The purpose of this study is to determine the safety, tolerability and pharmacokinetics of escalating single and multiple intravenous (IV) infusions and subcutaneous (SC) injections of PF 06823859 in healthy subjects.

Inclusion Criteria:

1. Healthy female subjects of non childbearing potential and male subjects who, at the time of screening, are between the ages of 18 and 55 years, inclusive. Healthy is defined as no clinically relevant abnormalities identified by a detailed medical history, full physical examination, including blood pressure and pulse rate measurement, 12 lead ECG or clinical laboratory tests.
2. Body Mass Index (BMI) of 17.5 to 30.5 kg/m2; and a total body weight >50 kg (110 lbs).

Exclusion Criteria:

1. History of active or latent tuberculosis (TB) regardless of treatment; positive Quantiferon - TB test.
2. Subjects with a history of autoimmune disorders.
3. Subjects with a history of or positive results for any of the following serological tests: Hepatitis B surface antigen (HBsAg), Hepatitis B core antibody (HBcAb), anti Hepatitis C antibody (HCVAb) or human immunodeficiency virus (HIV).