Abrogated NK-cell lysis of human papillomavirus (HPV)-16-bearing keratinocytes in patients with pre-cancerous and cancerous HPV-induced anogenital lesions

Human papillomavirus, high-grade intraepithelial neoplasia and killer immunoglogulin-like receptors: a Western Australian cohort study

Background

Human papillomavirus (HPV) is the causative agent in cervical cancer and HPV genotypes 16 and 18 cause the majority of these cancers. Natural killer (NK) cells destroy virally infected and tumour cells via killer immunoglobulin-like receptors (KIR) that recognize decreased MHC class I expression. These NK cells may contribute to clearance of HPV infected and/or dysplastic cells, however since KIR controls NK cell activity, KIR gene variation may determine outcome of infection.

Methods

KIR gene frequencies were compared between 147 patients with a history of high-grade cervical intraepithelial neoplasia (CIN) and a control population of 187, to determine if any KIR genes are associated with high-grade CIN. In addition a comparison was also made between cases of high grade CIN derived from 30 patients infected with HPV 16/18 and 29 patients infected with non-16/18 HPV to determine if KIR variation contributes to the disproportional carcinogenesis derived from HPV 16/18 infection.

Results

High-grade CIN was weakly associated with the absence of KIR2DL2 and KIR2DS2 (p = 0.046 and 0.049 respectively, OR 0.6; 95% CI 0.4 – 0.9) but this association was lost after correction for multi-gene statistical analysis. No difference in KIR gene frequencies was found between high-grade CIN caused by HPV 16/18 and non-16/18.

Conclusion

No strong association between KIR genes, high-grade CIN and HPV genotype was found in the Western Australian population.

Verrucous carcinoma masquerading as a giant fibroepithelial polyp

The authors report a case of a verrucous carcinoma (VC) of the buttocks clinically simulating a giant (6.5 cm in length and 5.4 cm in greatest diameter) fibroepithelial polyp (FEP) capped by a large cutaneous horn. The growth had been present for 15 years and had never been biopsied despite numerous physical exams. VC typically presents distinctly as a large cauliflower-like growth with histological features of acanthosis, parakeratosis, minimal cytological atypia, and deep pushing epithelial borders. It is considered a low-grade, well-differentiated variant of squamous cell cancer and is commonly associated with human papillomavirus (HPV). Anogenital VC has been associated more with "low-risk" (type 6 and 11) than "high-risk" (16 and 18) HPV types. Presentation of VC as a FEP is unusual and demonstrates the necessity of maintaining a high level of clinical suspicion of anogenital growths, particularly those involving atypical features such as ulceration or the presence of a cutaneous horn.

Effect of estrogen/progesterone hormone replacement therapy on natural killer cell cytotoxicity and immunoregulatory cytokine release by peripheral blood mononuclear cells of postmenopausal women

Sex steroids are known to affect immune responses; however, information on immunomodulatory effects of estrogen/progesterone hormone replacement therapy (HRT) is still limited. Therefore, the present study aimed to investigate the effect of estrogen/medroxyprogesterone HRT on natural killer (NK) cell cytotoxicity and immunoregulatory cytokine (IL-2, IL-4 and IFN-gamma) release by phytohemaglutinin (PHA)-stimulated peripheral blood mononuclear cells (PBMC) from 15 selected healthy postmenopausal women. NK cell cytotoxicity, cytokine production and serum levels of 17beta-estradiol (E2), progesterone (P) and FSH were tested in each patient before and after 90-days HRT. NK cell cytotoxicity was tested by (51)Cr-release assay using K562 erythroleukemic cells as target. Specific cytokine production and serum hormone levels were evaluated by enzyme-linked immunosorbent assay (ELISA) and immunochemiluminescent assays, respectively. HRT resulted in a significant decrease of Kupperman index, an increase of E2 and a decrease of FSH levels. These changes were associated with a significant decrease of NK cell cytotoxicity, IL-2 and IFN-gamma production. The levels of IL-4 production remained unchanged. Changes of NK cell cytotoxicity and cytokine release in individual patients did not correlate with changes of serum sex hormone levels. Nevertheless, the present results imply strongly that estrogen/progesterone HRT may affect cell-mediated immunity, thus being a potential factor influencing development and course of autoimmune disorders and neoplastic diseases.

