Langerhans' cells and subtypes of human papillomavirus in cervical intraepithelial neoplasia

Novel Concepts: Langerhans Cells in the Tumour Microenvironment

Langerhans cells (LCs) are immune cells that reside in the stratified epithelium of the skin and mucosal membranes. They play a range of roles in the skin, including antigen presentation and maintenance of peripheral tolerance. Reports of LC numbers have been variable in different cancer types, with the majority of studies indicating a reduction in their number. Changes in the cytokine profile and other secreted molecules, downregulation of surface molecules on cells and hypoxia all contribute to the regulation of LCs in the tumour microenvironment. Functionally, LCs have been reported to regulate immunity and carcinogenesis in different cancer types. An improved understanding of the function and biology of LCs in tumours is essential knowledge that underpins the development of new cancer immunotherapies.

Role of Immune Response in the Prognosis of Carcinoma of the Uterine Cervix: Can in Vitro Analysis Provide a better Framework for more Effective Management?

Cancer of the uterine cervix is the single largest female malignancy in India and also remains a major problem facing oncologists in other parts of the world. While advances in radiation therapy and surgical techniques have made the treatment of cervical carcinoma impressive, limitations to successful management still remain. In fact, the 5-year survival rate, stage for stage, has not improved in the United States or world wide in the past 40 years. With an estimated half a million women developing this disease annually, this lack of improved survival poses an international unresolved health problem. Immune response has been shown to be a major factor involved In the course of the disease for this cancer. Immunologic monitoring was also shown to be of effective value in assessing the prognosis for cervical carcinoma. We studied the various immunologic abnormalities in cervical cancer, the effects of radiation therapy on immune function, prospects of an immunologic staging system, the relationship between human papillomavirus infection and the Immune response, and the possibility of using in vitro Immunologic assessment to provide a better framework for more effective management of cancer of the uterine cervix.

Local Impairment of Immunoreactivity in Hiv-infected Women with Hpv-related Squamous Intraepithelial Lesions of the Cervix

Aims and background

The aim of this study was to compare the local immune response in two groups of patients with high-grade cervical intraepithelial squamous lesions (SIL): one with HIV infection and the other with HPV infection alone.

Materials and methods

16 conization specimens (8 from HIV-infected and 8 from non-HIV-infected patients) of HPV-related, high-grade SIL were selected. The specimens from non-HIV patients were considered as controls. The total number of Langerhans cells, CD4 and CD8 cells present in 10 field areas (3.120 mm2) was recorded in each case. In HIV patients CD4 and CD8 peripheral counts were performed immediately before surgery.

Results

The CD4/CD8 ratio never exceeded 0.71, whereas the lowest ratio in controls was 0.81: this difference was statistically significant (P=0.0009). The mean number of Langerhans cells was markedly reduced in the high-grade SILs in the HIV patients in comparison with controls (P=0.001). The number of CD4 cells and the CD4/CD8 ratio correlated with the peripheral CD4 count (P=0.001 and 0.02).

Conclusions

In our study a marked local impairment of cervical immunoreactivity was observed, which may play a major role in the progression of these lesions in HIV-infected women.

Epigenetic repression of E-cadherin by human papillomavirus 16 E7 protein

A common feature shared between several human cancer-associated viruses, such as Epstein-Barr virus, Hepatitis B virus and Hepatitis C virus, and Human papillomavirus (HPV) is the ability to reduce the expression of cellular E-cadherin. Since E-cadherin is used by Langerhans cells to move through the stratified epithelium, its reduction may affect the efficiency by which the immune system responds to HPV infection and the length of persistent HPV infections. We observed that the E7 protein of this virus (HPV16) is most efficient at reducing E-cadherin levels. This E7 activity is independent of retinoblastoma protein or AP-2α degradation. Instead it is associated with augmentation of cellular DNA methyltransferase I (Dnmt1) activity. Significantly, inhibition of Dnmt activity re-established E-cadherin levels of the cells, presenting the possibility that similar epigenetic intervention clinically may be a way to re-establish the influx of Langerhans cells into infected epithelium to counteract HPV persistence.

Distribution and density of CD1a+ and CD83+ dendritic cells in HPV-associated laryngeal papillomas

BACKGROUND

Respiratory papillomatosis associated with human papilloma virus (HPV) infection is the most common benign laryngeal neoplasm. The age of patients at disease onset, HPV type, number of surgeries are well known prognostic factors of the disease course. The correlation between dendritic cell (DC) density in tumor tissue and clinical prognosis was established.

AIM

The aim of our study was to estimate the density of DC in laryngeal papillomas associated with HPV types 6/11 infection and to evaluate the relationship between the number of DC and the disease severity.

MATERIALS AND METHODS

Our study included 40 randomly selected biopsy specimens from patients with HPV-positive laryngeal papillomatosis aged from 1.7 to 20 year. DC were immunohistochemically labelled with anti-CD1a antibodies and anti-CD83 antibodies. The density of DC was analysed in epithelial layer and lamina propria.

