The purpose of this study is to understand how genetics play a role in psoriasis. Specifically, a genetic allele HLA-Cw6 is known to be associated with psoriasis, and this study aims to find out how it affects genetic and protein expression in patients with psoriasis, compared to healthy people, at a single-cell level using a novel flow cytometry and RNA-sequencing protocol.

Inclusion Criteria:

For subjects in the psoriasis group:

1. Ability to provide written consent and comply with the protocol
2. At least 18 years of age
3. Diagnosis of plaque psoriasis for at least 6 months prior to enrollment
4. BSA > 5% and at least one target plaque on trunk or extremities greater than 10cm2

For control subjects:

1. Ability to provide written consent and comply with the protocol
2. At least 18 years of age
3. No previous diagnosis of psoriasis or other inflammatory skin conditions

Exclusion Criteria:

For subjects in the psoriasis group:

1. Subject has non-plaque form of psoriasis.
2. Subject has drug-induced psoriasis.
3. Pregnancy at any point during the study period.
4. Known allergy to lidocaine, other local anesthetics, or any component of local anesthetic agents.
5. Known HIV positive status.
6. Evidence of abnormality of any immune cell population from a drug-induced or genetic cause.
7. Known coagulopathy.

For control subjects:

1. Any physical examination findings by the investigators consistent with psoriasis or other inflammatory skin conditions.
2. Pregnancy at any point during the study period.
3. Known allergy to lidocaine, other local anesthetics, or any component of local anesthetic agents.
4. Known HIV positive status.
5. Evidence of abnormality of any immune cell population from a drug-induced or genetic cause.
6. Known coagulopathy.
7. Use of any immunosuppressant or immunomodulating therapies within 6 months.