E5 protein of human papillomavirus type 16 selectively downregulates surface HLA class I

Papillomaviruses have evolved mechanisms that result in escape from host immune surveillance. The E5 protein is expressed early in papillomavirus infection in the deep layers of the infected epithelium. It is localized to the Golgi apparatus (GA) and endoplasmic reticulum. The E5 protein of bovine papillomavirus (BPV) impairs the synthesis and stability of major histocompatibility (MHC) class I complexes and prevents their transport to the cell surface due to retention in the GA. Here we show that human papillomavirus type 16 (HPV-16) E5 also causes the retention of MHC (HLA) class I complexes in the GA and impedes their transport to the cell surface, which is rescued by treatment with interferon. Unlike BPV E5, HPV-16 E5 does not affect the synthesis of HLA class I heavy chains or the expression of the transporter associated with antigen processing TAP. These results show that downregulation of surface MHC class I molecules is common to both BPV and HPV E5 proteins. Moreover, we determined that HPV-16 E5 downregulates surface expression of HLA-A and HLA-B, which present viral peptides to MHC class I-restricted cytotoxic T lymphocytes (CTLs), but not the natural killer (NK) cell inhibitory ligands HLA-C and HLA-E. Selective downregulation of cell surface HLA class I molecules may allow the virus to establish infection by avoiding immune clearance of virus-infected cells by both CTLs and NK cells.

Evasion of host immunity directed by papillomavirus-encoded proteins

The nature of the interaction between papillomaviruses (PV) and their infected host has led to the identification of ways in which the viral oncoproteins can transform the infected host cells into cancer cells. As viral persistence is required for malignancy, and persistence requires avoidance of immune attack by the host, defining the relationship between PV and the immune system is also paramount in understanding tumorigenesis. It has emerged that PV have evolved several ways in which to prevent clearance by the host immune system. The limitation of the PV replication cycle to the epithelium, together with low level expression of the virus proteins and an absence of inflammation, minimises the exposure of virus to immune cells. In addition, more recently it has been shown that, like many other viruses, PV can directly subvert the immune response, including interference with the interferon pathway, modulation of antigen presentation, inhibition of interleukin-18 activity and down-regulation of major histocompatibility class I on infected cells. Collectively these mechanisms explain how PV lesions are able to persist for long periods of time in immunocompetent hosts.

Quantitative analysis of IL-10 and IFN-gamma mRNA levels in normal cervix and human papillomavirus type 16 associated cervical precancer

Human papillomavirus type 16 is a major factor in cervical carcinogenesis. Inappropriate cytokine synthesis may direct the local immune response away from a type-1 (cellular) pattern and may subsequently contribute to the development and progression of precancer. Quantitative reverse transcription-polymerase chain reaction (RT-PCR) using a competitive mimic was carried out to determine type-1 (interferon gamma (IFN-gamma)) and type-2 (interleukin-10 (IL-10)) cytokine mRNA levels in whole cervical specimens (without microdissection) from seven normal and nine HPV-16 positive CIN formalin-fixed paraffin-embedded tissues. Microdissection was used to measure separately the epithelial and sub-epithelial levels of IFN-gamma and IL-10 mRNAs in 11 specimens of normal cervix and 25 HPV-16 positive CIN (nine CIN 1, seven CIN 2 and nine CIN 3). IFN-gamma mRNA was lower in CIN than normal (p=0.04). IL-10 mRNA level in CIN was significantly higher (p=0.005) than in normal cervix (before microdissection). Epithelial IFN-gamma mRNA showed a significant decrease in all grades of CIN (median=3.58) compared with normal (7.74) (p<0.05), but there was no significant difference between the grades. A significant decrease in sub-epithelial IFN-gamma mRNA was found in CIN 1(9.81), CIN 2 (3.82) and CIN 3 (4.62) compared with normal cervix (27.35) (p<0.05). Also, sub-epithelial IFN-gamma mRNA was significantly lower in CIN 2 and CIN 3 than in CIN 1 (p=0.005 and 0.0005, respectively). IL-10 was detected in the epithelium of only one of 11 normal and one of 25 CIN, but sub-epithelial IL-10 was significantly higher in CIN 2 (0.08) and CIN 3 (0.26) than in normal (0.00) (p=0.036 and 0.0032, respectively). There was no significant difference in the sub-epithelial level of IL-10 between normal and CIN 1 (0.00) (p=0.96). Our results suggest that reduced epithelial and sub-epithelial IFN-gamma, as well as increased sub-epithelial IL-10 synthesis may play a role in the development and progression of HPV-16 associated cervical precancer.

