M Brönnimann

University Hospital RWTH Aachen, Aachen, North Rhine-Westphalia, Germany

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Publications (14)34.04 Total impact

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    ABSTRACT: Granzyme B and perforin messenger RNA (mRNA) expression has been shown to be a specific in vivo activation marker for cytotoxic cells. The aim of this study was to assess the contribution of cell-mediated cytotoxicity in the pathogenesis of lichen sclerosus. In situ hybridization and immunohistochemistry were performed on serial tissue sections of lesional skin biopsies and normal skin as control. Immunohistochemical staining showed that the cellular infiltrate of diseased skin consisted predominantly of T cells (CD3+) and some B cells (CD20+). Among T cells CD4+ and CD8+ cells were found in about equal numbers. In normal skin samples perforin and granzyme B mRNA expressing cells were only rarely found. In contrast, in biopsies from diseased skin a high percentage of infiltrating cells expressed mRNA for perforin and granzyme B. The perforin and granzyme B expressing cells were found in the dermal infiltrate and intraepidermally in close proximity to keratinocytes suggesting in situ activation of these cells. These findings provide evidence that cell-mediated cytotoxicity plays a significant role in tissue destruction in lichen sclerosus.
    Experimental Dermatology 06/2007; 16(5):416-20. · 3.58 Impact Factor
  • Der Hautarzt 02/2007; 58(1):68-71. · 0.50 Impact Factor
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    ABSTRACT: Ohne Zusammenfassung
    Der Hautarzt 12/2006; 58(1):68-71. · 0.50 Impact Factor
  • Marcel Brönnimann, Nikhil Yawalkar
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    ABSTRACT: Cutaneous eruptions are among the most common adverse drug reactions and may often represent a challenging diagnostic problem. This review focuses on histopathological and immunohistochemical findings of drug-induced maculo-papular exanthems and discusses the value of skin biopsies and consequent histopathological examination in the diagnosis of these reactions. Data from immunohistological studies indicate that CD4+ T cells expressing cytotoxic granule proteins such as perforin and granzyme B are critically involved in the pathogenesis and contribute to the generation of typical histopathological features of drug-induced maculo-papular exanthems, i.e. an interface dermatitis with vacuolar alteration and some apoptotic basal keratinocytes. In addition, an upregulation of both type 1 (i.e. IFN-gamma, TNF-alpha) and type 2 (i.e. IL-5) cytokines has been reported. IL-5 together with other chemokines (i.e. eotaxin/CCL-11) provides an explanation for tissue eosinophilia, which may be suggestive of a drug eruption if present. There are no absolute histological or immunohistological criteria for the diagnosis of drug-induced maculo-papular exanthems and even if the observed histological changes are compatible with a drug-induced eruption, biopsy may not definitely exclude alternative causes since there is considerable overlap with features seen in other entities. In mild cases with no severe signs or symptoms and a clear temporal relationship, clinical information and the morphologic pattern of skin lesions are often sufficient for diagnosis. However, in complex and severe cases or when the precise morphology is unclear, histopathological findings may provide some clues and assist in reaching a correct diagnosis.
    Current Opinion in Allergy and Clinical Immunology 09/2005; 5(4):317-21. · 3.40 Impact Factor
  • Der Hautarzt 08/2005; 56(7):684-6. · 0.50 Impact Factor
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    ABSTRACT: Mast cell chymase is a chymotrypsin-like serine proteinase primarily stored in secretory mast cell granules. Mast cell chymase has various effects on angiotensin, metalloproteases, lipoproteins, procollagen, neuropeptides and cytokines. Recent studies have demonstrated that chymase inhibitors inhibit skin inflammation. In this study we sought to determine the role of mast cell chymase in atopic dermatitis (AD) in comparison with its role in psoriasis and normal skin. Skin biopsy specimens were obtained from non-lesional and lesional skin of patients with chronic AD and psoriasis and from normal skin of non-atopic and