Radioimmunoassayfortheinvitrosemi-quantitativemeasurementofhumanfreeanti-insulinantibodies(AIA)inserumandplasma.

A.BIOLOGicalactivity

Thepresenceofcirculatinganti-insulinantibodies(AIA)indiabeticstreatedwithinsulinhasbeenrecognizedasearlyas1955.Thehighlypurifiedinsulinpreparations,presentlyavailable,arelessimmunogenicthansomeofthepreviouslyused,lesspure,preparations.Bovineinsulinismoreimmunogenicthantheporcinehormone.Also,ithasrecentlybeenrecognizedthatAIAmaydevelop,inpatientstreatedwithhumaninsulin.Thedeterminationofcirculatinganti-insulinantibodiesisofclinicalimportanceforthefollowingreasons:

• Thepresenceoffreeanti-insulinantibodiesinplasmainterfereswiththedeterminationofinsulinbyradioimmunoassay;
• Atveryhightiters,theanti-insulinantibodiesmayinduceastateofinsulinresistance;
• Anti-insulinantibodiesmayinfluencethequalityoftheglycemiccontrol,indiabeticpatients,byprolongingthehalflifeofinsulin.

B.Clinicalapplications

• Evaluationofthepresenceoffreeanti-insulinantibodiespriortothedeterminationofinsulinlevels,byradioimmunoassay,inpatientshavingreceivedpreviousinsulintherapy;
• Evaluationofstatesofinsulinresistance;


• Adjuncttothediagnosisofsurreptitiousinsulininjections(factitiousinsulin-inducedhypoglycaemia);
• Monitoringoftheevaluationofanti-insulinantibodies,inpatientsreceivingthenewlyformulatedhumaninsulinpreparations(newcases;patientsinwhomaprevioustreatmentwithporcineorbovineinsulinisreplacedbytheadmiNISTrationofhumaninsulin).