Human Leucocyte Elastase (HLE)
Definition
A serine protease secreted by vaginal epithelial cells and leucocytes. The primary immunological target for forensic identification of vaginal secretions, detected using ELISA or LFIA. Distinct from semen elastase and not present at significant levels in other body fluids.
- Type
- Serine protease
- Source
- Vaginal epithelial cells and leucocytes
- Detection methods
- ELISA or LFIA
- Specificity
- Distinct from semen elastase, not significant in other fluids
Common questions
Why is the distinction from semen elastase forensically important?+
Both are elastase enzymes but they originate from different tissues, and confusing the two in an immunoassay could lead an examiner to misattribute a stain, so HLE testing specifically targets vaginal secretion rather than the elastase associated with seminal fluid.
What kind of case relies on HLE testing?+
It is used in sexual assault casework where a stain needs to be attributed to vaginal secretion specifically, for example to establish contact or penetration, alongside or instead of other fluid-specific markers such as PSA for semen or amylase for saliva.
Is a positive HLE result alone sufficient to confirm vaginal secretion in court?+
Laboratories generally treat immunological markers like HLE as strong presumptive to confirmatory evidence depending on the assay and validation used, and results are typically interpreted alongside case context and, where available, corroborating biological or DNA findings.
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