Isolation and Functional Characterization of Regulatory CD4+ T Cells from the Inflamed Joints of Patients with Rheumatoid Arthritis.

Regulatory T cells play a critical role in maintaining immune homeostasis and in preventing and controlling unwanted immune activation. These cells are often studied in the context of human peripheral blood, but can also be isolated from other biofluids. Here we describe methods for the isolation and functional characterization of human CD4+ CD25hi CD127low regulatory T cells from the synovial fluid of patients with inflammatory arthritis.