Isolated extragenital bowenoid papulosis of the neck

We report a case of extragenital bowenoid papulosis (BP) in a healthy immunocompetent 42-year-old man. The lesions occurred on the anterolateral aspects of the neck and were not associated with genital, oral, or periungual lesions. Lesional skin tested positive with the Digene hybrid capture system cocktail assay that identifies infection with a mixture of high to intermediate oncogenic human papillomavirus (HPV) types, including types 16, 18, 31, 33, 35, 45, 51, 52, and 56. This cocktail assay identifies infection with HPV types typically associated with high-grade squamous intraepithelial lesions and invasive carcinoma. This case represents the sixth case of isolated cutaneous BP occurring a significant distance from the genital region.

Increased IL-6 and IL-8 levels in cervicovaginal secretions of patients with cervical cancer

OBJECTIVE

Conflicting data exist on IL-6 production by human papillomavirus (HPV) immortalized cell lines and several cervical carcinoma cell lines. However, no information has been reported on the levels of cytokines in cervicovaginal washings in relation to cervical neoplasia. The aim of this study was to investigate whether local production of IL-6 could be found and whether the level of this cytokine was related to the severity of cervical neoplasia. IL-8 was measured to obtain additional information on an inflammatory cytokine with possible epithelial origin.

METHODS

Cervicovaginal washings and sera were obtained from 35 patients with invasive cervical cancer, 62 patients with cervical intraepithelial neoplasia (CIN), and 25 control subjects. IL-6 and IL-8 levels were determined by ELISA. HPV DNA in cervical smears was detected by a HPV-16-specific PCR method and additionally by CPI/IIG PCR. Histological analysis of the inflammatory infiltrate was performed on hematoxylin-eosin-stained tissue sections.

RESULTS

In the patients with cervical cancer, those with CIN, and the controls, the median IL-6 concentration in cervicovaginal washings was 171 pg/ml (interquartile range: 54-780), 22 pg/ml (<2-73), and < 2 pg/ml (<2-<2), respectively. For IL-8, the levels were 2756 pg/ml (1651-7107), 489 pg/ml (248-1158), and 631 pg/ml (346-897), respectively. In most subjects the local levels were much higher than in serum. Local IL-6 and IL-8 levels were significantly higher in patients with cervical carcinoma compared with CIN patients and controls. Likewise, local IL-6 levels were increased in patients with CIN compared with controls. No relation was found between cytokine levels and CIN grade or between cytokine levels and the inflammatory infiltrate scored by histological analysis.

CONCLUSIONS

There is local production of IL-6 and IL-8 in cervicovaginal secretions, and the production of IL-6 was related to the severity of cervical neoplasia.

Natural killer cell activity and sex hormone levels in mastopathy

The aim of the study was to test the cytotoxic activity of peripheral blood natural killer (NK) cells in relation to serum levels of sex hormones in patients with mastopathy. The study included 37 patients classified into mastalgia, fibrosis, fibrocystic disease, and fibroadenoma groups and 19 healthy age-matched volunteer women. Estradiol, progesterone, luteinizing hormone (LH), follicle-stimulating hormone (FSH), and prolactin were evaluated in sera by specific radioimmunoassays. NK cell activity was evaluated by means of 51Cr-release assay. In all patient groups, progesterone levels were significantly decreased. There was also an increased frequency of patients with low levels of estradiol (< 50 pg/ml). On the other hand, LH levels in fibrocystic disease and fibroadenoma groups were significantly increased. NK cell activity was in the normal range in all patient groups. In individual women, NK cell cytotoxicity did not correlate with the levels of the studied hormones. However, in patients with low (< 50 pg/ml) and high (> 200 pg/ml) estradiol levels an increase and a decrease of NK cell activity was observed, respectively. This suggests that in patients with mastopathy, estradiol may directly or indirectly affect NK cell cytotoxicity. High levels of estradiol and low NK cell activity might constitute an increased risk for neoplasia.

