Major Neutrophilia Observed in Acute Phase of Human Leptospirosis Is Not Associated with Increased Expression of Granulocyte Cell Activation Markers.
It has long been known that pathogenic Leptospira can mobilize the immune system but the specific contribution of neutrophils to control the infectious challenge remains to be clarified. We herein analyzed the phenotype of circulating neutrophils of patients with leptospirosis and healthy controls for the expression of toll-like receptor (TLR) type 2 (TLR2, to sense the leptospiral LPS) and several activation markers: interleukin 8 chemokine receptor CD182 (CXCR2), CD11b of the integrin/opsonin complement receptor type 3 (CR3) and CD15 (ligand of the selectin). The plasmatic level of the main CD182 ligand, interleukin 8 (CXCL8), was measured by ELISA. Hospitalized leptospirosis cases showed marked neutrophilia, particularly in the most severe cases. Interestingly, TLR2 was significantly increased in leptospirosis but identical levels of CD182 and CD11b were detected when compared to controls. CD15 was significantly decreased on neutrophils in leptospirosis but returned to normal within 1 month. Basal levels of IL-8 were measured in control subjects and were not increased in leptospirosis cases at the initial stage of the disease. In conclusion, we observed that neutrophils failed to regulate the expression of several of the receptors involved in cell activation and recruitment. This study further emphasizes the paradigm that neutrophils may be impaired in their overall capacity to thwart bacterial infection in leptospirosis patients.
Université de La Réunion, CNRS 9192, INSERM U1187, IRD 249, CHU de La Réunion, Unité Mixte Processus Infectieux en Milieu Insulaire Tropical (PIMIT), Plateforme Technologique CYROI, Sainte-Clotilde, La Réunion, France.|Laboratoire d'immunologie clinique et expérimentale ZOI (LICE OI), CHU La Réunion site Félix Guyon, St Denis, La Réunion, France.|Internal Medicine Unit, CHU La Réunion site Félix Guyon, St Denis, La Réunion, France.
Loic
L
Raffray
Université de La Réunion, CNRS 9192, INSERM U1187, IRD 249, CHU de La Réunion, Unité Mixte Processus Infectieux en Milieu Insulaire Tropical (PIMIT), Plateforme Technologique CYROI, Sainte-Clotilde, La Réunion, France.|Microbiology/Virology Laboratory, CHU La Réunion site Félix Guyon, St Denis, La Réunion, France.
Claude
C
Giry
Intensive Care Unit, CHU La Réunion site Félix Guyon, St Denis, La Réunion, France.
David
D
Vandroux
Infectious Diseases Unit, CHU La Réunion site Félix Guyon, St Denis, La Réunion, France.
Barbara
B
Kuli
Internal Medicine Unit, GHER Hospital, St Benoit, La Réunion, France.
Andry
A
Randrianjohany
Hematology laboratory, CHU La Réunion site Félix Guyon, St Denis, La Réunion, France.
Anne-Marie
AM
Pequin
Internal Medicine Unit, CHU La Réunion site Félix Guyon, St Denis, La Réunion, France.
Frédéric
F
Renou
Université de La Réunion, CNRS 9192, INSERM U1187, IRD 249, CHU de La Réunion, Unité Mixte Processus Infectieux en Milieu Insulaire Tropical (PIMIT), Plateforme Technologique CYROI, Sainte-Clotilde, La Réunion, France.|Microbiology/Virology Laboratory, CHU La Réunion site Félix Guyon, St Denis, La Réunion, France.
Marie-Christine
MC
Jaffar-Bandjee
Université de La Réunion, CNRS 9192, INSERM U1187, IRD 249, CHU de La Réunion, Unité Mixte Processus Infectieux en Milieu Insulaire Tropical (PIMIT), Plateforme Technologique CYROI, Sainte-Clotilde, La Réunion, France.|Laboratoire d'immunologie clinique et expérimentale ZOI (LICE OI), CHU La Réunion site Félix Guyon, St Denis, La Réunion, France.
Philippe
P
Gasque
D000208:Acute Disease; D000328:Adult; D015415:Biomarkers / Q000378:metabolism; D005260:Female; D005786:Gene Expression Regulation; D006098:Granulocytes / Q000378:metabolism*; D006801:Humans; D007922:Leptospirosis / Q000235:genetics* / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D009504:Neutrophils / Q000166:cytology*; D051195:Toll-Like Receptor 2 / Q000235:genetics
D015415:Biomarkers; C495342:TLR2 protein, human; D051195:Toll-Like Receptor 2