Establishment of Human Pluripotent Stem Cell-Derived Skin Organoids Enabled Pathophysiological Model of SARS-CoV-2 Infection

Coronavirus disease 2019 (COVID-19) patients with impact on skin and hair loss are reported. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is detected in the skin of some patients; however, the detailed pathological features of skin tissues from patients infected with SARS-CoV-2 at a molecular level are limited. Especially, the ability of SARS-CoV-2 to infect skin cells and impact their function is not well understood. A proteome map of COVID-19 skin is established here and the susceptibility of human-induced pluripotent stem cell (hiPSC)-derived skin organoids with hair follicles and nervous system is investigated, to SARS-CoV-2 infection. It is shown that KRT17+ hair follicles can be infected by SARS-CoV-2 and are associated with the impaired development of hair follicles and epidermis. Different types of nervous system cells are also found to be infected, which can lead to neuron death. Findings from the present work provide evidence for the association between COVID-19 and hair loss. hiPSC-derived skin organoids are also presented as an experimental model which can be used to investigate the susceptibility of skin cells to SARS-CoV-2 infection and can help identify various pathological mechanisms and drug screening strategies.

Assessment of Prolonged Dengue Virus Infection in Dermal Fibroblasts and Hair-Follicle Dermal Papilla Cells

Dengue virus (DENV)-mediated hair loss is one of the post-dengue fatigue syndromes and its pathophysiology remains unknown. Whether long-term or persistent infection with DENV in the scalp results in hair loss is unclear. In this study, we cultured human dermal fibroblasts (WS1 cells) and primary human hair-follicle dermal papilla cells (HFDPCs) in the long term with DENV-2 infection. The production of virion, the expression of inflammatory and anti-virus genes, and their signaling transduction activity in the infected cells were analyzed. DENV-2 NS3 protein and DENV-2 5′ UTR RNA were detected in fibroblasts and HFDPCs that were subjected to long-term infection with DENV-2 for 33 days. A significant amount of DENV-2 virion was produced by both WS1 cells and HFDPCs in the first two days of acute infection. The virion was also detected in WS1 cells that were infected in the long term, but HFDPCs failed to produce DENV-2 after long-term culture. Type I and type III interferons, and inflammatory cytokines were highly expressed in the acute phase of DENV infection in HFPDC and WS1 cells. However, in the long-term cultured cells, modest levels of anti-viral protein genes were expressed and we observed reduced signaling activity, which was correlated with the level of virus production changes. Long-term infection of DENV-2 downregulated the expression of hair growth regulatory factors, such as Rip1, Wnt1, and Wnt4. This in vitro study shows that the long-term infection with DENV-2 in dermal fibroblasts and dermal papilla cells may be involved with the prolonged-DENV-infection-mediated hair loss of post-dengue fatigue syndrome. However, direct evidence for viral replication in the human hair of a dengue victim or animal infection model is required.

Statistical analysis of the usefulness of follicle-sinus complexes as a novel diagnostic material for canine rabies

In the present study, follicle-sinus complexes (FSCs) were harvested from the muzzle skin of 123 dogs with suspected canine rabies, and the sensitivity and specificity of FSC analysis were compared with those of brain tissue immunohistochemistry analysis. In the FSCs, viral antigen was detected from Merkel cells. Sensitivity was 97.3%, specificity was 100%, and the coefficient κ was 0.88. These results reconfirm that FSCs are very useful for the postmortem diagnosis of canine rabies, and suggest that 5 FSCs can yield results that are almost equivalent to those derived from brain tissue analysis in rabid dogs.

[Human papillomavirus in the pubic hair follicles of men and cervical lesions in their female sexual partners]

OBJECTIVE

To investigate the association of human papillomavirus (HPV) in the pubic hair follicles of males with HPV infection in their female sexual partners.

METHODS

We included in this study 21 female patients with HPV infection, including 8 cases of cervical cancer, 5 cases of atypical cervical hyperplasia, 5 cases of cervical condyloma, and 3 cases with unidentified causes. We also enlisted 52 men without visible condyloma acuminatum in the external genitalia as healthy controls. We detected HPV in the pubic hair follicles of the female patients' male sexual partners and the healthy male controls by PCR and reverse hybridization in situ.

