HLA-B and spondylitis: It's very difficult to explain to a patient. We know it well but to make it clear to patients, we need to start from scratch saying there is 6–8% of the population which is HLA-B*27 positive but I assure you there is no 6–8% of the population who has spondylitis et cetera et cetera. So we must start again on explanations...and they believe or they do not, huh...