Interleukin-4 induced down-regulation of skin homing receptor expression by human viral-specific CD8 T cells may contribute to atopic risk of cutaneous infection. (25/98)

Factors controlling the expression of cutaneous lymphocyte-associated antigen (CLA) by T cells are poorly understood, but data from murine and human CD4(+) T cell systems have suggested that cytokines play an important role. However, there are no data examining the influence of cytokines on the expression of CLA by human antigen-specific CD8(+) T cells. Peripheral blood mononuclear cells (PBMC) were isolated from 10 HLA-A*0201-positive healthy individuals. Using HLA-peptide tetrameric complexes refolded with immunodominant peptides from Epstein-Barr virus (EBV), cytomegalovirus (CMV) and influenza A virus, we investigated the temporal associations of CLA expression by viral-specific CD8(+) T cells following stimulation with antigen. Ex vivo influenza matrix-specific CD8(+) T cells expressed significantly (P < 0.05) greater levels of CLA than EBV BMLF1 and CMV pp65-specific CD8(+) T cells (mean 9.7% influenza matrix versus 1.4% BMLF1 versus 1.1% pp65) and these differences were sustained on culture. However, regardless of viral specificity, interleukin (IL)-12 and IL-4 induced significant (P < 0.05) dose-dependent up-regulation and down-regulation of CLA expression, respectively, with IL-4 showing a dominant negative effect. In many cases, IL-4 resulted in complete abrogation of detectable CLA expression by the viral-specific CD8(+) T cells. Overall these data demonstrate that CLA expression by human viral-specific CD8(+) T cells is highly dynamic and that IL-4 causes significant down-regulation. Disorders associated with a type 2 cytokine shift may reduce the efficiency of skin homing by viral-specific CD8(+) T cells. Furthermore, the ability to modify the local and systemic microenvironment may offer novel therapeutic strategies that influence tissue-specific T cell homing.  (+info)

Infective dermatitis and human T cell lymphotropic virus type 1-associated myelopathy/tropical spastic paraparesis in childhood and adolescence. (26/98)

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

A viral infection of the hand commonly seen after the feast of sacrifice: human orf (orf of the hand). (27/98)

Orf of the hand is an uncommon zoonotic infection caused by a dermotropic DNA virus that belongs to the Parapoxvirus genus of the family Poxviridae. It is transmitted to humans through contact with infected sheep and goats and is reported as an occupational disease. We report nine cases of human orf seen in the hands of individuals, who were not occupationally exposed, after the feast of sacrifice in Turkey. Three cases were teachers and six out of the nine were housewives. We observed musculoskeletal complications and misdiagnoses. It is important to consider human orf in the differential diagnosis of hand lesions to prevent overtreatment and complications.  (+info)

Chickenpox complications in Saudi Arabia: Is it time for routine varicella vaccination? (28/98)

INTRODUCTION: Varicella zoster (chickenpox) infection is a common and benign disease of childhood. The predominance of uncomplicated cases in children tends to overshadow the morbidity associated with severe cases and the resultant hospitalization. OBJECTIVE: The objective was to establish the complication rate of chickenpox in the Saudi National Guard population over a 2(1/2)-year period. METHODS: All reported cases of chickenpox at the King Abdulaziz Medical City, Riyadh were prospectively followed for development of complications during the period between 1 June 2001 and 30 December 2003. RESULTS: A total of 3802 cases of chickenpox were reported and followed during the acute illness phase. The majority of cases, 2984 (78%), occurred in children less than 15 years of age. Among all chickenpox cases, 78 (2%) required hospitalization, and 50 patients developed 58 (1.5%) complications. Skin and soft tissue infections were the most common complications, 20 (34%), followed by pneumonia in 16 (28%), bacteremia in six (10%), encephalitis in four (7%) and necrotizing fasciitis in four (7%). Complications were less common in children (36/2984, 1.2%) as compared to adults (14/818, 1.7%) (p = 0.26). However, pneumonia (p = 0.03) and hospitalization (p = 0.004) were more common in adults as compared to children. The overall fatality rate was 0.05%; two patients died, one aged two months the other 28 years. CONCLUSION: These data provide a baseline for morbidity and mortality from chickenpox, and further support the inclusion of varicella vaccine in the routine childhood immunization program in Saudi Arabia.  (+info)

