iRHOM2: A Regulator of Palmoplantar Biology, Inflammation, and Viral Susceptibility.

The palmoplantar epidermis is a specialized area of the skin that undergoes high levels of mechanical stress. The palmoplantar keratinization and esophageal cancer syndrome, tylosis with esophageal cancer, is linked to mutations in RHBDF2 encoding the proteolytically inactive rhomboid protein, iRhom2. Subsequently, iRhom2 was found to affect palmoplantar thickening to modulate the stress keratin response and to mediate context-dependent stress pathways by p63. iRhom2 is also a direct regulator of the sheddase, ADAM17, and the antiviral adaptor protein, stimulator of IFN genes. In this perspective, the pleiotropic functions of iRhom2 are discussed with respect to the skin, inflammation, and the antiviral response.

Cutaneous susceptibility to SARS-CoV-2 infection according to the expression of viral entry factors in the skin.

INTRODUCTION: Reports of dermatological manifestations in patients with COVID-19 suggest a possible cutaneous tropism of SARS-CoV-2; however, the capacity of this virus to infect the skin is unknown. OBJECTIVE: To determine the susceptibility of the skin to SARS-CoV-2 infection based on the expression of viral entry factors ACE2 and TMPRSS2 in this organ. METHOD: A comprehensive analysis of human tissue gene expression databases was carried out looking for the presence of the ACE2 and TMPRSS2 genes in the skin. mRNA expression of these genes in skin-derived human cell lines was also assessed. RESULTS: The analyses showed high co-expression of ACE2 and TMPRSS2 in the gastrointestinal tract and kidney, but not in the skin. Only the human immortalized keratinocyte HaCaT cell line expressed detectable levels of ACE2, and no cell line originating in the skin expressed TMPRSS2. CONCLUSIONS: Our results suggest that cutaneous manifestations in patients with COVID-19 cannot be directly attributed to the virus. It is possible that cutaneous blood vessels endothelial damage, as well as the effect of circulating inflammatory mediators produced in response to the virus, are the cause of skin involvement.

INTRODUCCIÓN: Reportes de manifestaciones dermatológicas en pacientes con COVID-19 sugieren un posible tropismo cutáneo del virus SARS-CoV-2; sin embargo, se desconoce la capacidad de este virus para infectar la piel. OBJETIVO: Determinar la susceptibilidad de la piel a la infección por SARS-CoV-2 con base en la expresión de los factores de entrada viral ACE2 y TMPRSS2 en dicho órgano. MÉTODO: Se buscaron los genes ACE2 y TMPRSS2 en la piel, para lo cual se realizó un análisis extenso de las bases de datos de expresión genética en tejidos humanos. Asimismo, se evaluó la expresión de dichos genes en líneas celulares humanas derivadas de la piel. RESULTADOS: Los análisis mostraron alta expresión conjunta de ACE2 y TMPRSS2 en el tracto gastrointestinal y en los riñones, pero no en la piel. Solo la línea celular de queratinocitos humanos inmortalizados HaCaT expresó niveles detectables de ACE2 y ninguna línea celular de origen cutáneo expresó TMPRSS2. CONCLUSIONES: Los resultados sugieren que las manifestaciones dermatológicas en pacientes con COVID-19 no pueden ser atribuidas directamente al virus; es posible que sean originadas por el daño endotelial a los vasos sanguíneos cutáneos y el efecto de los mediadores inflamatorios circulantes producidos en respuesta al virus.

Morphological characteristics and human papillomavirus genotype predict the treatment response in cutaneous warts.

BACKGROUND: Cutaneous warts have a cure rate after therapy of no more than approximately 50%. Recently, we developed and validated a standard assessment tool for warts (Cutaneous WARTS diagnostic tool, CWARTS) based on phenotypical characteristics. OBJECTIVES: To assess whether patient and morphological wart characteristics predict the human papillomavirus (HPV) type in a specific wart and whether these characteristics as well as the HPV type predict a favourable treatment response. METHODS: Photographs were used to score nine morphological wart characteristics using the newly developed CWARTS tool. Genotyping of 23 wart-associated HPV types was performed using the hyperkeratotic skin lesion-polymerase chain reaction/multiplex genotyping assay. The results were correlated with a favourable response to treatment with monochloroacetic acid, cryotherapy or a combination of cryotherapy and salicylic acid. Odds ratios were calculated using logistic regression in a generalized estimating equations model. RESULTS: Black dots (capillary thrombosis) strongly predicted the presence of any HPV type in a wart. From all characteristics tested, the HPV type most strongly predicted the treatment response when the warts were treated with monochloroacetic acid or a combination of cryotherapy and salicylic acid with a significantly decreased treatment response if the warts contained HPVs of the alpha genus (HPV2, HPV27 or HPV57). When cryotherapy alone was used for common warts, HPV type did not play a role, but cryotherapy was less effective in the presence of callus and when the wart was located deeper in the skin. CONCLUSIONS: Morphological characteristics of the warts and the HPV genotype influence treatment outcome and thus potentially influence future treatment decisions for common and plantar warts.