RESULTS

HPV positive was found in 6 (28.6%) of the 21 women's male partners, in whom the HPV types were correspondent situ. to those of the female patients.

CONCLUSION

HPV in the pubic hair follicles of men might be one of the causes of HPV-related cervical lesions in their female sexual partners.

Detection of rabies viral RNA by TaqMan real-time RT-PCR using non-neural specimens from dogs infected with rabies virus

To determine the burden of rabies in developing countries, a reliable and accurate diagnostic test for the examination of the brains of animals is needed. Recently, the number of samples and carcasses submitted to rabies diagnostic units has been declining. Methods for obtaining tissues from different regions of the brain are even more difficult, and direct florescent antibody examination may fail if the samples decomposed. The spread of rabies virus to peripheral non-nervous tissues starts early during the pre-clinical phase. It has been shown that saliva and skin biopsies taken at the neck and containing hair follicles can be used in the ante-mortem diagnosis of rabies in humans. Obtaining oral swab samples, whisker or hair follicles from the heads of canines is easy and practical and can be performed without special equipment. The objective of this study was to determine whether these non-neural specimens can be used for the detection of rabies viral RNA. The RNAs extracted from these specimens were tested using a real-time reverse transcriptase polymerase chain reaction (RT-PCR). The sensitivity of the TaqMan real-time RT-PCR analysis using samples from dogs confirmed to be infected with rabies virus was 84.6% (55/65), 81.8% (54/66) and 66.7% (44/66) when using oral swab samples, extracted whisker follicles and extracted hair follicles; the specificity of all specimen types was 100%. The negative predictive values were 77.8%, 74.4% and 61.4%, respectively. Although the rate of positivity when combining the three non-neural specimen types was increased to 86.4%, this level of sensitivity was not sufficient to help physicians whether to administer post exposure prophylaxis. However, these oral swab and whisker specimens may serve to enhance epidemiological surveillance; such data will contribute in the planning of rabies control programs.

Review of 20 years of HPV research in Slovenia

BACKGROUND

Human papillomaviruses (HPV), remarkably diverse DNA viruses etiologically linked with various benign and malignant neoplastic lesions of mucosal and skin epithelium have been the subject of intensive research for the last 30 years worldwide.

OBJECTIVE

Briefly to review 20 years of HPV research in Slovenia by analyzing the articles published in journals indexed in peer-reviewed databases Medline/Pubmed, Science Citation Index/Web of Science, Embase and PsycINFO.

METHODS AND RESULTS

Up until October 2011, Slovenian researchers published 73 articles in journals indexed in peer-reviewed databases, which can be divided into 15 categories: detection of HPV in archival clinical specimens, development of novel HPV tests, evaluation of various commercial tests for the detection of high- and low-risk alpha-HPV, HPV and anogenital tumours, HPV testing in routine gynecological practice, HPV and laryngeal benign tumours, HPV and laryngeal epithelial hyperplastic lesions and laryngeal cancer, HPV and tumors in oral cavity, HPV and esophageal benign and malignant tumors, HPV and inverted papillomas, genomic diversity of selected HPV types, hair follicles as an important endogenous reservoir of HPV, identification and characterization of novel HPV types, HPV vaccination and HPV basic research. Until October 2011, Slovenian HPV papers received 473 citations (self-citation excluded) and their Hirsch index is currently h=13.

CONCLUSION

In the last 20 years, Slovenian HPV researchers have been actively and successfully incorporated in the international HPV community and have contributed small but significant achievements in the field.

