Type II hypersensitivity ... Not to be confused with type 2 inflammation. ... The activation of the complement system results in opsonization, the agglutination of ...TypeIIhypersensitivityFromWikipedia,thefreeencyclopediaJumptonavigationJumptosearchNottobeconfusedwithtype2inflammation.MedicalconditionTypeIIhypersensitivitySpecialtyImmunologyTypeIIhypersensitivity,intheGellandCoombsclassificationofallergicreactions,isanantibodymediatedprocessinwhichIgGandIgMantibodiesaredirectedagainstantigensoncells(suchascirculatingredbloodcells)orextracellularmaterial(suchasbasementmembrane).Thissubsequentlyleadstocelllysis,tissuedamageorlossoffunctionthroughmechanismssuchascomplementactivationviatheclassicalcomplementpathwayantibodydependentcell-mediatedcytotoxicityoranti-receptoractivity.[1]Theactivationofthecomplementsystemresultsinopsonization,theagglutinationofredbloodcells,celllysis,andcelldeath.[2]Thesereactionsusuallytakebetween2and24hourstodevelop.[2]Contents1Examples2Seealso3References4ExternallinksExamples[edit]DiseaseAutoantibodytargetAutoimmunehemolyticanemiaRedbloodcellsGoodpasturesyndromeGlomerularbasementmembraneGravesdiseaseThyroidstimulatinghormonereceptorImmunethrombocytopeniaPlateletsMyastheniagravisMuscleacetylcholinereceptor[3]AnexampleofcomplementdependenttypeIIhypersensitivityisanacutehaemolytictransfusionreactionfollowingtransfusionofABOincompatibleblood.[4]Preformedantibody(predominantlyIgM)againstdonorredcellantigensnotfoundinanindividualofaparticularbloodgroup(e.g.anti-AIgMinanindividualwithbloodgroupB),bindtothedonorredcellsurfaceandleadtorapidcomplementmediatedhaemolysisandpotentiallylife-threateningclinicalconsequences.Complement-dependenttypeIIhypersensitivitycanalsooccurduringthetransmissionofincompatiblematernalantibodiestofetalredbloodcellscausinghemolyticanemiainthefetus,knownaserythroblastosisfetalis.[5][6]AnotherexampleofacomplementdependenttypeIIhypersensitivityreactionisGoodpasture'ssyndrome,wherethebasementmembrane(containingcollagentypeIV