non-psoriatic controls. The number of mast cells containing chymase was determined by immunohistochemistry using a chymase-specific monoclonal antibody. A significantly (P < 0.05) enhanced number of chymase-positive cells was found in lesional AD skin as compared to normal skin as well as to lesional and non-lesional skin of patients with psoriasis. A significant (P < 0.05) increase in the number of chymase-positive cells was also found in non-lesional AD skin in comparison to psoriasis. An enhanced, albeit not statistically significant difference was noted in non-lesional AD skin as compared to normal skin. In conclusion, these results suggest that mast cell chymase may play an integral part in eliciting and maintaining cutaneous inflammation in AD but not in psoriasis. The increased proteinase activity of mast cell chymase may also be involved in promoting a skin barrier defect in AD, which subsequently enhances the skin's permeability to allergens and microbes and thereby aggravates the eczema.
    Archives for Dermatological Research 05/2005; 296(10):503-6. · 2.71 Impact Factor
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    ABSTRACT: The atopy patch test (APT) was proposed to evaluate IgE-mediated sensitizations in patients with atopic eczema (AE). The prevalence and agreement with clinical history and specific IgE (sIgE) of positive APT reactions was investigated in six European countries using a standardized method. A total of 314 patients with AE in remission were tested in 12 study centers on clinically uninvolved, non-abraded back skin with 200 index of reactivity (IR)/g of house dust mite Dermatophagoides pteronyssinus, cat dander, grass, and birch pollen allergen extracts with defined major allergen contents in petrolatum. Extracts of egg white, celery and wheat flour with defined protein content were also patch tested. APT values were evaluated at 24, 48, and 72 h according to the European Task Force on Atopic Dermatitis (ETFAD) guidelines. In addition, skin-prick test (SPT) and sIgE and a detailed history on allergen-induced eczema flares were obtained. Previous eczema flares, after contact with specific allergens, were reported in 1% (celery) to 34% (D. pteronyssinus) of patients. The frequency of clear-cut positive APT reactions ranged from 39% with D. pteronyssinus to 9% with celery. All ETFAD intensities occured after 48 and 72 h. Positive SPT (16-57%) and elevated sIgE (19-59%) results were more frequent. Clear-cut positive APT with all SPT and sIgE testing negative was seen in 7% of the patients, whereas a positive APT without SPT or sIgE for the respective allergen was seen in 17% of the patients. APT, SPT and sIgE results showed significant agreement with history for grass pollen and egg white (two-sided Pr > /Z/ < or = 0.01). In addition, SPT and sIgE showed significant agreement with history for the other aeroallergens. With regard to clinical history, the APT had a higher specificity (64-91% depending on the allergen) than SPT (50-85%) or sIgE (52-85%). Positive APT were associated with longer duration of eczema flares and showed regional differences. In 10 non-atopic controls, no positive APT reaction was seen. Aeroallergens and food allergens are able to elicit eczematous skin reactions after epicutaneous application. As no gold standard for aeroallergen provocation in AE exists, the relevance of aeroallergens for AE flares may be evaluated by APT in addition to SPT and sIgE. The data may contribute to the international standardization of the APT.
    Allergy 01/2005; 59(12):1318-25. · 5.88 Impact Factor
  • Der Hautarzt 01/2005; 56(7):684-686. · 0.50 Impact Factor
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    ABSTRACT: Lentigo maligna (LM) is an in situ melanoma which usually occurs in sun-damaged skin on the head and neck of elderly patients. Depending on the anatomical site and its size treatment of LM can be problematic and usually includes surgical excision or radiotherapy. Recent reports indicate that topical imiquimod may be an effective treatment. However, no data on the underlying immune response in the skin during treatment of LM with topical imiquimod are available so far. We report a 62-year-old caucasian woman with a histologically verified LM which was successfully treated with topical imiquimod 5% cream. Skin biopsy specimens were obtained