Epidermal Langerhans cells, HIV-1 infection and psoriasis

Psoriasiform graft-versus-host disease distributed along Blaschko's lines

This case presents an unusual manifestation of cutaneous chronic graft-vs-host disease (cGVHD) mimicking psoriasis along Blaschko's lines. Such a presentation may pose a particular challenge to providers as it is quite rarely reported, and, therefore, it is possibly misdiagnosed. cGVHD may mimic psoriasis and should be considered in any patient previously transplanted even with a previous history of psoriasis. A Blaschkoid pattern of cGVHD is unusual and may be the manifestation of an immune reaction unveiling a previously masked mosaicism.

Chronic Graft-Versus-Host Disease Mimicking Psoriasis in a Patient with Hemophagocytic Lymphohistiocytosis

Graft-versus-host disease (GVHD) is a common complication of bone marrow transplantation (BMT) that can be classified as acute or chronic. Chronic GVHD, which usually occurs more than 3 months after BMT, includes typical lichenoid or sclerodermatous lesions. Psoriasiform eruption is a rare clinical manifestation of chronic GVHD, and there have been no reports of psoriasiform chronic GVHD associated with hemophagocytic lymphohistiocytosis. A 33-year-old woman who was diagnosed with hemophagocytic lymphohistiocytosis 10 years ago visited our outpatient clinic with psoriasiform eruption over her entire body. She underwent allogeneic BMT 7 months previously from her sibling. Skin biopsy was performed on the lesion, and the histological features suggested GVHD. The psoriasiform lesions improved with narrow-band ultraviolet B phototherapy, with secondary vitiligo remaining on the corresponding locations.

Pruritic papular eruption associated with HIV-etiopathogenesis evaluated by clinical, immunohistochemical, and ultrastructural analysis

Pruritic Papular Eruption with Human Immunodeficiency Virus infection (PPE-HIV) is characterized by symmetrically distributed papules with pruritus in the skin of patients suffering advanced HIV infection. Although known since 1985, the etiology of this symptomatic dermatitis is unclear. We set out to characterize the phenotype of the infiltrating cells and the cytokine profile in the lesions, as an attempt to contribute to determining its etiopathogenesis. Clinical data and histological, immunohistochemical, and ultrastructural features of skin biopsies from 20 HIV patients with PPE were studied. The histopathological aspects, cell immunophenotypes, and cytokine expressions in the lesions where quantified and compared to perilesional skin, and to those in the clinically normal skin of HIV patients without PPE-HIV (n=11) and those in normal skin samples from HIV negative individuals (n=10). PPE-HIV occurred mainly in HIV patients with mean CD4+ counts of 124.6 +/- 104 lymphocytes/mm3. Furthermore, their eosinophil counts were significantly increased. The skin lesions were characterized by a predominantly perivascular dermal lymphohistiocytic inflammatory infiltrate. Langerhans cells were normally distributed in the epidermis and seen among the cellular components of dermal infiltrates. The density of CD8+ lymphocytes was elevated and the density of CD4+ cells was reduced in dermal infiltrates. Interleukin 5 was the predominant cytokine in the lesions. Electron microscopic analysis didn't disclose HIV or other infectious agents in the lesions. These results refute the hypothesis of an infectious etiology of PPE-HIV. CD8+ lymphocytes and Langerhans cells seem to have roles in the pathogenesis of PPE-HIV. The increased frequency of IL5 was associated with abundant eosinophils in the lesions, suggesting a type Th2 response in this dermatitis.

Alterações dermatológicas em crianças com Aids e sua relação com categorias clínico-imunológicas e carga viral

FUNDAMENTOS: Desde o início da epidemia da Aids as dermatoses têm sido freqüentemente descritas em pacientes com essa doença, com relatos de casos atípicos e estudos de séries de pacientes adultos; no entanto, há poucas publicações sobre alterações cutâneas em pacientes pediátricos com Aids. OBJETIVOS: Estudo prospectivo para avaliar a presença de dermatoses em 40 pacientes pediátricos com Aids. MÉTODOS: Quarenta pacientes, com idade inferior a 13 anos e portadores de Aids, foram estudados por um período de seis meses para avaliação de: número de alterações dermatológicas; suas características clínicas; distribuição conforme as categorias clínico-imunológicas e o valor da carga viral. RESULTADOS: A prevalência de dermatoses foi de 82,4%, na primeira consulta, e, no acompanhamento longitudinal, 92,5% dos pacientes tiveram alterações dermatológicas, com proporção de cinco diagnósticos por doente. As crianças com classificação clínico-imunológica grave e carga viral acima de 100.000 cópias/ml apresentaram maior número de alterações dermatológicas quando comparadas àquelas das categorias clínico-imunológicas leves. A proporção de diagnósticos por paciente na categoria clínica C foi de 6,8 e na A de 3,6; na categoria imunológica grave, de sete, e na leve de 3,7; e na carga viral > 100.000 de 7,3, e na < 100.000 de 4,2 (todos com significância estatística). CONCLUSÃO: As dermatoses foram freqüentes nas crianças com Aids e ocorreram em maior número nos pacientes pertencentes às categorias graves. A elevada freqüência de alterações da pele nos pacientes pediátricos com a doença indica ser imprescindível sua avaliação dermatológica minuciosa e freqüente.

