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Updated: Mar 29, 2026
Fast and Specific Assessment of the Halogenating Peroxidase Activity in Leukocyte-enriched Blood Samples
Published on: July 28, 2016
Myeloperoxidase in human peripheral blood lymphocytes: Production and subcellular localization
Sabrina Sayori Okada1, Edson Mendes de Oliveira1, Tomaz Henrique de Araújo2
1Departamento de Análises Clínicas e Toxicológicas, Faculdade de Ciências Farmacêuticas, Universidade de São Paulo, São Paulo, SP 05508, Brazil.
Abstract:
Myeloperoxidase (MPO) is an important enzyme in the front-line protection against microorganisms. In peripheral blood, it is accepted that MPO is only produced by myeloid-lineage cells. Thus, MPO presence is unexpected in lymphocytes. We showed recently that B1-lymphocytes from mice have MPO. Here, we showed that subsets of human peripheral B, CD4(+) and CD8(+) T lymphocytes express MPO. The content of MPO in lymphocytes was very low compared to neutrophils/monocytes with a preferential distribution in the nucleus and perinuclear region. Also, we performed a MPO mRNA expression analysis from human blood cells derived from microarray raw data publicly available, showing that MPO is modulated in infectious disease. MPO was increased in CD4(+) T lymphocytes from HIV chronic infection and in CD8(+) T lymphocytes from HCV-positive patients. Our study points out MPO as a multifunctional protein due to its subcellular localization and expression modulation in lymphocytes indicating alternative unknown functions for MPO in lymphocytes.
Insights
Myeloperoxidase (MPO) is unexpectedly found in human lymphocytes, not just myeloid cells. This enzyme
Area of Science:
- Immunology
- Cell Biology
- Biochemistry
Background:
- Myeloperoxidase (MPO) is a key enzyme in innate immunity, primarily associated with myeloid cells.
- Its presence in lymphocytes is considered atypical and warrants further investigation.
Purpose of the Study:
- To investigate the expression and localization of MPO in human peripheral blood lymphocytes.
- To explore the modulation of MPO expression in lymphocytes during infectious diseases.
Main Methods:
- Flow cytometry and immunofluorescence to detect MPO in human B and T lymphocyte subsets.
- Analysis of publicly available microarray data for MPO mRNA expression in blood cells from patients with infectious diseases (HIV, HCV).
Main Results:
- Subsets of human B, CD4+ T, and CD8+ T lymphocytes express MPO at low levels, primarily in the nucleus and perinuclear region.
- MPO expression is modulated in lymphocytes during chronic HIV and HCV infections, with increased MPO in CD4+ T cells (HIV) and CD8+ T cells (HCV).
Conclusions:
- Human lymphocytes express MPO, challenging the traditional view of its cellular distribution.
- MPO's subcellular localization and altered expression in infectious diseases suggest novel, multifunctional roles in lymphocytes beyond microbial defense.