Skin mast cells protect mice against vaccinia virus by triggering mast cell receptor S1PR2 and releasing antimicrobial peptides.

Mast cells (MCs) are well-known effectors of allergic reactions and are considered sentinels in the skin and mucosa. In addition, through their production of cathelicidin, MCs have the capacity to oppose invading pathogens. We therefore hypothesized that MCs could act as sentinels in the skin against viral infections using antimicrobial peptides. In this study, we demonstrate that MCs react to vaccinia virus (VV) and degranulate using a membrane-activated pathway that leads to antimicrobial peptide discharge and virus inactivation. This finding was supported using a mouse model of viral infection. MC-deficient (Kit(wsh-/-)) mice were more susceptible to skin VV infection than the wild type animals, whereas Kit(wsh-/-) mice reconstituted with MCs in the skin showed a normal response to VV. Using MCs derived from mice deficient in cathelicidin antimicrobial peptide, we showed that antimicrobial peptides are one important antiviral granule component in in vivo skin infections. In conclusion, we demonstrate that MC presence protects mice from VV skin infection, MC degranulation is required for protecting mice from VV, neutralizing Ab to the L1 fusion entry protein of VV inhibits degranulation apparently by preventing S1PR2 activation by viral membrane lipids, and antimicrobial peptide release from MC granules is necessary to inactivate VV infectivity.

The biological significance of TLR3 variant, L412F, in conferring susceptibility to cutaneous candidiasis, CMV and autoimmunity.

OBJECTIVE: Toll-like receptors, a major component of the innate immune system, play an important role in the initial response against pathogens. Genetic abnormalities in some receptors like TLR2, TLR3 and TLR4 have been associated with susceptibility to fungal and viral infections while other aberrations in TLR genes such as TLR3, TLR7 and TLR9 may predispose to autoimmunity. Recently we have shown an association of a TLR3 receptor variant, L412F, to susceptibility to chronic candidiasis, recurrent viral and bacterial infections and autoimmunity. We investigated here the biological implications of this TLR3 mutant. METHODS: To study the functional impact of the L412F variant of TLR3 we tested patients' peripheral blood mononuclear cells (PBMCs) as well as fibroblasts for secretion of cytokines in response to TLR3 ligand, candida or cytomegalovirus (CMV). In addition, the P2.1 cell line was used as a model for the TLR3 WT and L412F variant receptors function. RESULTS: Patient's cells carrying the L412F variant showed reduced IFNγ as well as TNFα secretion in response to stimulation with the TLR3 ligand, CMV or Candida albicans. Fibroblasts with the L412F variant showed decreased secretion of IFNλ in response to stimulation with both polyinosine ploycytidylic acid (Poly I:C) and CMV and P2.1 cells transfected with the L412F variant showed reduced secretion of IFN-ß in comparison to cells transfected with the wild type receptor. CONCLUSION: We have shown here aberrant biological responses mediated by the TLR3 variant receptor, L412F, which may explain in part susceptibility of patients to chronic candidiasis, viral infections and autoimmunity.

Dendritic cell subsets and immunological milieu in inflammatory human papilloma virus-related skin lesions.

