I have been waiting to change from Enbrel to Abatacept and have had a barrage of blood test which showed that I have the HLAB27 antbody which is indicative of Psoriatic Arthritis. This usually, but not always follows Psoriasis which I do not have! However,sometimes it works the other way round. Has anybody else got any experience of this. This may also explain why the Enbrel was not particularly successful but Abatacept can be better in these cases - who knows, wait and see eh?