Characterization of novel cutaneous human papillomavirus genotypes HPV-150 and HPV-151

DNA from two novel HPV genotypes, HPV-150 and HPV-151, isolated from hair follicles of immuno-competent individuals, was fully cloned, sequenced and characterized. The complete genomes of HPV-150 and HPV-151 are 7,436-bp and 7,386-bp in length, respectively. Both contain genes for at least six proteins, namely E6, E7, E1, E2, L2, L1, as well as a non-coding upstream regulatory region located between the L1 and E6 genes: spanning 416-bp in HPV-150 (genomic positions 7,371 to 350) and 322-bp in HPV-151 (genomic positions 7,213 to 148). HPV-150 and HPV-151 are phylogenetically placed within the Betapapillomavirus genus and are most closely related to HPV-96 and HPV-22, respectively. As in other members of this genus, the intergenic E2-L2 region is very short and does not encode for an E5 gene. Both genotypes contain typical zinc binding domains in their E6 and E7 proteins, but HPV-151 lacks the regular pRb-binding core sequence within its E7 protein. In order to assess the tissue predilection and clinical significance of the novel genotypes, quantitative type-specific real-time PCR assays were developed. The 95% detection limits of the HPV-150 and HPV-151 assays were 7.3 copies/reaction (range 5.6 to 11.4) and 3.4 copies/reaction (range 2.5 to 6.0), respectively. Testing of a representative collection of HPV-associated mucosal and cutaneous benign and malignant neoplasms and hair follicles (total of 540 samples) revealed that HPV-150 and HPV-151 are relatively rare genotypes with a cutaneous tropism. Both genotypes were found in sporadic cases of common warts and SCC and BCC of the skin as single or multiple infections usually with low viral loads. HPV-150 can establish persistent infection of hair follicles in immuno-competent individuals. A partial L1 sequence of a putative novel HPV genotype, related to HPV-150, was identified in a squamous cell carcinoma of the skin obtained from a 64-year old immuno-compromised male patient.

[Prevalence of human papillomavirus in the pubic hair follicles of healthy men and male patients with genital warts]

OBJECTIVE

Human papillomavirus (HPV) commonly exists in healthy individuals, but its prevalence in the pubic hair follicles is not yet clear, nor is the relationship between HPV infection in the pubic hair follicles and the recurrence of genital warts in men. This study aimed to investigate HPV infection in the pubic hair follicles of healthy men and patients with genital warts, and to look into the correlation of HPV infection with recurrent genital warts.

METHODS

We included in this study 122 healthy men aged 21-80 years and 86 male patients with genital warts aged 24-61 years, detected HPV in their pubic hair follicles by PCR, and made comparative analysis of the data obtained from the two groups.

RESULTS

The positive rate of HPV in the pubic hair follicles of the healthy males was 17.21% (21/122), including 15 cases of HPV6, 4 HPV11, 1 non-HPV6/11 and 1 the mixed type (both HPV6 and HPV11), while that of the genital wart patients was 32.55% (28/86), including 17 cases of HPV6, 7 HPV11, 2 non-HPV6/11 and 2 the mixed type.

CONCLUSION

The incidence of HPV infection is higher in patients with genital warts than in healthy men, while the types of HPV involved are basically the same in the two groups, mainly HPV6 and HPV11.

Viral-associated trichodysplasia in a patient with lymphoma: a case report and review

Viral-associated trichodysplasia is a recently described entity associated with immunosuppression. We describe a 68-year-old man with a history of treated lymphoma who developed numerous, disfiguring, papular and spiny lesions involving most of the central face. Both facial and body alopecia was noted. Histopathologic findings of a facial papule showed dramatic alterations of the hair bulbs, including bulbar distention, lack of hair shaft formation and a marked expansion of inner root sheath type epithelium. These findings were identical to those of previously described cases, so electron microscopy was performed. Numerous intranuclear virus particles were identified. Shortly after the diagnosis of trichodysplasia was made, the patient was found to have a relapse of his lymphoma, which may represent the source of his immunosuppression. Based on his skin biopsy findings, successful antiviral therapy was initiated. This case and a review of previously reported cases are discussed in this study.

Trichodysplasia spinulosa associated with chemotherapy for acute lymphocytic leukaemia

We report two boys with trichodysplasia spinulosa associated with chemotherapy for acute lymphocytic leukaemia. Trichodysplasia spinulosa is a cutaneous viral infection of immunosuppressed patients that causes abnormal hair follicle maturation. Our patients presented with widespread papules, some extruding a central keratin spicule, which were most prominent on the face. Histopathology demonstrated hair follicles dilated by a proliferation of large eosinophilic cells containing numerous abnormal trichohyaline granules. Electron microscopy in case 1 revealed 30-nm viral particles in the stratum corneum consistent with a papovavirus. In case 1, the eruption persisted despite topical salicyclic acid 4%, ammonium lactate 17.5%, tretinoin 0.05% and oral acitretin. However, it resolved once the patient's immune function returned to normal (total duration of 2 years). In case 2, the eruption spontaneously resolved after 9 months. This case report discusses the characteristic clinicopathological features of trichodysplasia spinulosa and, for the first time, follows the condition's natural history.

