Comparison of Cathelicidin Expression in Skin and Saliva in Patients With Atopic Dermatitis and Psoriasis

People with AD or psoriasis are very sensitive to skin infections and inflammations. A group
of small proteins known as cathelicidins are known to be responsible for immune defense
against such infections. People with AD or psoriasis seem to be missing these proteins from
their skin. The purpose of this study is to determine if the amount of cathelicidins and
other small proteins in saliva is a predictor for the amount found in the skin.

This is a single visit observational study. People with AD or psoriasis, as well as healthy
participants, are being recruited for this study. Participants will provide a detailed
medical history and undergo a physical examination. In addition, saliva and blood
collection, and skin punch biopsies will be performed.

Inclusion Criteria:

- Diagnosis of typical AD for at least 6 months as defined by ADVN standardized
diagnostic criteria OR diagnosis of typical plaque psoriasis for at least 6 months

- ADEH participants as defined by ADVN standardized diagnostic criteria

- Healthy participants with no personal or family history of food allergy, AD, asthma,
or allergic rhinitis

- Persons residing in the US

- Healthy individuals with no systemic disorders as outlined in the exclusion criteria

- Subjects 18 to 70 years of age

- Male or female

Exclusion Criteria for All Participants:

- Under 18 or over 70 years of age

- Presence of allergic hypersensitivity without stringent AD features, allowing only a
presumptive diagnosis of AD

- Presence of AD with exfoliative erythroderma

- Presence of psoriasis with exfoliative erythroderma or presence of guttate psoriasis,
primary palmoplantar psoriasis, or pustular psoriasis

- Ongoing dental disease (e.g., gingivitis)

- Bleeding disorder

- Presence of AD or psoriasis in which temporarily stopping current medications would
cause worsening of the disease (Participants with active ADEH will be allowed to
continue medication)

- Systemic immunosuppressive or chemotherapeutic agents, anti-inflammatory biologics
(e.g., alefacept, etanercept), or oral calcineurin inhibitors within 30 days of
screening visit

- Topical corticosteroids, oral or topical antibiotics, oral antivirals, immune
enhancers (e.g., imiquimod), or topical calcineurin inhibitors within 7 days prior to
screening visit (Participants with active ADEH will be allowed to continue
medication)

- Receiving phototherapy (e.g., ultraviolet light B [UVB], psoralen plus ultraviolet
light A [PUVA]) within 30 days of study entry

- Autoimmune disease or immunodeficiency

- Active fungal, bacterial, or viral infections (Except ADEH subjects)

- Active systemic cancer. Participants with uncomplicated nonmelanoma skin cancer are
not excluded.

- Mental illness or history of drug or alcohol abuse that, in the opinion of the
investigator, would interfere with the study

- Diabetic requiring medication

- Pregnancy or breastfeeding

- Inability or unwillingness of a participant to give written informed consent