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Biomedical subjects

T J Stoof

Publications and source records attributed to T J Stoof.

At least 19 recordsLinked to original sources
PubMed2006

Induction of eruptive benign melanocytic naevi by immune suppressive agents, including biologicals.

BACKGROUND: Eruptive naevi have been described to potentially arise in immune compromised patients. OBJECTIVES: We describe three patients with eruptive benign melanocytic naevi during a phase of immunosuppressive therapy. METHODS/DIAGNOSIS: Two patients with Crohn disease were treated with either azathioprine monotherapy or a combination of azathioprine and infliximab, when eruptive naevi arose particularly at the palms and soles. Our third patient with plaque psoriasis developed eruptive naevi during two episodes of treatment: during a course with the biological agent alefacept and during etanercept therapy. CONCLUSIONS: We conclude that treatment with the recently available biological agents might be associated with the formation of eruptive naevi. Although positive evidence for the occurrence of malignant pigmented lesions is lacking, alertness to the development of eruptive melanocytic naevi during treatment with biological agents is indicated.

Adult↗
PubMed2005

Induction of cytokine (interleukin-1alpha and tumor necrosis factor-alpha) and chemokine (CCL20, CCL27, and CXCL8) alarm signals after allergen and irritant exposure.

The immune system is called into action by alarm signals generated from injured tissues. We examined the nature of these alarm signals after exposure of skin residential cells to contact allergens (nickel sulfate and potassium dichromate) and a contact irritant [sodium dodecyl sulfate (SDS)]. Nickel sulfate, potassium dichromate, and SDS were applied topically to the stratum corneum of human skin equivalents. A similar concentration-dependent increase in chemokine (CCL20, CCL27, and CXCL8) secretion was observed for all three chemicals. Exposure to nickel sulfate and SDS was investigated in more detail: similar to chemokine secretion, no difference was observed in the time- and concentration-dependent increase in pro-inflammatory cytokine [interleukin-1alpha (IL-1alpha) and tumor necrosis factor-alpha (TNF-alpha)] secretion. Maximal increase in IL-1alpha secretion occurred within 2 h after exposure to both nickel sulfate and SDS and prior to increased chemokine secretion. TNF-alpha secretion was detectable 8 h after chemical exposure. After allergen or irritant exposure, increased CCL20 and CXCL8, but not CCL27, secretion was inhibited by neutralizing human antibodies to either IL-1alpha or TNF-alpha. Our data show that alarm signals consist of primary and secondary signals. IL-1alpha and TNF-alpha are released as primary alarm signals, which trigger the release of secondary chemokine (CCL20 and CXCL8) alarm signals. However, some chemokines, for example, CCL27 can be secreted in an IL-1alpha and TNF-alpha independent manner. Our data suggest that skin residential cells respond to both allergen and irritant exposure by releasing mediators that initiate infiltration of immune responsive cells into the skin.

Allergens↗
PubMed2004

Nickel-responding T cells are CD4+ CLA+ CD45RO+ and express chemokine receptors CXCR3, CCR4 and CCR10.

BACKGROUND: Whereas T lymphocytes are widely accepted as effector cells determining the pathogenesis of allergic contact dermatitis, contradictory results have been found regarding the roles of different T-cell subsets. The use of various experimental models, involving long-term cultured T-cell lines or clones, may explain these contradictory results. OBJECTIVE: To investigate the involvement of distinct T-cell subsets in patients with nickel contact allergy. METHODS: Different T-cell subsets were directly isolated from peripheral blood mononuclear cells (PBMCs) of nickel-allergic patients, and their proliferative capacity, type-1 or type-2 cytokine secretion [measured by interferon (IFN)-gamma or interleukin (IL)-5 release] and phenotypical marker expression were analysed after stimulation with nickel. RESULTS: Only CD4+ CLA+ CD45RO+ and not CD8+ T cells proliferate and produce both type-1 (IFN-gamma) and type-2 (IL-5) cytokines in response to nickel. Moreover, cells expressing the marker CLA in combination with CD4, CD45RO or CD69 are increased after nickel-specific stimulation. Interestingly, in addition, CD45RA+ CLA+ cells showed an increased frequency after allergen-specific stimulation. Analysis of nickel-reactive T cells for expression of distinct chemokine receptors showed that both proliferative capacity and cytokine production are restricted to subsets expressing CXCR3, CCR4 but not CCR6. Fluorescence-activated cell sorting analysis of chemokine receptors expressed on nickel-stimulated T cells confirmed these results; a subset of T cells expressing CLA and CXCR3, CCR4 and, most importantly, CCR10 increased in response to allergen, while these CLA+ nickel-reactive T cells were all negative for CCR6. CONCLUSIONS: These findings demonstrate that freshly isolated nickel-reactive T cells can be characterized as CD4+ CLA+ memory T cells which express the chemokine receptors CXCR3, CCR4 and CCR10, but not CCR6.

