title: Stimulation of PBMC and Monocyte-Derived MacrophagesviaToll-Like Receptor Activates Innate Immune Pathways in HIV-Infected Patients on Virally Suppressive Combination Antiretroviral Therapy.
abstract: In HIV-infected, combination antiretroviral therapy (cART)-treated patients, immune activation and microbial translocation persist and associate with inadequate CD4 recovery and morbidity/mortality. We analyzed whether alterations in the toll-like receptor (TLR) pathway could be responsible for the immune hyperactivation seen in these patients. PBMC/monocyte-derived macrophages (MDMs) of 28 HIV+ untreated and 35 cART-treated patients with HIV-RNA < 40 cp/mL [20 Full Responders (FRs): CD4 ≥ 350; 15 Immunological Non-Responders (INRs): CD4 < 350], as well as of 16 healthy controls were stimulated with a panel of TLR agonists. We measured: CD4/CD8/CD14/CD38/HLA-DR/Ki67/AnnexinV/CD69/TLR4/8 (Flow Cytometry); PBMC expression of 84 TLR pathway genes (qPCR); PBMC/MDM cytokine release (Multiplex); and plasma lipopolysaccharide (LPS)/sCD14 (LAL/ELISA). PBMC/MDM from cART patients responded weakly to LPS stimulation but released high amounts of pro-inflammatory cytokines. MDM from these patients were characterized by a reduced expression of HLA-DR+ MDM and failed to expand activated HLA-DR+ CD38+ T-lymphocytes. PBMC/MDM from cART patients responded more robustly to ssRNA stimulation; this resulted in a significant expansion of activated CD38 + CD8 and the release of amounts of pro-inflammatory cytokines comparable to those seen in untreated viremic patients. Despite greater constitutive TLR pathway gene expression, PBMC from INRs seemed to upregulate only type I IFN genes following TLR stimulation, whereas PBMC from full responders showed a broader response. Systemic exposure to microbial antigens drives immune activation during cART by triggering TLRs. Bacterial stimulation modifies MDM function/pro-inflammatory profile in cART patients without affecting T-lymphocytes; this suggests translocating bacteria as selective stimulus to chronic innate activation during cART. High constitutive TLR activation is seen in patients lacking CD4 recovery, suggesting an exhausted immunemilieu, anergic to further antigen encounters.
authors.affiliation: Department of Health Sciences, Clinic of Infectious Diseases, ASST Santi Paolo e Carlo, University of Milan , Milan , Italy.
authors.forename: Esther
authors.initials: E
authors.lastname: Merlini
authors.affiliation: Department of Health Sciences, Clinic of Infectious Diseases, ASST Santi Paolo e Carlo, University of Milan , Milan , Italy.
authors.forename: Camilla
authors.initials: C
authors.lastname: Tincati
authors.affiliation: Department of Biomedical and Clinical Sciences - "L. Sacco", University of Milan , Milan , Italy.
authors.forename: Mara
authors.initials: M
authors.lastname: Biasin
authors.affiliation: Department of Biomedical and Clinical Sciences - "L. Sacco", University of Milan , Milan , Italy.
authors.forename: Irma
authors.initials: I
authors.lastname: Saulle
authors.affiliation: Department of Health Sciences, Clinic of Infectious Diseases, ASST Santi Paolo e Carlo, University of Milan , Milan , Italy.
authors.forename: Federico Angelo
authors.initials: FA
authors.lastname: Cazzaniga
authors.affiliation: Department of Health Sciences, Clinic of Infectious Diseases, ASST Santi Paolo e Carlo, University of Milan , Milan , Italy.
authors.forename: Antonella
authors.initials: A
authors.lastname: d'Arminio Monforte
authors.affiliation: EMD Millipore , Danvers, MA , USA.
authors.forename: Amedeo J
authors.initials: AJ
authors.lastname: Cappione
authors.affiliation: Flow Cytometry Core, Boston University , Boston, MA , USA.
authors.forename: Jennifer
authors.initials: J
authors.lastname: Snyder-Cappione
authors.affiliation: Department of Physiopathology and Transplants, University of Milan, Milan, Italy; Don C. Gnocchi Foundation, Istituti di Ricovero e Cura a Carattere Scientifico (IRCCS), Milan, Italy.
authors.forename: Mario
authors.initials: M
authors.lastname: Clerici
authors.affiliation: Department of Health Sciences, Clinic of Infectious Diseases, ASST Santi Paolo e Carlo, University of Milan , Milan , Italy.
authors.forename: Giulia Carla
authors.initials: GC
authors.lastname: Marchetti
keywords: HIV-1; TLR pathway; cART; immune activation; immunological non-responders