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  • Human papillomavirus type 16 in vulvar carcinoma, vulvar intraepithelial neoplasia, and associated cervical neoplasia.

    27 October 2017

    Vulvar intraepithelial neoplasia (VIN) is becoming more widespread and the patients are becoming still younger. Although progression to invasive vulvar carcinoma is uncommon, local recurrences are frequent and about one-quarter of the patients have multicentric genital disease. The aim of the present study was to search for a possible significant association of human papillomavirus (HPV) infection with vulvar carcinoma, recurrences, and multicentric disease. We used the polymerase chain reaction to examine vulvar and cervical biopsies from 43 patients with vulvar neoplasia for HPV type 16, which is the subtype most often detected in genital malignant or premalignant lesions. HPV 16 DNA sequences were found in 14 of 24 (58%) vulvar squamous carcinomas and in 15 of 19 (79%) VIN lesions. Nine patients (21%) had associated cervical neoplasia and six of these harbored HPV 16 in both lesions. Patients with recurrent intraepithelial neoplasia had a significantly higher incidence of HPV 16-positive lesions. No association was found with regard to the occurrence of multicentric disease or risk of malignant progression.

  • Antigen processing influences HIV-specific cytotoxic T lymphocyte immunodominance.

    23 November 2017

    Although cytotoxic T lymphocytes (CTLs) in people infected with human immunodeficiency virus type 1 can potentially target multiple virus epitopes, the same few are recognized repeatedly. We show here that CTL immunodominance in regions of the human immunodeficiency virus type 1 group-associated antigen proteins p17 and p24 correlated with epitope abundance, which was strongly influenced by proteasomal digestion profiles, affinity for the transporter protein TAP, and trimming mediated by the endoplasmatic reticulum aminopeptidase ERAAP, and was moderately influenced by HLA affinity. Structural and functional analyses demonstrated that proteasomal cleavage 'preferences' modulated the number and length of epitope-containing peptides, thereby affecting the response avidity and clonality of T cells. Cleavage patterns were affected by both flanking and intraepitope CTL-escape mutations. Our analyses show that antigen processing shapes CTL response hierarchies and that viral evolution modifies cleavage patterns and suggest strategies for in vitro vaccine optimization.

  • Detection of human papillomavirus type 16 DNA sequences in archival cervical tissues by the polymerase chain reaction.

    27 October 2017

    We have evaluated the polymerase chain reaction for the detection of viral DNA sequences in paraffin-embedded archival tissues. In 63 frozen cervical biopsy specimens that were taken from premalignant and invasive lesions, Southern blotting detected human papillomavirus (HPV) type 16 DNA in 28 (44%) of the samples. In the polymerase chain reaction analysis of the formalin-fixed, paraffin-embedded mirror biopsy specimens, 46 (73%) of the tissues were found to be positive for HPV type 16. In three Southern blotting-positive cases, the DNA of the paraffin-embedded sections was too scant or too degraded to allow the detection of HPV DNA by the polymerase chain reaction. In 21 Southern blotting-negative cases, HPV type 16 DNA could be demonstrated in the archival sections by the polymerase chain reaction technique--a sensitivity improvement of more than 80% over the standard method of HPV detection in tissues.

  • Distinct determinants of human immunodeficiency virus type 1 RNA and DNA loads in vaginal and cervical secretions.

    27 October 2017

    The relationship between human immunodeficiency virus type 1 (HIV-1) viral RNA and proviral DNA load in vagina and cervix and that found in the plasma and peripheral blood mononuclear cells (PBMC) was investigated in 28 HIV-1-infected women. Of the patients, 64% had > or = 1 HIV-1 RNA-positive genital sample, while 71% had > or = 1 DNA-positive sample. The higher the cervical HIV load, the more widespread was the virus in the genital tract. A strong correlation was found between viral RNA load in plasma and the genital tract, whereas the association between proviral DNA load in PBMC and the genital tract was less evident. Cervical HIV-1 DNA correlated with a viral RNA load > or = 50,000 copies/mL. Cervical HIV-1 RNA levels ranged from 10% to 100% of the plasma levels. Thus, a continuous transmission risk from untraumatized genital epithelium exists in the majority of HIV-1-infected women at all stages of infection.

  • Prevalence of human papillomavirus types 11, 16 and 18 in cervical swabs. A study of 1362 pregnant women.

    27 October 2017

    Cervical smears from 1362 pregnant women were examined by filter in situ hybridisation for human papillomavirus (HPV) types 11, 16 and 18. 119 women (8.7%) had HPV-positive smears, HPV 16 being the most common type (61% of all infections). There was a correlation with age (r = 0.63, p = 0.004), the highest incidence found in women less than 22 years old with a decline after the age of 30. The incidence of cervical HPV infection was significantly higher (20.3%, p less than 0.01) in the subgroup of women with past or present vulvar condyloma, but not in women with previous pelvic inflammatory disease or genital herpes. In 18 women with current dysplasia the smears harboured HPV 16, 18, or both in eight cases (40%). The incidence of HPV infection in 71 women with earlier dysplasia did not differ from that of the women who never had dysplasia.

  • Combination therapy with zidovudine and didanosine selects for drug-resistant human immunodeficiency virus type 1 strains with unique patterns of pol gene mutations.

