Centocor Microarray Study of Patients

Inclusion Criteria: Rheumatoid Arthritis * 18 years of age or older * 3 years duration of disease or less * Must meet ACR criteria * 3 tender or swollen joints * Positive RF or anti-CCP antibodies or evidence of erosions on plain radiographs * CRP \> 1.5 * Non-responder to methotrexate, but on a stable dose of 12.5 to 20 mg/week * Only subjects scheduled to receive infliximab as part of their care are eligible to participate. Crohn's disease * 12 years of age or older * Clinical and endoscopic confirmation of disease * CDAI \> 220 or evidence of intestinal inflammation on endoscopy * Documented failure to conventional therapy. * Only subjects scheduled to receive infliximab as part of their care are eligible to participate. Psoriatic arthritis * 18 years of age or older * Must meet CASPAR® criteria for diagnosis * RF and anti-CCP negative * 3 tender or swollen joints * Non-responder to methotrexate, but on a stable dose of 12.5 to 20 mg/week * Only subjects scheduled to receive infliximab as part of their care are eligible to participate. Psoriasis * 18 years of age or older * Total BSA \> 5% Exclusion Criteria: * Candidates for whom the procedures would be medically contraindicated would be excluded. * Patients with any active infections (viral or bacterial) will not be considered for inclusion into the trial. * Patients with history of chronic infection such as hepatitis, pneumonia or chronic pyelonephritis; those with current signs or symptoms of severe or progressive or uncontrolled renal, hepatic, hematologic, gastrointestinal, endocrine, pulmonary, cardiac, neurologic or cerebral disease including demyelinating disease such as multiple sclerosis. * Those with history of lymphoproliferative disease such as lymphoma or signs suggestive of lymphoproliferative disease, such as lymphadenopathy of unusual size or location (such as nodes in the posterior triangle of the neck, supraclavicular, epitrochlear, or periaortic areas), or splenomegaly will be excluded. * Patients with concomitant diagnosis of CHF, including medically controlled asymptomatic patients will not be eligible to participate. * Any current known malignancy or history of malignancy in the last 10 years will be excluded. History of basal cell carcinoma is not excluded. * Those with known bacterial, tuberculosis or opportunistic infections including but not limited to evidence of active cytomegalovirus , active Pneumocystis carinii, aspergillosis, or atypical mycobacterium infection within the previous 6 months will be ineligible. * Those with known infection with Human immunodeficiency virus (HIV) or known active hepatitis B or C (including associated active hepatitis) will be excluded. * Known substance abuse (drug or alcohol) within the previous 3 years. * Patients who have previously taken anti-TNF therapy are not eligible. * Patients who have been treated with DMARDS, biologic or investigational agents must wash out for at least 6 weeks prior to enrollment with the exception of those on methotrexate, who must be on a stable dose at least 2 weeks prior to start of study. * Have a history of latent or active granulomatous infection, including TB, histoplasmosis, or coccidioidomycosis, prior to screening. * Have had a Bacille Calmette-Guerin (BCG) vaccination within 12 months of screening. * Have a chest radiograph within 3 months prior to the first administration of study agent that shows an abnormality suggestive of a malignancy or current active infection, including TB. * Have had a nontuberculous mycobacterial infection or opportunistic infection (eg, cytomegalovirus, Pneumocystis carinii, aspergillosis) within 6 months prior to screening.