before, during (at week 10) and 4 weeks after cessation of topical treatment with imiquimod 5% cream. Histological and immunohistochemical examination was performed in order to detect residual atypical melanocytes and to characterize the inflammatory infiltrate. A complete clinical and histological clearance of the skin lesion was achieved, with no recurrence up to 9 months after the end of treatment. During topical application of imiquimod 5% cream a depletion of epidermal and dermal CD1a+ dendritic cells was observed. The inflammatory infiltrate consisted of CD68+ macrophages and mainly of CD3+ T cells with a slight predominance of CD8+ T cells. An enhanced expression of granzyme B and TIA-1 was also noted particularly in the epidermis and near the dermoepidermal junction. In conclusion, our data indicate that imiquimod 5% cream induces a cytotoxic T-cell-mediated immune response in situ which may account for the complete destruction of the malignant melanocytes in LM. Further clinical trials and longer follow-up periods on the use of imiquimod for LM are warranted.
    British Journal of Dermatology 11/2004; 151(4):903-6. · 3.76 Impact Factor
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    ABSTRACT: A 70-year-old Caucasian man with chronic lymphocytic leukemia suffered from widespread, histologically proven cutaneous lichen planus responding to topical corticosteroids. 2 years later, he presented with painful erosive stomatitis and increasing dyspnea. Histology, direct and indirect immunofluorescence were diagnostic for paraneoplastic pemphigus. A full diagnostic workup could not disclose the cause of the progressive respiratory insufficiency. Despite aggressive treatment of the lymphocytic leukemia and the paraneoplastic pemphigus, the patient died 3 months after diagnosis. Paraneoplastic pemphigus may lead to pulmonary failure which is refractory to treatment and has a fatal outcome.
    Dermatology 02/2004; 208(3):251-4. · 2.02 Impact Factor
  • Source
    Allergy 01/2004; 59:1318-1325. · 5.88 Impact Factor
  • G Haeberli, M Brönnimann, T Hunziker, U Müller
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    ABSTRACT: Mastocytosis and/or elevated basal serum tryptase may be associated with severe anaphylaxis. To analyse Hymenoptera venom-allergic patients with regard to basal tryptase in relation to the severity of sting reactions and the safety and efficacy of venom immunotherapy. Basal serum tryptase was measured in 259 Hymenoptera venom-allergic patients (158 honey bee, 101 Vespula). In 161 of these (104 honey bee, 57 Vespula), a sting challenge was performed during venom immunotherapy. Nineteen of the 259 patients had an elevated basal serum tryptase. Evidence of cutaneous mastocytosis as documented by skin biopsy was present in 3 of 16 patients (18.8%). There was a clear correlation of basal serum tryptase to the grade of the initial allergic reaction (P<0.0005). Forty-one of the 161 sting challenged patients reacted to the challenge, 34 to a bee sting and 7 to a Vespula sting. Thereof, 10 had an elevated basal serum tryptase, i.e. 1 (2.9%) of the reacting and 2 (2.9%) of the non-reacting bee venom (BV) allergic individuals, as compared to 3 (42.9%) of the reacting and 4 (8%) of the non-reacting Vespula venom-allergic patients. Thus, there was a significant association between a reaction to the sting challenge and an elevated basal serum tryptase in Vespula (chi2=6.926, P<0.01), but not in BV-allergic patients. Systemic allergic side-effects to venom immunotherapy were observed in 13.9% of patients with normal and in 10% of those with elevated basal serum tryptase. An elevated basal serum tryptase as well as mastocytosis are risk factors for severe or even fatal shock reactions to Hymenoptera stings. Although the efficacy of venom immunotherapy in these patients is slightly reduced, most of them can be treated successfully. Based on currently available data, lifelong treatment has to be discussed in this situation.
    Clinical & Experimental Allergy 09/2003; 33(9):1216-20. · 4.79 Impact Factor

Publication Stats

285 Citations
34.04 Total Impact Points

Institutions

  • 2007
    • University Hospital RWTH Aachen
      Aachen, North Rhine-Westphalia, Germany
  • 2004–2007
    • Inselspital, Universitätsspital Bern
      • Department of Dermatology
      Bern, BE, Switzerland