The 19 th International Papillomavirus Conference

successfully hosted by Luisa Villa, Gustavo Amestoy, Eduardo Franco and their colleagues in Florianópolis, Brazil, 1–7 September 2001. The meeting continues to offer the most comprehensive forum for the dissemination of the advancements achieved in the diverse areas of papillomavirus research. As in recent years, the main axes of investigation continue to be the mechanisms of carcinogenesis, viral replication and expression, the screening of genital human papillomavirus (HPV) infection and disease, and the development of vaccines, both prophylactic and therapeutic. Laura Koutsky and colleagues presented the first, yet preliminary evidence that an HPV type 16 virus-like particle (VLP) vaccine made of the major capsid protein (L1) was effective in preventing HPV-16 infection, which is responsible, with HPV-18 infection, for the majority of cervical cancers (abstract O-50). The study enrolled 195 women with HPV-16 DNA negative cervical samples. Sixty-six received HPV-16 L1 VLP vaccine at day 0, and months 2 and 6. None of these subjects developed cervical HPV-16 infection in the 7–24 months following the first immunization. In contrast, nine of the 129 subjects in the control group acquired cervical HPV16 infection during the follow-up. Should these positive results be confirmed by the several on-going Phase II studies, they will not abrogate the need for effective therapeutic approaches and agents. First, the great and incessantly growing number of HPV genotypes (92 fully characterized genotypes, and approximately 130 others that are partially characterized – data courtesy of Ethel-Michele de Villiers) presents itself as a potential challenge for the development of vaccines. Second, vaccine availability, even if the vaccine is very effective, will not necessarily imply utilization. Third, a difficult to quantitate but large proportion of the population is already infected and susceptible to the development of diseases for which our therapeutic armamentarium remains unsatisfactory. The development of therapeutic approaches and antivirals for HPV infections and diseases continues to be difficult in part because papillomaviruses offer few enzymatic targets, and a high-throughput simple model of permissive HPV replication does not exist. Nevertheless, many approaches are being developed and evaluated, as illustrated by this report on selected presentations made at the Florianópolis conference. In recent years, the need for better microbicides for the prevention of the transmission of sexually transmitted diseases has been recognized. ND Christensen et al. presented the results of their study of three sulfated/sulfonated polysaccharides/polymers: cellulose sulfate, dextran sulfate, and polystyrene sulfonate. The cidal activity of these compounds was evaluated in vitro, mostly against bovine papillomavirus (BPV) type 1 in the focus forming assay, and against HPV-11, one of the main agents of genital warts, in a transient infection assay of A431 human epithelial carcinoma cells. All three compounds had virucidal activities in the 10–100 μg/ml range. Cells pre-incubated for 1 h with dextran sulfate and polystyrene sulfonate were also protected from infection by BPV-1; cellulose sulfate was less effective. Polystyrene sulfonate appears to be the most attractive compound because it was also able to inactivate HPV-11 for between 4 and 8 h after the virus was bound to the cell. These results have been published recently [1]. Several therapeutic agents and modalities evaluated against HPV diseases have often already found other clinical indications. G Metzner et al. presented a retrolective cohort study of LeukoNorm for the treatment of high-risk HPV DNA-positive cervical intraepithelial neoplasia (CIN) grades 1 and 2 (abstract P-129). LeukoNorm is a leukocytic ultrafiltrate made by CytoChemia AG (Ihringen, Germany) that is approved in Germany as an immunomodulator for the treatment of immunologically-based recurrent spontaneous abortions. A retrolective study is retrospective, thus the subjects cannot be randomized, but randomization is applied to the different centres (17 in this study) to determine which ones should provide the controls or the cases for the analysis. Differences in baseline characteristics of the subjects are controlled by Antiviral Therapy 7: 67–72