Dermatomal vesicular eruption in an asymptomatic infant. (29/98)

We present a case of infantile herpes zoster without clinical evidence of varicella infection in the mother or apparent exposure in the child; our patient's diagnosis was confirmed by serology and by Tzanck smear. We briefly review the etiopathogenesis factors of this condition. We emphasize the benign course and spontaneous uneventful resolution.  (+info)

In vivo ablation of CD11c-positive dendritic cells increases susceptibility to herpes simplex virus type 1 infection and diminishes NK and T-cell responses. (30/98)

The precise role of each of the seven individual CD11c+ dendritic cell subsets (DCs) identified to date in the response to viral infections is not known. DCs serve as critical links between the innate and adaptive immune responses against many pathogens, including herpes simplex virus type 1 (HSV-1). The role of DCs as mediators of resistance to HSV-1 infection was investigated using CD11c-diphtheria toxin (DT) receptor-green fluorescent protein transgenic mice, in which DCs can be transiently depleted in vivo by treatment with low doses of DT. We show that ablation of DCs led to enhanced susceptibility to HSV-1 infection in the highly resistant C57BL/6 mouse strain. Specifically, we showed that the depletion of DCs led to increased viral spread into the nervous system, resulting in an increased rate of morbidity and mortality. Furthermore, we showed that ablation of DCs impaired the optimal activation of NK cells and CD4+ and CD8+ T cells in response to HSV-1. These data demonstrated that DCs were essential not only in the optimal activation of the acquired T-cell response to HSV-1 but also that DCs were crucial for innate resistance to HSV-1 infection.  (+info)

An antivector vaccine protects against a lethal vector-borne pathogen. (31/98)

Vaccines that target blood-feeding disease vectors, such as mosquitoes and ticks, have the potential to protect against the many diseases caused by vector-borne pathogens. We tested the ability of an anti-tick vaccine derived from a tick cement protein (64TRP) of Rhipicephalus appendiculatus to protect mice against tick-borne encephalitis virus (TBEV) transmitted by infected Ixodes ricinus ticks. The vaccine has a "dual action" in immunized animals: when infested with ticks, the inflammatory and immune responses first disrupt the skin feeding site, resulting in impaired blood feeding, and then specific anti-64TRP antibodies cross-react with midgut antigenic epitopes, causing rupture of the tick midgut and death of engorged ticks. Three parameters were measured: "transmission," number of uninfected nymphal ticks that became infected when cofeeding with an infected adult female tick; "support," number of mice supporting virus transmission from the infected tick to cofeeding uninfected nymphs; and "survival," number of mice that survived infection by tick bite and subsequent challenge by intraperitoneal inoculation of a lethal dose of TBEV. We show that one dose of the 64TRP vaccine protects mice against lethal challenge by infected ticks; control animals developed a fatal viral encephalitis. The protective effect of the 64TRP vaccine was comparable to that of a single dose of a commercial TBEV vaccine, while the transmission-blocking effect of 64TRP was better than that of the antiviral vaccine in reducing the number of animals supporting virus transmission. By contrast, the commercial antitick vaccine (TickGARD) that targets only the tick's midgut showed transmission-blocking activity but was not protective. The 64TRP vaccine demonstrates the potential to control vector-borne disease by interfering with pathogen transmission, apparently by mediating a local cutaneous inflammatory immune response at the tick-feeding site.  (+info)

Varicella zoster virus meningitis complicating sodium stibogluconate treatment for cutaneous leishmaniasis. (32/98)

Sodium stibogluconate (Pentostam(R); GlaxoSmithKline) is a pentavalent antimonial compound used in the treatment of leishmaniasis, which has an association with reactivation of varicella zoster virus (VZV). We report the first known case of an immunocompetent adult who developed VZV aseptic meningitis and dermatomal herpes zoster during treatment with sodium stibogluconate.  (+info)