Emerging differential roles of the pRb tumor suppressor in trichodysplasia spinulosa-associated polyomavirus and Merkel cell polyomavirus pathogeneses.

BACKGROUND: Merkel cell carcinoma (MCC) and trichodysplasia spinulosa (TS) are two proliferative cutaneous diseases caused by the Merkel cell polyomavirus (MCPyV) and trichodysplasia spinulosa-associated polyomavirus (TSPyV) respectively. Recently, studies have elucidated a key role of the small tumor (sT) antigen in the proliferative pathogenic mechanisms of MCPyV and likely TSPyV. While both sT antigens have demonstrated a capacity in regulating cellular pathways, it remains unknown whether MCPyV and TSPyV sT antigens contribute similarly or differentially to cell proliferation. OBJECTIVES: The present study aims to explore the proliferative potential of MCPyV and TSPyV sT antigens by investigating their regulatory effects on the retinoblastoma protein (pRb) tumor suppressor. STUDY DESIGN: Inducible cell lines expressing MCPyV sT or TSPyV sT were created using a lentiviral packaging system. Cellular proteins were extracted and subjected to SDS-PAGE followed by Western blot detection and densitometric analysis. RESULTS: Expression of TSPyV sT markedly enhanced the phosphorylation of pRb in Western blot experiments. In contrast, expression of MCPyV sT did not alter pRb phosphorylation under the same experimental conditions. Densitometric analysis revealed that TSPyV sT antigen expression nearly doubled the ratio of phosphorylated to total pRb (P<0.001, Student's T-test), while MCPyV sT antigen expression did not cause significant change in pRb phosphorylation status. CONCLUSION: Given that hyperphosphorylation of pRb is associated with dysregulation of the cell cycle, S-phase induction, and increased cell proliferation, our findings support an important role of TSPyV-mediated pRb deactivation in the development of TS. The observation that the pRb tumor suppressor is inactivated by TSPyV sT but not MCPyV sT provides further insights into the distinct pathobiological mechanisms of MCC and TS.

Viral-associated trichodysplasia secondary to antineoplastic treatment in a patient with lymphoblastic leukemia.

Viral-associated trichodysplasia spinulosa is an unusual condition with distinctive clinical and histopathological features. Initially described in patients immunosupressed as a result of solid organ transplantation, it has also been reported in patients treated with immunosuppressive drugs other than cyclosporine or being treated for hematological malignancies. Patients presented with disseminated follicular, hyperkeratotic papules, and variable degrees of alopecia. Histopathological examination revealed shaftless bulbous and dilated hair follicles with keratotic plugging of the infundibulum. The authors reported a case of viral-associated trichodysplasia in a 5-year-old boy treated for a lymphoblastic leukemia. Eruption persisted, although treated with emollients and keratolytics, but resolved spontaneously after completing the antineoplastic medication.

Dermatological manifestations of individuals infected with human T cell lymphotropic virus type I (HTLV-I).

BACKGROUND: Human T cell lymphotropic virus type I (HTLV-I) is associated with specific manifestations such as adult T cell lymphoma/leukemia (ATLL), HTLV-I-associated myelopathy/tropical spastic paraparesis (HAM/TSP), HTLV-I-associated uveitis, and infective dermatitis associated with HTLV-I (IDH). Although ATLL and IDH are considered specific manifestations of HTLV-I infection, several dermatological manifestations have been described in HTLV-I seropositive patients. OBJECTIVES: This study was conducted to determine the prevalences of skin lesions in patients infected with HTLV-I in an area of Brazil endemic for HTLV-I infection and to compare these prevalences with those in seronegative individuals in the same region. METHODS: A prevalence study was conducted between 2008 and 2010 with two groups of individuals comprising, respectively, 179 HTLV-I seropositive (positive enzyme-linked immunosorbent assay [ELISA] and positive Western blot analysis) and 193 HTLV-I seronegative individuals (ELISA-negative). The subjects were selected on a random basis and evaluated using a questionnaire to obtain epidemiological and clinical data. A physical examination was performed to verify the presence of skin lesions. RESULTS: Superficial mycoses were found in 54 (30.2%) seropositive subjects and in 26 (13.5%) of the seronegative group (P < 0.001). Xerosis was found in 39.1% of HTLV-I infected subjects and in 9.3% of seronegative controls (P < 0.001). Ichthyosis was diagnosed in nine (5.0%) HTLV-I seropositive subjects but in none of the control group (P = 0.001). A diagnosis of seborrheic dermatitis was made in 43 (24.0%) HTLV-I infected subjects and in 24 (12.4%) seronegative controls (P = 0.004). Furthermore, dermatological manifestations were more intense in the HTLV-I seropositive group. CONCLUSIONS: Several dermatological manifestations are more common and more severe in HTLV-I seropositive subjects. The presence of these manifestations in an area endemic for HTLV-I infection may provide some clues in the investigation of this infection.

Ultrastructural and molecular confirmation of the trichodysplasia spinulosa-associated polyomavirus in biopsies of patients with trichodysplasia spinulosa.

Trichodysplasia spinulosa (TS) is a rare and only recently characterized cutaneous disease occurring in immunocompromised patients. The disease is characterized by spiny follicular papules on clinical examination and by the presence of viral inclusions at ultrastructural examination. In the last year, this virus has been identified as a new member of the polyomavirus family and designated as TS-associated polyomavirus (TSPyV). We report two organ transplant patients with this disease in which we were able to identify the TSPyV at ultrastructural and molecular level from formalin-fixed paraffin-embedded biopsies of lesional skin. Similar to prior described cases, the patients presented with follicular papules which were concentrated on the central face and associated with alopecia. Histopathology of both cases showed dilated follicular infundibula plugged with cornified eosinophilic cells containing large trichohyaline granules. Transmission electron microscopy on paraffin-embedded tissue in case 1 showed 28-nm intracellular viral particles morphologically consistent with polyoma virus. For both cases the presence of TSPyV was confirmed by polymerase chain reaction with virus-specific primers followed by identification by direct sequencing. These two cases show the presence of the newly described TSPyV in TS further establishing its association with this distinctive disease.

