Expression of herpes simplex virus DNA fragments located in epidermal keratinocytes and germinative cells is associated with the development of erythema multiforme lesions

Clinical and histologic features of Mycoplasma pneumoniae-related erythema multiforme: A single-center series of 33 cases compared with 100 cases induced by other causes

BACKGROUND

Mycoplasma pneumoniae infection has been documented in erythema multiforme (EM) and Stevens-Johnson syndrome-toxic epidermal necrosis (SJS-TEN). Clinical aspects of M pneumoniae-related EM have been poorly described in the literature.

OBJECTIVE

To highlight differences between M pneumoniae EM and non-M pneumoniae EM.

METHODS

This single-center, retrospective cohort study included all patients admitted to our dermatology department for EM during 2000-2015. We compared epidemiologic, clinical, and histologic data and follow-up for M pneumoniae EM and non-M pneumoniae EM cases.

RESULTS

Thirty-three patients with M pneumoniae EM were compared with 100 patients with non-M pneumoniae EM. Disease onset in winter was more frequent with M pneumoniae EM (P = .003). Acrally distributed lesions (32% vs 88%, P < .0001) and typical targets (45% vs 74%, P = .01) were less common in M pneumoniae EM than non-M pneumoniae EM. Multiple (≥2) mucousal membrane involvement was more frequent in M pneumoniae EM than non-M pneumoniae EM (97% vs 60%; P < .0001), as were mucosal and respiratory tract sequelae (P < .05). The mean hospital stay was longer with M pneumoniae EM patients: 9.5 days versus 5.1 days (P = .0002). A TEN-like pattern was observed in all 14 (100%) M pneumoniae EM skin biopsies versus 10 of 27 (48%) non-M pneumoniae EM biopsies (P < .001).

LIMITATIONS

The retrospective design.

CONCLUSION

M pneumoniae EM has a distinctive presentation compared with non-M pneumoniae EM, with more diffuse and atypical targets, more mucositis and respiratory tract sequelae. Histologic data show a TEN-like pattern in all M pneumoniae EM skin samples.

Expression of interleukin-17 in lesions of erythema multiforme may indicate a role for T helper 17 cells

Introduction

The aim of this study was to evaluate levels of interleukin (IL)-2, IL-6, IL-8, IL-10, IL-17A and interferon γ (IFN-γ) in the serum of patients with erythema multiforme (EM) and to search for the presence of IL-17-expressing cells in lesional samples of EM.

Material and methods

A total of 32 patients (22 females and 10 males) diagnosed with EM of the minor or major type were included in the study. Levels of IL-2, IL-6, IL-8, IL-10, IL-17A and IFN-γ in the serum were determined and compared with healthy controls. Biopsy specimens were stained with haematoxylin and eosin (HE) and monoclonal antibodies to CD4, CD8 and IL-17 for immunohistochemical examination.

Results

IL-2, 6, 8 and 17A were significantly higher in the patient group (p = 0.016, p = 0.001, p = 0.004, p = 0.006, respectively) and levels of IL-10 were significantly lower than in the control group (p = 0.046). The cellular infiltrate in lesions of EM was composed mainly of CD4+ T lymphocytes. The presence of IL-17-expressing cells, at proportion of 5 to 50%, was observed in the infiltrate.

Conclusions

The demonstration of IL-17-expressing cells in lesions of EM in this study has brought forth the assumption that Th17 cells may be involved in the pathogenesis of EM.

Erythema multiforme, Stevens-Johnson syndrome and toxic epidermal necrolysis: a comparative review

BACKGROUND

Human erythema multiforme (EM) and Stevens-Johnson syndrome/toxic epidermal necrolysis (SJS/TEN) are separate conditions. There is no consensus on classification criteria for the eponymous diseases in animals.

RESULTS

Animal EM is very different from 90% of human EM, which is herpes virus associated (HAEM). Animals lack acrally distributed, typical raised targets. Unlike canine parvovirus 'EM', HAEM is not an active infection. Animal EM is often attributed to drugs, but this is rarely proved. Conversely, human and animal SJS/TEN are almost identical, life-threatening disorders of epidermal necrosis and detachment, typically triggered by drugs (occasionally by infectious agents). Both EM and SJS/TEN are mediated by cytotoxic lymphocyte responses against altered keratinocytes (infectious agents or drugs). Apoptosis results from direct cytotoxicity or through soluble mediators, namely Fas ligand, granzymes, perforin and granulysin. Diagnosis in humans is clinicopathological, with emphasis on clinical lesions; histopathology confirms the pathological process as interface (cytotoxic) dermatitis. Human EM is self-limiting; only recurrent and rare persistent cases require antiviral/immunosuppressive therapies. Drug-induced EM responds to drug withdrawal. Idiopathic canine EM (>40%) is usually chronic, refractory to treatment and may represent heterogeneous conditions. Early identification and removal of the causative drug and high-quality supportive care are critical in SJS/TEN. Mortality rate is nevertheless high.