Oncogenicity of human papillomavirus- or adenovirus-transformed cells correlates with resistance to lysis by natural killer cells

The reasons for the dissimilar oncogenicities of human adenoviruses and human papillomaviruses (HPV) in humans are unknown but may relate to differences in the capacities of the E1A and E7 proteins to target cells for rejection by the host natural killer (NK) cell response. As one test of this hypothesis, we compared the abilities of E1A- and E7-expressing human fibroblastic or keratinocyte-derived human cells to be selectively killed by either unstimulated or interferon (IFN)-activated NK cells. Cells expressing the E1A oncoprotein were selectively killed by unstimulated NK cells, while the same parental cells but expressing the HPV type 16 (HPV-16) or HPV-18 E7 oncoprotein were resistant to NK cell lysis. The ability of IFN-activated NK cells to selectively kill virally transformed cells depends on IFN's ability to induce resistance to NK cell lysis in normal (i.e., non-viral oncogene-expressing) but not virally transformed cells. E1A blocked IFN's induction of cytolytic resistance, resulting in the selective lysis of adenovirus-transformed cells by IFN-activated NK cells. The extent of IFN-induced NK cell killing of E1A-expressing cells was proportional to the level of E1A expression and correlated with the ability of E1A to block IFN-stimulated gene expression in target cells. In contrast, E7 blocked neither IFN-stimulated gene expression nor IFN's induction of cytolytic resistance, thereby precluding the selective lysis of HPV-transformed cells by IFN-activated NK cells. In conclusion, E1A expression marks cells for destruction by the host NK cell response, whereas the E7 oncoprotein lacks this activity.

Verrucous carcinoma of the skin and mucosa

The concept of verrucous carcinoma as a clinicopathologic variant of squamous cell carcinoma is worthy of recognition. It is known by a confusing array of names, such as Ackerman's tumor, Buschke-Loewenstein tumor, florid oral papillomatosis, epithelioma cuniculatum, carcinoma cuniculatum, and cutis papillomatosis carcinoides of Gottron. Its apparent clinical benignity may lead to lengthy periods of misdiagnosis, during which it is likely not to spread to distant lymph nodes, but rather to destroy a nose, mandible, or penis as it slowly but relentlessly extends into underlying tissue. Morphologically warty or verrucous, its relatively bland histologic features are often more suggestive of a verruca vulgaris or pseudoepitheliomatous hyperplasia than of squamous cell carcinoma to those unfamiliar with the diagnosis. Alternatively, when it extends into underlying tissues, it may be mistaken histologically for a benign adnexal tumor or even an epidermoid cyst. Therapy may also be challenging because recurrences are common and concerns about potential anaplastic transformation after radiotherapy are often expressed.

Neoplasms of the anus

Anal cancers can be grouped into three major categories. First, anal margin lesions are usually well-differentiated, keratinized squamous cell carcinomas that are amenable to local treatment measures. Second, anal canal cancers distal to the dentate line are mostly epidermoid, nonkeratinizing, moderately differentiated tumors. They are usually best treated with a multimodality approach using chemoradiotherapy and reserving surgery for clinical failures. Third, cancers arising in the ATZ are usually adenocarcinomas, and their treatment depends upon local factors. APR is in order for locally aggressive lesions, but newer protocols are studying multimodality therapy for this entity as well. Other, less common cancers of this region should be evaluated based upon their biologic potential and local involvement, with treatments selected accordingly.

HPV replication in experimental models: effects of interferon

Preclinical evaluation of the effectiveness of interferon (IFN) therapy on human papillomaviruses (HPV) has been hampered by the inability to propagate these viruses in cell culture. Nonetheless, interferon is used extensively in the treatment of HPV infections. Alpha interferons in particular have found a place in the treatment of anogenital disease, plantar warts, and laryngeal papillomas. While their is significant clinical evidence to suggest that interferon is useful in therapy of disease, the cellular mechanism(s) (i.e., antiviral, antiproliferative, immunomodulatory) by which IFN is able to control HPV-induced pathology is not well understood. This review focuses on experimental animal and cell culture models which are currently being used to help identify the antiviral, antiproliferative and immunomodulatory effects of IFN on HPV infection.