BACKGROUND: Human papilloma virus (HPV)-related warts persist, evading host immune surveillance, but sometimes disappear with inflammation. OBJECTIVES: To elucidate the immune evasion mechanisms of HPV, we have examined the density, dynamics, and subsets of dendritic cell (DC) types in non-inflammatory or inflammatory HPV-related skin lesions such as warts and Bowen's disease (HPV-Bowen), and compared the epidermal expression levels of macrophage inflammatory protein (MIP)-3α and E-cadherin. METHODS: The expression of various DC markers, MIP-3α, and E-cadherin in the tissue samples obtained from patients with warts, HPV-Bowen and HPV-unrelated skin diseases was evaluated by immunohistochemistry. MIP-3α gene expression levels were examined in warts and HPV-Bowen by in situ hybridization (ISH) and real-time quantitative polymerase chain reaction (RT-qPCR). RESULTS: The numbers of Langerhans cells (LCs) and the expression levels of MIP-3α and E-cadherin were decreased in non-inflammatory warts and HPV-Bowen, as compared with normal skin. Both epidermal LCs and MIP-3α expression reappeared in inflammatory warts, associated with dermal infiltrates composed of many cytotoxic T cells and various subsets of DCs, while cellular infiltrates in HPV-Bowen contained many B cells and plasma cells with sparse infiltration of DCs. The upregulation of MIP-3α gene expression was confirmed in the inflammatory warts and HPV-Bowen by ISH and RT-qPCR. CONCLUSIONS: The depletion of LCs in the non-inflammatory warts and HPV-Bowen is associated with a down-regulation of expression levels of MIP-3α and E-cadherin in the lesional keratinocytes. MIP-3α expression is upregulated in lesional keratinocytes of inflammatory warts, with the subsequent recruitment of various DC subsets and cytotoxic T cells, whereas plasma cell-rich infiltration was induced in HPV-Bowen.

The signal transducer and activator of transcription 6 gene (STAT6) increases the propensity of patients with atopic dermatitis toward disseminated viral skin infections.

BACKGROUND: Atopic dermatitis (AD) is a chronic inflammatory skin disease associated with increased susceptibility to recurrent skin infections. OBJECTIVE: We sought to determine why a subset of patients with AD have an increased risk of disseminated viral skin infections. METHODS: Human subjects with AD with a history of eczema herpeticum (EH) and various control groups were enrolled. Vaccinia virus (VV) expression was measured by means of PCR and immunofluorescent staining in skin biopsy specimens from each study group after incubation with VV. Transgenic mice with a constitutively active signal transducer and activator of transcription 6 gene (STAT6) were characterized for response to VV skin inoculation. Genotyping for 10 STAT6 single nucleotide polymorphisms (SNPs) was performed in a white patient sample (n = 444). RESULTS: VV gene and protein expression were significantly increased in the skin of patients with EH compared with other subject groups after incubation with VV in vitro. Antibody neutralization of IL-4 and IL-13 resulted in lower VV replication in patients with a history of EH. Mice that expressed a constitutively active STAT6 gene compared with wild-type mice had increased mortality and satellite lesion formation after VV skin inoculation. Significant associations were observed between STAT6 SNPs and EH (rs3024975, rs841718, rs167769, and rs703817) and IFN-γ production. The strongest association was observed for a 2-SNP haplotype (patients with AD with a history of EH vs patients with AD without a history of EH, 24.9% vs 9.2%; P = 5.17 × 10(-6)). CONCLUSION: The STAT6 gene increases viral replication in the skin of patients with AD with a history of EH. Further genetic association studies and functional investigations are warranted.

Toxicogenomics of nevirapine-associated cutaneous and hepatic adverse events among populations of African, Asian, and European descent.

OBJECTIVE: Nevirapine is widely prescribed for HIV-1 infection. We characterized relationships between nevirapine-associated cutaneous and hepatic adverse events and genetic variants among HIV-infected adults. DESIGN: We retrospectively identified cases and controls. Cases experienced symptomatic nevirapine-associated severe (grade III/IV) cutaneous and/or hepatic adverse events within 8 weeks of initiating nevirapine. Controls did not experience adverse events during more than 18 weeks of nevirapine therapy. METHODS: Cases and controls were matched 1: 2 on baseline CD4 T-cell count, sex, and race. Individuals with 150 or less CD4 T cells/µl at baseline were excluded. We characterized 123 human leukocyte antigen (HLA) alleles and 2744 single-nucleotide polymorphisms in major histocompatibility complex (MHC) and drug metabolism and transport genes. RESULTS: We studied 276 evaluable cases (175 cutaneous adverse events, 101 hepatic adverse events) and 587 controls. Cutaneous adverse events were associated with CYP2B6 516G→T (OR 1.66, all), HLA-Cw*04 (OR 2.51, all), and HLA-B*35 (OR 3.47, Asians; 5.65, Thais). Risk for cutaneous adverse events was particularly high among Blacks with CYP2B6 516TT and HLA-Cw*04 (OR 18.90) and Asians with HLA-B*35 and HLA-Cw*04 (OR 18.34). Hepatic adverse events were associated with HLA-DRB*01 (OR 3.02, Whites), but not CYP2B6 genotypes. Associations differed by population, at least in part reflecting allele frequencies. CONCLUSION: Among patients with at least 150 CD4 T cells/µl, polymorphisms in drug metabolism and immune response pathways were associated with greater likelihood of risk for nevirapine-related adverse events. Results suggest fundamentally different mechanisms of adverse events: cutaneous, most likely MHC class I-mediated, influenced by nevirapine CYP2B6 metabolism; hepatic, most likely MHC class II-mediated and unaffected by such metabolism. These risk variants are insensitive for routine clinical screening.

