Introduction/Background Programmed cell death protein (PD-1) after contact with its ligands (PD-L1 and PD-L2) exerts an inhibitory role on immune cells, playing an important role in maintaining self-response. Knowing that increased expression of the PD-1/PD-L1 pathway can interfere with cervical immunity for the progression of cervical lesions, we decided to investigate whether the use of 5% imiquimod can modulate the expression of the PD-1/PD-L1 pathway in uterine cervix injuries.

Methodology We studied 52 women aged 18 to 40 years with histological diagnosis of high-grade HSIL intraepithelial lesion (CIN2p16+ and CIN3), who self-applied 250mg cream containing 5% imiquimod three times a week for 16 weeks. Biopsies were collected on admission and after completion of treatment, and the successful treatment was defined by lesion regression after treatment. The expression of PD-1 and PD-L1 was evaluated by immunohistochemistry, whose values (in pixels) were used to assess protein levels.

Results The success of topical imiquimod treatment in high-grade cervical lesions was associated with lesions that had the highest levels of PD-1 (P= 0.0319) and PD-L1 (P= 0.0199) before treatment. Paired sample analysis before and after treatment showed that imiquimod acts on the PD-1/PD-L1 pathway, decreasing PD-1 expression (P= 0.0155) in cases of successful treatment (figure 1), possibly controlling the inflammation. We observed that PD-1 levels were not correlated with PD-L1 levels (p=0.5177).

Conclusion Our results suggested that imiquimod modulates PD-1 expression in cervical lesions and that treatment success depends on PD-1 levels at admission. In contrast, increased PD-L1 expression is associated with a higher risk of unsuccessful treatment.

Disclosures The authors report no conflict of interests.