CONCLUSIONS AND CLINICAL IMPORTANCE

(1) Histopathological lesions do not reliably differentiate EM, SJS and TEN. (2) A multicentre study to develop a consensus set of clinical criteria for EM and SJS/TEN in animals is overdue. (3) No adjunctive therapies, including intravenous immunoglobulin and ciclosporin, have met evidence-based standards.

Herbal toothpowder induced erythema multiforme

Herbal toothpowders are available in market in a wide varieties, which consist of various ingredients. In rural areas of the developing countries, they are still used for cleansing teeth. Erythema multiforme (EM) is an acute mucocutaneous disorder that is believed to be a sequel of a cytotoxic immunologic attack on keratinocytes which express non-self-antigens. A 31-year-old male who used herbal toothpowder for oral-hygiene maintenance presented with ulcers in mouth, encrustation on lips and target lesions on both hands, suggesting Erythema multiforme. An oral biopsy confirmed the diagnosis. To the best of our knowledge, there is no report of an association of herbal extracts and EM in the English literature. With this report, we present a rare new triggering factor of Erythema mutiforme, thus adding it to the endless list of aetiologies.

Acute skin graft-versus-host disease with molecular features mimicking herpes simplex virus-associated erythema multiforme: report of three cases

BACKGROUND

Acute skin erythematous lesions that follow allogeneic hematopoietic stem cell transplantation (HSCT) and are histologically diagnosed as graft-versus-host disease (GVHD) are often associated with reactivation of latent herpes simplex virus (HSV).

OBJECTIVE

To further examine the relationship between reactivated HSV and GVHD development.

METHODS

We present 3 patients with acute skin GVHD after allogeneic HSCT who were studied prospectively for expression of the HSV antigen Pol, which is involved in HSV-associated erythema multiforme.

RESULTS

Pol was expressed in the GVHD lesions but not the pre-HSCT normal skin or peripheral blood mononuclear cells. Lesion severity correlated with the Pol levels but not the histopathologically defined GVHD grade. Lesion development was accompanied by increased numbers of Pol+ circulating/skin-infiltrating CD34+ stem cells and CD1a+ and other dermal dendritic cells.

CONCLUSIONS

Subclinical HSV infection of circulating CD34+ cells can contribute to some post-HSCT skin lesions histologically diagnosed as GVHD, with potential preventive and therapeutic implications.

Immune-mediated interface dermatitis in a rhesus macaque

BACKGROUND

Autoimmune dermatitis, specifically interface dermatitis, is rarely reported in nonhuman primates.

RESULTS AND CONCLUSIONS

This report describes a case of idiopathic immune-mediated dermatitis clinically manifesting as palmoplantar hyperkeratosis in a rhesus macaque, successfully controlled with the use of long-term oral corticosteroid therapy.

Erythema multiforme-oral variant: case report and review of literature

Erythema multiforme (EM) is an interesting dermatologic disease which has oral manifestations. EM is clinically characterized by a "minor" form and a "major" form. It presents a diagnostic dilemma because the oral cavity has the ability to produce varied manifestations. Infections (particularly herpes simplex and mycoplasma pneumonia) and drugs seem to predispose toward the development of EM. The range of possible etiologies for oral disease is immense. Therefore, an otolaryngologist or a dentist while treating such patients should have a differential diagnosis for all oral lesions. We report a case of erythema multiforme in which alcohol (ethanol) seems to be the precipitating factor and have also reviewed the English literature in the present context.

Acute skin eruptions that are positive for herpes simplex virus DNA polymerase in patients with stem cell transplantation: a new manifestation within the erythema multiforme reactive dermatoses

BACKGROUND

Patients with stem cell transplantation (SCT) develop erythematous eruptions (SCTE) that are often misdiagnosed and poorly treated. Latent herpes simplex virus (HSV) is likely to be reactivated by SCT-associated immunosuppression. Therefore, one of the differential diagnostic possibilities for SCTE is HSV-associated erythema multiforme (HAEM) in which HSV genetic fragments localize in stem cells that deliver them to the skin on differentiation.

