title: CD14(+) macrophages that accumulate in the colon of African AIDS patients express pro-inflammatory cytokines and are responsive to lipopolysaccharide.
abstract: BACKGROUND
  Intestinal macrophages are key regulators of inflammatory responses to the gut microbiome and play a central role in maintaining tissue homeostasis and epithelial integrity. However, little is known about the role of these cells in HIV infection, a disease fuelled by intestinal inflammation, a loss of epithelial barrier function and increased microbial translocation (MT).
  
  
  METHODS
  Phenotypic and functional characterization of intestinal macrophages was performed for 23 African AIDS patients with chronic diarrhea and/or weight loss and 11 HIV-negative Africans with and without inflammatory bowel disease (IBD). AIDS patients were treated with cotrimoxazole for the prevention of opportunistic infections (OIs). Macrophage phenotype was assessed by flow cytometry and immuno-histochemistry (IHC); production of proinflammatory mediators by IHC and Qiagen PCR Arrays; in vitro secretion of cytokines by the Bio-Plex Suspension Array System. Statistical analyses were performed using Spearman's correlation and Wilcoxon matched-pair tests. Results between groups were analyzed using the Kruskal-Wallis with Dunn's post-test and the Mann-Whitney U tests.
  
  
  RESULTS
  None of the study participants had evidence of enteric co-infections as assessed by stool analysis and histology. Compared to healthy HIV-negative controls, the colon of AIDS patients was highly inflamed with increased infiltration of inflammatory cells and increased mRNA expression of proinflammatory cytokine (tumour necrosis factor (TNF)-α, interleukin (IL)-1β, IFN-γ, and IL-18), chemokines (chemokine (C-C motif) ligand (CCL)2 and chemokine (C-X-C) motif ligand (CXCL)10) and transcription factors (TNF receptor-associated factor (TRAF)6 and T-box (TXB)21). IHC revealed significant co-localization of TNF-α and IL-1β with CD68(+) cells. As in IBD, HIV was associated with a marked increase in macrophages expressing innate response receptors including CD14, the co-receptor for lipopolysaccharide (LPS). The frequency of CD14(+) macrophages correlated positively with plasma LPS, a marker of MT. Total unfractionated mucosal mononuclear cells (MMC) isolated from the colon of AIDS patients, but not MMC depleted of CD14(+) cells, secreted increased levels of proinflammatory cytokines ex vivo in response to LPS.
  
