Immunohistochemical Evaluation of NKP46 Receptor Expression and the Number of NK Cells in the Endometrium of Patients with Endometriosis

Mahdi Alimoradi Fard; Mehri Ghafourian; Abdolah Mousavi Salehi; Farideh Moramazi; Farideh Moramezi; Nastaran Ranjbari

doi:10.22034/iji.2024.100630.2715

Immunohistochemical Evaluation of NKP46 Receptor Expression and the Number of NK Cells in the Endometrium of Patients with Endometriosis

Mahdi Alimoradi Fard, Mehri Ghafourian, Abdolah Mousavi Salehi, Farideh Moramazi, Farideh Moramezi, Nastaran Ranjbari

Iranian journal of immunology : IJI · 2024 · vol. 21(1) , pp. 27–36 · doi:10.22034/iji.2024.100630.2715 · PMID:38375785 · W4394739487

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⚙ AI-generated summary by gemini-2.5-flash-lite, 2026-06-07 ⓘ

Endometriosis patients, particularly those with severe disease, showed increased endometrial NK cells but decreased NKP46 expression and NKP46/CD56 ratio compared to fertile women.

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⚙ AI-generated deep summary by claude@2026-06, 2026-06-07 · read from full text ⓘ

This study evaluated, by immunohistochemistry, the number of uterine NK cells (CD56+) and the expression of the NKP46 receptor (NKP46) in endometrial tissue from women with mild (n=11), moderate (n=10), or severe endometriosis (n=9) versus normal fertile controls (n=20). The authors stained endometrial specimens with monoclonal antibodies against CD56 and NKP46 and compared NK cell counts and NKp46+/CD56+ ratios across groups. They found that severe endometriosis was associated with a significantly higher number of CD56+ uterine NK cells than controls and with lower NKP46 expression and a lower NKp46+/CD56+ ratio. A key limitation is that all analyses are based on tissue immunohistochemical measures without direct functional assessment of NK cytotoxicity, and sample sizes are modest. This paper is centrally about endometriosis—specifically, immunohistochemical quantification of NK cells (CD56+) and NKP46 receptor expression in the endometrium across endometriosis severity.

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Abstract

BACKGROUND: Endometriosis is a medical condition that can cause infertility in women. Women with endometriosis experience a decrease in NK cell cytotoxic activity against endometrial cells, ultimately contributing to the spread of these cells. OBJECTIVE: To assess the frequency of NK cells and the expression of the NKP46 receptor in endometrial tissue from patients with endometriosis using immunohistochemistry. METHODS: 30 endometrial tissue specimens were collected from three groups of cases with mild (n=11), moderate (n=10), and severe endometriosis (n=9), respectively. Additionally, 20 normal endometrial tissue specimens were collected as the control group. Immunohistochemical staining was carried out using specific human monoclonal antibodies against CD56 and NKP46 molecules. RESULTS: Cases with severe endometriosis had a significantly higher number of CD56+ uterine NK cells (26.19±2.50) compared to fertile women (15.02±0.622) and women with mild to moderate endometriosis (p0.05). Endometrial NKp46 expression was lower in women with severe endometriosis (0.447±0.0829) compared to fertile women (0.987±0.115, p=0.03). The NKp46+/CD56+ cell ratio was also lower in women with severe endometriosis (0.019±0.003) compared to fertile women (0.072±0.011, p=0.01). CONCLUSION: Women with severe endometriosis demonstrated an increased rate of infiltrated uterine NK cells and a significant decrease in NKP46 expression compared to fertile women. Therefore, NK cells and the NKp46 receptor may be involved in the development of endometriosis.

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Abstract

Background: Endometriosis is a medical condition that can cause infertility in women. Women with endometriosis experience a decrease in NK cell cytotoxic activity against endometrial cells, ultimately contributing to the spread of these cells.

Objective

To assess the frequency of NK cells and the expression of the NKP46 receptor in endometrial tissue from patients with endometriosis using immunohistochemistry.

Methods

30 endometrial tissue specimens were collected from three groups of cases with mild (n=11), moderate (n=10), and severe endometriosis (n=9), respectively. Additionally, 20 normal endometrial tissue specimens were collected as the control group. Immunohistochemical staining was carried out using specific human monoclonal antibodies against CD56 and NKP46 molecules.

Results

Cases with severe endometriosis had a significantly higher number of CD56+ uterine NK cells (26.19±2.50) compared to fertile women (15.02±0.622) and women with mild to moderate endometriosis (p0.05). Endometrial NKp46 expression was lower in women with severe endometriosis (0.447±0.0829) compared to fertile women (0.987±0.115, p=0.03). The NKp46+/CD56+ cell ratio was also lower in women with severe endometriosis (0.019±0.003) compared to fertile women (0.072±0.011, p=0.01).

Conclusion

Women with severe endometriosis demonstrated an increased rate of infiltrated uterine NK cells and a significant decrease in NKP46 expression compared to fertile women. Therefore, NK cells and the NKp46 receptor may be involved in the development of endometriosis. Keywords

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Condition tags

endometriosisinfertility

MeSH descriptors

Endometriosis Endometriosis Endometriosis Endometriosis Endometriosis Endometriosis Endometriosis Endometriosis Endometriosis Endometriosis Endometriosis Endometriosis Endometriosis Endometriosis Endometriosis Endometriosis Endometriosis Endometriosis Endometriosis Endometriosis

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