ICOS and lymphoma: In order to confirm the functional relevance of this pathway in humans, and evaluate the requirement for this pathway in established disease, we treated minor salivary gland explant tissue from patients with SS and a major salivary gland from a patient diagnosed with a low grade mucosal associated lymphoid tissue (MALT) lymphoma with an anti-human ICOS blocking antibody (or isotype control) in vitro and assessed LTα production in the lymphocyte subsets as described above for the murine cells.