Effects of CXCR3 signaling on development of fatal encephalitis and corneal and periocular skin disease in HSV-infected mice are mouse-strain dependent.

PURPOSE: The host inflammatory response to ocular infection with herpes simplex virus (HSV) can be either protective, with disease-free survival, or it can promote diseases such as HSV corneal disease (or herpes stromal keratitis [HSK] in humans) and encephalitis (HSE), depending on mouse strain. The role of CXCR3 chemokine signaling in HSV-induced central nervous system (CNS) inflammation and corneal disease was evaluated, and responses in genetically susceptible and resistant strains of mice were contrasted. METHODS: Resistant C57BL/6J (B6) and susceptible 129S6 (129) mice were given monoclonal antibodies (mAbs) to neutralize the CXCR3 ligands monokine induced by interferon-gamma (MIG, CXCL9) and interferon inducible protein-10 (IP-10, CXCL10) during HSV infection. In addition, the development of HSV disease was monitored in CXCR3-null mutant mice derived from resistant (B6) and susceptible (BALB/c) strains. Inflammatory cells infiltrating the cornea and brain stem were isolated and stained for flow cytometric analysis. RESULTS: MIG and IP-10 were induced in nervous system tissue after HSV inoculation by the corneal route. HSV-infected 129 mice treated with MIG- or IP-10-neutralizing mAbs showed significantly enhanced survival compared with mice treated with control isotype antibody, whereas survival of the B6 mice was unaltered. Similarly, greater survival was observed for BALB.CXCR3(-/-) mice compared with control BALB/c mice. Reduced CNS inflammation was documented that extended to the cornea, such that HSV corneal disease severity was reduced in susceptible BALB.CXCR3(-/-). In contrast, although survival of B6 and B6.CXCR3(-/-) mice was indistinguishable, B6.CXCR3(-/-) mice developed more severe corneal and periocular skin disease. CONCLUSIONS: The effects of CXCR3 signaling in HSV infection are strongly dependent on mouse strain.

Infective dermatitis and human T cell lymphotropic virus type 1-associated myelopathy/tropical spastic paraparesis in childhood and adolescence.

BACKGROUND: Human T cell lymphotropic virus type 1 (HTLV-1)-associated infective dermatitis (IDH) is a chronic and recurrent eczema occurring during childhood and adolescence. HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP) is a chronic myelopathy of adulthood, presenting with slowly progressive spastic paraparesis and sphincter dysfunction with mild sensory involvement. There are few reports describing an association between IDH and HAM/TSP. The objective of this study was to evaluate the occurrence of HAM/TSP in patients with IDH and in seropositive members of their families and to determine the blood levels of antibodies against HTLV-1 in patients with HAM/TSP. METHODS: Twenty patients with IDH and their seropositive mothers and siblings underwent clinical, neurological, and laboratory evaluations. The diagnosis of HAM/TSP was made in accordance with the World Health Organization criteria. RESULTS: Nine individuals had HAM/TSP (6 of the patients with IDH, 2 mothers, and 1 seropositive brother). In 3 families, > 1 individual had HAM/TSP. The serum antibody titers of the patients with HAM/TSP varied from 1 : 3.125 to 1 : 78.125. CONCLUSIONS: A strong association was observed between IDH and HAM/TSP. The familial clustering of both diseases suggests a genetic background. Serological screening for HTLV-1 in children with symptoms of myelopathy is essential in areas where HTLV-1 is endemic.

Infection with parapoxvirus induces CD30-positive cutaneous infiltrates in humans.

Expression of CD30 is a distinct feature of B- or T-cell activation, found in Hodgkin's disease, large cell anaplastic lymphoma, lymphomatoid papulosis, as well as in certain viral infections such as human T-lymphotropic virus type I, HIV, hepatitis B and C virus, and Epstein-Barr virus. Here, we report highly proliferative CD30-positive cutaneous infiltrates in 3 patients with Milkers's nodules, adding parapoxvirus infection to the spectrum of CD30-positive benign lympho-proliferations.

