Definition and characterization of the systemic T cell dysregulation in untreated indolent B cell lymphoma and very early CLL

Epidemiological data show that the immune system may control or promote emergence and growth of a neoplastic lymphomatous clone. Conversely, systemic lymphomas, especially myeloma and CLL, are associated with clinical immunodeficiency. This prospective controlled study demonstrates substantially reduced circulating T helper cells, predominantly naive CD4+ cells, in patients with non-leukemic follicular and extranodal marginal zone lymphomas, but not in monoclonal gammopathy and early CLL. These numerical changes were correlated with a preactivated phenotype, hyperreactivity in vitro, presenescence, and a Th2 shift of peripheral T helper cells. No prominent alterations were found in the regulatory T cell compartment. Gene expression profiling of in vitro-stimulated CD4+ cells revealed an independent second alteration of T helper cell physiology which was most pronounced in early CLL but also detectable in FL/eMZL. This pattern consisted of downregulation of proximal and intermediate T-cell receptor signaling cascades and globally reduced cytokine secretion. Both types of T cell dysfunction may contribute to significant immunodeficiency in non-leukemic indolent B-cell lymphomas as demonstrated by refractoriness to hepatitis B vaccination. The precise definition of systemic T cell dysfunction serves as the basis to study its prognostic impact, its relationship to the established influence of the lymphoma microenvironment, and its therapeutic manipulation 8 samples from FL/eMZL patients, 7 samples from CLL patients, 5 samples of MGUS patients, 5 MALT, 16 healthy controls