PsoriasisPUVA TherapyUltraviolet TherapyDermatologic AgentsAcitretinKeratolytic AgentsArthritis, PsoriaticSeverity of Illness IndexAntibodies, Monoclonal, HumanizedAntibodies, MonoclonalCohort StudiesCardiovascular DiseasesGreat BritainTreatment OutcomeRisk FactorsCoal TarHLA-C AntigensSkinAnthralin