Defective interfering (DI) RNAs have been detected in several human viruses. HCV in-frame deletions mutants (IFDMs), missing mainly the envelope proteins, have been found in patient sera and liver tissues. IFDMs replicate independently and can be trans-packaged into infectious virions in the presence of full length viral genome. So far, their biological role is unclear. In this study, we have isolated and cloned IFDMs from sera samples and liver tissues of patients infected with HCV genotypes 1b, 2a, and 3a. IFDMs were present in up to 26% of samples tested. Using the in vitro HCV cell culture system, co-expression of the wild type (wt) HCV replicon with HCV IFDMs RNA resulted in increased HCV replication. Additionally, co-transfection of the HCV full length genome RNA and a defective mutant missing the envelope region led to increased viral release, collectively suggesting an important biological role for IFDMs in the virus life cycle. Recently, exosomes, masters of intercellular communication, have been implicated in the transport of HCV viral genomes. We report for the first time that exosomal RNA isolated from HCV sera samples contains HCV defective genomes. We also demonstrate that inhibition of exosomal biogenesis and release influences HCV viral replication. Overall, we provide evidence that the presence of HCV IFDMs affects both viral replication and release. IFDMs exploit exosomes as means of transport, a way to evade the immune system, to spread more efficiently and possibly maintain persistent infection.

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Lasers have been used in otolaryngology for more than 40 years and are widely considered an established way of addressing laryngeal pathology, benign and malignant. Carbon dioxide (CO2) laser is considered a gold standard, but over the last 2 decades, a new technology has been developed and established in other medical specialties, not so much in Ear Nose and Throat (ENT), the diode laser. It consists of a flexible fiber that passes through a hollow guidance system and is capable of reaching certain angled spots easier than straight beam systems. Portability, lower cost, easier setup, and improved photocoagulation are just some of the many features rendering it an excellent choice for the surgeon and the patient. The few studies published worldwide for the usage and efficacy of this system show no major differences related to the oncologic outcome and survival rate of patients having an early glottic tumor between diode laser microsurgery and CO2 laser cordectomy. Nevertheless, the advantages offered by fiber-optic laser surgery render it a worthy and perhaps equal alternative for treating this kind of pathology.

Background: To demonstrate the efficacy of a new laser surgical technique for bilateral vocal fold immobility (BVFI) on postoperative quality of voice and swallowing. Methods: Prospective study in a tertiary university hospital and a private hospital. Patients with iatrogenic BVFI were included. Outcome measures were Voice Handicap Index 10, 10-item Eating Assessment Tool, flexible laryngoscopy, and success of decannulation. Results: Forty patients with post thyroidectomy BVFI were initially enrolled in our study; only 12 patients returned questionnaires and kept their follow-ups and were included in the study. All patients were successfully decannulated and remain decannulated up to 24-month follow-up. There was a statistically significant improvement in quality of swallowing and no significant deterioration in quality of voice. There was no need for revision up to 24-month follow up. Conclusions: The “Π” technique using diode laser technology is a new and safe technique for BVFI with excellent long-term decannulation rates and improvement in quality of life and swallowing without significant changes in voice quality.

In this special issue of the Ear Nose and Throat (ENT) journal entitled Lasers in Otolaryngology, we attempted to cover and accommodate different experiences from around the globe on both established and some not so well-known techniques and indications for Lasers in most ENT subspecialties. Despite the COVID 19 pandemic, authors from all over the world have expressed their interest in publishing their Laser experiences with ENT journal and for this we are very grateful.