Antigens, CD↗
PubMed2004

Identification of anti-inflammatory drugs according to their capacity to suppress type-1 and type-2 T cell profiles.

BACKGROUND: Down-regulation or modulation of T cell activity by immunosuppressive drugs is an effective treatment in diseases where exaggerated T cell responses play a role. A primary effect of the anti-inflammatory drugs (AIDs) is inhibition of the synthesis of growth factors, such as IL-2, thereby down-regulating T cell proliferation. However, it is still largely unknown to what extent these AIDs are able to down-regulate specifically type-1 or type-2 T cell cytokine production, and whether they can down-modulate chemokine receptor expression, thereby preventing migration of T cells to the site of inflammation. OBJECTIVE: We investigated the suppressive effect of dermatologically used AID (cyclosporin A (CsA), lactoferrin (LF), 1 alpha, 25-dihydroxyvitamin D(3) (VD(3)), hydrocortisone (HC), di-methyl-fumarate (DMF), diclofenac (DF)) on both type-1 and type-2 T cells. Since allergic contact dermatitis is a skin disorder in which an exaggerated T cell response of both types of T cell subsets can be observed, we used this disorder as a model to study the capacity of AID to suppress type-1 or type-2 T cell responses. METHODS: Peripheral blood mononuclear cells of nickel allergic patients were cultured in the presence of allergen and increasing concentrations of AID. Proliferation was determined by measuring (3)H thymidine incorporation; chemokine receptor (CCR10, CCR4, CXCR3) expression was studied by flow cytometric analysis and IFN-gamma or IL-5 cytokine production was measured by ELISA. RESULTS: Three major patterns can be distinguished regarding the effect of AID on T cell responses. The first group, including CsA and LF, inhibited non-selectively T cell proliferation, chemokine receptor expression and cytokine production, with CsA as the most potent drug tested. A second group of AID, which included VD(3), HC and DMF, suppressed mainly type-1 T cell responses, as revealed by strong interference with IFN-gamma production and CXCR3 expression, and limited effects on either or both IL-5 and CCR4 expression. The third pattern was displayed by DF, which down-regulated IL-5 production and CCR4 expression, whereas IFN-gamma and CXCR3 were unaltered. CONCLUSIONS: Using a contact allergy model, we have demonstrated that various AIDs show distinct pharmacological profiles in that either type-1 or type-2 or both T cell responses are suppressed. These results should contribute to a more rational selection of AID in treating inflammatory skin diseases mediated by either or both of these T cell subsets.

Anti-Inflammatory Agents↗
PubMed2003

Ano-genital granulomatosis: the counterpart of oro-facial granulomatosis.

Ano-genital granulomatosis encompasses the previously recognized clinical entities of vulvitis granulomatosa, posthitis granulomatosa, and ano-perineitis granulomatosa. We report three patients with ano-genital granulomatosis. The pathological features of the disease are lymphoedema and the presence of non-caseating giant cell granulomas. These granulomas are histologically indistinguishable from those found in both Crohn's disease and sarcoidosis, therefore, patients with ano-genital granulomatosis with accompanying gastro-intestinal or pulmonary symptoms should be investigated for the presence of Crohn's disease or sarcoidosis, respectively. The value of ano-genital granulomatosis as a unifying clinicopathologic concept is to provide a label for the affliction as well as to stimulate a careful search for possibly underlying systemic disorders, thus also permitting a more specific approach to therapy.

Adult↗
PubMed2002

[Netherton's syndrome in two sisters].

Two girls, sisters aged 4.5 years and 6 months, had experienced serious erythrodermia since birth, with scarcely any hair growth and they exhibited poor growth despite a hypoallergenic diet. On the basis of the dermatological condition ichthyosis linearis circumflexa and microscopic examination of a hair shaft in which trichorrhexis invaginata (bamboo hair) was observed, the diagnosis of Netherton's syndrome was established. In this autosomal recessive hereditary condition there is a defective production or maintenance of the stratum corneum. Apart from the skin and the hair abnormalities there is often an atopic constitution as well. The treatment consists of skin ointments and a high-energy diet due to the loss of protein via the skin.

Child, Preschool↗
PubMed2002

Follicular and epidermal alterations in patients treated with ZD1839 (Iressa), an inhibitor of the epidermal growth factor receptor.

