title: Effects of cyclophosphamide and IL-2 on regulatory CD4+ T cell frequency and function in melanoma patients vaccinated with HLA-class I peptides: impact on the antigen-specific T cell response.
abstract: The frequency and function of regulatory T cells (Tregs) were studied in stage II-III melanoma patients who were enrolled in a phase II randomized trial of vaccination with HLA-A*0201-modified tumor peptides versus observation. The vaccinated patients received low-dose cyclophosphamide (CTX) and low-dose interleukin-2 (IL-2). Tregs were analyzed in the lymph nodes (LNs) of stage III patients who were undergoing complete lymph node dissection and in peripheral blood mononuclear cells (PBMCs) collected before vaccination and at different time points during the vaccination period. The LNs of the vaccinated patients, which were surgically removed after two rounds of vaccination and one dose of CTX, displayed a low frequency of Tregs and a less immunosuppressive environment compared with those of the untreated patients. The accurate time-course analysis of the PBMCs of patients enrolled in the vaccination arm indicated a limited and transient modulation in the frequencies of Tregs in PBMCs collected after low-dose CTX administration and a strong Treg boost in those PBMCs collected after low-dose IL-2 administration. However, a fraction of the IL-2-boosted Tregs was functionally modulated to a Th-1-like phenotype in the vaccinated patients. Moreover, low-dose IL-2 promoted the concomitant expansion of conventional activated CD4(+) T cells. Despite the amplification of Tregs, IL-2 administration maintained or further increased the number of antigen-specific CD8(+) T cells that were induced by vaccination as demonstrated by the ex vivo human leukocyte antigen-multimer staining and IFN-γ ELISpot assays. Our study suggests that the use of CTX as a Treg modulator should be revised in terms of the administration schedule and of patients who may benefit from this drug treatment. Despite the Treg expansion that was observed in this study, low-dose IL-2 is not detrimental to the functional activities of vaccine-primed CD8(+) T cell effectors when used in the inflammatory environment of vaccination.
authors.affiliation: Unit of Immunotherapy of Human Tumors, Fondazione IRCCS Istituto Nazionale dei Tumori, Via G. Venezian 1, 20133, Milan, Italy.
authors.forename: Chiara
authors.initials: C
authors.lastname: Camisaschi
authors.forename: Paola
authors.initials: P
authors.lastname: Filipazzi
authors.forename: Marcella
authors.initials: M
authors.lastname: Tazzari
authors.forename: Chiara
authors.initials: C
authors.lastname: Casati
authors.forename: Valeria
authors.initials: V
authors.lastname: Beretta
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Pilla
authors.forename: Roberto
authors.initials: R
authors.lastname: Patuzzo
authors.forename: Andrea
authors.initials: A
authors.lastname: Maurichi
authors.forename: Agata
authors.initials: A
authors.lastname: Cova
authors.forename: Michele
authors.initials: M
authors.lastname: Maio
authors.forename: Vanna
authors.initials: V
authors.lastname: Chiarion-Sileni
authors.forename: Gabrina
authors.initials: G
authors.lastname: Tragni
authors.forename: Mario
authors.initials: M
authors.lastname: Santinami
authors.forename: Barbara
authors.initials: B
authors.lastname: Vergani
authors.forename: Antonello
authors.initials: A
authors.lastname: Villa
authors.forename: Emilio
authors.initials: E
authors.lastname: Berti
authors.forename: Ludmila
authors.initials: L
authors.lastname: Umansky
authors.forename: Philipp
authors.initials: P
authors.lastname: Beckhove
authors.forename: Viktor
authors.initials: V
authors.lastname: Umansky
authors.forename: Giorgio
authors.initials: G
authors.lastname: Parmiani
authors.forename: Licia
authors.initials: L
authors.lastname: Rivoltini
authors.forename: Chiara
authors.initials: C
authors.lastname: Castelli
mesh_terms: D000328:Adult; D000368:Aged; D000951:Antigens, Neoplasm / Q000276:immunology; D018906:Antineoplastic Agents, Alkylating / Q000627:therapeutic use; D015496:CD4-Positive T-Lymphocytes / Q000166:cytology*; D018414:CD8-Positive T-Lymphocytes / Q000166:cytology; D045744:Cell Line, Tumor; D003520:Cyclophosphamide / Q000627:therapeutic use*; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005434:Flow Cytometry; D015395:Histocompatibility Antigens Class I / Q000276:immunology*; D006801:Humans; D007166:Immunosuppressive Agents / Q000627:therapeutic use; D007167:Immunotherapy / Q000379:methods; D007371:Interferon-gamma / Q000378:metabolism; D007376:Interleukin-2 / Q000627:therapeutic use*; D007963:Leukocytes, Mononuclear / Q000166:cytology; D008297:Male; D008545:Melanoma / Q000188:drug therapy* / Q000378:metabolism; D008875:Middle Aged; D010641:Phenotype; D012878:Skin Neoplasms / Q000188:drug therapy* / Q000378:metabolism; D013601:T-Lymphocytes / Q000166:cytology; D013997:Time Factors
chemical_list: D000951:Antigens, Neoplasm; D018906:Antineoplastic Agents, Alkylating; D015395:Histocompatibility Antigens Class I; D007166:Immunosuppressive Agents; D007376:Interleukin-2; D007371:Interferon-gamma; D003520:Cyclophosphamide