OBSERVATIONS

Lesional skin from patients with SCTE, HAEM, HSV, or drug-induced erythema (DIEM) was stained with antibodies to the HSV antigen DNA polymerase (Pol) and the major capsid protein, virion protein 5 (VP5). The HSV DNA polymerase Pol was expressed in 79% of patients with SCTE and 75% of those with HAEM. The protein VP5 was not expressed in these patients, indicative of the absence of virus replication. Findings in patients with DIEM were negative for both antigens, and those with HSV lesions were positive for both antigens.

CONCLUSIONS

There is a growing problem with SCTE, related to the increasing numbers of performed SCT. The greater frequency of SCT-generated circulating stem cells in patients with hematological malignant neoplasms (who have latent HSV infection) may result in a widespread SCTE characterized by skin deposition of HSV DNA fragments, notably those expressing Pol antigen. This HAEM-like presentation should be considered in the differential diagnosis of SCTE. Prolonged high-dosage antiviral chemotherapy during and after hospitalization may be warranted.

Herpes Simplex Virus Type 1 infection: overview on relevant clinico-pathological features

Herpes Simplex Virus Type 1 (HSV-1) is a nuclear replicating enveloped virus, usually acquired through direct contact with infected lesions or body fluids (typically saliva). The prevalence of HSV-1 infection increases progressively from childhood, the seroprevalence being inversely related to socioeconomic background. Primary HSV-1 infections in children are either asymptomatic or following an incubation period of about 1 week gives rise to mucocutaneous vesicular eruptions. Herpetic gingivostomatitis typically affects the tongue, lips, gingival, buccal mucosa and the hard and soft palate. Most primary oro-facial HSV infection is caused by HSV-1, infection by HSV-2 is increasingly common. Recurrent infections, which occur at variable intervals, typically give rise to vesiculo-ulcerative lesions at mucocutaneous junctions particularly the lips (herpes labialis). Recurrent HSV-1 infection within the mouth is uncommon in otherwise healthy patients, although in immunocompromised patients, recurrent infection can be more extensive and/or aggressive. The diagnosis of common herpetic infection can usually be based upon the clinical history and presenting features. Confirmatory laboratory diagnosis is, however, required when patients are, or may be, immunocompromised.

Oral mucosal diseases: Erythema multiforme

Erythema multiforme (EM) is a rare acute mucocutaneous condition caused by a hypersensitivity reaction with the appearance of cytotoxic T lymphocytes in the epithelium that induce apoptosis in keratinocytes, which leads to satellite cell necrosis. EM can be triggered by a range of factors, but the best documented association is with preceding infection with herpes simplex virus (HSV). Most other cases are initiated by drugs. EM has been classified into a number of variants, mainly minor and major forms, as it may involve the mouth alone, or present as a skin eruption with or without oral or other lesions of the mucous membrane. EM minor typically affects only one mucosa, and may be associated with symmetrical target skin lesions on the extremities. EM major typically involves two or more mucous membranes with more variable skin involvement. A severe variant of EM major is Stevens-Johnson syndrome, which typically extensively involves the skin. Both EM major and Stevens-Johnson syndrome can involve internal organs and produce systemic symptoms. Treatment of EM is controversial, as there is no reliable evidence. Precipitants should be avoided or treated and, in severe cases, corticosteroids may be needed. Toxic epidermal necrolysis may be similar to Stevens-Johnson syndrome, but many experts regard it as a discrete disease, and therefore it is not discussed here.

Human herpes simplex virus infections: epidemiology, pathogenesis, symptomatology, diagnosis, and management

Eight of the more than 80 known herpesviruses are human pathogens. Human herpes simplex virus (HSV) is a contagious infection with a large reservoir in the general population. It has a potential for significant complications in the immunocompromised host. In addition, psychological distress caused by the negative stigma associated with genital herpes and visible facial lesions in those experiencing frequent outbreaks renders it a challenging clinical dilemma. This article reviews the epidemiology, pathogenesis, and diagnostic features of HSV infections, providing the clinician with an up-to-date understanding of the available management strategies for mucocutaneous HSV-induced disease.

The herpes simplex virus type 2 gene ICP10PK protects from apoptosis caused by nerve growth factor deprivation through inhibition of caspase-3 activation and XIAP up-regulation