We report the cutaneous side-effects of ZD1839 (Iressa), a new anticancer agent that acts by inhibiting epidermal growth factor (EGF) receptor signal transduction. Three patients receiving ZD1839 developed an eruption consisting of follicular papules and pustules in an acneiform distribution as well as diffuse fine scaling of the skin. Additionally, hair growth abnormalities were noted in two patients. Histologically, a superficial purulent folliculitis and disordered differentiation with focal parakeratosis were seen. The follicular eruption appeared to respond favourably to treatment with tretinoin cream and minocycline. The cutaneous adverse effects of ZD1839 are similar to those of other EGF receptor-targeted agents and result from direct interference with the functions of EGF receptor signalling in the skin.

Acneiform Eruptions↗
PubMed2001

[Acute hemorrhagic edema of childhood and its differentiation from Schoenlein-Henoch purpura].

In two young patients with an elevated temperature, a girl aged 6 months and a boy aged 10 months, purpura and oedema were noticed on the face, ears, arms and legs. On one occasion the boy lost blood anally. A histopathological examination revealed leucocytoclastic vasculitis with fibrin deposits. The diagnosis was 'acute haemorrhagic oedema of infancy' (AHOI), a relatively unknown variant of palpable purpura due to leucocytoclastic vasculitis affecting infants and young children (up to two years of age). AHOI is characterised clinically by marked oedema and fever as well as large palpable purpuric and ecchymotic skin lesions in a target-like pattern mainly on the face, ears and extremities. The skin lesions heal spontaneously within one to three weeks and internal organs are rarely affected. This is in contrast to Henoch-Schönlein purpura, which was observed in a 5-year old boy suffering from similar skin lesions on the legs as well as painful joints, in whom IgA deposits were found in the vasculitis. Henoch-Schönlein purpura is clinically characterised by palpable purpura on the extensor surfaces of the legs and on the buttocks, whereas in AHOI larger purpura and ecchymoses are found on the face, ankles and wrists, with far more extensive oedema. There are also histological differences: in AHOI there is more extensive vasculitis with fibrin deposits and IgA deposits are seen in a minority of cases. Awareness of this relatively unknown form of leucocytoclastic vasculitis will assist in making an early diagnosis possible, thereby avoiding unnecessary treatment and concern.

Acute Disease↗
PubMed2001

Differential expression of CXCR3 targeting chemokines CXCL10, CXCL9, and CXCL11 in different types of skin inflammation.

Recruitment of activated T-cells to the skin is a common feature in a wide variety of inflammatory skin diseases. As CXCR3 activating chemokines CXCL10 (IP-10), CXCL9 (Mig), and CXCL11 (IP-9/I-TAC) specifically attract activated T-cells, this study addressed the question of whether differences in the expression of these chemokines correlate with the site and cellular composition of the skin infiltrates in different types of inflammatory skin disease. Skin biopsies from lichen planus, chronic discoid lupus erythematosus, allergic patch test reactions, psoriasis, and Jessner's lymphocytic infiltration of the skin were investigated for chemokine expression using RNA in situ hybridization, and for the expression of CXCR3 using immunohistochemistry. The results showed differential expression of CXCL10, CXCL9, and CXCL11, which correlated with differences in the localization and cellular composition of the infiltrates. Whereas CXCL10 and CXCL11 were mainly expressed by basal keratinoctyes, CXCL9 mRNA expression was located predominantly in the dermal infiltrates. Correlation with immunohistochemical data suggested that macrophages and activated keratinocytes were the main producers of these chemokines. CXCR3 was expressed by a majority of both CD4+ and CD8+ infiltrating T-cells, suggesting a functional interaction between locally produced chemokines and CXCR3-expressing T-cells. In conclusion, these findings indicate that these CXCR3 activating chemokines play a significant role in the recruitment and maintenance of T-cell infiltrates in the inflammatory skin diseases studied.

Chemokine CXCL10↗
PubMed2001

The antipsoriatic drug dimethylfumarate strongly suppresses chemokine production in human keratinocytes and peripheral blood mononuclear cells.