RESULTS

In the epithelial layer of papillomas the number of CD1a+ and CD83+ DC was 86.2 (47.5-119.9) cells/mm(2) and 2.6 (0.6-7.9) cells/mm(2), respectively. In lamina propria - 15.3 (5.1-27.9) and 16.0 (6.7-33.2) cells/mm(2). For subgroups of patients with high number of operations (more than 3), early disease onset (children under 3 years of age) and lingering duration of disease (more than 1 year) we detected an increase of CD83+ DC in the epithelial layer. However, our data did not demonstrate a statistically significant difference in CD1a+ DC count neither in the epithelium nor in the lamina propria. Probably, the increase of CD83+ DC density in epithelial layer of patients with severe course of disease can be an evidence of impaired migration of matured DC.

Immunological role of dendritic cells in cervical cancer

Cervical cancer is the second most frequent gynecological malignancy in the world. Human papillomavirus (HPV) infection is the primary etiologic agent of cervical cancer. However, HPV alone is not sufficient for tumor progression. The clinical manifestation of HPV infection depends also on the host's immune status. Both innate and adaptive immunity play a role in controlling HPV infection. In untransformed HPV-infected keratinocytes, the innate immunity is induced to eliminate the invading HPV pathogen through sensitization to HPV-related proteins by epithelial-residing Langerhans cells (LCs), macrophages, and other immune cells. Once the HPV infection escapes from initial patrolling by innate immunity, cellular immunity becomes in charge of killing the HPV-infected keratinocytes of the uterine cervix through systemic immune response developing by dendritic cells (DCs) in the regional lymphoid organs or through local immune response developing by LCs in the cervix. Thereby, DC/LC plays a critical role in eliciting innate and adaptive cellular immune responses against HPV infection. HPV-associated cervical malignancies might be prevented or treated by induction of the appropriate virus-specific immune responses in patients. Encouraging results from experimental vaccination systems in animal models have led to several prophylactic and therapeutic vaccine clinical trials.

Langerhans' cell count and HLA class II profile in cervical intraepithelial neoplasia in the presence or absence of HIV infection

OBJECTIVES

The progression of immunosuppression in human immunodeficiency virus (HIV)+ women has been correlated with elevated incidence of squamous intraepithelial lesions (SIL), probably indicating the role of local immune milieu. In this study, we analysed S100, and HLA class II molecule expression in cervical biopsies according to HIV status, to the severity of SIL and to human papillomavirus (HPV) type.

METHODS

Biopsies from 34 HIV+ and 44 HIV- patients with normal cervix or low- or high-grade SIL were studied. Langerhans' cells (LC) (S100), HLA class II and HLA-DQ molecules were evaluated by immunohistochemistry. HPV detection was performed using polymerase chain reaction (PCR). For statistical analysis Mann-Whitney (P< or =0.05) and Spearman test were used.

RESULTS

Epithelial S100 and HLA class II density were significantly increased with the severity of lesion (P=0.032; P=0.005). Epithelial S100+ increased in HPV+ (P=0.038), and HLA class II density decreased in HPV 16+ (P=0.035) or 18+ (P<0.0001) samples. HIV infection was associated with increased stromal S100+ (P=0.0005) and decreased HLA class II densities (P=0.0001). Decreased stromal S100+ was observed in women with CD4<500 cells/microl (P=0.050). Among HIV+ patients with SIL, the lowest S100 and epithelial HLA class II densities were detected in women with CD4<200 cells/microl (P=0.045).

CONCLUSIONS

After the establishment of AIDS, increased numbers of immature LCs and a reduction in HLA class II occurred, possibly turning the cervical milieu more favourable to HPV persistence. HPV 16 and 18 infections may interfere with the antigen presenting activity, possibly as an evasion mechanism.

Human papillomavirus and cervical carcinogenesis

Epidemiological studies show that infection with a subset of genital human papillomavirus (HPV) infections is the major risk factor for the subsequent development of cervical cancer. Experimental studies show that that the E6 and E7 genes of these high risk HPVs are oncogenes that deregulate key cell cycle controls. In the normal infectious cycle high level expression of these genes is confined to non-dividing differentiated cells: HPV oncogenesis requires deregulation of viral and cellular genes permitting inappropriate expression of E6 and E7. These are rare events but viral persistence and chronic exposure to steroid hormones increase the probability of this deregulation.