The herpes simplex virus type 2 (HSV-2) protein ICP10PK has anti-apoptotic activity in virus-infected hippocampal cultures through activation of the Ras/Raf-1/MEK/ERK pathway. To exclude the possible contribution of other viral proteins to cell fate determination, we examined the survival of primary hippocampal cultures and neuronally differentiated PC12 cells transfected with ICP10PK from apoptosis caused by nerve growth factor (NGF) withdrawal. NGF deprivation caused apoptosis in cultures mock-transfected or transfected with the kinase-negative ICP10 mutant p139(TM), but not in ICP10PK-transfected cultures. In one clone (PC47), ICP10PK inhibited caspase-3 activation through up-regulation/stabilization of adenylate cyclase (AC), activation of PKA and MEK, and the convergence of the two pathways on extracellular signal-regulated kinase activation. The anti-apoptotic proteins Bag-1 and Bcl-2 were stabilized and the pro-apoptotic protein Bad was phosphorylated (inactivated). In another clone (PC70), ICP10PK inhibited apoptosis through MEK-dependent up-regulation of the anti-apoptotic protein XIAP (that inhibits the activity of processed caspase-3) and down-regulation of the apoptogenic protein Smac/DIABLO. This may be cell-type specific, but the baculovirus p35 protein did not potentiate the neuroprotective activity of ICP10PK in PC12 cells, suggesting that ICP10PK inhibits both caspase activation and activity. The data indicate that ICP10PK inhibits apoptosis independent of other viral proteins and is a promising neuronal gene therapy platform.

The Herpes simplex virus gene Pol expressed in herpes-associated erythema multiforme lesions upregulates/activates SP1 and inflammatory cytokines

BACKGROUND/AIMS

Herpes-simplex-virus-associated erythema multiforme (HAEM) is characterized by lesional skin expression of the viral protein Pol and localized inflammation. The objective of this study is to examine the mechanism whereby Pol induces localized inflammation.

METHODS

A431 cells transfected with Pol or an empty vector and lesional skin from HAEM or drug-induced erythema multiforme patients were examined for expression of the transcription factor SP1 and SP1-regulated genes by immunoblotting, immunohistochemistry and immunofluorescence.

RESULTS

SP1, TGF-beta, p21(waf1) and Hsp27 were upregulated in A431 cells transfected with Pol but not the empty vector. Expression was further increased by exposure to IFN-gamma. Pol+ HAEM lesional skin expressed SP1, Hsp27, TGF-beta and p21(waf1). Normal skin and drug-induced erythema multiforme lesional skin were negative.

CONCLUSION

The data indicate that Pol activates SP1, causing upregulation of SP1 target genes (notably TGF-beta) involved in localized inflammation. Upregulation is potentiated by IFN-gamma.

Erythema multiforme and related disorders

Erythema multiforme (EM) and related disorders comprise a group of mucocutaneous disorders characterized by variable degrees of mucosal and cutaneous blistering and ulceration that occasionally can give rise to systemic upset and possibly compromise life. The clinical classification of these disorders has often been variable, thus making definitive diagnosis sometimes difficult. Despite being often caused by, or at least associated with, infection or drug therapy, the pathogenic mechanisms of these disorders remain unclear, and as a consequence, there are no evidence-based, reliably effective therapies. The present article reviews aspects of EM and related disorders of relevance to oral medicine clinical practice and highlights the associated potential etiologic agents, pathogenic mechanisms and therapies.

Erythema multiforme due to Mycoplasma pneumoniae infection in two children

Mycoplasma pneumoniae is an important and highly relevant cause of bullous erythema multiforme, isolated mucositis, and Stevens-Johnson syndrome in children. In this article, we present two children with respiratory Mycoplasma pneumoniae infection and associated cutaneous findings within the spectrum of erythema multiforme. We review the literature associating these three entities with Mycoplasma pneumoniae infection and discuss controversies regarding the classification of erythema multiforme, as well as update reported infectious causes of the bullous form. Many understand the erythema multiforme spectrum to include bullous erythema multiforme, mucositis, and Stevens-Johnson syndrome in the order of increasing severity. We feel that this relationship should be reconsidered to help better understand the prognosis and outcomes. It is our opinion that bullous erythema multiforme is a separate, yet related condition that can occur in the context of Mycoplasma pneumoniae infection. With many similarities to mucositis and Stevens-Johnson syndrome, bullous erythema multiforme can be considered part of a spectrum of disease that includes Stevens-Johnson syndrome. Unlike mucositis and Stevens-Johnson syndrome, bullous erythema multiforme caused by Mycoplasma pneumoniae infection has low morbidity for the child. Mycoplasma pneumoniae-associated mucositis and Stevens-Johnson syndrome seem to occur along a spectrum with separate prognosis and potential pathogenesis compared with bullous erythema multiforme. Making the distinction between these conditions is valuable for predicting the child's prognosis. Patients who develop symptoms consistent with these conditions should be appropriately evaluated for Mycoplasma pneumoniae infection and closely monitored.

