Association between human papillomavirus particle production and the severity of recurrent respiratory papillomatosis

Genomic diversity of HPV6 and HPV11 in recurrent respiratory papillomatosis: Association with malignant transformation in the lungs and clinical outcomes

Recurrent respiratory papillomatosis (RRP) is a rare, proliferative disease caused by human papillomavirus 6 (HPV6) and HPV11. RRP can occasionally spread and undergo malignant transformation. We analysed samples across time for five RRP patients with malignant transformation and four with highly recurrent, non-malignant RRP by applying high-throughput sequencing. Patients with malignant transformation were infected by HPV11_A1/A2, while most non-malignant cases were associated with HPV6. Transient multiple infections with HPV6 and HPV11 were found in two patients, and resolved later to single infections. Viral genome loads were homogeneous across groups (median = 78 viral genomes per human genome). Within-patient, we did not observe differences between the viral sequences in the papillomatous lesions and in the malignant tissue. Genetic analysis of the NLRP1 gene revealed no known mutations linked to idiopathic RRP, though some novel variants merit to be explored in larger cohorts. HPV11 infections appear associated with RRP malignant transformation in young patients. Multiple infections can occur in RRP, but within-patient viral diversity is minimal for a given genotype. Our results confirm the importance of viral genotype in disease prognosis and are consistent with growing evidence of HPV11 infections to be differentially associated with RRP malignant transformation in young patients.

Clinical, Histological, and HPV-Related Factors Associated to Diffuse Presentation of Exophytic Nasal Papillomas

Background: Sinonasal exophytic papillomas (SNEP) are benign tumours arising from nasal mucosa. Human papillomavirus (HPV) infection seems to be related to the aetiology of a fraction of SNEP cases. SNEP presentation can be focal (FSNEP) or diffuse (DSNEP), but factors related to focal or diffuse presentation have not yet been well ascertained. This study aimed to analyse clinical, histological, and HPV-related differences between FSNEP and DSNEP. Methods: A retrospective cohort of 18 patients with SNEP from our centre were evaluated. Demographic, clinical and follow-up data were collected. All samples were subject to histopathological evaluation, DNA quality control, HPV-DNA detection, and viral load assessment. Univariate analyses were performed to evaluate differences between FSNEP and DSNEP. Results: Twelve SNEP patients were included in the final analysis. Seven patients had a diffuse nasal presentation, being younger than patients affected with FSNEP (42.7 years vs. 65.2 years, p = 0.019). The nasal septum was significantly more affected in DSNEP than in FSNEP (85.7% vs. 20%, p = 0.029). HPV-DNA was detected more frequently (100%) in DSNEP (HPV11 in six cases, HPV6 in one case) than in FSNEP (40%, p = 0.045, HPV6 in two cases). The median viral load among HPV6-positive samples was 626.8 virus/cell for FSNEP and 80.2 for DSNEP, and among HPV11-positive samples was 1673.7 for DSNEP. Recurrences were more frequent in the diffuse than in the focal group (85.7% vs. 20%, p = 0.029). Conclusions: The diffuse presentation of SNEP seems to be related to younger patients, nasal septum involvement, HPV infection, mostly HPV11, and a higher risk of recurrence.

Cell-free DNA analysis for recurrent respiratory papillomatosis: A case report

A 35-year-old male presented with recurrent respiratory papillomatosis. Human papillomavirus type 11 was detected from all sites of tumor tissue DNA by PCR. The pre-surgery cell-free DNA (cfDNA) viral load (3.33 × 103 copies/ng DNA) fell below the post-surgical detection limits on achieving remission, suggesting cfDNA's potential as a biomarker.

Human induced pluripotent stem cells are resistant to human cytomegalovirus infection primarily at the attachment level due to the reduced expression of cell-surface heparan sulfate

Cytomegalovirus (CMV), a type of herpes virus, is the predominant cause of congenital anomalies due to intrauterine infections in humans. Adverse outcomes related to intrauterine infections with human cytomegalovirus (HCMV) vary widely, depending on factors such as fetal infection timing, infection route, and viral virulence. The precise mechanism underlying HCMV susceptibility remains unclear. In this study, we compared the susceptibility of neonatal human dermal fibroblast cells (NHDFCs) and human induced pluripotent stem cells (hiPSCs) derived from NHDFCs, which are genetically identical to HCMV, using immunostaining, microarray, in situ hybridization, quantitative PCR, and scanning electron microscopy. These cells were previously used to compare CMV susceptibility, but the underlying mechanisms were not fully elucidated. HCMV susceptibility of hiPSCs was significantly lower in the earliest phase. No shared gene ontologies were observed immediately post-infection between the two cell types using microarray analysis. Early-stage expression of HCMV antigens and the HCMV genome was minimal in immunostaining and in in situ hybridization in hiPSCs. This strongly suggests that HCMV does not readily bind to hiPSC surfaces. Scanning electron microscopy performed using the NanoSuit method confirmed the scarcity of HCMV particles on hiPSC surfaces. The zeta potential and charge mapping of the charged surface in NHDFCs and hiPSCs exhibited minimal differences when assessed using zeta potential analyzer and scanning ion conductance microscopy; however, the expression of heparan sulfate (HS) was significantly lower in hiPSCs compared with that in NHDFCs. Thus, HS expression could be a primary determinant of HCMV resistance in hiPSCs at the attachment level.

IMPORTANCE

Numerous factors such as attachment, virus particle entry, transcription, and virus particle egress can affect viral susceptibility. Since 1984, pluripotent cells are known to be CMV resistant; however, the exact mechanism underlying this resistance remains elusive. Some researchers suggest inhibition in the initial phase of HCMV binding, while others have suggested the possibility of a sufficient amount of HCMV entering the cells to establish latency. This study demonstrates that HCMV particles rarely attach to the surfaces of hiPSCs. This is not due to limitations in the electrostatic interactions between the surface of hiPSCs and HCMV particles, but due to HS expression. Therefore, HS expression should be recognized as a key factor in determining the susceptibility of HCMV in congenital infection in vitro and in vivo. In the future, drugs targeting HS may become crucial for the treatment of congenital CMV infections. Thus, further research in this area is warranted.