DNA fingerprinting of Fusarium solani isolates related to a cutaneous infection in a sea turtle.

Random amplified polymorphic DNA (RAPD) fingerprinting was applied to Fusarium solani from a cutaneous hyalohyphomycosis in a loggerhead sea turtle. A total of seven F. solani isolates were examined, three from culture collections and four from the turtle infection (one from the turtle's lesions and three from the sand of the tank in which the turtle was kept). The banding patterns of the isolates from culture collections were markedly different from the patterns of the isolates from both the turtle and the sand. The RAPD banding patterns were the same with all the primers used, suggesting that this opportunistic infection may be related to the presence of F. solani in the tank. RAPD techniques can be particularly useful for large-scale epidemiological studies and for identifying sources of infection.

Decreased CD7 expression in cutaneous infiltrates of HIV-1+ patients. Military Medical Consortium for the Advancement of Retroviral Research (MMCARR).

CD7 is an early T-cell marker that has been used in the diagnosis of stem cell leukemias. Loss of expression of CD7 with a battery of other mature T-cell markers has also been used as one criteria in the diagnosis cutaneous T-cell lymphomas. More recently, CD7-negative T cells have been shown to be a normal population of T cells in the peripheral blood and the skin, and may represent a mature T-cell population with a different pattern of maturation and activation. In addition, in HIV-1 disease expansion of CD7-negative T cells has been found in the peripheral blood. We evaluated the number of CD7-negative T cells in skin infiltrates to determine whether there was an increase of CD7-negative T cells. We studied T-cell markers including CD3, CD4, CD7, CD8, CD20, CD29, and HLA-DR on cutaneous biopsy material from inflammatory dermatoses in 57 patients with HIV-1 disease in Walter Reed stages (WR) 1-6, and in 14 HIV-1-negative patients WR0. The inflammatory infiltrates showed a moderate to marked decrease in CD7 expression on CD3+ T cells in benign inflammatory infiltrates of the majority of HIV-1+ patients. The majority of HIV-1-negative patients showed no decrease in CD7 expression, although 5 of 14 showed a moderate decrease and 1 of 14 showed a marked decrease. Although the nature of CD7- T cells has not been clearly defined, this population of mature T cells appears to have distinct immunologic properties as well as a trophism for skin. Better characterization of these T cells, as well as factors that promote their maturation and activation, may give clues to the high incidence as well as the pathogenesis of skin disease in HIV-1+ patients.

Effect of interferon therapy on human papillomavirus copy number in patients with Condyloma acuminatum.

Interferons exert antiviral, antiproliferative, and immunomodulatory effects on target cells. The effectiveness of interferon treatment can be followed by measuring parameters involved in interferon action. The clinical effectiveness of interferons has been proved in the human papillomavirus (HPV)-associated disease condyloma acuminatum. Because one of the most important goals in the treatment of this condition is the elimination of recurrences, it was asked whether clinically effective interferon therapy was associated with elimination of HPV DNA. The authors used a polymerase chain reaction-based method to detect the HPV from minute amounts of clinical biopsies. Human papillomavirus-transformed cell lines or cloned HPV genomes served as different copy number controls. The intensity ratio of L1 HPV and the human beta-globin (which served as an internal control) fragments was determined and used for estimation of HPV copy number in different biopsies. A direct effect of interferon treatment on HPV viral genome copies was observed in a group of responder patients, but not in the clinically resistant group. With these data, a correlation was found between virologic data and clinical findings. This method also can be used in other lesions to determine the HPV copy number and HPV type and may have value in determining the antiviral activities of other agents used in the treatment of HPV-related lesions.

Viral glycoproteins in herpesviridae granulomas.

Granulomatous reactions after varicella zoster virus (VZV) and herpes simplex virus (HSV) infections are rare, and their pathogenesis remains unclear. We studied by immunohistochemistry and in situ hybridization early granulomatous reactions after VZV and HSV infections. In the five cases studied, the VZV glycoproteins gp I and gp II were present in cells abutted to altered vessels, but the corresponding genome sequences were disclosed in similar locations in only one of these cases. In an immunocompromised patient with diffuse HSV eruption, HSV I antigens were present in cells of the reticular dermis, while viral nucleic acids were not evident. Immunophenotyping of the granulomas showed strong Mac 387 and CD68 positive labelings of macrophages/monocytes, without any involvement of Factor XIIIa-positive cells. These findings suggest that the major viral envelope glycoproteins, rather than complete viral particles could trigger granuloma formation following HSV and VZV skin infections.