BACKGROUND: The effectiveness of systemic treatment of psoriasis with fumaric acid esters has been proven, but their mode of action at the cellular and molecular level has not yet been fully elucidated. OBJECTIVES: To study the effect of dimethylfumarate (DMF) on the production of the chemokines CXCL1, CXCL8, CXCL9, CXCL10 and CXCL11, formerly known as GROalpha, interleukin-8, Mig, IP-10 and IP-9/I-TAC, respectively, in human keratinocytes and peripheral blood mononuclear cells (PBMC). METHODS: Cultured keratinocytes were stimulated with interferon (IFN) -gamma to produce CXCL9, CXCL10 and CXCL11 and with phorbol myristate acetate to produce CXCL1 and CXCL8 in the absence and presence of DMF (5, 15 and 45 micromol L(-1)). PBMC were stimulated with either IFN-gamma to produce CXCL9 and CXCL10 or lipopolysaccharide to produce CXCL8, in the absence and presence of DMF (5, 15 and 45 micromol L(-1)). RNA preparations from isolated keratinocytes were analysed by Northern blotting; protein production by keratinocytes and PBMC was monitored by an enzyme-linked immunosorbent assay. RESULTS: Northern blot analysis on isolated keratinocyte RNA preparations showed a dose-dependent inhibition of CXCL1, CXCL8, CXCL9, CXCL10 and CXCL11 transcription by DMF. At 45 micromol L(-1) the inhibition was almost complete. In addition, keratinocytes and PBMC showed in the presence of DMF a dose-dependent inhibition of CXCL8, CXCL9 and CXCL10 protein production. CONCLUSIONS: These results show the ability of DMF to inhibit the production of chemokines that may be critically involved in the development and perpetuation of psoriatic lesions. This might explain, at least in part, the beneficial effects of treatment with fumaric acid esters in psoriasis patients.

Blotting, Northern↗
PubMed2000

Paraneoplastic pemphigus caused by an epithelioid leiomyosarcoma and associated with fatal respiratory failure.

A patient is described who initially presented with pemphigus vulgaris, limited to the oral cavity, and weight loss. Although the various laboratory studies pointed to the diagnosis of paraneoplastic pemphigus (PNP), the underlying neoplasm was not detected until 6 months later, when the patient developed shortness of breath and routine physical examination on admission revealed an abdominal mass, which eventually was proven to be an epithelioid leiomyosarcoma. In spite of radical excision of the tumour and intensive treatment of the dyspnoea, the patient died of respiratory failure 19 months after the PNP had been diagnosed. Early diagnosis of PNP is stressed to possibly prevent fatal pulmonary involvement.

Abdominal Neoplasms↗
PubMed1999

IP-10 mRNA expression in cultured keratinocytes is suppressed by inhibition of protein kinase-C and tyrosine kinase and elevation of cAMP.

IFN-gamma-inducible protein-10 (IP-10) is a chemokine, which plays an important role in mediating inflammation by attracting activated T cells, and it has been demonstrated in inflammatory skin diseases and cutaneous T cell lymphomas. Keratinocytes can abundantly produce IP-10 mRNA after IFN-gamma treatment. In this study we explored possibilities to downregulate IP-10 expression using human cultured keratinocytes as a model system. Decreased IP-10 mRNA levels were found using specific inhibitors of protein kinase (PK)-C (H-7 and Calphostin C). Moreover, depletion of PK-C by pretreatment of the cells with phorbol myristate (PMA) also down-regulated IP-10 mRNA expression. In addition, elevated cAMP levels were shown to inhibit IP-10 mRNA expression as could be concluded from experiments with forskolin and W-7, substances which, directly or indirectly, raise the intracellular cAMP level. With Genistein, an inhibitor of tyrosine kinase, the IFN-gamma-induced IP-10 mRNA expression was also found to be diminished. These data suggest that inhibitors of the IP-10 mRNA expression in cultured keratinocytes may be potentially of clinical relevance to suppress inflammatory processes in the skin.

Cells, Cultured↗
PubMed1999

The CXCR3 activating chemokines IP-10, Mig, and IP-9 are expressed in allergic but not in irritant patch test reactions.

Differentiation between allergic and irritant contact dermatitis reactions is difficult, as both inflammatory diseases are clinically, histologically, and immunohistologically very similar. Previous studies in mice revealed that the chemokine IP-10 is exclusively expressed in allergic contact dermatitis reactions. In the present study, we investigated whether the mRNA expression of IP-10 and the related CXCR3 activating chemokines, Mig and IP-9 are also differentially expressed in human allergic contact dermatitis and irritant contact dermatitis reactions. Skin biopsies from allergic (13 cases) and sodium lauryl sulfate-induced irritant patch test reactions (13 cases), obtained 1-72 h after patch testing, were studied by means of an in situ hybridization technique. Results of chemokine mRNA expression were correlated with clinical scoring, histology, and immunohistochemical data including the proportion of inflammatory cells expressing CXCR3, the receptor for IP-10, Mig, and IP-9, and ICAM-1 and HLA-DR expression on keratinocytes. IP-10, Mig, and IP-9 mRNA were detected in seven of nine allergic contact dermatitis reactions after 24-72 h, but not in sodium lauryl sulfate-induced irritant contact dermatitis reactions. ICAM-1 expression by keratinocytes was only found in allergic contact dermatitis reactions and correlated with chemokine expression. Moreover, up to 50% of the infiltrating cells in allergic contact dermatitis expressed CXCR3, in contrast to only 20% in irritant contact dermatitis reactions. In conclusion, we have demonstrated differences in chemokine expression between allergic contact dermatitis and irritant contact dermatitis reactions, which might reflect different regulatory mechanisms operating in these diseases and may be an important clue for differentiation between allergic contact dermatitis and irritant contact dermatitis reactions.