Human herpesvirus 6 chromosomal integration in immunocompetent patients results in high levels of viral DNA in blood, sera, and hair follicles

Six immunocompetent patients with human herpesvirus 6 (HHV-6) chromosomal integration had HHV-6 and beta-globin DNA quantified in various samples by PCR. The mean HHV-6 DNA concentration (log(10) copies/milliliter) in blood was 7.0 (>/=1 HHV-6 DNA copies/leukocyte), and in serum it was 5.3 (>/=1 HHV-6 DNA copies/lysed cell). The mean HHV-6 DNA load (log(10) copies)/hair follicle was 4.2 (>/=1 copies/hair follicle cell), demonstrating that viral integration is not confined to blood cells. The characteristically high HHV-6 DNA levels in chromosomal integration may confound laboratory diagnosis of HHV-6 infection and should be given due consideration.

Exclusive Involvement of Folliculosebaceous Units by Herpes

The histopathological changes of herpes simplex, herpes zoster, and varicella are considered to be indistinguishable from one another. Evaluation of the clinical setting, with adjunctive studies if necessary, generally clarifies the specific diagnosis. Vesicular lesions in all three conditions can involve epidermal and adnexal epithelium with characteristic cytopathic features. We describe three patients with non-vesicular eruptions on the head and neck whose biopsies revealed exclusive folliculosebaceous involvement by herpes. All three patients developed typical herpes zoster within days of the biopsy. There is compelling scientific evidence in the literature indicating that, in herpes zoster, the virus is transported from dorsal root or trigeminal ganglia via myelinated nerves to the skin. These terminate at the isthmus of hair follicles and primary infection of follicular and sebaceous epithelium occurs. Spread of infection to the epidermis follows. In contrast, data pertaining to recurrent herpes simplex indicates that axonal transport of the virus from sensory ganglia to the skin is directed primarily to the epidermis, via terminal non-myelinated nerve twigs. The clinical evolution of our three cases and scientific data in the literature indicate that exclusive folliculosebaceous involvement by herpes, in the setting of a non-vesicular eruption, represents early herpes zoster.

Reactive Syringofibroadenomatous Hyperplasia in Peristomal Skin with Formation of Hybrid Epidermal-Colonic Mucosa Glandular Structures, Intraepidermal Areas of Sebaceous Differentiation, Induction of Hair Follicles, and Features of Human Papillomavirus Infection

We report a case of reactive syringofibroadenomatous hyperplasia in peristomal skin. The patient was a 62-year-old woman who had undergone abdominoperineal resection of the rectum for rectal adenocarcinoma with subsequent colostomy 2 years earlier. Clinically, a nodule and small, whitish, warty lesions developed at the outer margin of the stoma extending onto the adjacent skin. Following a clinical suspicion of adenocarcinoma, recurrent at the colostomy site, a 5 x 4 x 3-cm excision of the peristomal skin and the affected portion of the stoma was performed and submitted for histologic examination. The biopsy revealed a peculiar composite lesion of reactive syringofibroadenomatous hyperplasia and the excised part of the stoma. Several unusual histopathological features were detected in the syringofibroadenomatous part of the lesion such as the formation of plentiful hybrid epidermal-colonic mucosa glandular structures, intraepidermal areas of sebaceous differentiation, koilocytic changes, induction of rudimentary hair follicles, and intradermal mucinous lakes. The cellular composition of the glandular structures was mainly similar to that seen in a normal colonic mucosa epithelium. They also contained occasional Paneth cells. Being located at a distance from the stoma, these accentuated colonic mucosa epithelial glands reaching the epidermis may be a diagnostic pitfall prompting the consideration of adenocarcinoma involving the stoma. The rudimentary follicles and sebaceous differentiation were probably induced by an altered stroma and/or human papillomavirus (HPV): HPV, type 36 was identified by PCR using consensus primers followed by sequencing of the PCR products.

