproventocausethedisease.Itwouldseemtobetheeasiest modelofautoimmunediseaseforinvestigatorstostudy,yetitisoftenignoredbyimmunologists, eventhosespecializinginautoimmunedisease.AIHAissaidtooccurin1per40,000-80,000 ofthepopulation(1,2).Itcanbeassociatedwithautoantibodiesreactingoptimallyat37°C, causingtheso-calledwarmAIHA(WAIHA),orautoantibodiesthatreactoptimallyatG-5°C butcapableofreactinguptotemperatures(e.g.,30°C)achievedintheperipheralcirculation. Thelattergrouparecomposedofthemorecommoncoldagglutininsyndrome(CAS)andthe rarerparoxysmalcoldhemoglobinuria(PCH).Asmallpercentageofpatientspresentwith featuresofbothwarmandcoldAIHA.BothwarmandcoldAIHAcanoccurasprimary idiopathicconditionsorsecondarytootherdiseases(Tables1and2).Althoughmost drug-inducedimmunehemolyticanemiasareassociatedwithdrug-inducedautoantibodies, reactingoptimallyat37°C,andthuscanbeclassifiedasWAIHA,weprefertoclassifythem separately(3).Table1showsonewayofclassifyingtheimmunehemolyticanemias.Table2 listssomeofthediseasesmostcommonlyassociatedwithAIHA.
