
Description:
Anti-centromereantibodies(ACA)areanimmunologicalMarkerfordiagnosisofCRESTsyndrome,alimitedformofsystemicsclerosis.Atleast9proteinsareknowntobeassociatedwiththecentromerecomplex,butCENP-Bisnormallyconsideredtobethemajorcentromereantigen.CENP-Bhasamolecularweightofapproximately66kDaandplaysanimportantroleintheformationofthecentromericchromatin.CENP-Bantibodiesarepresentintheseraofupto80%ofpatientswithCRESTsyndrome.TheseautoantibodiesarealsooftendetectedinserafrompatientswithRaynaud’sphenomenonandoccasionallyinotherrheumaticdiseasessuchassystemiclupuserythematosus,Sjögren’ssyndrome,andrheumatoidarthritis.ACAhavealsobeenreportedtooccurwithhighprevalenceinpatientswithprimarybiliarycirrhosis,inpatientswithmalignanciesandoccasionallyinnormalindividuals.Principle:
AutoimmuneELISAkitsmeasureautoimmuneantibodiesintheserum.Itisbasedontheprincipleofasolidphaseenzyme-linkedimmunosorbentassay.Theassayutilizesaspecificantigenforimmobilizationonthemicrotiterwellsandanti-humanIgGantibodyconjugatedtohorserADIshperoxidase(HRP)fordetection.Thetestsampleisallowedtoreactsimultaneouslywiththetwocomponents,resultingin autoimmuneantibodiesbeingsandwichedbetweenthesolidphaseandenzyme-linkedantibodies.Afterincubation,thewellsarewashedtoremoveunbound-labeledantibodies.AHRPsubstrate,TMB,isaddedtoresultinthedevelopmentofabluecolor.ThecolordevelopmentisthenstoppedwiththeadditionofStopSolutionchangingthecolortoyellow.Theconcentrationofautoimmuneantibodies isdirectlyproportionaltothecolorintensityofthetestsample.Absorbanceismeasuredspectrophotometricallyat450nm.