Malignant anal tumours

Anal tumours represent 5 per cent of anorectal cancers and exist as two clinical entities: tumours of the anal canal and those of the anal margin. Smoking and sexual behaviour, particularly homosexual anal intercourse, are important aetiological factors. This association is related to anal warts and human papillomavirus infection, notably type 16, which is found in around 70 per cent of warts. Symptoms are non-specific and are frequently attributed to benign conditions. Rectal examination reveals a characteristically infiltrating lesion and any suspicious anal area should be biopsied. There are two histological types. Squamous carcinoma comprises approximately 95 per cent of anal tumours and includes the 35 per cent of tumours derived from the anal transition zone (cloacogenic tumours), containing a mixture of squamous and mucinous elements. The remaining 5 per cent of anal tumours are adenocarcinoma. Squamous cell tumours of the anal canal are probably best treated using radiotherapy (with chemotherapy) as complete response rates, 5-year survival rates, and incidences of normal sphincter function and significant toxicity are around 80, 70, 75 and 20 per cent respectively. Treatment failures may be salvaged by surgery. The 5-year survival and local recurrence rates for radical surgery are around 60 and 25 per cent respectively; there are few indications for local excision. In contrast, 60 per cent of anal margin tumours are suitable for local excision, the 5-year survival rate being in excess of 80 per cent. Combining radiotherapy with surgery may give additional benefit. Current randomized controlled trials should further clarify the relative merits and demerits of the treatment options.

A case of verrucous carcinoma associated with human papillomavirus type 16 DNA

We report here a case of verrucous carcinoma which occurred on the penis of a 75-year-old male. The nodule was first noted six months earlier and was whitish, cauliflower-like, and 17 x 19 mm in size. The histopathological examination revealed hypertrophic epidermal proliferation with pale staining keratinocytes, extending into the deep dermis. Partial penectomy and inguinal lymph node dissection were done. No lymph node metastasis was recognized. DNA was isolated from the frozen tumor tissue and examined for the presence of human papillomavirus (HPV) 16, 18, and 33 DNA by the polymerase chain reaction (PCR), using common and specific primers. A 140 base pair (bp) band was amplified and finally determined to be the HPV16 sequence by dot-blot hybridization.

NK-cell activity in patients with HPV16-associated anogenital tumors: defective recognition of HPV16-harboring keratinocytes and restricted unresponsiveness to immunostimulatory cytokines

Peripheral blood mononuclear cells (PBMC) from patients with active HPV16-associated pre-malignant and malignant anogenital lesions display a significantly decreased NK-cell activity against HPV16-harboring SKv keratinocytes (NK/SKv) while their cytotoxicity against erythroleukemic K562 cells (NK/K562) remains unaffected. A similar defect can also be seen in some healthy individuals displaying no symptoms of HPV infection (low responders). Analysis with specific Leu IIa monoclonal antibodies (MAbs) has revealed that all patients as well as weakly responding control subjects had normal numbers of circulating CD16+ NK cells. However, PBMC from patients with active disease and weakly responding controls displayed a significantly decreased ability to bind SKv cells. Binding of K562 was in the normal range. In patients in whom the lesions were successfully removed or regressed spontaneously (patients with no lesions), NK/SKv activity did not differ from that of normally responding healthy subjects and the ability of their PBMC to bind SKv cells was unaffected. To determine whether an abrogated NK/SKv cytotoxicity may be corrected by NK-cell stimulatory cytokines. PBMC were pre-incubated overnight with IL-2 and interferon-alpha. Both cytokines stimulated NK/K562 activity in all tested groups. Significant stimulation of NK/SKv activity was observed in PBMC from normal and weakly responding controls as well as patients with no lesions. No increase could be seen in patients with active disease. Evaluations of NK-cell activity before and after surgical removal or spontaneous regression of the lesions showed normalization of primarily depressed NK/SKv activity. Malignant progression was associated with a significant drop in SKv cell killing. Our results suggest that abrogation of NK-cell activity against HPV16-harboring targets in patients with HPV16-associated anogenital neoplasia is associated with restricted inability to recognize the disease-specific target cells, and may depend on persistence of the lesions.

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.