Number IV Erythema multiforme

Erythema multiforme (EM) is an acute mucocutaneous hypersensitivity reaction characterised by a skin eruption, with or without oral or other mucous membrane lesions. Occasionally EM may involve the mouth alone. EM has been classified into a number of different variants based on the degree of mucosal involvement and the nature and distribution of the skin lesions. EM minor typically affects no more than one mucosa, is the most common form and may be associated with symmetrical target lesions on the extremities. EM major is more severe, typically involving two or more mucous membranes with more variable skin involvement - which is used to distinguish it from Stevens-Johnson syndrome (SJS), where there is extensive skin involvement and significant morbidity and a mortality rate of 5-15%. Both EM major and SJS can involve internal organs and typically are associated with systemic symptoms. Toxic epidermal necrolysis (TEN) may be a severe manifestation of EM, but some experts regard it as a discrete disease. EM can be triggered by a number of factors, but the best documented is preceding infection with herpes simplex virus (HSV), the lesions resulting from a cell mediated immune reaction triggered by HSV-DNA. SJS and TEN are usually initiated by drugs, and the tissue damage is mediated by soluble factors including Fas and FasL.

CD34+ cells in the peripheral blood transport herpes simplex virus DNA fragments to the skin of patients with erythema multiforme (HAEM)

Herpes simplex virus (HSV)-associated erythema multiforme (HAEM) is a recurrent disease characterized by the presence and expression of HSV DNA fragments in lesional skin. Our studies examined the mechanism of viral DNA transport to the skin of HAEM patients. CD34+ cells were isolated from the blood of normal subjects and HSV and HAEM patients during acute lesions and at quiescence. They were cultured with cytokines that favor their differentiation into Langerhans cells (LC) precursors (CD1a+/CD14-) and examined for HSV replication, HSV-induced cellular alterations, viral DNA fragmentation, and clearance. CD34+ cells from all study groups were non-permissive for HSV replication but infection favored their differentiation into CD1a+/CD14- LC precursors and upregulated E-cadherin expression, thereby assisting LC targeting to the skin. Only HAEM patients had CD34+ cells that retained viral DNA fragments, notably polymerase DNA, for at least 7 d of in vitro culture. The percentages of circulating CD34+ (and CD34+/CLA+) cells were significantly higher in HAEM patients at the time of acute lesions. A similar increase was not seen for HSV patients. The data are the first report implicating CD34+ cells in HAEM pathogenesis, likely by transporting HSV DNA fragments to lesional skin.

Detection of Herpes simplex Virus Genomic DNA in Various Subsets of Erythema multiforme by Polymerase Chain Reaction

BACKGROUND

The wide variation in the detection of herpes simplex virus (HSV) DNA (36-75%) by polymerase chain reaction (PCR) in erythema multiforme (EM) may be partly attributed to differences in case selection in terms of subsets of EM studied.

OBJECTIVE

To determine the frequencies of detection of HSV DNA in specific subsets of EM.

METHODS

Nested PCR was used to detect HSV DNA in skin biopsies with histologically proven EM.

RESULTS

PCR was performed on skin biopsies from 63 patients with EM. HSV DNA was detected in 3/11 (27.2%) of single-episode HSV-associated EM (HAEM), 6/10 (60%) of recurrent HAEM, 1/4 (25%) of single-episode idiopathic EM and 6/12 (50%) of recurrent idiopathic EM. HSV DNA was not detected in atypical EM (0/11), suspected drug-induced EM (0/9) or Stevens-Johnson syndrome (0/6).

CONCLUSION

The overall PCR positive rates of HAEM (42.9%) and idiopathic EM (43.8%) were comparable suggesting that idiopathic EM is likely to be related to a subclinical HSV infection.

Detection and genotyping of human herpes simplex viruses in cutaneous lesions of erythema multiforme by nested PCR

A subset of erythema multiforme (erythema multiforme) is associated with herpes simplex virus (HSV) infection; viral cultures of erythema multiforme lesions are, however, usually negative and viral antigens difficult to identify. Polymerase chain reaction (PCR) has been used to demonstrate the association, hence, is currently the only available sensitive diagnostic means for HSV-associated erythema multiforme. A nested PCR, which could simultaneously detect and genotype HSV in erythema multiforme lesions and in clinical swab specimen was developed using the DNA polymerase gene of HSV as target gene because it is the only detectable HSV gene in a high proportion of erythema multiforme lesions. The PCR has demonstrated its robust sensitivity on swab samples by being able to detect further 45.3% HSV cases in comparison with virus isolation with 100% specificity in both detection and genotyping confirmed by virus isolation and DNA sequencing. This study represents the first investigation of typing HSV virus in HSV-associated erythema multiforme patients, and the finding that 66.7% of the patients was attributed to HSV1, 27.8% to HSV2, and 5.6% to HSV1 and 2 co-infection may reflect the distribution of HSV1 and 2 in local general population.

