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Interferon α-enhanced clearance of group a streptococcus despite neutropenia


Uchiyama, Satoshi; Keller, Nadia; Schlaepfer, Erika; Grube, Christina; Schuepbach, Reto A; Speck, Roberto F; Zinkernagel, Annelies S (2016). Interferon α-enhanced clearance of group a streptococcus despite neutropenia. Journal of Infectious Diseases, 214(2):321-328.

Abstract

BACKGROUND Neutrophils and monocytes are crucial for controlling bacterial infections. More-frequent bacterial infections are accordingly encountered in neutropenic patients undergoing chemotherapy. This is not the case for pegylated interferon α (IFN-α)-induced neutropenia. We hypothesized that IFN-α induces a compensatory innate antibacterial state that prevents bacterial infections despite the neutropenia. METHODS To investigate whether patients with hepatitis C virus infection treated with IFN-α killed group A Streptococcus (GAS) better than before initiating therapy, whole blood was used to perform ex vivo GAS killing assays before, during, and after IFN-α therapy. RESULTS We found that IFN-α therapy enhanced GAS killing in whole blood ex vivo despite the decreased neutrophil and monocyte numbers during IFN-α therapy. IFN-α also boosted neutrophil- and monocyte-mediated GAS killing in vitro. Underlying mechanisms included increased production of the antibacterial properdin, a regulator of the complement activation, as well as reactive oxygen species. CONCLUSIONS These findings help to explain the rather discrepant facts of neutropenia but preserved antibacterial immune defenses in patients treated with IFN-α.

Abstract

BACKGROUND Neutrophils and monocytes are crucial for controlling bacterial infections. More-frequent bacterial infections are accordingly encountered in neutropenic patients undergoing chemotherapy. This is not the case for pegylated interferon α (IFN-α)-induced neutropenia. We hypothesized that IFN-α induces a compensatory innate antibacterial state that prevents bacterial infections despite the neutropenia. METHODS To investigate whether patients with hepatitis C virus infection treated with IFN-α killed group A Streptococcus (GAS) better than before initiating therapy, whole blood was used to perform ex vivo GAS killing assays before, during, and after IFN-α therapy. RESULTS We found that IFN-α therapy enhanced GAS killing in whole blood ex vivo despite the decreased neutrophil and monocyte numbers during IFN-α therapy. IFN-α also boosted neutrophil- and monocyte-mediated GAS killing in vitro. Underlying mechanisms included increased production of the antibacterial properdin, a regulator of the complement activation, as well as reactive oxygen species. CONCLUSIONS These findings help to explain the rather discrepant facts of neutropenia but preserved antibacterial immune defenses in patients treated with IFN-α.

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Additional indexing

Item Type:Journal Article, refereed, original work
Communities & Collections:04 Faculty of Medicine > University Hospital Zurich > Institute of Intensive Care Medicine
04 Faculty of Medicine > University Hospital Zurich > Clinic for Infectious Diseases
Dewey Decimal Classification:610 Medicine & health
Language:English
Date:15 July 2016
Deposited On:04 Aug 2016 09:47
Last Modified:02 Feb 2018 10:13
Publisher:Oxford University Press
ISSN:0022-1899
OA Status:Closed
Publisher DOI:https://doi.org/10.1093/infdis/jiw157
PubMed ID:27338768

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