Towards vaccines against human papillomavirus type-16 genital infections

Human papillomavirus type-16 (HPV-16) is strongly associated with cervical carcinoma and cervical intraepithelial neoplasia. It may soon be possible to develop prophylactic vaccines designed to induce neutralizing antibodies to HPV-16 virions in genital secretions and therapeutic vaccines to induce cytotoxic T-cell responses against HPV-16 early proteins in cervical intraepithelial neoplasia and cervical cancers. Although significant advances have been achieved, problems remain before such vaccines can be used routinely.

Epidermodysplasia verruciformis as a model of human papillomavirus-induced genetic cancers: the role of local immunosurveillance

Epidermodysplasia verruciformis (EV) presents a genetically determined, unusual susceptibility to infection with EV-specific human papillomaviruses (HPVs) related to abrogation of immunosurveillance exclusively against these viruses. The cutaneous viral carcinogenesis depends upon potentially oncogenic HPVs, the cocarcinogenic effect of ultraviolet irradiation, and genetic host factors, presumably a defect of anti-oncogenes or alleles of major histocompatibility complex and tumor necrosis factor locus involved in antigen presentation.

Production of natural killer cell activity-augmenting factor (interleukin-6) by human epiphyseal chondrocytes

OBJECTIVE

We sought to determine the capacity of human epiphyseal chondrocytes to modulate the cytotoxic activity of human natural killer (NK) cells by determining whether they release interleukin-6 (IL-6), a cytokine recently shown to stimulate NK cell activity.

METHODS

Conditioned medium from human epiphyseal chondrocyte cultures (Ch-CM) was tested for IL-6 activity using the B9 cell hybridoma assay. Its NK cell-stimulating capacity in the presence of K562 (myelogenous leukemia) cells or human chondrocytes was evaluated in a 4-hour 51Cr-release assay. Ch-CM-derived IL-6/NK cell-augmenting factor activity was partially purified by high-performance liquid chromatography (HPLC) gel filtration and Western blot.

RESULTS

Ch-CM contained an NK cell-augmenting factor (NKAF) which was blocked by IL-2 or IL-6 antibodies. Ch-CM did not contain detectable IL-2 activity, but it stimulated IL-2 production by human peripheral blood lymphocytes (PBL). This IL-2-inducing capacity was inhibited by IL-6 antibodies, indicating that chondrocytes release an IL-6-like activity. Ch-CM significantly enhanced the proliferation of IL-6-dependent B9 hybridoma cells, and Western blot analysis of Ch-CM revealed specific bands corresponding to those of highly purified IL-6. Upon HPLC gel filtration, chondrocyte NKAF copurified with chondrocyte IL-6. Pure IL-6 and chondrocyte IL-6 were tested for their ability to stimulate the cytotoxic activity of human PBL against chondrocytes. Both mediators significantly enhanced chondrocyte killing. Lysis of chondrocytes by PBL was mediated by NK cells, since depletion of CD16+ cells resulted in inhibition of the activity.

CONCLUSION

Thus, upon stimulation, chondrocytes produce IL-6 which, through IL-2 induction, augments the activity of NK cells against K562 target cells as well as against chondrocytes.

Efficacy of chemical and/or surgical therapy against condylomata acuminata: a retrospective evaluation

In order to estimate treatment resistance of condylomas, standardized records of 230 males aged 17-80 years (mean 27) attending at an STD clinic were analysed retrospectively. Anal warts occurred in 38 (17%) men; in 19 (50%) intranal warts were extensive enough to require further referral to the Department of Surgery. Urinary meatal warts occurred in 30 men; 9 of them (30%) were referred to the Department of Urology. The remaining 202 (88%) men were treated in the STD clinic with simple surgery and/or home-treatment with 0.5% podophyllotoxin-ethanol twice a day for one or more 3 day sessions. After a follow-up of at least one year, 46 (23%) patients still had condylomas. However, 77 (49%) of the remaining 156 men were cured after a single therapeutic session, and after 1-4 sessions the cumulative cure rate was 77%.

