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Updated: Jul 5, 2025
Fast and Specific Assessment of the Halogenating Peroxidase Activity in Leukocyte-enriched Blood Samples
Published on: July 28, 2016
Immunohistochemical analysis of myeloperoxidase expression in cutaneous leucocytoclastic vasculitis
Sarra Ben Rejeb1, Dorsaf Beltaifa1, Yasmine Ben Romdhane1
1Pathology Department, Security Forces Hospital, Marsa, Tunisie.
Abstract:
Myeloperoxidase (MPO) is a pro-oxidant enzyme mainly found in the azurophilic granules of neutrophils. It not only displays a key role in the intracellular microbial killing process but also contributes to the extracellular clearance of several pathogens. This study aimed to detect MPO in cutaneous leukocytoclastic vasculitis (LCV) using immunohistochemistry. We retrospectively collected 22 confirmed cases of skin LCV diagnosed in our pathology department over 11 years (2012-2023). Immunohistochemistry was performed using anti-myeloperoxidase antibody (Leica clone 59A5) on the LeicaBond MAX automated system, following manufacturer's instructions. Two pathologists assessed immunohistochemical staining, scoring intensity as weak (+), moderate (++), or strong (+++). Patients' mean age was 56.9 years, with a male-to-female ratio of 1.18. Pathologically, vasculitis involved small blood vessels in all cases. Immunohistochemical analysis showed granular positive MPO staining in 59.1% of cases. Staining intensity was weak in 46.15%, moderate in 46.15%, and strong in 7.69%. Staining was patchy in 84.62% and diffuse in 15.38% of cases. MPO expression, detected in 59.1% of cutaneous LCV tissues, exhibited a patchy and peri-vascular distribution. It holds potential as a diagnostic marker for patients with early or minor histological changes.
Insights
Myeloperoxidase (MPO) was detected in over half of cutaneous leukocytoclastic vasculitis (LCV) cases using immunohistochemistry. This finding suggests MPO may serve as a valuable diagnostic marker for LCV, especially in early stages.
Area of Science:
- Immunohistochemistry
- Pathology
- Dermatology
Background:
- Myeloperoxidase (MPO) is a pro-oxidant enzyme crucial for neutrophil-mediated microbial killing and pathogen clearance.
- Its role in inflammatory conditions like cutaneous leukocytoclastic vasculitis (LCV) requires further investigation.
Purpose of the Study:
- To investigate the presence and distribution of MPO in cutaneous LCV tissues.
- To evaluate MPO's potential as a diagnostic marker for LCV.
Main Methods:
- Retrospective analysis of 22 confirmed cutaneous LCV cases diagnosed between 2012 and 2023.
- Immunohistochemistry using anti-MPO antibody on the LeicaBond MAX automated system.
- Pathological assessment of MPO staining intensity (weak, moderate, strong) and distribution (patchy, diffuse).
Main Results:
- MPO staining was detected in 59.1% of cutaneous LCV cases.
- Staining intensity was predominantly weak (46.15%) or moderate (46.15%), with strong staining in 7.69%.
- MPO expression showed a patchy (84.62%) and peri-vascular distribution.
Conclusions:
- Myeloperoxidase is expressed in a significant proportion of cutaneous LCV cases.
- The patchy, peri-vascular MPO distribution suggests its involvement in the vasculitic process.
- MPO immunohistochemistry holds potential as a diagnostic marker for cutaneous LCV, particularly in cases with subtle histological findings.