  
  CONCLUSIONS
  Intestinal macrophages, in the absence of overt OIs, play an important role in driving persistent inflammation in HIV patients with late-stage disease and diarrhea. These results suggest intensified treatment strategies that target inflammatory processes in intestinal macrophages may be highly beneficial in restoring the epithelial barrier and limiting MT in HIV-infected patients.
authors.affiliation: MRC Unit for Inflammation and Immunity, Department of Immunology and the Tshwane Academic Division of the National Health Laboratory Service, University of Pretoria, Pretoria, South Africa. edana.cassol@carleton.ca.|Department of Health Sciences, Carleton University, 5433 Herzberg Laboratories, 1125 Colonel By Drive, Ottawa, Ontario, K1S 5B6, Canada. edana.cassol@carleton.ca.
authors.forename: Edana
authors.initials: E
authors.lastname: Cassol
authors.affiliation: MRC Unit for Inflammation and Immunity, Department of Immunology and the Tshwane Academic Division of the National Health Laboratory Service, University of Pretoria, Pretoria, South Africa. theresa.rossouw@up.ac.za.|Department of Family Medicine, University of Pretoria, Pretoria, South Africa. theresa.rossouw@up.ac.za.
authors.forename: Theresa
authors.initials: T
authors.lastname: Rossouw
authors.affiliation: MRC Unit for Inflammation and Immunity, Department of Immunology and the Tshwane Academic Division of the National Health Laboratory Service, University of Pretoria, Pretoria, South Africa. susan.malfeld@up.ca.za.
authors.forename: Susan
authors.initials: S
authors.lastname: Malfeld
authors.affiliation: MRC Unit for Inflammation and Immunity, Department of Immunology and the Tshwane Academic Division of the National Health Laboratory Service, University of Pretoria, Pretoria, South Africa. thakgalo03@gmail.com.
authors.forename: Phetole
authors.initials: P
authors.lastname: Mahasha
authors.affiliation: Department of Anatomical Pathology, University of Pretoria and Ampath Pathology Laboratories, Pretoria, South Africa. slavikt@ampath.co.za.
authors.forename: Tomas
authors.initials: T
authors.lastname: Slavik
authors.affiliation: Jembi Health Systems NPC, Durban, South Africa. chris@jembi.org.|School of Mathematics, Statistics and Computer Science, University of KwaZulu-Natal, Durban, South Africa. chris@jembi.org.
authors.forename: Chris
authors.initials: C
authors.lastname: Seebregts
authors.affiliation: Hepatology and GI-Research Laboratory, University of Pretoria, Pretoria, South Africa. robertbond@mweb.co.za.
authors.forename: Robert
authors.initials: R
authors.lastname: Bond
authors.affiliation: Hepatology and GI-Research Laboratory, University of Pretoria, Pretoria, South Africa. johannie.duplessis@kuleuven.be.
authors.forename: Johannie
authors.initials: J
authors.lastname: du Plessis
authors.affiliation: Hepatology and GI-Research Laboratory, University of Pretoria, Pretoria, South Africa. carljanssen@uz.leuven.be.
authors.forename: Carl
authors.initials: C
authors.lastname: Janssen
authors.affiliation: Translational Cell and Tissue Research, Department of Imaging and Pathology, University of Leuven, Leuven, Belgium. Tania.Roskams@med.kuleuven.be.
authors.forename: Tania
authors.initials: T
authors.lastname: Roskams
authors.affiliation: Department of Hepatology, University of Leuven, Leuven, Belgium. frederik.nevens@uz.kuleuven.ac.be.
authors.forename: Frederik
authors.initials: F
authors.lastname: Nevens
authors.affiliation: San Raffaele Scientific Institute, School of Medicine, Milan, Italy. alfano.massimo@hsr.it.|Present Address: Division of Experimental Oncology/Unit of Urology, URI, IRCCS Ospedale San Raffaele, Milan, Italy. alfano.massimo@hsr.it.
authors.forename: Massimo
authors.initials: M
authors.lastname: Alfano
authors.affiliation: San Raffaele Scientific Institute, School of Medicine, Milan, Italy. poli.guido@hsr.it.|Vita-Salute San Raffaele University, School of Medicine, Milan, Italy. poli.guido@hsr.it.|Institute of Human Virology, University of Maryland School of Medicine, Baltimore, MD, USA. poli.guido@hsr.it.
authors.forename: Guido
authors.initials: G
authors.lastname: Poli
authors.affiliation: MRC Unit for Inflammation and Immunity, Department of Immunology and the Tshwane Academic Division of the National Health Laboratory Service, University of Pretoria, Pretoria, South Africa. schalk.vandermerwe@uzleuven.be.|Department of Internal Medicine, Division of Liver and Biliopancreatic Disorders, University of Leuven, Leuven, Belgium. schalk.vandermerwe@uzleuven.be.
authors.forename: Schalk W
authors.initials: SW
authors.lastname: van der Merwe
mesh_terms: D000163:Acquired Immunodeficiency Syndrome / Q000276:immunology / Q000473:pathology*; D000328:Adult; D015703:Antigens, CD / Q000378:metabolism; D015214:Antigens, Differentiation, Myelomonocytic / Q000378:metabolism; D018925:Chemokines / Q000235:genetics / Q000378:metabolism; D060085:Coinfection / Q000473:pathology; D003106:Colon / Q000276:immunology* / Q000382:microbiology / Q000473:pathology; D016207:Cytokines / Q000235:genetics / Q000378:metabolism*; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D007150:Immunohistochemistry; D007249:Inflammation; D015212:Inflammatory Bowel Diseases / Q000473:pathology; D018950:Lipopolysaccharide Receptors / Q000378:metabolism*; D008070:Lipopolysaccharides / Q000633:toxicity; D008264:Macrophages / Q000187:drug effects / Q000276:immunology* / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D009092:Mucous Membrane / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D018417:Th1 Cells / Q000276:immunology / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha; D000097382:CD68 Molecule
chemical_list: D015703:Antigens, CD; D015214:Antigens, Differentiation, Myelomonocytic; D018925:Chemokines; D016207:Cytokines; D018950:Lipopolysaccharide Receptors; D008070:Lipopolysaccharides; D012333:RNA, Messenger; D014409:Tumor Necrosis Factor-alpha; C067980:CD68 antigen, human; D000097382:CD68 Molecule