Neonatal erythema multiforme major

A 25-day-old neonate developed an unusual eruption with bullae and marked systemic symptoms. Investigation for bacterial, viral, autoimmune and immunobullous causes did not reveal any identifiable trigger and histological examination was highly suggestive of bullous erythema multiforme. Pulmonary infiltrates were noted late in the course of the disease. Differential diagnoses included bullous impetigo, primary herpes simplex infection, immunobullous disease, neonatal lupus and erythema multiforme. This case illustrates the difficulties in diagnosing and managing an unwell child with bullae and emphasizes the need to exclude treatable underlying causes.

[Herpes and skin lesions: what's new?]

The spectrum of clinical lesions of herpes has grown, since the research of viruses by PCR permitted to bind to their etiology discrete or atypical lesions, and even, to display periods of asymptomatic viral excretion. These variable clinical aspects depend on the balance between, on the one hand, the qualitative and quantitative virulence of HSV and, on the other hand, the quality of the immunological defenses of the patient. So, "herpetic primary infection" and "herpetic recurrences" are serological definitions; the clinical aspects of the different stages can be interchangeable. Cultures or PCR and type-specific serologies also showed the increased frequency of HSV1 in genitals, explained by the increased oro-genital sex, since the beginning of AIDS.

A growth and latency compromised herpes simplex virus type 2 mutant (ICP10DeltaPK) has prophylactic and therapeutic protective activity in guinea pigs

A growth compromised herpes simplex virus type 2 (HSV-2) mutant which is deleted in the PK domain of the large subunit of ribonucleotide reductase (ICP10DeltaPK) protects from fatal HSV-2 challenge in the mouse model (Aurelian L, Kokuba H, Smith CC. Vaccine potential of a Herpes Simplex Virus type 2 mutant deleted in the PK domain of the large subunit of ribonucleotide reductase (ICP10). Vaccine 1999;17:1951-1963). Here we report the results of our studies with ICP10DeltaPK in the guinea pig model of recurrent HSV-2 disease. ICP10DeltaPK was also compromised for growth and disease causation in this model. It was not isolated from latently infected ganglia by explant co-cultivation. The proportions of latently infected ganglia were significantly lower for ICP10DeltaPK than HSV-2 [3/25 (12%) and 7/10 (70%), respectively]. Similar results were obtained for the levels of viral DNA (8 x 10(3) and 2 x 10(5) molecules/ganglion for ICP10DeltaPK and HSV-2, respectively]. ICP10DeltaPK immunization caused a significant (P< or = 0.001) decrease in the proportion of animals with primary [1/14 (6%) and 16/16 (100%) for ICP10DeltaPK and PBS, respectively) and recurrent [1/14 (6%) and 11/14 (79%) for ICP10DeltaPK and PBS, respectively) HSV-2 skin lesions. It also protected from genital HSV-2 disease [1/10 and 10/10 for ICP10DeltaPK and PBS, respectively] and decreased the severity of the lesions in both models. Quantitative PCR (Q-PCR) with primers that distinguish between HSV-2 and ICP10DeltaPK indicated that immunization reduced the proportion of ganglia positive for HSV-2 DNA [8/25 (32%) and 7/10 (70%) for ICP10DeltaPK and PBS, respectively) and its levels [3 x 10(3) and 2 x 10(5) molecules/ganglion for ICP10DeltaPK and PBS, respectively]. The proportion of HSV-2 infected animals with recurrent disease was also significantly (P < or = 0.001) decreased by immunization with ICP10DeltaPK [1/15 (7%) and 11/14 (79%) with recurrent disease for ICP10DeltaPK and PBS, respectively], suggesting that ICP10DeltaPK has prophylactic and therapeutic activity in the guinea pig.

Interaction of HSV-1 infected peripheral blood mononuclear cells with cultured dermal microvascular endothelial cells: a potential model for the pathogenesis of HSV-1 induced erythema multiforme