Virus-associated trichodysplasia spinulosa

Virus-associated trichodysplasia spinulosa (VATS) is a cutaneous eruption of spiny papules predominantly affecting the face that is associated with a distinctive histologic picture of abnormally maturing anagen follicles with excessive inner root sheath differentiation and hyperkeratotic infundibula. Ultrastructurally, intranuclear viral particles consistent with polyoma virus are found. Only 2 patients have thus far been reported. Both had developed the eruption after a kidney transplant. We report 2 additional cases of VATS. One is an 8-year-old boy who presented with facial papules after a kidney transplant. The other is a 19-year-old man with a history of acute lymphocytic leukemia who never had a transplant. He developed a papular facial eruption as well as alopecia. Light microscopic and ultrastructural examinations revealed a spectrum in the severity of the histologic alterations as well as the number of intranuclear viral particles. This report expands the range of pathologic alterations associated with VATS and documents for the first time that it can affect patients without a solid organ transplant. The similarity of the clinical and histologic features of VATS with those previously reported by others as cyclosporine-induced "follicular dystrophy" or "pilomatrix dysplasia" raises the possibility that the described phenomena may reflect the same entity. Increased awareness of the distinct histologic picture associated with VATS will likely lead to more frequent diagnosis of this underrecognized entity.

Human papillomaviruses and skin cancer

Cutaneous epidermodysplasia verruciformis (EV)-associated human papillomaviruses (HPVs) are found frequently in skin cancers especially in immunosuppressed people. They are also detectable in the normal skin and hair follicles of a proportion of individuals who have no immune defect. The available evidence to link HPVs causally with skin carcinogenesis is not conclusive, but includes epidemiological, molecular and immunological studies.

Gene and stem cell therapy of the hair follicle

The hair follicle is a highly complex appendage of the skin containing a multiplicity of cell types. The follicle undergoes constant cycling through the life of the organism including growth and resorption with growth dependent on specific stem cells. The targeting of the follicle by genes and stem cells to change its properties, in particular, the nature of the hair shaft is discussed. Hair follicle delivery systems are described such as liposomes and viral vectors for gene therapy. The nature of the hair follicle stem cells is discussed, in particular, its pluripotency.

Detection of human papillomavirus type 56 DNA, belonging to a mucous high-risk group, in hair follicles in the genital area of a woman no longer suffering from viral warts

BACKGROUND

Human papillomaviruses (HPVs) parasitize human epithelium, but it is not clear where they reside when they do not cause apparent infection. Hair follicles are important candidates as reservoirs.

OBJECTIVES

A patient reported previously by us as having perianal warts caused mainly by HPV 56, demonstrated hair follicles in her genital area which bulged a little from the surface and appeared somewhat enlarged. We therefore examined whether DNA of HPV 56, a member of the mucous high-risk group, might be detectable in these structures.

METHODS

We obtained plucked hairs and performed an examination by polymerase chain reaction and subsequent reverse-phase dot blot hybridization (PCR-RDBH) and in situ hybridization (ISH).

RESULTS

Strong positive signals were obtained not only with PCR-RDBH but also with ISH.

CONCLUSIONS

Hair follicles in the genital area might serve as reservoirs for HPVs belonging to the mucous high-risk group.

Detection and sequences of human papillomavirus DNA in nongenital seborrhoeic keratosis of immunopotent individuals

BACKGROUND

The etiology of seborrhoeic keratosis (SK) is unknown. Its clinical and histopathological similarities to verrucae vulgaris and condyloma acuminatum prompted us to examine whether human papillomavirus (HPV) is present in SK lesions. In the present study, HPVs were frequently detected from genital lesions or hair follicle in immunocompromised host.

OBJECTIVE

We analyzed 104 nongenital SK specimens diagnosed by clinical and histopathological examinations for HPV DNA in immunopotent individuals.