Evaluation of Langerhans' cells in the cervical epithelium of women with cervical intraepithelial neoplasia

OBJECTIVE

Cervical infection with human papillomavirus (HPV) results in a more permissive environment for malignant transformation. In squamous epithelia the Langerhans' cell (LC) is responsible for antigen presentation. Studies that use S-100 immunostaining demonstrate low LCs in cervical intraepithelial neoplasia (CIN) while those that use other methods have shown normal numbers of LCs. This observation led us to postulate that a defect in S-100 proteins, not a simple decrease in LC number, may be the cause of immune suppression. To evaluate this we identified LCs in the cervix of women with HPV/CIN in a prospective fashion using two antibodies, S-100 and CD1, each targeting a different element of the LC.

METHODS

Paired biopsies of the cervix were taken, one paraffin embedded for S-100 and the other snap frozen for CD1 staining. LCs were counted and expressed as the number of cells per millimeter of epithelium. Analysis of variance was used to assess differences between counts in normal, low-grade, and high-grade lesions. HPV was tested by hybrid capture.

RESULTS

S-100 LCs were significantly reduced in dysplasia, LG 8.6 and HG 6.0, compared to normal at 16.7 cells/mm (P = 0.04). S-100 LCs were reduced in HPV-infected cases at 5.9 vs 12.8 cells/mm in HPV negatives (P = 0.02). Acute inflammatory infiltrates were associated with increased S-100 LCs independent of pathology. CD1 LCs were not significantly altered by any parameters tested.

CONCLUSIONS

HPV/CIN may exert an immunosuppressive effect by decreasing the S-100 LCs. The association of S-100-positive LCs coupled with cervical inflammatory changes suggests an important function of the S-100 proteins in the development of an anti-HPV response.

Lymphocytes and dendritic cells in the normal uterine cervix. An immunohistochemical study

OBJECTIVE

Assessment of the appearance, distribution and numerical density of immune cell populations in the normal human uterine cervix.

STUDY DESIGN

SETTING

University Hospital Gasthuisberg.

SUBJECTS

29 healthy women undergoing total hysterectomy for non-cervical benign uterine disease.

ANALYSIS

Immunohistochemistry and morphometrical analysis on histological sections containing ectocervix, transformation zone and endocervix, using antibodies against the following antigens: HLA-DR, CD4, CD22, CD1a and CD8.

STATISTICAL ANALYSIS

Wilcoxon rank sum test.

RESULTS

Lymphocytes in the epithelial and stromal compartments are predominantly T-lymphocytes. Intraepithelial T-lymphocyte and Langerhans' cell densities and their distribution are not influenced by the menstrual cycle and are the same in both ectocervix and transformation zone.

CONCLUSION

The wide variation of T lymphocyte subpopulations and Langerhans' cell densities in the normal epithelium of the uterine cervix is stressed. We are the first to present a large and well-defined control series, which is indispensable to study the effect of smoking and other factors on the cervical immune system.

Cutaneous Langerhans cell histiocytosis of the genitalia in the elderly: a report of three cases

Langerhans cell histiocytosis (LCH) is a disease with a broad spectrum of clinical presentations. All of the variants have in common the proliferation of cells which are morphologically, biochemically, and immunophenotypically indistinguishable from Langerhans cells. A retrospective study of three elderly patients revealed the unique presentation of cutaneous Langerhans cell histiocytosis limited to the genitalia. These cases produced a diagnostic challenge because of their unusual clinical presentation and their morphological similarity to certain other entities, including extramammary Paget's disease and malignant melanoma, which may also show S-100-positive atypical cells. All three cases showed infiltrates of histiocytic-appearing cells with folded nuclei and moderate amounts of cytoplasm which involved the epidermis, dermis, or both. Immunoperoxidase studies using antibody to S-100, CD1a and CD68 in each case showed positive staining.

Triage of the abnormal Papanicolaou smear in pregnancy

Triage of the abnormal Papanicolaou smear in pregnancy requires colposcopic evaluation and directed biopsy. If histologic cervical intraepithelial neoplasia is confirmed, the patient can be managed with observations and can be re-evaluated in the postpartum period. If evidence of microinvasion is present, conization must be performed. For patients with invasive disease, a delay in therapy until fetal maturity is achieved does not compromise survival.

Migration of Lymphoid Cells from Vaginal Epithelium to Iliac Lymph Nodes in Relation to Vaginal Infection by Herpes Simplex Virus Type 2

To determine whether lymphocytes and Langerhans cells in vaginal epithelium are migratory, we stained mouse vaginal epithelium, including its lymphoid cells, by intraluminal administration of H33342, a fluorescent, vital dye. Stromal staining was superficial, and no free dye reached the iliac lymph nodes. The numbers and phenotypes of H33342-stained cells that migrated from the vagina to the iliac lymph nodes during the next 48 h were determined in four groups: normal mice, mice infected intravaginally with wild-type herpes simplex virus type 2 (HSV-2), mice that were immune to vaginal HSV-2 infection, and immune mice that received vaginal challenge with HSV-2. H33342-stained cells migrated from the vaginal epithelium to the iliac lymph nodes in all groups and were mainly Thy-1.2+ cells and B220+ cells. The number of migrating Thy-1.2+ cells was similar to the sum of CD4+ and CD8+ cells in all groups and was not significantly different from the number of CD44+ cells, suggesting that most of the migrating T cells were memory cells. B lymphocytes comprised 31, 32, 43, and 68% of the migrating cells in the four groups, respectively. We found no evidence that Langerhans cells or macrophages were migrating. Thus, most MHC class II+ cells in all groups were accounted for by B cells, and migrating cells did not express B7.1 or F4/80 or exhibit indented nuclei or dendritic processes. We suggest that the migrating T cells and B cells probably belonged to a pool of lymphocytes that recirculates from blood to tissues and back to the lymph nodes via their afferent lymphatics.