Cutaneous manifestations associated with HTLV-1 infection.

Skin lesions are frequent in human T-cell lymphotropic virus type 1 (HTLV-1) infection and may constitute an alert for the diagnosis of this condition. The most severe skin diseases related to this virus are adult T-cell leukemia/lymphoma (ATLL), an aggressive form of leukemia/lymphoma that fails to respond to chemotherapy, and infective dermatitis associated with HTLV-1 (IDH), a severe and recurrent form of eczema occurring in childhood. ATLL affects the skin in 43-72% of cases. In this review, the clinical, histopathological and immunohistochemical aspects of ATLL and IDH will be discussed, as well as the differential diagnoses, giving particular focus to the primary cutaneous ATLL. IDH may progress to HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP) and to ATLL. Adult onset IDH and reactional and inflammatory dermatoses found in carriers and also in patients with HAM/TSP will be considered. Other dermatological diseases that occur more frequently in HTLV-1-infected individuals such as xerosis, acquired ichthyosis, seborrheic dermatitis and infectious and parasitic dermatoses will also be discussed.

Histopathological and immunohistochemical assessment of acquired ichthyosis in patients with human T-cell lymphotropic virus type I-associated myelopathy.

BACKGROUND: Patients with human T-cell lymphotropic virus type I (HTLV-I)-associated myelopathy frequently display cutaneous alterations such as acquired ichthyosis. OBJECTIVES: Elucidation of the pattern of acquired ichthyosis in HTLV-I-associated myelopathy. METHODS: Skin fragments from 10 patients with HTLV-I-associated myelopathy presenting with acquired ichthyosis were assessed by histopathological and immunohistochemical tests. We used anticytokeratin antibodies related to normal keratinization (K1/K10), and others related to cutaneous conditions such as activation, migration and hyperproliferation of keratinocytes (K6/K16), and involucrin, a precursor protein in the formation of the protein envelope in keratinocytes. For quantification of the proliferating basal and parabasal cells the anti-Ki-67 antibody was employed. RESULTS: On light microscopy, all skin specimens displayed orthokeratotic hyperkeratosis and hypogranulosis. Three of them presented focal parakeratosis. A slight to moderate perivascular infiltrate of mononuclear lymphocytes was observed in seven cases, three of which showed discrete spongiosis with epidermotropism of lymphocytes. All fragments displayed coexpression of K1, K10 and K16 in the suprabasal layers. Expression of involucrin was also observed in all cases, in the upper spinous and granular layers. Focal expression of K6 was observed in three cases, under a parakeratotic area. The mean number of Ki-67+ basal and parabasal cells was 3.5 cells per mm, similar to that in control skin. CONCLUSIONS: In acquired ichthyosis related to HTLV-I-associated myelopathy, histopathology revealed orthokeratotic hyperkeratosis and a perivascular inflammatory infiltrate of mononuclear lymphocytes, with areas of parakeratosis and foci of epidermotropism in rare cases. The expression profiles of K1, K10 and involucrin were similar to those in normal skin. The diffuse coexpression of K16 with K1 and K10 throughout the analysed epidermis, as well as the occurrence of restricted areas of parakeratosis expressing K6, indicate the presence of keratinocyte activation with induction of the alternative keratinization pathway, probably dependent on the cytokines liberated by the mononuclear cells of the dermal inflammatory infiltrate infected with HTLV-I. The absence of acanthosis and of increased cellular kinetics, as shown by the low rate of Ki-67 antigen expression, allow the inference that the pattern of acquired ichthyosis related to HTLV-I-associated myelopathy may be retentional. The observation of foci of parakeratosis expressing K6 in three specimens suggests that, at least in certain areas and in some cases, interference with epidermal differentiation and maturation occurs.

Dermatologic lesions in asymptomatic blood donors seropositive for human T cell lymphotropic virus type-1.

Dermatologic manifestations are quite common in patients with adult T cell leukemia/lymphoma and myelopathy/tropical spastic paraparesis associated with infection with human T cell lymphotropic virus type-1 (HTLV-1). In this study, we evaluated the dermatologic lesions of eligible blood donors in the state of Minas Gerais in Brazil who were seropositive but asymptomatic for infection with HTLV-1. The study population was composed of 128 HTLV-1-seropositive individuals and 108 seronegative controls. All individuals underwent a dermatologic evaluation. Biopsy specimens were obtained from abnormal and normal skin samples of seropositive individuals in an attempt to detect HTLV-1 in tissue samples by a polymerase chain reaction. Dermatologic alterations were observed more frequently in the seropositive group (adjusted odds ratio [OR] = 8.77, 95% confidence interval [CI] = 4.11-18.71). The most common skin diseases were dermatophytoses (adjusted OR = 3.32, 95% CI = 1.50-7.35), seborrheic dermatitis (OR = 3.53, 95% CI = 0.67-24.66), and acquired ichthyosis (P = 0.001). Virus was detected more frequently in abnormal skin samples. Dermatologic lesions probably related to HTLV-1 infection were diagnosed in eligible blood donors who were infected with this virus, who were previously considered to be asymptomatic carriers of HTLV-1.