The effect of herpes virus infection on human dermal microvascular endothelial cells and herpes-virus-1-infected peripheral blood mononuclear cells on human dermal microvascular endothelial cells was studied as a model of herpes-associated erythema multiforme. After infection of human dermal microvascular endothelial cells with native herpes virus and overnight culture, 60%--90% of human dermal microvascular endothelial cells showed cytopathic effects. HLA class I molecules and CD31 (PECAM-1) surface expression in herpes-virus-infected endothelial cells were substantially downregulated, whereas CD54 (ICAM-1) remained unchanged. Cocultivation with herpes-virus-1-infected peripheral blood mononuclear cells left characteristic plaques on the human dermal microvascular endothelial cell monolayer; however, very few human dermal microvascular endothelial cells (1%--3%) were infected. Adhesion molecule expression of human dermal microvascular endothelial cells cocultivated with herpes-virus-infected peripheral blood mononuclear cells demonstrated a 5-fold increase in CD54 expression, a 2-fold increase in HLA class I expression, but no change of CD31 by fluorescence-activated cell sorter analysis. Incubation of human dermal microvascular endothelial cells with ultraviolet-C irradiated herpes-virus-infected peripheral blood mononuclear cells had no effect on morphology or adhesion molecule expression levels. Changes of adhesion molecule expression by direct infection or cocultivation with peripheral blood mononuclear cells (with native and ultraviolet-C inactivated herpes virus infection) were also documented at the mRNA level. Adhesion assays demonstrated an increased binding of herpes-virus-infected peripheral blood mononuclear cells versus noninfected peripheral blood mononuclear cells to noninfected human dermal microvascular endothelial cells. Our results suggest that incubation of herpes-virus-infected peripheral blood mononuclear cells with human dermal microvascular endothelial cells induces significant upregulation of CD54 and major histocompatibility complex class I molecules in the surrounding noninfected human dermal microvascular endothelial cells, which is associated with an increased binding of peripheral blood mononuclear cells. Our in vitro findings may serve as a model for herpes-associated erythema multiforme possibly explaining the dermal inflammatory reaction seen in that condition.

Parvovirus infection of keratinocytes as a cause of canine erythema multiforme

Erythema multiforme major was diagnosed in a dog with necrotizing parvoviral enteritis. Skin lesions consisted of ulceration of the footpads, pressure points, mouth, and vaginal mucosa; vesicles in the oral cavity; and erythematous patches on the abdomen and perivulvar skin. Microscopic examination of mucosal and haired skin specimens revealed lymphocyte-associated keratinocyte apoptosis at various levels of the epidermis. Basophilic cytoplasmic inclusions were seen in basal and suprabasal keratinocytes. Immunohistochemical staining, performed with canine parvovirus-2-specific monoclonal antibodies, confirmed the parvovirus nature of the inclusions in the nucleus and cytoplasm of oral and skin epithelial cells. This is the first case of canine erythema multiforme reported to be caused by a viral infection of keratinocytes. This case study indicates that the search for epitheliotropic viruses should be attempted in cases of erythema multiforme in which a drug cause cannot be identified.

Understanding the pathogenesis of HSV-associated erythema multiforme

Erythema multiforme (EM) is a polymorphic, often recurring eruption caused by exposure to medication or various infections, notably herpes simplex virus (HSV). Understanding the pathogenesis of HSV-associated EM (HAEM) is essential for patient management. We suggest that HAEM results from the combination of viropathic effects mediated by HSV proteins, notably DNA polymerase (Pol), and an immunological reaction to viral antigens. Presumably, viral DNA and proteins ingested by macrophages at HSV lesion sites undergo fragmentation and processing for presentation to T cells with HSV memory. HSV DNA is deposited on the skin, where it is expressed. Activated T cells are recruited to the skin site of Pol expression, directly or indirectly resulting in the generation of an inflammatory cascade. Factors potentially involved in the incidence of recurrences, lesion severity and anatomical localization include the identity of the deposited HSV genes, cutaneous capillary size, degree of vasoconstriction and ambient temperature. Evidence in support of this interpretation is reviewed.

Taking aim at erythema multiforme. How to spot target lesions and less typical presentations

Erythema multiforme is a distinct cutaneous condition characterized by target lesions. Most cases are associated with HSV infection, which may be subclinical. When the classic target lesions are absent, skin biopsy may be necessary to confirm the diagnosis. Treatment is directed at suppressing outbreaks of HSV infection and controlling symptoms during acute episodes.

Herpes simplex virus associated erythema multiforme (HAEM) is mechanistically distinct from drug-induced erythema multiforme: interferon-gamma is expressed in HAEM lesions and tumor necrosis factor-alpha in drug-induced erythema multiforme lesions