METHOD

We analyzed SK specimens for HPV DNA using in situ hybridization (ISH), polymerase chain reaction (PCR), Southern blot hybridization, and sequencing of viral DNA of PCR-amplified fragments. And we also examined virion, which is the capsid protein of HPV in ISH-positive specimens by immunochemical examination. We identified eight mucosal and two cutaneous type HPVs.

RESULT

ISH revealed that 30 of 104 (28.8%) SK samples contained HPV DNA. All ISH-positive specimens were demonstrated virion in the nuclei of the epidermal keratinocytes. PCR analysis showed that 87 (83.7%) samples contained HPV-18, 81 (77.9%) HPV-6, and 73 (70.2%) contained both HPV-18 and -6. The incidence of HPV-1 (7.7%) and HPV-2 (14.4%) was relatively low. All 20 normal controls were negative for HPV DNA by ISH but seven were positive by PCR sequencing.

CONCLUSION

Our results suggest that HPV, possibly coinfection with HPV-6 and -18 and unknown type(s) of HPV, plays an important role in the pathogenesis of SK.

Pathway of viral spread in herpes zoster: detection of the protein encoded by open reading frame 63 of varicella-zoster virus in biopsy specimens

Reactivation of varicella-zoster virus (VZV) in the dorsal root or trigeminal ganglia causes herpes zoster. The pathway of viral spread from the ganglia to the skin and also within the skin is not yet completely understood. Histological studies have revealed that each skin lesion in herpes zoster progresses sequentially through the stages of erythema, vesicles, pustules and finally ulceration. An immunohistochemical study of the early skin lesions of herpes zoster demonstrated a high incidence of hair follicle involvement and the main localization of the virus at the isthmus. This evidence suggests that VZV initially spreads from the ganglia through myelinated nerves, which predominantly end around the isthmus of hair follicles. To further investigate the viral spread within the skin, we analyzed the sequential appearance of the immediate early proteins encoded by ORF 63 of VZV (IE63), using an anti-IE63 antibody raised by immunization of rabbits with a recombinant protein. This antibody could detect IE63 in a western blot analysis of infected cells and also in immunohistochemical analysis of the skin lesions of herpes zoster. IE63 initially appeared in the nuclei of the follicular epithelial cells and basal or parabasal epidermal cells. Later, the nuclei and cytoplasm of cells in the epidermis and hair follicles became positive. IE63 remained in the virus-infected cells even during their degeneration. When we examined the hair follicles in the early erythematous lesions, cells positive for IE63 were predominantly distributed around the isthmus. In addition, some lymphocytes around the blood vessels were also positive for IE63, but these cells were seldom positive for the structural antigen. Thus, these observations suggest that VZV arriving through myelinated nerves infects not only permissive cells, but also non-permissive cells in the involved skin of herpes zoster.

Benign keratosis with a spectrum of follicular differentiation: a case series and investigation of a potential role of human papilloma virus

BACKGROUND

A variety of dermatopathologic entities are histologically defined by the presence of follicular differentiation. Follicular differentiation confined to the epidermis may follow induction from dermal mesenchymal proliferations, as in a nevus sebaceus of Jadassohn, or represent endogenous proliferations such as the tumor of the follicular infundibulum or trichilemmoma.

METHODS

We report on five cases of a histologically distinct form of benign keratosis showing variable follicular differentiation. Clinicopathologic correlation and analysis of a potential human papilloma virus pathogenesis was investigated.

RESULTS

Each of the cases arose on the trunk or extremities of three men and two women with a mean age at presentation of 66.6 years. All of the lesions showed variable follicular differentiation, with germinative basaloid cells, matrical cells with matrical keratinization, inner root sheath with trichohyalin granules, or glycogenated lower outer root sheath. Immunohistochemical staining for human papilloma virus was negative in each case.

CONCLUSIONS

There exists a distinct entity, histologically defined as a keratosis with variable follicular differentiation, which has not been previously described. These lesions do not appear to be pathogenically related to human papilloma virus infection.