Identification of T- and B-cell epitopes of the E7 protein of human papillomavirus type 16

There is strong evidence implicating human papillomavirus type 16 (HPV16) in the genesis of human genital cancer. Viral DNA has been identified in invasive carcinoma of the uterine cervix and in cell lines derived from cervical carcinomas. These sequences are actively transcribed, and translation products corresponding to the early (E)-region genes have been identified. The most abundant viral protein is the E7 protein, which has been shown to possess transforming activity for both established and primary cells. In addition, it has been shown to bind to a cellular tumor suppressor, the retinoblastoma gene product (pRb-105). In view of these properties, we have undertaken the immunological analysis of this protein and have identified four T-cell epitopes and three B-cell epitopes by using a series of overlapping peptides spanning the entire HPV16 E7 sequence. Two of the B-cell epitopes were recognized by antisera from mice with three different murine (H-2) haplotypes (k, d, and s) immunized with two different E7 fusion proteins and from Fischer rats seeded with baby rat kidney cells transformed by HPV16 E7 and ras. A third B-cell epitope was recognized by antisera from CBA mice seeded with HPV16 E7-expressing L cells. Two regions of the protein contain common B- and T-cell epitopes, one of which appears to be particularly immunodominant.

Constitutive release of IL6 by human papillomavirus type 16 (HPV16)-harboring keratinocytes: a mechanism augmenting the NK-cell-mediated lysis of HPV-bearing neoplastic cells

In the present study we demonstrate that the cultured human keratinocyte cell line (SK-v cells) harboring and expressing integrated human papillomavirus type 16 (HPV16) DNA sequences constitutively releases IL6, which is known as a pleiotropic immunoregulatory cytokine of potential antitumor properties. The presence of IL6 activity in SK-v cell-conditioned media (SK-v CM) was demonstrated by tritiated thymidine incorporation into IL6-dependent B9 murine plasmacytoma cells. The effect on B9 cells was specific since it could be inhibited by anti-IL6 neutralizing antibodies but not by a normal control serum. IL6 did not affect SK-v cell growth; however, it significantly augmented NK cell activity of human peripheral blood lymphocytes against both K562 erytholeukemic and SK-v cells as assessed by 51Cr release assay. SK-v CM displayed NK cell-augmenting activity that copurified with IL6 activity in both size exclusion and anion-exchange HPLC. Furthermore, SK-v cell-derived NK cell stimulatory activity could be neutralized with anti-IL6 antibodies. These results suggest that HPV-harboring neoplastic cells can release IL6 which may indirectly mediate tumor death by augmentation of NK cell activity.

Bowenoid papulosis

Bowenoid papulosis is an uncommon genital dysplasia induced by human papillomavirus infection. Clinically, it usually resembles persistent warts, but histologically it may be suggestive of squamous cell carcinoma in situ. This unusual disorder and recent advances in our understanding of it are reviewed.

Buschke-Loewenstein tumor: verrucous carcinoma of the penis

The Buschke-Loewenstein tumor is an anogenital tumor of characteristic clinical and histologic pattern best considered as a low-grade, well-differentiated squamous cell carcinoma. This remarkable neoplasm and its features are reviewed in detail, stressing salient advances in our understanding of it.

Natural cell-mediated cytotoxicity against various target cells in patients with epidermodysplasia verruciformis

Natural cell-mediated cytotoxicity of peripheral blood mononuclear cells was studied in eight patients with epidermodysplasia verruciformis induced by human papillomaviruses specific for epidermodysplasia verruciformis and in five patients with epidermodysplasia verruciformis-induced exclusively by human papillomavirus type 3. Nine patients with various cutaneous warts and 25 age- and sex-matched healthy persons were control subjects. Natural cell-mediated cytotoxicity against both K-562 erythroleukemic and Sk-v cells was in the normal range in patients with epidermodysplasia verruciformis induced by epidermodysplasia verruciformis-specific human papillomaviruses and in patients with cutaneous warts. The lysis of both targets, however, was significantly decreased in patients with the form of epidermodysplasia verruciformis associated with human papillomavirus type 3. Experiments with normal keratinocytes and with keratinocytes isolated from a malignant lesion bearing human papillomavirus type 5 genomes showed that the latter were susceptible to lysis by the peripheral blood mononuclear cells of healthy persons and of patients with cutaneous warts. Lysis of keratinocytes in epidermodysplasia verruciformis, however, was strongly reduced in patients with epidermodysplasia verruciformis induced by specific human papillomaviruses. This reduction was not associated with a decrease in anti-K-562 natural cell-mediated cytotoxicity. Our results suggest that in patients with epidermodysplasia verruciformis induced by disease-specific human papillomaviruses, there is reduced natural cell-mediated cytotoxicity against epidermodysplasia verruciformis keratinocytes.