    27 October 2017

    Drug resistance conferred by specific human immunodeficiency virus type 1 (HIV-1) pol gene mutations has been associated with clinical progression in HIV-infected patients receiving anti-retroviral therapy. This study examined drug susceptibilities and pol mutations of HIV-1 strains from patients treated for 1 year with zidovudine, didanosine (ddI), or zidovudine and ddI. Ten (42%) of 24 patients receiving combination therapy versus 8/26 (31%) receiving only zidovudine had HIV-1 strains with phenotypic zidovudine resistance or a zidovudine resistance pol mutation at codon 215 (P = .6). In contrast, a ddI resistance mutation at codon 74 was less common among patients receiving combination therapy (2/24) than among those receiving ddI only (17/26; P < .001). Two patients receiving combination therapy developed resistance to zidovudine and ddI; they had HIV strains with amino acid mutations at codons 62, 75, 77, 116, and 151. Combination therapy with zidovudine and ddI selects for zidovudine-resistant HIV-1 strains lacking a ddI resistance mutation and for multidrug-resistant strains containing novel pol mutations.

  • Heterozygosity for a deletion in the CKR-5 gene leads to prolonged AIDS-free survival and slower CD4 T-cell decline in a cohort of HIV-seropositive individuals.

    27 October 2017

    OBJECTIVE: Recently, it has been shown that a homozygous 32 base-pair deletion in the gene encoding CKR-5, a major coreceptor for HIV-1, leads to resistance to infection with HIV-1. We have investigated whether HIV-seropositive individuals who were heterozygous for the CKR-5 deletion had a different course of the disease. DESIGN: Thirty-five high-risk HIV-seronegative and 99 HIV-seropositive Danish homosexual men followed form 1985 to 1996 and 37 blood donors were analysed for their CKR-5 genotype by polymerase chain reaction. RESULTS: Two (6%) of the 35 HIV-seropositive subjects at high-risk of infection were homozygous and seven (20%) were heterozygous for the CKR-5 deletion. This was not significantly different from the distribution in normal donors. Twenty-two (22%) of the 99 HIV-seropositive subjects were heterozygous and none was homozygous. Two subgroups of patients who had an opposite course of the HIV disease were identified. Of nine long-term non-progressors, six (66%) were heterozygous for the deletion. This frequency is significantly higher than in nine rapid progressors of whom non was heterozygous. The frequency of heterozygotes in long-term non-progressors was also significantly higher than in the cohort as a whole. A Kaplan-Meier plot of the HIV-seropositive subjects, of whom 57 developed AIDS, showed a significantly better prognosis within the first 7 years of follow-up for those who were heterozygous for the deletion. Heterozygous individuals also had a significantly slower decrease in CD4 T-cell count per year. CONCLUSION: Individuals who are heterozygous for the 32-base-pair deletion in the CKR-5 gene have a slower decrease in their CD4 T-cell count and a longer AIDS-free survival than individuals with the wild-type gene for up to 11 years of follow-up.

  • The prevalence of human papillomavirus in cervical lesions with koilocytosis and/or CIN I.

    27 October 2017

    Thirty-one patients with koilocytosis and/or concomitant CIN I were analysed for the presence of HPV types 11, 16 and 18 by in situ hybridization and Southern blot analysis. The prevalence of HPV was 48% and 55%, respectively, when measured by the two methods and among the HPV positive, HPV 11 and 16 were present in 47% and 60%, respectively, whereas HPV 18 was not found.

  • Conflicting selective forces affect T cell receptor contacts in an immunodominant human immunodeficiency virus epitope.

    20 November 2017

    Cytotoxic T lymphocytes (CTLs) are critical for the control of human immunodeficiency virus, but containment of virus replication can be undermined by mutations in CTL epitopes that lead to virus escape. We analyzed the evolution in vivo of an immunodominant, HLA-A2-restricted CTL epitope and found two principal, diametrically opposed evolutionary pathways that exclusively affect T cell-receptor contact residues. One pathway was characterized by acquisition of CTL escape mutations and the other by selection for wild-type amino acids. The pattern of CTL responses to epitope variants shaped which variant(s) prevailed in the virus population. The pathways notably influenced the amount of plasma virus, as patients with efficient CTL selection had lower plasma viral loads than did patients without efficient selection. Thus, viral escape from CTL responses does not necessarily correlate with disease progression.

  • Multidrug-resistant human immunodeficiency virus type 1 strains resulting from combination antiretroviral therapy.

    27 October 2017

    Multidrug-resistant human immunodeficiency virus type 1 (HIV-1) strains with reverse transcriptase (RT) mutations at codons A62-->V, V75-->I, F77-->L, F116-->Y, and Q151-->M have been reported in patients receiving combination therapy with zidovudine (AZT) and didanosine (ddI). Infectious clones with each mutation alone, all five mutations together, and various combinations of mutations were created by site-directed mutagenesis. Mutation Q151-->M conferred partial resistance to AZT, ddI, zalcitibine, and stavudine, whereas a combination of four mutations conferred increased resistance to AZT, ddI, zalcitibine, and stavudine. The positions of residues 75, 77, and 151 in the three-dimensional crystal structure of HIV-1 RT suggest that these residues may affect the ability of the enzyme to discriminate between deoxynucleoside triphosphates and nucleoside analog RT inhibitors. Replication experiments showed that clones with mutation F77-->L but without V75-->I (HIV-1(77), HIV-1(77,151), and HIV-1(77,116,151) had attenuated growth compared with that of the original HIV-1NL4-3 strain and strains containing mutations at both positions 75 and 77 (HIV-1(75,77,151) and HIV-1(75,77,116,15)). Sequence analysis of viral RNA and proviral DNA from several patients indicated that RT mutations developed in a sequential and cumulative pattern over the course of a 2- to 4-year observation period. The present results suggest that drug resistance and viral replicative capacity both may play a role in selection of HIV-1 RT mutations.