Importance of human papillomaviruses for the development of skin cancer

The frequent detection of HPV DNA in non-melanoma skin cancers was shown in several studies; however, the role of HPV in the development of these cancers remains speculative. We analyzed different skin tumors, normal skin, and hair follicles for HPV DNA using a PCR system designed to detect all HPV types known so far. HPV DNA was found in 93% of common warts, 69% of squamous cell carcinomas (SCC), 52% of basal cell carcinomas (BCC), 41% of actinic keratoses, 31% of extragenital Bowen's disease, 22% of keratoacanthomas, 16% of normal skin tissues and 47% of hair follicles. No individual HPV type predominated in any of the skin tumors. The number of HPV genomes in individual neoplasms (SCC and BCC) seems to be less than I per cancer cell. These results indicate that a direct role of HPV in skin cancerogenesis remains questionable. Possibly, mechanisms different from the activity of HPV oncoproteins in genital cancers are involved in skin neoplastic transformation.

Trichodysplasia spinulosa--a newly described folliculocentric viral infection in an immunocompromised host

This is a case report of an immunocompromised individual who presented with progressive alopecia, friable follicular spinous processes, and erythematous, indurated papules. Examination of skin biopsies using light microscopy and immunohistochemistry revealed pathologic changes of the follicular inner root sheath epithelium with dystrophic trichohyaline granules. Electron microscopy of thin sections of tissue revealed intracellular viral particles with a size and appearance consistent with those in the Papovaviridae family. Electron microscopy of negatively stained extract from a homogenized lesion also demonstrated icosahedral viruses with papovavirus morphology. We believe this is a previously unreported folliculocentric viral infection in an immunosuppressed human host and have termed this entity "trichodysplasia spinulosa".

Moloney murine leukemia virus infects cells of the developing hair follicle after neonatal subcutaneous inoculation in mice

The nature of Moloney murine leukemia virus (M-MuLV) infection after a subcutaneous (s.c.) inoculation was studied. We have previously shown that an enhancer variant of M-MuLV, Mo+PyF101 M-MuLV, is poorly leukemogenic when used to inoculate mice s.c., but not when inoculated intraperitoneally. This attenuation of leukemogenesis correlated with an inability of Mo+PyF101 M-MuLV to establish infection in the bone marrow of mice at early times postinfection. These results suggested that a cell type(s) is infected in the skin by wild-type but not Mo+PyF101 M-MuLV after s.c. inoculation and that this infection is important for the delivery of infection to the bone marrow, as well as for efficient leukemogenesis. To determine the nature of the cell types infected by M-MuLV and Mo+PyF101 M-MuLV in the skin after a s.c. inoculation, immunohistochemistry with an anti-M-MuLV CA antibody was performed. Cells of developing hair follicles, specifically cells of the outer root sheath (ORS), were extensively infected by M-MuLV after s.c. inoculation. The Mo+PyF101 M-MuLV variant also infected cells of the ORS but the level of infection was lower. By Western blot analysis, the level of infection in skin by Mo+PyF101 M-MuLV was approximately 4- to 10-fold less than that of wild-type M-MuLV. Similar results were seen when a mouse keratinocyte line was infected in vitro with both viruses. Cells of the ORS are a primary target of infection in vivo, since a replication defective M-MuLV-based vector expressing beta-galactosidase also infected these cells after a s.c. inoculation.

Measles virus was present in the inner cell of the acrosyringium in the skin rash

A case of measles in a 26-year-old Japanese man is reported. A skin specimen taken on the third eruptive day from a maculopapular eruption on his chest was immunohistopathologically and electron microscopically examined using a rabbit polyclonal antibody against the nucleocapsid protein of the measles virus. The measles virus antigen was found in the inner cells of the acrosyringium and hair follicles. The measles virus nucleocapsid was electron microscopically identified in the nuclei of the inner cells of the acrosyringium. The findings suggest that the sweat from skin lesions might contain the measles virus.