Physiology and pathophysiology of dendritic cells

Dendritic cells are antigen-presenting cells derived from the hematopoietic stem cell. The dendritic cell family includes Langerhans' cells (CD1a-positive dendritic cells of the skin), and antigen-presenting cells that are found in the lymphoreticular system and throughout the organ parenchyme. Dendritic cells play a key role in both the primary and secondary immune responses. Several studies indicate that these cells participate in antitumor immunity, tumor surveillance, graft-versus-host disease, and in the pathogenesis of clinical syndromes of unknown origin or those induced by viruses, such as the human immunodeficiency virus. Different disorders are characterized by an abnormal proliferation and accumulation of dendritic cells; for example, the Langerhans' histiocytes, which accumulate in Langerhans' cell histiocytosis. In this review the immunophenotypic, morphological, and functional characteristics of the dendritic cell family is described. The clinical and laboratory studies suggesting a unique role for these cells in various syndromes and diseases are reviewed. The Langerhans' cell histiocytoses and the malignant disorders associated with transformation of cells belonging to the dendritic cell family, are discussed.

Interferon-beta and -gamma, but not tumor necrosis factor-alpha, demonstrate immunoregulatory effects on carcinoma cell lines infected with human papillomavirus

BACKGROUND

Mechanisms whereby cells infected with human papillomavirus (HPV) escape immune surveillance, ultimately leading to invasive cervical carcinoma, may involve changes in local cytokine production, loss of responsiveness to cytokines, and alterations in the expression of immune-regulatory molecules such as histocompatibility-related leukocyte antigen (HLA) Class 1 and 2 and ICAM-I. This study examined the separate and combined effects of immune-activating cytokines, interferon (IFN)-gamma, IFN-beta, and tumor necrosis factor (TNF)-alpha, on the expression of these molecules.

METHODS

Membrane protein expression and cellular mRNA levels were analyzed in cervical carcinoma-derived cell lines, SiHa and CaSki (with low and high HPV16 copy number, respectively), after exposure to cytokines.

RESULTS

Both cell lines demonstrated constitutive expression of HLA Class 1 but not HLA Class 2 membrane antigens. IFN-gamma and -beta induced changes in Class 1 mRNA levels but not in membrane molecule expression. IFN-gamma induced dose-dependent expression of Class 2 membrane and mRNA molecules in both cell lines (more pronounced in SiHa than in CaSki cells), which was antagonized by IFN-beta. Constitutive ICAM-I membrane expression was observed only on CaSki cells, although ICAM-I mRNA was expressed in both cell lines. IFN-gamma up-regulated the membrane expression of this molecule, whereas IFN-beta led to its suppression. Differential modulation of ICAM-I mRNA was observed in both cell lines. A lack of response to TNF-alpha was observed throughout the experiments.

CONCLUSIONS

The findings of this study point to possible mechanisms leading to suppression of local immune response in the pathogenesis of HPV-associated neoplasia. They also emphasize the complexity of developing an efficient cytokine therapy for patients with premalignant cervical disease.

Langerhans and other immunocompetent cells in vocal cord epithelial hyperplastic lesions of patients with chronic laryngitis

The aim of the study was to evaluate the intraepithelial and stromal density of Langerhans cells and lymphoid infiltrate in different stages of carcinogenesis in vocal cord biopsies of 24 randomly selected patients with chronic laryngitis. The Langerhans and lymphoid cells were counted using immunolabelling with antibodies against CD1a, S100, CD3, CD20, and CD68 on paraffin-embedded sections of 24 archival laryngeal vocal cord mucosa biopsy specimens, 6 classified as simple, 7 as abnormal, and 11 as atypical epithelial hyperplasia. Results were statistically evaluated using the Kruskal-Wallis and Wilcoxon sign rank tests. The mean number of Langerhans cells and T lymphocytes per mm2 of cross-sectioned epithelium was found to increase from simple to atypical hyperplasia. There were statistically significant differences in Langerhans cell density between atypical hyperplasia and each of the other 2 grades, simple and abnormal hyperplasia, with p < 0.05. Our study suggests the involvement of immune mechanisms, particularly cell mediated, during laryngeal carcinogenesis and the possibility that the assessment of Langerhans cell density might be of prognostic significance.

