Immunology of human papillomavirus infection in lower genital tract neoplasia

Immunohistochemical and ultrastructural features of Langerhans cells in condyloma acuminatum

BACKGROUND

There are few studies on the abnormal morphology of Langerhans cells (LCs) in condyloma acuminatum (CA) lesions and the essence of the abnormal morphology of LCs in CA lesions is still not well elucidated. The aim of this study was to further investigate the morphological features of LCs in CA lesions.

METHODS

CD1a(+) LCs in 13 CA lesions and in 13 normal controls were labeled using immunohistochemistry and examined by light microscopy. Ultrastructural investigation on LCs in six CA lesions and in six normal controls was performed by electron microscopy.

RESULTS

Compared with those in normal controls, most CD1a(+) LCs in CA lesions exhibited dysplastic dendrities and abnormal distribution. The number of CD1a(+) LCs in CA lesions (26.31 +/- 18.84) was statistically lower (p < 0.001) than that in normal controls (72.00 +/- 27.40). Electron microscopy showed that the number of Birbeck granules within lesional LCs (4.00 +/- 2.94) was significantly decreased (p < 0.001) than that within normal LCs (10.80 +/- 4.78). The ultrastructures of most lesional LCs displayed degenerative changes.

CONCLUSIONS

The morphology of most LCs in CA lesions shows degenerative changes, which suggest that these LCs have been functionally impaired.

Functional attributes of mucosal immunity in cervical intraepithelial neoplasia and effects of HIV infection

The role of mucosal immunity in human papillomavirus (HPV)-related cervical diseases is poorly understood. To characterize the local immune microenvironment in cervical intraepithelial neoplasia (CIN) 2/3 and determine the effects of HIV infection, we compared samples from three groups: normal cervix, CIN 2/3 from immunocompetent women (HIV- CIN 2/3), and CIN 2/3 from HIV seropositive women (HIV+ CIN 2/3). CIN 2/3 lesions contained increased numbers of immune cells from both the acquired and innate arms of the immune response in stroma [CD4+ and CD8+ T cells, macrophages, mast cells, B cells, neutrophils, and natural killer (NK) cells] and dysplastic epithelium (CD4+ T cells, macrophages, and NK cells). Immune cells in CIN 2/3 expressed activation markers, as measured by interleukin-2 receptor (IL-2R) and transcription factor T bet. Interferon-gamma production was significantly up-regulated in CIN lesions and was expressed by CD4+ and CD8+ T cells and NK cells, indicating the activation of immune cells. Abundant presence of transforming growth factor-beta+ CD25+ cells in the infiltrates associated with CIN lesions, and of immature CD1a+ dendritic cells expressing IL-10 and transforming growth factor-beta, indicate that CIN is associated with an influx of immune cells that produce a mixture of proinflammatory and regulatory cytokines. In HIV+ CIN, immune cell densities (CD4+ T cells, macrophages, neutrophils, and NK cells) and expression of interferon-gamma were significantly decreased compared with HIV- CIN. Regulatory cytokines were also down-regulated in this group. Therefore, both pro- and anti-inflammatory responses present in CIN 2/3 lesions are suppressed in HIV-seropositive women.

Human papillomavirus and cervical cancer: issues for biobehavioral and psychosocial research

There is now overwhelming evidence that high-risk, sexually transmitted types of human papillomavirus (HPV) are the main causal agent in cervical cancer. Biobehavioral and psychosocial research is uniquely capable of addressing many of the issues raised by HPV and its link with cervical cancer. In this article we review current findings in this area and identify issues for future research. The first of the three sections explores issues associated with the introduction of HPV testing for the detection and management of cervical abnormalities and the impact of growing public awareness of the sexually transmitted nature of cervical cancer. The implications for public understanding of cervical cancer, psychosocial issues associated with screening, and the potential impact on screening uptake are discussed. The second section addresses the role of biobehavioral factors in the persistence and progression of HPV infection as well as possible interventions to minimize the risk of persistence. Finally, primary prevention of HPV is discussed.

Interplay between human papillomaviruses and dendritic cells

The design of the human papillomavirus (HPV) infection cycle is tightly fitted to the differentiation program of its natural host, the keratinocyte. This has important consequences for the role of antigen-presenting cells in the priming of antiviral immunity. The confinement of HPV infection to epithelia puts the epithelial dendritic cell, the Langerhans cell (LC), in charge of the induction of T cell-dependent immunity. Because HPV-infected keratinocytes cannot reach the regional lymphoid organs, and HPV-infection of LCs does not result in viral gene expression, priming of antiviral T cells exclusively depends on cross-presentation of viral antigens by the LC. Sensitization of the immune system in the regional lymphoid organs elicits systemic anti-HPV immunity as well as intraepithelial immune surveillance by memory-type intraepithelial T cells and locally produced antibodies. The high rate of spontaneous rejections of high-risk HPV-infections and HPV-positive premalignant lesions indicates that in general the LC-driven antigen presentation machinery is capable of raising an effective immune defense against HPV. Epidemiological studies also reveal that a decrease in the vigilance of the immune system is readily exploited by HPV to escape immune destruction, resulting in persistent infections and development of HPV-positive cancers. In view of the inherent antigenicity of HPV, immune intervention strategies constitute a promising approach for both the prevention and the therapeutic treatment of HPV-induced diseases. Importantly, the mechanisms that govern the induction and effector phases of the intraepithelial immune surveillance against HPV must be taken into account when designing such strategies.

Primary prevention of uterine cervix cancer: focus on vaccine history and current strategy

Primary prevention of uterine cervix cancer spans the gamut of human papillomavirus vaccine development, dietary adjustment, chemoprevention, and risk reduction. Lifestyle and social behaviors impact on risk for cervical cancer. Before examining the growing body of molecular evidence, animal studies, and phase I clinical trials that suggest that a virus-based vaccine for cervical cancer may soon become a reality, one must reflect on what has gone before in the vaccine-based battle with viral disease.

Cervicovaginal coinfections with human papillomavirus and Chlamydia trachomatis

Human papillomavirus (HPV) and Chlamydia trachomatis (CT) are the two most common sexually transmitted pathogens, and infection with either reportedly was associated with cervical intraepithelial neoplasia (CIN) in women. In view of their similar mode of transmission, CT infection was examined as a possible HPV cofactor in the etiology of CIN disease. In total, 129 women were included in the study, of whom 80 were negative (mean age 34.17 +/- 6.9) and 49 were positive (mean age 33.16 +/- 6.8) for HPV DNA (assessed by PCR). CT DNA was determined in endocervical and first-catch urine specimens by PCR. Whereas HPV-positive and HPV-negative women were similar with respect to age (p = 0.419) and pregnancy outcomes (p = 0.628), the number of smokers (p = 0.001), women with multiple male sex partners (p = 0.002) or with abnormal cytology (p < 0.001) was higher in the HPV-positive group. There was an increase in CT infection rate in HPV-positive (29/49) as compared to HPV-negative (10/80) women (p < 0.01). Within HPV-positive patients, there was no significant difference between CT-positive and CT-negative patients with regards to the risk factors studied. Collectively, this suggests that CT infection is a cofactor of HPV in CIN disease development, possibly by modulating the host's immunity and/or precipitation of chronic inflammation.