Detection of HPV DNA in trichilemmomas by polymerase chain reaction

Paraffin sections of 11 formalin-fixed trichilemmomas were investigated for the presence of human papillomavirus (HPV) DNA by the polymerase chain reaction (PCR) with the degenerated consensus primer pairs. PCRs were conducted with different annealing temperatures. When the annealing temperature was reduced from 55 degrees C to 50 degrees C, amplification products of the expected size were obtained for all 11 cases investigated. Determination of the HPV type was performed by cloning and sequencing of the amplification products. The sequence analysis of the eleven cloned amplicons gave the following data: based on sequence comparison with published amino acid sequences, the best homology was found to epidermodysplasia verruciformis (EV)-associated HPVs (supergroup B). In four specimens an HPV type 23 related type was found; five specimens contained HPV sequences which did not match with one of the known HPV types, but had the closest homology to HPV types 15, 17, and 37. Three of the HPV variants which had not been characterised, displayed identical sequences. Two additional HPV amplification fragments displayed played 100% homology to HPV-6b. These results demonstrate, for the first time, the presence of HPV DNA in trichilemmomas. The sequence data suggest that HPV variants or types in trichilemmoma are members of the EV-associated HPV supergroup B.

Hair follicle involvement in herpes zoster: pathway of viral spread from ganglia to skin

Herpes zoster is caused by reactivation of varicella-zoster virus (VZV) persisting in dorsal root or trigeminal ganglia. To clarify the pathway of viral spread from the ganglia to skin, 16 biopsy specimens of early skin lesions of herpes zoster obtained from the face and trunk of 13 patients were studied histologically and immunohistochemically using monoclonal antibodies to the structural proteins of VZV. VZV-infected cells were detected in the hair follicles in 10 of the 16 specimens and in the epidermis in 2 specimens. Infected cells were localized in the isthmus of every involved follicle (12/12), frequently in the stem (8/10) and infundibulum (6/10), and never in the bulb. The high frequency of follicular involvement in herpes zoster suggests that VZV spreads to the area of skin innervated by myelinated nerves, which end around the isthmus of hair follicles and sebaceous glands.

The primary target cells of the high-risk cottontail rabbit papillomavirus colocalize with hair follicle stem cells

Papillomaviruses are small DNA tumor viruses with a life cycle inseparably linked to the differentiation of the pluristratified epithelium. The infection of epithelial layers of the skin may remain latent or may result in the development of benign tumors. A certain number of distinct papillomavirus types, however, cause lesions which have a high risk of progression into carcinomas, and extensive efforts have been made to understand this process. comparatively little is known about the initial events during the establishment of a persistent infection and papilloma development. Although it is generally accepted that the growth of a papilloma requires the infection of cells in the basal layer of the epithelium, it remains unknown which cells perform this task. We have analyzed by in situ hybridization biopsy samples taken at various time points after infection of domestic rabbits with cottontail rabbit papillomavirus. The positive cells detected at a low frequency in biopsy samples taken after 11 days predominantly expressed high levels of E6 and E7 mRNA and were localized in the outer epithelial root sheath and in the bulbs of hair follicles. A clonal analysis of keratinocytes isolated from different subfragments of individual rabbit hair follicles demonstrated a clear colocalization of cottontail rabbit papillomavirus mRNA-positive cells with clonogenic cells in hair follicles. These data suggest that the cells competent to establish papillomatous growth represent a subpopulation of keratinocytes in hair follicles with properties expected of epithelial stem cells.

Subtle clues to the diagnosis of the herpesvirus by light microscopy. Herpetic syringitis

Among the numerous infections to which AIDS patients are susceptible, those caused by herpesvirus (simplex and varicella/zoster) are among the most common. Because herpetic infections may be the first manifestations of AIDS and often are associated with poor prognosis, rapid and accurate diagnosis of them is imperative. Herpesvirus infection may be diagnosed histopathologically by the presence of ballooned, acantholytic, and multinucleated keratinocytes; intranuclear eosinophilic viral inclusions; steel gray color of affected keratinocytic cytoplasm and nuclei, chromatin margination, and necrotic acantholytic keratinocytes in older lesions. These changes are often limited to the epidermis, but there may frequently be involvement of epithelia of follicles (herpetic folliculitis) and sebaceous glands as well. Similar changes, although seldom noted, may be present in eccrine ducts and glands (herpetic syringitis). Recognition of subtle histologic clues concerning the secretory and ductal components of sweat glands in an unusual case of herpes infection facilitated rapid diagnosis in an AIDS patient, allowing appropriate treatment.