title: Differential effects of IL-2 and IL-21 on expansion of the CD4+ CD25+ Foxp3+ T regulatory cells with redundant roles in natural killer cell mediated antibody dependent cellular cytotoxicity in chronic lymphocytic leukemia.
abstract: CD4(+) CD25(+) regulatory T cells are expanded in solid and hematological malignancies including chronic lymphocytic leukemia (CLL). Several cytokines and co-stimulatory molecules are required for generation, survival and maintenance of their suppressive effect. We and others have shown direct cytotoxic effect of the novel common gamma chain cytokine interleukin (IL)-21 on primary B cells from CLL patients. Since members of this family of cytokines are known to exhibit their effects on diverse immune cells, we have examined the effects of IL-21 on CLL patient derived regulatory T cell (Treg) induction, expansion and the inhibitory effect on natural killer cells in vitro. We demonstrate here the expression of IL-21 receptor in CD4(+)CD25(High) regulatory cells from CLL patients. In contrast to IL-2, the IL-21 cytokine failed to mediate expansion of regulatory T cells or induced expression of Foxp3 in CD4(+)CD25(Intermediate) or CD4(+)CD25(Dim/-) T cells in whole blood derived from CLL patients. Interestingly, in contrast to their differential effects on expansion of the CD4(+)CD25(+)Foxp3(+)T cells, IL-2 and IL-21 exhibited a redundant role in Treg mediated suppression of NK cell mediated antibody dependent cytotoxicity function. Given the infusion related toxicities and pro-survival effect of IL-2 in CLL, these studies provide a rationale to explore IL-21 as an alternate gamma chain cytokine in CLL therapy.
authors.affiliation: Division of Hematology and Oncology, Department of Internal Medicine, Seattle, WA, USA.
authors.forename: Aruna
authors.initials: A
authors.lastname: Gowda
authors.forename: Asha
authors.initials: A
authors.lastname: Ramanunni
authors.forename: Carolyn
authors.initials: C
authors.lastname: Cheney
authors.forename: Darlene
authors.initials: D
authors.lastname: Rozewski
authors.forename: Wayne
authors.initials: W
authors.lastname: Kindsvogel
authors.forename: Amy
authors.initials: A
authors.lastname: Lehman
authors.forename: David
authors.initials: D
authors.lastname: Jarjoura
authors.forename: Michael
authors.initials: M
authors.lastname: Caligiuri
authors.forename: John C
authors.initials: JC
authors.lastname: Byrd
authors.forename: Natarajan
authors.initials: N
authors.lastname: Muthusamy
mesh_terms: D000920:Antibody-Dependent Cell Cytotoxicity / Q000187:drug effects; D015704:CD4 Antigens / Q000096:biosynthesis; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D002469:Cell Separation; D005434:Flow Cytometry; D051858:Forkhead Transcription Factors / Q000096:biosynthesis; D006801:Humans; D007376:Interleukin-2 / Q000494:pharmacology*; D053645:Interleukin-2 Receptor alpha Subunit / Q000096:biosynthesis; D007378:Interleukins / Q000494:pharmacology*; D007694:Killer Cells, Natural / Q000378:metabolism / Q000473:pathology; D015451:Leukemia, Lymphocytic, Chronic, B-Cell / Q000188:drug therapy* / Q000276:immunology* / Q000473:pathology; D053655:Receptors, Interleukin-21 / Q000276:immunology / Q000378:metabolism; D050378:T-Lymphocytes, Regulatory / Q000187:drug effects* / Q000276:immunology / Q000378:metabolism / Q000473:pathology; D000098546:Interleukin-21
chemical_list: D015704:CD4 Antigens; C418974:FOXP3 protein, human; D051858:Forkhead Transcription Factors; D007376:Interleukin-2; D053645:Interleukin-2 Receptor alpha Subunit; D007378:Interleukins; D053655:Receptors, Interleukin-21; D000098546:Interleukin-21