Guselkumab Immunogenetics

Inclusion Criteria: For subjects with guttate psoriasis: * Ability to provide written informed consent and comply with the protocol. * At least 18 years of age. * Diagnosis of guttate psoriasis. * Onset of guttate psoriasis within 12 months. * Body surface area (BSA) involvement greater than or equal to 5%. * PASI greater than or equal to 4. * Subject is considered a candidate for phototherapy or systemic therapy. * Subject is unlikely to conceive due to male, post-menopausal, or using adequate contraceptive (barrier, hormonal, implant, or permanent sterilization methods). Women of childbearing potential will be allowed to enroll provided they practice adequate forms of birth control. * Physical exam with no evidence of active skin infection and/or other findings that indicate chronic disease or concomitant inflammatory/immune-mediated skin disease other than psoriasis. For subjects with chronic plaque psoriasis (control): * Ability to provide written informed consent and comply with the protocol. * At least 18 years of age. * Diagnosis of plaque psoriasis. * Duration of plaque psoriasis \>5 years. * Body surface area (BSA) involvement greater than or equal to 5%. * Subject is considered a candidate for phototherapy or systemic therapy. * Subject is unlikely to conceive due to male, post-menopausal, or using adequate contraceptive (barrier, hormonal, implant, or permanent sterilization methods). Women of childbearing potential will be allowed to enroll provided they pract…