It will describe the medical features and natural course of the disease and determine participants' eligibility for experimental treatment protocols. Patients with known or suspected psoriatic arthritis 5 years of age and older and their relatives may enroll in this study. Patients will be evaluated with a medical history and physical examination, electrocardiogram, blood tests and X-rays. Leukapheresis-Collection of white blood cells for genetic analysis.
Whole blood is collected through a needle placed in an arm vein.
The blood circulates through a machine that separates it into its components. The plasma is removed and the cells are returned to the body through a second needle placed in the other arm. Skin biopsy-Removal of a small skin sample for microscopic analysis. An area of skin around the biopsy site is numbed with an anesthetic, and a needle is inserted into the joint to pull out a small fluid sample. An area of skin around the biopsy site is numbed with an anesthetic and a large needle is inserted into the joint.