Langerhans cells in human papillomaviruses types 6/11 associated laryngeal papillomas

Some studies have shown a reduced density of Langerhans cells (LCs) within epithelium infected by human papillomaviruses (HPV) types 16/18. However, data on a correlation between HPV types 6/11 infection and LCs have been missing. To solve this problem, we analysed 24 biopsy specimens of laryngeal papillomas, selected randomly, 20 multiple and 4 solitary. The presence of HPV 6 and 11 was proven by polymerase chain reaction (PCR) using 2 different sets of primers in 23 biopsy specimens. Abnormalities of the covering stratified squamous epithelium were graded according to the Kambic-Gale classification. LCs were immunohistochemically labelled with 2 different antibodies, CD1a and S100. Quantitative analysis was performed to determine the density of LC per mm2 in different grades of epithelial abnormalities covering laryngeal papillomas. Although no statistically significant differences in the mean number of LCs per mm2 of the cross-sectioned epithelium covering laryngeal papillomas were observed comparing simple, abnormal and atypical hyperplasia groups, the mean number of LCs per mm2 in laryngeal papillomas associated with HPV types 6/11 infection substantially exceeded that of the vocal cord surface epithelium in patients with chronic laryngitis.

Local immune response in endometrial carcinomas

OBJECTIVE

To determine whether Langerhans cells act as antigen-presenting cells in endometrial carcinomas and their related lesions.

SAMPLES

Frozen endometrial samples were obtained from 13 women with normal menstrual cycles, 3 postmenopausal women, 11 women with hyperplasia (simple 4, complex 4 and atypical 3) and 32 women with endometrial carcinomas.

MAIN OUTCOME MEASURES

Langerhans cells (CD1), T lymphocytes (CD4 and CD8), B lymphocytes (CD22), natural killer (NK) cells (CD57) and HLA-DR were all quantitatively assessed in endometrial samples using immunohistochemical method.

RESULTS

The numbers of Langerhans, CD4+, CD8+ and B cells were higher in the secretory phase than in the proliferative endometrium. The CD8+ cells appeared to be more plentiful than the CD4+ cells. When compared with the proliferative endometrium, the numbers of Langerhans cells were higher in hyperplasias and carcinomas. Most of Langerhans cells were HLA-DR+, showing a strong correlation with CD4+ cells in carcinomas. This suggests that MHC class II antigen restricted lymphocytes in carcinomas are activated by HLA-DR+ Langerhans cells. However, epithelial expression of HLA-DR in carcinomas did not show on association with high numbers of Langerhans and CD4+ cells. No correlation was observed between Langerhans cells and clinicopathologic features of carcinomas. In contrast, the number of NK cells significantly decreased in noninvasive carcinomas but increased in Grade 3 tumours.

CONCLUSION

Based on the above findings, Langerhans cells are considered to act as antigen-presenting cells in carcinomas, but it was not shown that they were activated by epithelial expression of HLA-DR in carcinomas.

Infiltration by immunocompetent cells in early stage invasive carcinoma of the uterine cervix: a prognostic study

In various tumor types dentritic cell, infiltration and the presence of tumor-infiltrating lymphocytes have been associated with an improved clinical outcome. In the uterine cervix these immunocompetent cells have been associated with improved prognosis in high stage disease. The current study examines the significance of stromal and tumor T-lymphocyte infiltration together with S-100 positive dendritic cell infiltration in a series of 73 women with low stage (FIGO 1b) invasive squamous and adenosquamous cervical carcinoma. Thirty four percent of cases contained S-100 positive dendritic cells. These were under-represented in cases showing pelvic recurrence or distant disease (1 of 11 compared to 24 of 62 free of recurrence, P = 0.05) and over-represented in cases showing lymphatic/capillary space involvement (12 of 23 compared to 13 of 46 without vascular space invasion, P = 0.05). The women were followed up for an average of 5.2 years and the five-year survival for women whose tumors contained S-100 positive dendritic cells was 92% compared to 73% for negative cases (P = 0.04). There was a significant association between a low density of tumor infiltrating T-cells and risk of pelvic lymph node spread and subsequent local or distant disease control failure (P = 0.008). A five year survival advantage was seen with five or more CD 3 positive tumor infiltrating T-lymphocytes per high power field (90%) compared to a lower count (68%) (P = 0.04). A similar advantage could not be demonstrated for a high stromal infiltrate of T-cells. As yet neither the specific mechanisms that induce these cells to infiltrate some cervical carcinomas nor the nature of the immunological injury that the cells co-ordinate in tumor tissue are well understood.

