Recurrent respiratory papillomatosis (RRP)

$\textbf {Objectives:}$ Recurrent respiratory papillomatosis (RRP) is a rare disease, but one with severe morbidity and occasional mortality. The aetiological agent is human papillomavirus (HPV), and HPV types 6 and 11 account for over 90% of all cases. In the active phase of the disease, patients require multiple hospital admissions for surgical removal or ablation of these benign tumors, which are likely to obstruct the airways if left unchecked. Long-term sequelae include scarring of the vocal cords, change in voice timbre, or even muteness if a tracheostomy is required. The aim of this study was to determine if adjuvant vaccination with the quadrivalent HPV L1 vaccine ($Gardasil^{TM}$) would decrease numbers of surgical treatments postvaccination. $\textbf {Methods:}$ A prospective pilot study following a cohort of 12 RRP patients, all of whom gave fully informed consent to participate. All patients had their papillomas typed and if they were found to have types 6 or 11, were vaccinated at the time of first surgical treatment in the hospital, according to the manufacturer’s protocols. Patients were followed up closely with 3 or 6 month follow-up visits. Standard surgical treatments were given and were not affected by whether they participated in the study. $\textbf {Results:}$ We found a >7-fold decrease in the incidence rates of papillomatosis requiring surgical intervention from the pre-vaccination period (47.44/1000 patient-months) compared to the post-vaccination period (6.71/1000 patientmonths). $\textbf {Discussion:}$ Surgical treatments for RRP are robust markers for papillomata which require treatment because of the dangers of obstruction of the airway. Despite the small size of this cohort (due to the rarity of this disease), the data suggests that adjuvant use of quadrivalent HPV L1 vaccine imparts significant benefit to this group of patients. A large multi-center randomized placebo controlled trial is required to definitively establish whether this hypothesis is true and can become the new standard of therapy

NOD-like receptor signaling in cholesteatoma

$\textit {Background.}$ Cholesteatoma is a destructive process of the middle ear resulting in erosion of the surrounding bony structures with consequent hearing loss, vestibular dysfunction, facial paralysis, or intracranial complications. The etiopathogenesis of cholesteatoma is controversial but is associated with recurrent ear infections. The role of intracellular innate immune receptors, the NOD-like receptors, and their associated signaling networks was investigated in cholesteatoma, since mutations in NOD-like receptor-related genes have been implicated in other chronic inflammatory disorders. $\textit {Results.}$ The expression of NOD2 mRNA and protein was significantly induced in cholesteatoma compared to the external auditory canal skin, mainly located in the epithelial layer of cholesteatoma. Microarray analysis showed significant upregulation for NOD2, not for NOD1, TLR2, or TLR4 in cholesteatoma. Moreover, regulation of genes in an interaction network of the NOD-adaptor molecule RIPK2 was detected.In addition to NOD2, NLRC4, and PYCARD, the downstream molecules IRAK1 and antiapoptotic regulator CFLAR showed significant upregulation, whereas SMAD3, a proapoptotic inducer, was significantly downregulated. Finally, altered regulation of inflammatory target genes of NOD signaling was detected. $\textit {Conclusions.}$ These results indicate that the interaction of innate immune signaling mediated by NLRs and their downstream target molecules is involved in the etiopathogenesis and growth of cholesteatoma

Virus-induced cancers of the skin and mucosa

$\textit {Introduction:}$ Human papillomavirus (HPV) alone is thought to cause ~ 610,000 cases of cancer per year, and is the dominant aetiological agent for ano-genital (esp. cervical) and head and neck cancers (esp. oropharyngeal). Merkel cell polyomavirus (MCV) is a more recently discovered virus which causes Merkel cell car cinoma, a rare but highly aggressive skin malignancy. $\textit {Methods:}$ We explored the available published evidence to see if transmission of live HPV or MCV virus in smoke generated by laser or diathermy was feasible, and would pose an infection risk. Long-term infection with such carcinogenic viruses would then pose an increased risk for the development of virus-induced cancers in medical personnel. $\textit {Results:}$ The morphological structures of both HPV and MCV are very similar, and the size, external capsids and genomic structures show striking similarity. Both viruses have a non-enveloped external protein capsid consisting of 72 capsomeres, and a double-stranded DNA core. Sizes of both viruses range from 50 to 60 nm. There are now recent data demonstrating live and infectious HPV in smoke, and that these viruses can be used to infect cells in vitro. Further, anecdotal reports of virus transmission leading to disease causation in the production of respiratory airway viral warts (benign disease), and, finally, reports of HPV-induced oropharyngeal carcinoma (malignant disease) in two gynaecological surgeons as an occupational health hazard have been published recently. $\textit {Conclusion:}$ There is now sufficient evidence to support the hypotheses that live infectious carcinogenic viruses can be transmitted via smoke generated from surgical procedures, and, in rare instances, actually cause significant disease. Protective measures such as smoke extraction and airway protection should be instituted for all healthcare personnel, particularly those with multiple repeated exposures such as gynaecological surgeons

Stem cells in middle ear cholesteatoma contribute to its pathogenesis

Cholesteatoma is a potentially life-threatening middle ear lesion due to the formation of an inflamed ectopic mass of keratinizing squamous epithelium. Surgical removal remains the only treatment option, emphasizing the need to gain a better understanding of this severe disease. We show for the first time that stem cells residing in cholesteatoma tissue contribute to disease progression. Cells expressing the “stemness” markers Nestin and S100B were detected in middle ear cholesteatoma and auditory canal skin. Isolated Nestin +/S100B +-cells showed the capability for self-renewal, neurosphere formation and differentiation into mesodermal and ectodermal cell types. Compared to auditory canal skin stem cells middle ear cholesteatoma-derived stem cells displayed an enhanced susceptibility to inflammatory stimuli, and this suggested a possible contribution to the inflammatory environment in cholesteatoma tissue. Cholesteatoma derived stem cells were able to differentiate into keratinocyte-like cells using factors mimicking the microenvironment of cholesteatoma. Our findings demonstrate a new perspective on the pathogenesis of cholesteatoma and may lead to new treatment strategies for this severe middle ear lesion