A sustained type I IFN-neutrophil-IL-18 axis drives pathology during mucosal viral infection

Neutrophil responses against pathogens must be balanced between protection and immunopathology. Factors that determine these outcomes are not well-understood. In a mouse model of genital herpes simplex virus-2 (HSV-2) infection, which results in severe genital inflammation, antibody-mediated neutrophil depletion reduced disease. Comparative single-cell RNA-sequencing analysis of vaginal cells against a model of genital HSV-1 infection, which results in mild inflammation, demonstrated sustained expression of interferon-stimulated genes (ISGs) only after HSV-2 infection primarily within the neutrophil population. Both therapeutic blockade of IFNα/β receptor 1 (IFNAR1) and genetic deletion of IFNAR1 in neutrophils concomitantly decreased HSV-2 genital disease severity and vaginal IL-18 levels. Therapeutic neutralization of IL-18 also diminished genital inflammation, indicating an important role for this cytokine in promoting neutrophil-dependent immunopathology. Our study reveals that sustained type I interferon (IFN) signaling is a driver of pathogenic neutrophil responses and identifies IL-18 as a novel component of disease during genital HSV-2 infection.

A sustained type I IFN-neutrophil-IL-18 axis drives pathology during mucosal viral infection

ABSTRACTNeutrophil responses against pathogens must be balanced between protection and immunopathology. Factors that determine these outcomes are not well-understood. In a mouse model of genital herpes simplex virus-2 (HSV-2) infection, which results in severe genital inflammation, antibody-mediated neutrophil depletion reduced disease. Comparative single cell RNA-sequencing analysis of vaginal cells against a model of genital HSV-1 infection, which results in mild inflammation, demonstrated sustained expression of interferon-stimulated genes (ISGs) only after HSV-2 infection primarily within the neutrophil population. Both therapeutic blockade of IFNα/β receptor 1 (IFNAR1) and genetic deletion of IFNAR1 in neutrophils concomitantly decreased HSV-2 genital disease severity and vaginal IL-18 levels. Therapeutic neutralization of IL-18 also diminished genital inflammation, indicating an important role for this cytokine in promoting neutrophil-dependent immunopathology. Our study reveals that sustained type I IFN signaling is a driver of pathogenic neutrophil responses, and identifies IL-18 as a novel component of disease during genital HSV-2 infection.

Human Papillomavirus and Genital Disease in Men: What We Have Learned from the HIM Study

It is currently recognized that in addition to the major impact of human papillomavirus (HPV) infection in females, HPV causes considerable disease in men at the genitals, anal canal, and oropharynx. Specifically, genital HPV infections may progress to genital warts and penile carcinoma. Although studies concerning the natural history of HPV infections and associated neoplasias have mainly focused on women, during the last 2 decades considerable attention has been given in further understanding these infections in men. The HIM (HPV infection in men) Study, the only prospective multicenter study of male HPV natural history, consisted of a large prospective international cohort study in which men from Brazil, the United States, and Mexico were enrolled. The design and protocols of this study allowed unraveling crucial information regarding the relationship between HPV infection and clinical consequences in men, and associated risk factors at each of the anatomic sites where HPV is known to cause cancer in men.

Genital disease

The term ‘genital disease’ refers to a spectrum of diseases. Certain systemic diseases preferentially affect mucous membranes. Local factors including warmth, occlusion, irritants, and friction are important and contribute to skin disease in this region and increase the risk of certain infections. Skin conditions may be difficult to diagnose, as they may have atypical appearances. Therefore, the diagnosis of disease in the anogenital region may be complex. This chapter will focus on the most common diseases seen in the dermatology clinic: lichen sclerosus, lichen planus, eczema, genital pain syndromes, and pre-malignant and malignant disease. Other less common dermatological conditions seen in this area will be briefly covered.