Depletion of stromal and intraepithelial antigen-presenting cells in cervical neoplasia in human immunodeficiency virus infection

Human immunodeficiency virus-positive (HIV+) women have an increased risk of lower genital tract dysplasia and neoplasia, and studies of the central lymphoid system suggest that impaired immunosurveillance plays a role in the development of their cervical tumors. Intraepithelial and stromal immunocompetent cell counts were compared in cervical specimens from 50 HIV+ and 50 appropriately matched HIV-women (controls) with low and high grade squamous intraepithelial lesions (SIL), or carcinoma. Each histological class of HIV+ women displayed fewer intraepithelial Langerhans' (S100+) cells (LC) (as already known), and also fewer stromal LC and both intraepithelial and stromal (CD68+) macrophages. LC and macrophages were reduced in all HIV+ patients, whereas reduction of cervical T lymphocytes was found in only immunocompromised subjects (peripheral blood CD4+ T-cell count < 500/microL). A mucosal quantitative deficiency of antigen-presenting cells (APC) thus precedes that of T cells. HIV infection appears to lead to early impairment of mucosal immunoreactivity mainly because of defective antigen presentation. This impairment may be one mechanism underlying the increased frequency of cervical dysplasia/neoplasia, and the enhanced aggressiveness of invasive cancers in HIV+ women.

Epidemiology of cervical intraepithelial neoplasia: the role of human papillomavirus

The evidence implicating specific HPV types in the aetiology of cervical cancer is now strong enough to establish a causative role. HPV infection of the cervix affects the developing immature metaplastic cells of the transformation zone. Cervical neoplasia can be viewed as the interaction of high risk papillomavirus and immature metaplastic epithelium. Once maturity is reached, there is minimal risk of subsequent development of cervical squamous neoplasia. Exposure to HPV is an extremely common event, especially in young sexually active women. Yet, despite frequent HPV exposure at that phase of life in which the cervical transformation zone is at its most vulnerable, established expressed disease is relatively uncommon. Most studies in which the natural history of CIN is not altered by cervical biopsy reveal a progression rate from low to high grade CIN of less than one third. Where viral type is taken into account, however, the progression rate from normal but high risk HPV-infected cervical epithelium to CIN 2 or 3 is higher. Despite this, most cervical abnormalities will not transform into invasive cancer, even if left untreated. The variance between the high rate of HPV infection, the intermediate rate of CIN and the relatively low rate of cervical cancer establishes a stepwise gradient of disease of increasing severity with decreasing prevalence. In an immunocompetent host, HPV infection alone does not appear to be sufficient to induce the step from high grade CIN to invasion. Epidemiological studies indicating that HPV infection with oncogenic viral types is far more common than cervical neoplasia suggest the necessity of cofactors in cervical carcinogenesis. The long time-lag between initial infection and eventual malignant conversion suggests that random events may be necessary for such conversion, and the spontaneous regression of many primary lesions suggests that most patients are not exposed to these random events. Potential cofactors include cigarette smoking, hormonal effects of oral contraceptives and pregnancy, dietary deficiencies, immunosuppression and chronic inflammation. In those women who develop cervical cancer, malignant progression is rarely rapid, more commonly taking many years or decades. Malignant progression has been documented in patients who presented initially with only low grade HPV-induced atypia. On the other hand, progression may be a misnomer, as 'apparent' progression may really represent adjacent 'de novo' development of higher grade CIN. Although most cervical cancers contain high risk HPV types, up to 15% of such cancers test negative for HPV, raising the possibility that a few, usually more aggressive, cervical cancers may arise from from a non-viral source.(ABSTRACT TRUNCATED AT 400 WORDS)

Characterization and functional analysis of the expression of vascular adhesion molecules in human papillomavirus-related disease of the cervix

BACKGROUND

Cervical intraepithelial neoplasia (CIN) is associated with changes in local immune cell populations, although the role of vascular adhesion molecules in mediating such changes by controlling the traffic of mononuclear cells to the cervix has not been investigated previously.

METHODS

The authors used immunohistochemistry to examine the expression of three vascular adhesion molecules--ICAM-1, VCAM-1 and E-selectin--in the normal cervix and in biopsies of CIN Grade 1 (CIN-1) (low grade squamous intraepithelial lesions [LG-SIL]) and CIN-2/3 (high grade squamous intraepithelial lesions[HG-SIL]). In addition, the authors examined the functional role of these molecules by adapting the frozen section adhesion assay of Stamper and Woodruff to investigate in vitro the molecular basis of the interaction between cervical endothelial cells and activated T-lymphocytes.

RESULTS

Whereas there was no difference in adhesion molecule expression between normal cervix and CIN-1 (LG-SIL), all three molecules investigated were significantly up-regulated in CIN-2/3 (HG-SIL), an observation that correlated with an enhanced ability of stromal endothelial cells in CIN-2/3 (HG-SIL) biopsies to bind activated peripheral blood lymphocytes in vitro. Monoclonal antibodies blocking ICAM-1 function were able to reduce such adhesion significantly in three of three experiments, and antibodies blocking VCAM-1 produced a significant reduction in one of three experiments. No inhibition was seen with antibodies against E-selectin.

