Local immune response in the microenvironment of CIN2-3 with and without spontaneous regression

Regulation of immune responses to HPV infection and during HPV-directed immunotherapy

The recent development of vaccines prophylactic against human papillomavirus (HPV) infection has the potential to reduce the incidence of cervical cancer globally by up to 70% over the next 40 years, if universal immunization is adopted. As these prophylactic vaccines do not alter the natural history of established HPV infection, immunotherapies to treat persistent HPV infection and associated precancers would be of benefit to assist with cervical cancer control. Efforts to develop immuno-therapeutic vaccines have been hampered by the relative non-immunogenicity of HPV infection, by immunoregulatory processes in skin, and by subversion of immune response induction and immune effector functions by papillomavirus proteins. This review describes HPV-specific immune responses induced by viral proteins, their regulation by host and viral factors, and highlights some conclusions from our own recent research.

The impact of epithelial biomarkers, local immune response and human papillomavirus genotype in the regression of cervical intraepithelial neoplasia grades 2–3

Background and aims

15–30% of cases of cervical intraepithelial neoplasia grades 2–3 (CIN2–3) detected in punch biopsies regress spontaneously (ie, show CIN1 or less in the follow-up cone). Epithelial retinoblastoma protein (pRb), tumour suppressor protein (p53), HPV genotype and immunoreactive cells have been reported to be helpful in predicting regression but their interaction in regression prediction is unknown.

Material and methods

55 cases of CIN2–3 in cervical biopsies with subsequent cervical cones were studied retrospectively to assess how epithelial biomarkers, immunoreactive cells (with immunohistochemistry) and high-risk (hr) HPV genotypes (by the AMPLICOR and linear array tests) prognostically interact with epithelial pRb and p53.

Results

18% of CIN2–3s regressed (median biopsy–cone interval of 12.0 weeks, range 5.0–34.1 weeks). CIN2–3s that regressed had higher epithelial pRb and p53, lower stromal CD25+ and CD138+, and higher CD8 cells than persistent lesions. They also had higher ratios of CD4+/CD25+ and CD8+/CD25 in stroma and epithelium. HPV16 correlated with low pRb and low CD8+. With multivariate analysis a combined high ratio of CD8+/CD25+ in the stroma, high epithelial pRb and p53 expression had independent value to predict the regression.

Conclusions

CIN2–3 lesions with a non-hrHPV16 infection, high ratios of stromal CD8+/CD25+ and high epithelial expression of pRb or p53 are associated with spontaneous regression.

The immunoregulatory mechanisms of carcinoma for its survival and development

The immune system in patients detects and eliminates tumor cells, but tumors still progress persistently. The mechanisms by which tumor cells survive under the pressure of immune surveillance are not fully understood. This review is to present the evidence from clinical studies, showing a significant correlation of clinicopathological features of carcinoma with: (1) the loss of classical human leukocyte antigen class I, (2) the up-regulation of non-classical human leukocyte antigen class I, pro-apoptotic Fas ligand and receptor-binding cancer antigen expressed on SiSo cells I, and (3) the formation of immunosuppressive microenvironment by up-regulation of transforming growth factor-beta, Galectin-1, inhibitory ligand B7s, indoleamine 2,3-dioxygenase and arginase, as well as by recruitment of tumor-induced myeloid-derived suppressor cells and regulatory T cells. All of these factors may together protect carcinoma cells from the immune-cytotoxicity.