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Activation-induced cytidine deaminase (AID) not only promotes immune diversity by initiating somatic hypermutation and class switch recombination in immunoglobulin genes but also provokes genomic instability by introducing translocations and mutations into non-immunoglobulin genes. To test whether AID is essential for virus-induced tumor development, we used two transgenic tumor models: mice expressing hepatitis C virus (HCV) core proteins (HCV-Tg), driven by the hepatitis B virus promoter, and mice expressing human papillomavirus type 8 proteins (HPV8-Tg), driven by the Keratin 14 promoter. Both strains were analyzed in the absence and presence of AID by crossing each with AID−/− mice. There was no difference in the liver tumor frequency between the HCV-Tg/AID+/+ and HCV-Tg/AID−/− mice at 20 months of age although the AID+/+ mice showed more severe histological findings and increased cytokine expression. Furthermore, a low level of AID transcript was detected in the HCV-Tg/AID+/+ liver tissue that was not derived from hepatocytes themselves but from intra-hepatic immune cells. Although AID may not be the direct cause of HCV-induced oncogenesis, AID expressed in B cells, not in hepatocytes, may prolong steatosis and cause increased lymphocyte infiltration into HCV core protein-induced liver lesions. Similarly, there was no difference in the time course of skin tumor development between the HPV8-Tg/AID−/− and HPV8-Tg/AID+/+ groups. In conclusion, AID does not appear to be required for tumor development in the two virus-induced tumor mouse models tested although AID expressed in infiltrating B cells may promote inflammatory reactions in HCV core protein-induced liver pathogenesis.

Objectives: To analyse HIV Gag cleavage site (CS) and non-CS mutations in HIV non-B isolates from patients failing antiretroviral therapy. Patients and methods: Twenty-one HIV isolates were obtained from patients infected with HIV subtype G during an outbreak in Russia 20 years ago. Most patients were failing antiretroviral therapy when genotyping was performed. Results: HIV Gag CS mutations accumulated in protease inhibitor (PI)-resistant HIV isolates and were correlated with the presence of three or more PI resistance mutations. Only 1 of 11 HIV isolates carrying major protease mutations did not harbour treatment-associated CS mutations. Natural polymorphism 453T often found in HIV non-B subtypes seems to favour the selection of CS mutation 453I rather than treatment-associated CS mutation 453L. Resistance-associated non-CS mutations (123E and 200I) were also observed in PI-resistant clinical isolates. Non-CS mutations in the frameshift-regulating site which controls the synthesis of Gag-Pol did not affect frameshift efficiency in dual luciferase assays. Of note one of four HIV isolates from patients failing PI therapies without protease mutations harboured Gag mutations associated with PI resistance (123E and 436R) and reverse transcriptase inhibitor mutations conferring resistance to the backbone drug. Conclusions: HIV Gag CS mutations commonly occurred in HIV isolates from patients failing PI therapies and natural polymorphisms at the same position influence their emergence. Non-CS mutations previously associated with PI resistance were also observed in clinical isolates. Gag mutations might indicate the evolution of PI resistance even in the absence of protease mutations.

Summary Background Anal intraepithelial neoplasia (AIN), a human papillomavirus (HPV)-associated potential precursor lesion of anal cancer, is frequent among human immunodeficiency virus (HIV)-positive men who have sex with men (MSM). There is a paucity of data published on the progression of high-grade AIN to invasive cancer as well as on clinical and virological characteristics comparing anal margin and anal canal carcinoma. Objectives To search for anal carcinoma and AIN in a large series of HIV-positive MSM, to assess treatment response of anal carcinoma, and to analyse lesional HPV spectrum of anal cancers. Methods Detection of anal carcinoma and AIN was performed using cytology, high-resolution anoscopy, and histology in case of abnormal findings. Additionally, HPV analyses for 36 high- and low-risk α-HPV types were performed in patients with anal carcinoma. Results In total, 446 German HIV-positive MSM were examined within an observation period of 5 years and 10 months. Of these, 116 (26·0%) patients had normal findings, 163 (36·5%) had low-grade AIN, 156 (35·0%) had high-grade AIN, and 11 (2·5%) had anal carcinoma as evidenced by the highest grade of cytology/histology. Five patients with anal cancer, who had refused treatment of their precancerous lesions, had progressed from high-grade AIN to invasive cancer within a median time of 8·6 months. All anal cancers carried high-risk α-HPV types. All five squamous cell carcinomas (SCCs) of the anal canal were HPV16 positive. In contrast, only one of the four anal margin SCCs were HPV16 positive (HPV31, HPV33 and HPV33 + HPV68 were found in the other three anal margin SCCs). HPV59 was found in two adenocarcinomas, one of which additionally carried HPV33. In contrast to the cancer biopsies, a broad spectrum of surface high- and low-risk HPV types was found in anal swabs of the patients. Surgical excision resulted in long-term disease control of all anal margin carcinomas, whereas combined chemoradiotherapy in carcinomas of the anal canal was associated with high recurrence rates, high toxicity, and high mortality. Conclusions Anal carcinoma and AIN are frequent in HIV-positive men, even in patients participating in anal cancer prevention programmes. High-grade dysplasia in these patients can progress to invasive cancer within a short period of time. Anal margin carcinoma and anal canal carcinoma differ substantially in their lesional HPV spectrum, prognosis and treatment response.