CONCLUSIONS

The enhanced expression of vascular adhesion molecules in CIN-2/3 (HG-SIL) appears to be functionally important in enabling the local recruitment of immunocompetent cells and supports the notion of a local antineoplastic immune response in high grade cervical intraepithelial lesions.

Depletion of Langerhans cells in cervical HPV infection is associated with replication of the virus

We studied the quantity of Langerhans cells in 36 patients with cervical human papillomavirus (HPV) infection. Significantly fewer Langerhans cells (p < 0.05) were found in patients with compared to those without DNA tetraploidy. Similarly, patients positive for HPV 16/18 DNA by in situ hybridization or antipeptide IgA antibodies to HPV 18 tended to have fewer Langerhans cells than those negative for HPV 16/18 DNA or IgA antibodies. Our results suggest that depletion of Langerhans cells is associated with productive HPV 16/18 infection in the cervical epithelium.

Pathogenesis of genital HPV infection

Clinical, subclinical, and latent human papillomavirus (HPV) infections are distinguished from HPV-associated neoplasia. Besides HPV additional cofactors are necessary to transform HPV infected tissue to intraepithelial or invasive neoplasia. Risk factors for the presence of HPV are high number of sexual partners, early cohabitarche, young age at first delivery, suppression and alteration of immune status, young age and hormonal influences. While the fact of a high number of sexual partners exclusively increases the risk of HPV infection, it is not known whether the other factors lead to either an increased risk for HPV infection and/or to HPV-associated neoplasia. Subclinical and latent genital HPV infections are highly prevalent. The prevalence rate depends on the sensitivity of the HPV detection system used, on age and sexual activity of the population screened, and on the number of subsequent examinations performed for each subject. Sexual transmission is the main pathway for genital HPV's, however, vertical, peripartal, and oral transmission are also possible. Seroreactivity against genital HPV may be due to an active infection or the result of contact with HPV earlier in life. Antibodies against the HPV 16 E7 protein indicate an increased risk for cervical cancer. Compared with humoral response cellular immune response is probably more important for regression of genital HPV infection: impaired cellular response is characterized by depletion of T helper/inducer cells and/or Langerhans cells and impaired function of natural killer cells and/or the infected keratinocyte. In condylomata replication and transcription of viral nucleic acids and antigen production coincide with cellular differentiation. However, the interaction between HPV and the keratinocyte on a molecular level in subclinical and latent disease is not well understood. Regression or persistence of subclinical and latent genital HPV infections as observed in longitudinal investigations show a constant come-and-go of HPV presence. Subclinical or latent cervical infections with high-risk HPV types (such as HPV 16 and 18) have an increased risk for the development of HPV-associated neoplasia.

Role of Langerhans cells and other dendritic cells in viral diseases

Langerhans cells are part of a vast system of potent antigen-presenting cells known under the name of dendritic cells. During the last decade, much has been learned on dendritic cell involvement in the immune response to infectious diseases. This review briefly summarizes our current understanding of the role played by Langerhans cells and other dendritic cells in the pathogenesis of DNA and RNA virus infections. These data may form the basis for the development of innovative approaches in the diagnosis, prevention, and treatment of viral diseases.

Density and distribution of Langerhans cells in the human uterine cervix

Using a combination of immunohistochemistry and planimetric observation we report the density and distribution of Langerhans cells (LCs) in epithelium from the normal ectocervix and from the normal transformation zone (TZ). The density of LCs increased towards the basement membrane. Dendritic LCs aspect was more prominent in the superficial layers.

A T-helper cell epitope overlaps a major B-cell epitope in human papillomavirus type 18 E2 protein

Cultivated CD4+ T-helper cells from two patients with cervical adenocarcinoma showed responses to a peptide EKTGILTVTYHSETQRTK derived from an E2 protein of human papillomavirus type 18 (HPV 18), but not to a corresponding HPV 16 peptide (HKSAIVTLTYDSEWQRDQ). Serum antibodies in the HPV 18 peptide were also demonstrated in these patients. The GILT motif resembles a common pattern present in many T-cell epitopes, and is located at the beginning of an 11-amino acid-long A-helix structure close to the carboxyterminal end of HPV 18 E2. We conclude that two epitopes (a T-helper cell epitope and a B-cell epitope) overlap in the HPV 18 E2.

