Crosstalk between the mesothelium and lymphomatous cells: insight into the mechanisms involved in the progression of body cavity lymphomas.

The peculiar localization of body cavity lymphomas implies a specific contribution of the intracavitary microenvironment to the pathogenesis of these tumors. In this study, primary effusion lymphoma (PEL) was used as a model of body cavity lymphoma to investigate the role of mesothelial cells, which line the serous cavities, in lymphoma progression. The crosstalk between mesothelial and lymphomatous cells was studied in cocultures of primary human mesothelial cells (HMC) with PEL cells and a xenograft mouse model of peritoneal PEL. PEL cells were found to induce type 2 epithelial-mesenchymal transition (EMT) in HMC, which converted into a myofibroblastic phenotype characterized by loss of epithelial markers (pan cytokeratin and E-cadherin), expression of EMT-associated transcriptional repressors (Snail1, Slug, Zeb1, Sip1), and acquisition of α-smooth muscle actin (α-SMA), a mesenchymal protein. A progressive thickening of serosal membranes was observed in vivo, accompanied by loss of cytokeratin staining and appearance of α-SMA-expressing cells, confirming that fibrosis occurred during intracavitary PEL development. On the other hand, HMC were found to modulate PEL cell turnover in vitro, increasing their resistance to apoptosis and proliferation. This supportive activity on PEL cells was retained after transdifferentiation, and was impaired by interferon-α2 b treatment. On the whole, our results indicate that PEL cells induce type 2 EMT in HMC, which support PEL cell growth and survival, providing a milieu favorable to lymphoma progression. Our findings provide new clues into the mechanisms involved in lymphoma progression and may indicate new targets for effective treatment of malignant effusions growing in body cavities.

Oral human papillomavirus and human herpesvirus-8 infections among human immunodeficiency virus type 1-infected men and women in Italy.

BACKGROUND: Oral human papillomavirus (HPV) and human herpesvirus-8 (HHV8) infections are sexually transmitted and respectively associated with the development of oropharyngeal carcinoma and Kaposi sarcoma. The aim of the study was to evaluate HPV prevalence and its possible correlation with HHV8 oral shedding, in relation to sex, human immunodeficiency virus (HIV) behavioral risk factor, and immune function. METHODS: The study population comprised 100 HIV-infected individuals divided into 3 groups: (1) 38 men who have sex with men (MSM), (2) 24 heterosexual men, and (3) 38 women. DNA was obtained from cells of unstimulated whole saliva. Human papillomavirus sequences were searched for by polymerase chain reaction (PCR) with MY09/MY11 primers or by nested PCR with GP5+/GP6+ primers as the second step. Typing was accomplished by restriction fragment length polymorphism analysis or by direct sequencing or by reverse line blot. Human herpesvirus-8 sequences were detected and quantified by nested PCR and real-time PCR, respectively. RESULTS: Oral HPV infection was present in 37 (prevalence, 37%) of 100 (13 with high-risk and 24 with low-risk types) patients; the most frequent types were HPV16, HPV6, HPV10, HPV61, HPV66, and HPV83. Human herpesvirus-8 DNA was detected in 46 (46%) of 100 subjects. Both infections had the highest prevalence among MSM and the lowest among women; women had a lower prevalence of high-risk HPV types than did both male groups (P = 0.05). An inverse correlation was observed with concomitant oral HHV8 infection (P = 0.007). CONCLUSIONS: High prevalence of oral HPV and HHV8 infections was observed; MSM had the highest figures, despite better control of HIV infection.

Evaluation of fast PCR reagents for rapid and sensitive detection of human herpesvirus 8.

The potential advantage of using fast PCR to detect human herpesvirus 8 (HHV-8) was tested by running a rapid cycling protocol (5s-steps) in one standard and two fast ramping thermal cyclers to evaluate the performance of 8 different fast reagents. Under this extremely short time profile, assay sensitivity comparable to that of the original protocol was maintained using fast reagents from five suppliers. Reproducibility was higher using fast ramping thermal cyclers, suggesting that fast chemistry may be better matched with advanced instruments. Few fast reagents showed a 2-log-increase in sensitivity and good consistency, that allowed the substitution of the standard nested PCR method with the fast, single round technique. Overall, these studies indicate that some of the fast reagents tested may be used to perform a highly sensitive and reproducible HHV-8 detection with a considerable time saving.