Chemokine CXCL10↗
PubMed1998

Chemokine IP-10 expression in cultured human keratinocytes.

IP-10, a member of the CXC family of chemokines, is considered to play an important role in inflammation via its T-cell chemotactic and adhesion-promoting properties. Elevated IP-10 levels in the epidermis of psoriasis, delayed-type hypersensitivity reactions, cutaneous T-cell lymphoma and fixed drug eruptions prompted us to study its expression in keratinocytes. IP-10 mRNA could be detected using the sensitive RT-PCR method, but not by Northern blotting in RNA preparations from unstimulated normal cultured keratinocytes, indicating a low steady-state level of IP-10 mRNA. Upon stimulation with IFN-gamma, IP-10 mRNA was found to accumulate in high amounts in a time- and dose-dependent manner. Superexpression was found with the combination of IFN-gamma and TNF-alpha or IL-1, although these latter cytokines by themselves did not induce accumulation of IP-10 mRNA. Nuclear run-on experiments performed to investigate the regulation of IP-10 mRNA expression, showed a very high constitutive transcriptional activity of the IP-10 gene in unstimulated keratinocytes, which was not affected by stimulation with IFN-gamma, TNF-alpha, or a combination of IFN-gamma and TNF-alpha. Protein kinase C (PKC) was shown to be involved in IP-10 mRNA expression since the PKC inhibitor H7 decreased IP-10 mRNA accumulation. A protein was isolated from culture supernatants of stimulated keratinocytes using HPLC techniques and, by sequence analysis, was found to be identical to IP-10. The dynamics of secretion of IP-10 protein as monitored by ELISA was shown to parallel the mRNA expression.

Antineoplastic Agents↗
PubMed1998

Pentoxifylline and skin inflammation.

Cyclic nucleotide phosphodiesterase inhibitors, such as pentoxifylline, have been shown to beneficially influence a large number of inflammatory skin diseases. The biological effects of pentoxifylline on the production of proinflammatory cytokines, leukocyte-endothelial cell adhesion, chemokines and leukocyte-keratinocyte adhesion in skin inflammation are discussed.

Cell Adhesion↗
PubMed1997

Pentoxifylline inhibits human T-cell adhesion to dermal endothelial cells.

Pentoxifylline (PTX), a methyl xanthine derivative with phosphodiesterase inhibitory activity, has been shown to have antiinflammatory effects. Previous studies have demonstrated that PTX can suppress TNF alpha production and function, and can inhibit the adhesion of neutrophils and monocytes to endothelial cells. In the present study, we sought to determine whether PTX also interferes with the adhesion of human peripheral blood T lymphocytes to cells of the human dermal endothelial cell line HMEC-1. Using a cell adhesion immunoassay, the effect of different doses of PTX (10(-5)-10(-2) M) on the binding of unactivated or PMA-activated T cells to unstimulated or TNF alpha-stimulated endothelial cells was investigated. In addition, blocking experiments with monoclonal antibodies against pairs of adhesion molecules known to be involved in endothelial cell/T-cell adhesion were performed. Unactivated T cells showed minimal adhesion to unstimulated endothelial cells. PMA-activated T cells showed an eightfold increased binding to TNF alpha-stimulated endothelial cells, which was found to be mediated largely by LFA-1/ICAM-1. PTX inhibited the binding of PMA-activated T cells to TNF alpha-stimulated endothelial cells in a dose-dependent manner. This inhibition was only found when PTX was present during the adhesion assay. A similar inhibition was found when PTX was replaced by isobutylmethylxanthine, another methyl xanthine derivative, or by a combination of two cAMP analogues. The results suggest that interference with T-cell/endothelial cell adhesion, which forms an essential step in the migration of T cells from the peripheral blood into sites of inflammation, may be another explanation for the beneficial effect of PTX in several inflammatory dermatoses.

Anti-Inflammatory Agents, Non-Steroidal↗