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In 't Veld AE, Grievink HW, van der Plas JL, Eveleens Maarse BC, van Kraaij SJW, Woutman TD, Schoonakker M, Klarenbeek NB, de Kam ML, Kamerling IMC, Jansen MAA, Moerland M. Immunosuppression by hydroxychloroquine: mechanistic proof in in vitro experiments but limited systemic activity in a randomized placebo-controlled clinical pharmacology study. Immunol Res 2023; 71:617-627. [PMID: 36811819 PMCID: PMC9945836 DOI: 10.1007/s12026-023-09367-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Accepted: 02/14/2023] [Indexed: 02/24/2023]
Abstract
Based on its wide range of immunosuppressive properties, hydroxychloroquine (HCQ) is used for the treatment of several autoimmune diseases. Limited literature is available on the relationship between HCQ concentration and its immunosuppressive effect. To gain insight in this relationship, we performed in vitro experiments in human PBMCs and explored the effect of HCQ on T and B cell proliferation and Toll-like receptor (TLR)3/TLR7/TLR9/RIG-I-induced cytokine production. In a placebo-controlled clinical study, these same endpoints were evaluated in healthy volunteers that were treated with a cumulative dose of 2400 mg HCQ over 5 days. In vitro, HCQ inhibited TLR responses with IC50s > 100 ng/mL and reaching 100% inhibition. In the clinical study, maximal HCQ plasma concentrations ranged from 75 to 200 ng/mL. No ex vivo HCQ effects were found on RIG-I-mediated cytokine release, but there was significant suppression of TLR7 responses and mild suppression of TLR3 and TLR9 responses. Moreover, HCQ treatment did not affect B cell and T cell proliferation. These investigations show that HCQ has clear immunosuppressive effects on human PBMCs, but the effective concentrations exceed the circulating HCQ concentrations under conventional clinical use. Of note, based on HCQ's physicochemical properties, tissue drug concentrations may be higher, potentially resulting in significant local immunosuppression. This trial is registered in the International Clinical Trials Registry Platform (ICTRP) under study number NL8726.
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Affiliation(s)
- Aliede E In 't Veld
- Centre for Human Drug Research, Leiden, The Netherlands
- Leiden University Medical Centre, Leiden, The Netherlands
| | - Hendrika W Grievink
- Centre for Human Drug Research, Leiden, The Netherlands
- Division of BioTherapeutics, Leiden Academic Center for Drug Research, Leiden University, Leiden, The Netherlands
| | - Johan L van der Plas
- Centre for Human Drug Research, Leiden, The Netherlands
- Leiden University Medical Centre, Leiden, The Netherlands
| | - Boukje C Eveleens Maarse
- Centre for Human Drug Research, Leiden, The Netherlands
- Leiden University Medical Centre, Leiden, The Netherlands
| | - Sebastiaan J W van Kraaij
- Centre for Human Drug Research, Leiden, The Netherlands
- Leiden University Medical Centre, Leiden, The Netherlands
| | | | | | | | | | - Ingrid M C Kamerling
- Centre for Human Drug Research, Leiden, The Netherlands
- Leiden University Medical Centre, Leiden, The Netherlands
| | | | - Matthijs Moerland
- Centre for Human Drug Research, Leiden, The Netherlands.
- Leiden University Medical Centre, Leiden, The Netherlands.
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Grievink HW, Jirka SMG, Woutman TD, Schoonakker M, Rissmann R, Malone KE, Feiss G, Moerland M. Antimicrobial Peptide Omiganan Enhances Interferon Responses to Endosomal Toll-Like Receptor Ligands in Human Peripheral Blood Mononuclear Cells. Clin Transl Sci 2020; 13:891-895. [PMID: 32314872 PMCID: PMC7485948 DOI: 10.1111/cts.12789] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2019] [Accepted: 02/17/2020] [Indexed: 01/08/2023] Open
Abstract
LL‐37 is a cationic antimicrobial peptide and the sole human member of cathelicidins. Besides its bactericidal properties, LL‐37 is known to have direct immunomodulatory effects, among which enhancement of antiviral responses via endosomal toll‐like receptors (TLRs). Omiganan pentahydrochloride is a synthetic cationic peptide in clinical development. Previously, omiganan was primarily known for its direct bactericidal and antifungal properties. We investigated whether omiganan enhances endosomal TLR responses, similar to LL‐37. Human peripheral blood mononuclear cells were treated with endosomal TLR3, −7, −8, and −9 ligands in the presence of omiganan. Omiganan enhanced TLR‐mediated interferon‐α release. Subsequent experiments with TLR9 ligands showed that plasmacytoid dendritic cells were main contributors to omiganan‐enhanced IFN production. Based on this type I interferon‐enhancing effect, omiganan may qualify as potential treatment modality for virus‐driven diseases. The molecular mechanism by which omiganan enhances endosomal TLR responses remains to be elucidated.
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Affiliation(s)
- Hendrika W Grievink
- Centre for Human Drug Research, Leiden, The Netherlands.,Leiden Academic Center for Drug Research, Leiden, The Netherlands
| | | | | | | | - Robert Rissmann
- Centre for Human Drug Research, Leiden, The Netherlands.,Leiden Academic Center for Drug Research, Leiden, The Netherlands
| | | | - Gary Feiss
- Cutanea Life Sciences, Inc., Wayne, Pennsylvania, USA
| | - Matthijs Moerland
- Centre for Human Drug Research, Leiden, The Netherlands.,Leiden University Medical Center, Leiden, The Netherlands
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