A strikingly constant ratio exists between Langerhans cells and other epidermal cells in human skin. A stereologic study using the optical disector method and the confocal laser scanning microscope

Langerhans cells play an important part in the immune surveillance of the human epidermis. Therefore, a certain distribution and numerical relationship to other epidermal cells can be expected. To quantify epidermal Langerhans cells population extensive studies have been performed using two-dimensional quantification methods on vertical sections or epidermal sheet preparations. Whereas methods using vertical sections were complicated considerably by the sampling procedure, the dendritic shape, and the suprabasal, nonrandom distribution of Langerhans cells, epidermal sheet preparations have their limitations regarding the numerical relationship of Langerhans cells to total epidermal cells and the epidermal morphology as such. In order to improve the validity of data the three-dimensional dissector method combined with confocal laser scanning microscopy has been applied to quantify the number of Langerhans cells and other epidermal cell nuclei per volume unit in cryosections of 24 punch biopsies of normal breast skin of eight women. Furthermore, the ratio of Langerhans cells to other epidermal cells, their number per biopsy, and per skin surface area were calculated. To minimize the bias by shrinkage the reference volume was estimated using Cavalieri's principle. A constant ratio of one Langerhans cells to 53 other epidermal cells was identified in breast skin (interindividual correlation coefficient: 0.952, p < 0.0001). Thus, Langerhans cells represent 1.86% of all epidermal cells; however, a wide interindividual range was found for the number of Langerhans cells per mm2 (912-1806; mean +/- SD 1394 +/- 321) and other epidermal cells per mm2 (47,315-104,588; mean +/- SD 73,952 +/- 19,426). This explains the conflicting results achieved by conventional morphometric assessments relating cell numbers to skin surface area, ignoring the varying thickness of the epidermis. The surprisingly constant relationship of Langerhans cells to other epidermal cells stresses the hypothesis of an epidermal Langerhans cells unit where one Langerhans cells seems to be responsible for the immune surveillance of 53 epidermal cells.

HIV-infected Langerhans cells constitute a significant proportion of the epidermal Langerhans cell population throughout the course of HIV disease

Human immunodeficiency virus (HIV) is known to infect Langerhans cells, but controversy still exists about the occurrence of HIV-infected Langerhans cells in the skin of HIV-infected individuals and about the density of epidermal Langerhans cells during the course of HIV disease. In this study, epidermal Langerhans cell population densities were analyzed quantitatively in serial biopsies from two burn patients acquired over an 11-y period following infection with HIV from transfusions received during their acute treatment. At each biopsy time point, the density of epidermal Langerhans cells and the proportion that were infected with HIV were analyzed by immunostaining. In both patients, skin grafts were slow to repopulate with Langerhans cells and did not attain normal Langerhans cell densities until about 2 y after grafting. Thereafter, Langerhans cell densities remained within normal limits with the exception of six biopsies at random times that showed a supernormal number of epidermal Langerhans cells. HIV-infected Langerhans cells were first detected at about 2 y post-infection and comprised about one-third of the Langerhans cell population. At subsequent times, HIV p24-stained Langerhans cells were identified in most biopsies and typically constituted about one third to one half of the total Langerhans cell population. The findings show that HIV-bearing Langerhans cells constitute a significant proportion of the epidermal Langerhans cell population over long periods of asymptomatic disease but are unevenly distributed throughout the skin. Normal population densities of epidermal Langerhans cells are maintained for years, although transient increases may occur randomly.

Reiter's syndrome-like pattern in AIDS-associated psoriasiform dermatitis

BACKGROUND

The prevalence of psoriasiform dermatitis in HIV-infected patients is similar to that in the general population, but its clinical severity and the immunosuppression in these patients pose special problems of therapeutic management. Furthermore, a distinctive clinical pattern has been reported in some cases. In order to assess these features in our clinical setting, we have done a retrospective study on the clinical records of all human immunodeficiency virus (HIV)-positive patients with psoriasiform dermatitis requiring systemic treatment.

METHODS

The clinical records were reviewed of seven HIV-positive patients who were referred between 1988 and 1994 to a University Hospital Dermatology Department from an HIV-clinic because of psoriasiform dermatitis, resistant to topical treatment.

RESULTS

The clinical appearance was rather uniform, with the following common features: facial seborrhea, flexural and acral involvement, with pustulosis of the palms and soles, and frequent arthritis. Lesions appeared in nonterminal stages of acquired immunodeficiency syndrome (AIDS). Three patients developed cutaneous lesions after the diagnosis of HIV infection was made and showed the most severe clinical involvement and arthritis. Etretinate, followed by RePUVA, proved to be the most effective systemic therapy prescribed, with only rare adverse effects. Methotrexate was shown to be effective, but it's use was accompanied by hematologic toxicity. Cyclosporine A treatment was moderately effective and was not associated with progression of AIDS.

CONCLUSIONS

A characteristic Reiter-like clinical picture was observed in AIDS-related psoriasiform dermatitis. Etretinate and RePUVA were effective and safe in controlling the lesions. Physiopathologic mechanisms involved in the development of AIDS-related psoriasis might provide an explanation for the outstanding similarity of the clinical pattern in those patients.

The skin as target, vector, and effector organ in human immunodeficiency virus disease

Langerhans cells are CD4+ antigen-presenting cells in the dendritic cell family that can initiate primary and secondary immune responses after emigration from skin and mucosa. Because of these properties, Langerhans cells have been proposed as potential targets for human immunodeficiency virus (HIV) infection and as potential vectors for the transmission of primary HIV infection to T cells after mucosal exposure. In support of this theory, previous investigative studies have demonstrated that Langerhans cells are targets for HIV infection both in vivo and in vitro and that HIV-pulsed Langerhans cells, as well as blood dendritic cells, induce a productive infection in co-cultured T cells in vitro. In addition, Langerhans cell dysfunction has been proposed as contributing to the pathogenesis of some of the cutaneous manifestations observed in HIV+ individuals. In a recent study, we detected Langerhans cell dysfunction in patients with acquired immune deficiency syndrome, but not in earlier stages of HIV disease. Here we review previous and current investigative studies on HIV and the skin, with an emphasis on Langerhans cells, and discuss possible future investigations in this field.