Summary Background Antimicrobial peptides and proteins (AMPs) are widely distributed effector molecules of the innate immune system with well-known antibacterial activity. However, there is a paucity of information regarding antiviral effects of AMPs. Objectives The present study was performed to analyse expression of AMPs in human papillomavirus (HPV)-associated anal skin lesions of human immunodeficiency virus (HIV)-positive men who have sex with men (MSM), a special high-risk group for persistent HPV infections and anal dysplasia. Methods Skin lesions were analysed for the presence of LL-37, RNase 7, and human β-defensin (hBD)-1, hBD-2 and hBD-3. Moreover, HPV typing and HPV DNA load determination for HPV types 6, 11, 16, 18, 31 and 33 were performed to evaluate possible correlations between expression of AMPs and lesional HPV types. Results Skin biopsies of 45 HIV-positive MSM with anal intraepithelial neoplasia (AIN), anal condylomata acuminata or unaffected anal mucosa, as well as condylomata acuminata of eight HIV-negative MSM, were analysed for AMP mRNA expression. Additionally, immunohistochemical analysis for hBD-2 and hBD-3 was performed in a total of 45 samples. hBD-2 and hBD-3 gene and protein expression was significantly increased in both AIN and condyloma, whereas LL-37, RNase 7 and hBD-1 gene expression did not differ significantly from unaffected anal mucosa. AMP expression correlated neither with the number of HPV types nor with the high-risk and low-risk HPV DNA loads of the quantified types. No significant differences in AMP expression were observed in condylomata of HIV-positive and HIV-negative MSM. Conclusions hBD-2 and hBD-3 expression was shown to be significantly upregulated in HPV-associated anal skin lesions of both HIV-positive and HIV-negative MSM. Their biological significance in the innate immunity against these lesions needs further research.

Background Netherton’s syndrome (NS) is a hereditary disorder with dermatological signs (e.g. ichthyosis) and a complex immunological dysfunction. In immunodeficient individuals human papillomavirus (HPV) types are associated with carcinomas on non-mucosal sites. Objectives To study the presence of HPV infection in different skin lesions of three male NS patients and to investigate a possible association between HPV and malignancies in NS. Methods Patient 1 had extraordinary widespread multiple skin carcinomas on sunlight-exposed areas, as well as common viral warts. Patient 2 showed disseminated viral plane warts that resolved spontaneously, and patient 3 was free of skin lesions suspicious for HPV infection; only pseudoepitheliomatous wart-like lesions as a symptom of ichthyosis were apparent. We performed nested polymerase chain reaction analysis of DNA from benign and malignant skin lesions and HPV-8 serology in these three patients. Results Antibodies to HPV-8 were not detectable in our patients; however, seven of 22 (31%) biopsies of the three NS patients were positive for HPV DNA. Epidermodysplasia verruciformis (EV) -associated HPV types and normal cutaneous types (HPV-2, HPV-28) were detected. Interestingly, only the patient with cutaneous carcinomas harboured, preferentially in malignant lesions, EV-HPV types (HPV-19, 23, 38 and HPV-RTRX9, closely related to EV-HPVs), whereas plane warts of patient 2 were positive for HPV-28. The pseudoepitheliomatous skin lesions were HPV-DNA negative in all investigated probes. Conclusions These data in NS patients further confirm an association of EV-HPVs with non-melanoma skin cancer (NMSC) and suggest a possible carcinogenic role similar to that assumed for NMSC in transplant recipients. A complex immunological disorder facilitating EV-HPV infection, negative HPV serology and photochemotherapy may all have contributed to the unusual occurrence of multiple cancers in one of our NS patients.

Epidermodysplasia verruciformis-associated human papillomaviruses (EV-HPVs) are possibly involved in the development of actinic keratoses and may play a part in the pathogenesis of squamous cell carcinoma (SCC) of the skin, as the DNA of these viruses is frequently detected in biopsies of such lesions. Properly designed epidemiological studies, using serological tests to investigate the role of infection with EV-HPVs in cutaneous oncogenesis, are still rare. An IgG-specific enzyme-linked immunosorbent assay using virus-like particles composed of the major capsid protein L1 of the EV-specific HPV 8 (HPV 8 VLPs) was developed and used to test the seroprevalence of HPV 8 in 114 inhabitants of a tropical island, of whom 13 had developed SCC, and 19 had developed basal cell carcinoma. Gender, age, eye and hair colour, sun exposure and number of actinic keratoses were recorded for all individuals. The presence of antibodies against HPV 8 VLPs was associated with the development of large numbers of actinic keratoses. After adjusting for gender, age, eye and hair colour, and sun exposure, the odds ratio to develop 37 (the median in this dataset) or more actinic keratoses in the presence of antibodies against HPV 8 VLPs was 2.3 (95% confidence interval: 1.0; 5.3), Similarly, after adjustment for the same factors, the presence of these antibodies was associated with SCC with an odds ratio of 3.1 (0.74; 13.3), but the small number of individuals with SCC does not permit any definite conclusions. The presence of these antibodies did not appear to be associated with basal cell carcinoma as, after adjustment for the same factors, the odds ratio was 0.73 (0.23; 2.4). This study provides serological evidence that infection with EV-HPVs may play a part in the pathogenesis of actinic keratoses. The role of EV-HPVs in the development of SCC, however, remains to be elucidated.

The regulatory regions of the human papillomaviruses (HPVs) 9, 17, 20, and 36 were mapped, sequenced, and aligned. They revealed an arrangement of putative protein binding sites specific for the epidermodysplasia verruciformis associated HPVs. Three subgroups could be differentiated.

Bovine and human sera were analyzed for the presence of antibodies against bovine papillomavirus types 1 and 2 (BPV 1 and 2) and human papillomavirus type 1 (HPV 1) in a solid-phase radioimmunoassay. Human sera did not react with BPV antigens, and bovine sera showed no evidence of antibodies against HPV 1. In contrast, 19% of all bovine sera tested reacted with BPV 1 and 2 antigens, and 35% of human sera revealed antibodies against HPV 1. No serologic evidence was obtained for heterologous infections of persons exposed preferentially to cattle (farmers, butchers, and patients with Q-fever).