Assessment by planimetry of Langerhans' cell density in penile epithelium with human papillomavirus infection: changes observed after topical treatment

Langerhans' cells could have an important role in the immune surveillance for the malignant transformation associated with certain viral infections. A planimetric study of Langerhans' cells was performed on epithelial sheets obtained from male and female patients who presented with human papillomavirus-induced condylomata. Preliminary epidemiological studies have indicated that after a human papillomavirus infection the risk of malignant transformation is higher in the cervix than in the penis. Our study was designed in such a way that the Langerhans' cell density observed in condylomata could be compared to that detected in adjacent normal areas from the same patients. The results showed that a highly significant decrease in Langerhans' cells occurred in male and female human papillomavirus infected genital tracts. In the penis the local treatment with 5-fluorouracil restored the normal Langerhans' cell density. The significance of these findings in relationship with malignant transformation is discussed.

Immunocytochemical characterization of large granular lymphocytes in normal cervix and HPV associated disease

A quantitative immunocytochemical study of large granular lymphocytes (LGLs) in the normal cervix and in human papillomavirus (HPV) associated disease was performed using a panel of monoclonal antibodies which included those for LGL surface markers CD56, CD16, and CD57. Only CD56-positive cells were found within the ectocervical epithelium and these cells increased in number in cervical intraepithelial neoplasia (CIN) in comparison with normal cervix. Examination of serial sections and double labelling suggests that these cells are CD3+, CD8+, CD56+, CD16+. The observed increase in number of this subset was not associated specifically with HPV infection but was related to CIN. Lymphocytes expressing all three LGL markers were found in the stroma and CD16(+)-positive cells clustered around endocervical glands with occasional cells extending into the endocervical epithelium. These results indicate that a small subset of LGLs which express T-cell markers is increased in number in CIN. Cells expressing classical NK markers are restricted to the stroma and are not found within the ectocervical epithelium.

Langerhans cell histiocytosis of the female genital tract

Langerhans cell histiocytosis (LCH) of the female genital tract is rare. Four new cases are reported, and there is a review of the 38 cases in the literature. This disease may involve the vulva, vagina, cervix, endometrium, and ovary. Four distinct patient groups, segregated on the basis of initial presentation and subsequent anatomic extent of disease, were categorized as follows: (1) "pure" genital LCH, (2) genital LCH with subsequent multi-organ involvement, (3) oral or cutaneous LCH with subsequent genital and multi-organ involvement, and (4) diabetes insipidus with subsequent genital and multi-organ disease. Although involvement of the genital tract can occur at any age, it is most common in young adulthood. Clinically, LCH may mimic either primary neoplasia or various inflammatory lesions; the major pathologic differential diagnosis is venereal and other inflammatory diseases. The pure genital form may have a distinct nosologic position in the spectrum of LCH similar to the "pure," self-limited cutaneous histiocytosis seen in infants. There is no correlation between histologic findings and the outcome of the genital lesions. There is also no correlation between clinical presentation and/or the extent of involvement and outcome of genital lesions; complete regression, partial improvement, persistent lesions, and recurrences were seen in all four groups of patients. The treatment of genital LCH is not well defined and is highly individualized. Therapy has included surgery, radiation, topical corticosteroids, topical nitrogen mustard, systemic chemotherapy, and combination therapy; mixed results were obtained with all treatment modalities. Although no modality has been shown to yield a superior outcome, complete surgical excision is advocated as initial therapy.

Human immunodeficiency virus seroprevalence among cervical cancer patients

Human immunodeficiency virus (HIV) infection and cervical neoplasia intimately share several epidemiologic factors, the most important being the role of sexuality in their prevalence. Recent reports have suggested a strong association between the two conditions. In Africa HIV transmission is predominantly heterosexual and there is no significant sex preference. The prevalence of cervical cancer is also high in Africa and may be rising. Two hundred African patients with cervical carcinoma in Nairobi, Kenya, were screened for HIV seropositivity by both ELISA and Western blot. A seroprevalence rate of only 1.5% was obtained. This was comparable to the 2% found in the general population but much lower than the 18-59% recorded in recognized high-risk groups. The background to these surprising results and their implications are discussed.

A histological and immunohistological study of cervical intraepithelial neoplasia in relation to recurrence after local treatment

A retrospective histological study was performed on 23 patients who had presented with recurrent cervical intraepithelial neoplasia (CIN) 18 months or more after apparently adequate local destructive treatment and a comparable control group of 23 patients who had no recurrence at 18 months. All recurrences were in women with CIN 3. Detailed examination of pretreatment biopsies showed that there were significant differences in both the extent of crypt involvement (P less than 0.01) and maximum depth of CIN (P less than 0.01) between the recurrent groups and the comparison group of women without recurrence. There was also a significant difference in mitotic count between the two groups (P less than 0.01). Immunocytochemical staining for Langerhans' cells or human papilloma virus common antigen showed no significant difference between the two groups. A mitotic count of 35 per ten high-power fields or a depth of crypt involvement greater than 1.7 mm in the pretreatment biopsy was invariably associated with recurrence and identified 13/22 (59%) cases of recurrent disease. The histological reporting of these features may be of value in predicting a group of women at high risk of recurrence of CIN after local treatment.