Erythema multiforme follows administration of several drugs or infection with various agents, including herpes simplex virus, a syndrome designated herpes simplex virus associated erythema multiforme. Lesional skin from 21 of 26 (81%) herpes simplex virus associated erythema multiforme patients was positive for herpes simplex virus gene expression as evidenced by reverse transcriptase-polymerase chain reaction with primers for DNA polymerase and/or immunohistochemistry with DNA polymerase antibody. Reverse transcriptase-polymerase chain reaction and immunohistochemistry studies indicated that herpes simplex virus associated erythema multiforme lesional skin from 16 of 21 (76%) DNA polymerase positive herpes simplex virus associated erythema multiforme patients was also positive for interferon-gamma, a product of T cells involved in delayed-type hypersensitivity (p < 0. 0001 by Pearson correlation coefficient). Interferon-gamma signals were in infiltrating mononuclear cells and in intercellular spaces within inflammatory sites in the epidermis and at the epidermis/dermis junction. Herpes simplex virus lesional skin was also positive for DNA polymerase [five of five (100%)] and interferon-gamma [four of five (80%)], but lesional skin from drug-induced erythema multiforme patients was negative. Lesional herpes simplex virus associated erythema multiforme keratinocytes also stained with antibody to transforming growth factor-beta [14 of 23 (61%)] and cyclin-dependent kinase inhibitor waf [12 of 18 (67%)]. Staining was also seen in keratinocytes from herpes simplex virus lesions [five of five (100%)], but not in normal skin. By contrast, staining with antibody to tumor necrosis factor-alpha, another pro-inflammatory cytokine, was seen in seven of 11 (64%) drug-induced erythema multiforme patients, but not in herpes simplex virus or herpes simplex virus associated erythema multiforme patients, and lesional keratinocytes from drug-induced erythema multiforme patients were negative for transforming growth factor-beta and cyclin-dependent kinase inhibitor waf. We interpret the data to indicate that herpes simplex virus associated erythema multiforme pathology includes a delayed-type hypersensitivity component and is mechanistically distinct from drug-induced erythema multiforme.

Longitudinal study of a patient with herpes-simplex-virus-associated erythema multiforme: viral gene expression and T cell repertoire usage

BACKGROUND

Erythema multiforme is a polymorphous self-limited, often recurrent eruption that can follow herpes simplex virus (HSV) infection, hereby designated HAEM. Studies of relatively large groups of patients during one recurrent episode indicated that HAEM pathogenesis is associated with HSV gene expression, Vbeta2 T cell infiltration of lesional skin and altered T cell receptor (TCR) repertoire usage by HSV-stimulated peripheral blood mononuclear cells (PBMC). However, HAEM recurrences are not always preceded by overt HSV eruptions and virus cannot be isolated from HAEM lesional skin. Therefore, it is unknown whether all HAEM recurrences experienced by a given patient are HSV related.

OBJECTIVE

The studies described in this report were designed to examine whether all HAEM recurrences experienced by a given patient are HSV related.

METHODS

We describe one patient who was studied longitudinally during 6 HAEM recurrences and in the intervening lesion-free periods. Lesional skin from all HAEM episodes was studied for HSV gene expression and infiltration by Vbeta2 and Vbeta3 T cells. PBMC obtained at these times were assayed for TCR repertoire usage upon HSV stimulation.

RESULTS

Lesional skin from all HAEM episodes was positive for HSV gene expression (RNA and protein) as well as Vbeta2 T cell infiltration. HSV-stimulated PBMC obtained at these times had an altered TCR repertoire characterized by a predominance of Vbeta2 cells. The duration of viral gene expression, Vbeta2 cell infiltration and altered TCR repertoire usage correlated with the duration of clinical symptoms.

CONCLUSION

The data suggest that HSV and a virus-specific immunopathology component are involved in the causation of all HAEM episodes experienced by the patient.

Erythema multiforme lesions are associated with expression of a herpes simplex virus (HSV) gene and qualitative alterations in the HSV-specific T-cell response

A common form of erythema multiforme, herpes-associated erythema multiforme (HAEM), occurs following infection with herpes simplex virus (HSV). Here we report that HSV gene expression and the qualitative nature of the virus-specific T-cell responses are related to HAEM lesion development. Skin from HAEM lesions and 1-3 months healed HAEM lesional skin were positive for the viral DNA polymerase gene (Pol) by polymerase chain reaction. However, gene expression as determined by immunohistochemistry with Pol-specific antibody was seen only in HAEM lesions, suggesting that lesion development is associated with Pol gene expression. Similar HSV-specific T-cell lymphoproliferative responses were seen in peripheral blood mononuclear cells (PBMCs) from patients with acute or healed HAEM lesions or HSV lesions and from HSV-seropositive patients with unrelated inflammatory diseases. However, the T-cell receptor variable (V beta) chain repertoire of HSV-stimulated PBMCs obtained from HAEM lesions was altered; the prevalence of some families of variable chain (namely V beta 16 and V beta 19) was reduced, whereas the prevalence of others was increased (namely V beta 2 and V beta 7). V beta 2 cells were found in HAEM lesional skin positive for Pol antigen, suggesting that these cells home to viral antigen-positive skin.