The purpose of this study is to evaluate the association between genetic factors and response to treatment (guselkumab, ustekinumab, adalimumab, or etanercept) and psoriasis (scaly skin rash).

This is a Phase 0, exploratory (intended to be conducted early in Phase 1, involve limited human exposure, have no therapeutic intent and are not intended to examine clinical tolerability), multicenter (when more than one hospital or medical school team work on a medical research study) and pharmacogenomics study in participants with psoriasis. Participants who were treated in study Phase 2 NCT01483599 (X-PLORE), Phase 3 NCT00267969 (PHOENIX 1), Phase 3 NCT00307437 (PHOENIX 2) or Phase 3 NCT00454584 (ACCEPT), will be returning to their study site where a deoxyribonucleic acid (DNA) sample will be obtained for pharmacogenomics assessment. There will be no follow-up beyond the study site visit.

Inclusion Criteria:

• Participants must have been randomly assigned and treated in the NCT01483599 (X-PLORE), NCT00267969 (PHOENIX 1), NCT00307437 (PHOENIX-2) , or NCT00454584 (ACCEPT) studies
• Sign an informed consent document indicating that they understand the purpose of and procedures required for this study and are willing to participate in this study

Exclusion Criteria:

• Participants has any condition for which, in the opinion of the investigator, participation would not be in the best interest of the subject (for example, compromise the well-being) or that could prevent, limit, or confound the protocol-specified assessments

Participants who were treated in the CNTO1959PSO2001 study, C0743T08 study, C0743T09 or C0743T12 study will be assessed.