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Epidermal mast cells in atopic dermatitis
amplification. Sequencing of the KS330233 PCR products yielded the Kaposi-associated HHVL DNA sequence with a mutation at nucleotide 101 (T -> C). This case confirms HHVL that KS-associated (KSHV) has a pathogenic role in post-transplant KS. The possibility that KSHV was transmitted by the healthy homosexual donor remain unresolved. *Eliane Gluckman, Nathalie Parquet, Catherine Scieux, Martine Deplanche, Richard Traineau, Philippe Betheau, Frédéric Morinet *Bone Marrow
Transplant Unit, 2 Service de Microbiologie Unité de Virologie, and Blood Bank, Pathology Department, Hôpital Saint-Louis, 1 Av Claude Velte faux, 75475 Paris Cedex 10, France
1 Helg C, Adatto M, Salomon D, et al. Kaposi’s sarcoma following allogeneic bone marrow transplantation. Bone Marrow Transplant 1994; 14: 999-1101. 2
Chang Y, Cesarman E, Pessin MS,
3
Moore PS,
4
et al. Identification of herpesviruslike DNA sequences in AIDS-associated Kaposi’s sarcoma. Science
1994; 266: 1865-69. Chang Y. Detection of herpesvirus-like DNA sequences in Kaposi’s sarcoma in patients with and those without HIV infection.
N Engl J Med 1995; 332: 1181-85. Cesarman E, Chang Y, Moore PS, Said JW, Knowles DM. Kaposi’s sarcoma-associated herpesvirus-like DNA sequences in AIDS-related body cavity-based lymphomas. N Engl J Med 1995; 332: 1186-91.
Epidermal mast cells in atopic dermatitis participate in the IgE-mediated immediate hypersensitivity reaction by releasing mediators that include histamine, prostaglandins, leukotrienes, and neutral proteases. Such cells have been identified in the epithelium of the nasal mucosa of patients with allergic rhinitis’ and in the epithelium of the intestinal mucosa of normal subjects.2 Although mast cells have been identified in the connective tissue of the skin, they have not been observed in the epidermis, even in patients with atopic dermatitis. We examined skin from ten patients with atopic dermatitis, four males and six females, aged 10 to 32 years (mean 21-5), who were attending our hospital clinic. Mean duration of disease was 8-6 years. Disease was in the active state in all patients, who were receiving no corticosteroids either systemically or topically. As controls, we studied eight healthy volunteers, four males and four females, aged 12 to 45 years (mean 26-4). Informed consent was obtained from each participant. Specimens of skin were obtained from non-involved skin of the upper arm of each subject. Each specimen was cut into four blocks to be processed for light and electron microscopy. One block was conventionally fixed with formaldehyde, one was fixed with Carnoy’s fixative (ethanol, chloroform, and acetic acid), and one was quick-frozen in liquid nitrogen for immunohistochemical study. The remaining block was fixed with glutaraldehyde and osmium tetroxide, and processed for electronmicroscopy. Criteria for identifying mast cells were: metachromatic response to staining with toluidine blue; positive immunoreaction for antihuman mast-cell tryptase monoclonal antibody (MAB1222; Chemicon International, Temecula, CA); and typical ultrastructural features observed on electron microscopy. We observed mast cells in the epidermis (as well as the dermis) of three of the ten skin specimens from patients with atopic dermatitis fixed with Carnoy’s, but in none of the conventionally fixed specimens. Observations by immunohistochemistry (not shown) and electronmicroscopy confirmed the findings. In all specimens, mast cells were seen in the dermal connective tissue, particularly around the capillaries. Special fixation and staining are required to observe mast cells in the epidermis. These cells are a source of the cytokines that recruit and activate the inflammatory cells SIR-Mast cells
Figure: Light (a) and
electron (b) micrographs showing the of mast cells in the epidermis of a patient with atopic presence dermatitis Mast cells are displaced in the basal layer of the epidermal processes (rete pegs). The cells are identified by a, metachromasia with toluidine blue, and b, intracytoplasmic granules and microvilli on their plasma membrane. Bar=1 µ.
involved in the allergic reactionTheir presence may explain the initiation of the late-phase inflammatory response in the skin of patients with atopic dermatitis. *Shuhei Imayama, Yosaburo Shibata, Yoshiaki Hori Departments of Dermatology and Anatomy, Faculty of Medicine, Kyushu University, Fukuoka 812-82, Japan 1
2 3
Igarashi Y, Goldrich MS, Kaliner MA, Irani AMA, Schwartz LB, White MV. Quantitation of inflammatory cells in the nasal mucosa of patients with allergic rhinitis and normal subjects. J Allergy Clin Immunol 1995; 95: 716-25. Atkins FM. Intestinal mucosal mast cells. Ann Allergy 1987; 59: 44-53. Horsmanheimo L, Harvima LT, Jarvikalho A, Harvima RJ, Naukkarinen A, Horsmanheimo M. Mast cells are one major source of interleukin-4 in atopic dermatitis. Br J Dermatol 1994; 131: 348-53. 1559
Transplant Unit, 2 Service de Microbiologie Unité de Virologie, and Blood Bank, Pathology Department, Hôpital Saint-Louis, 1 Av Claude Velte faux, 75475 Paris Cedex 10, France
1 Helg C, Adatto M, Salomon D, et al. Kaposi’s sarcoma following allogeneic bone marrow transplantation. Bone Marrow Transplant 1994; 14: 999-1101. 2
Chang Y, Cesarman E, Pessin MS,
3
Moore PS,
4
et al. Identification of herpesviruslike DNA sequences in AIDS-associated Kaposi’s sarcoma. Science
1994; 266: 1865-69. Chang Y. Detection of herpesvirus-like DNA sequences in Kaposi’s sarcoma in patients with and those without HIV infection.
N Engl J Med 1995; 332: 1181-85. Cesarman E, Chang Y, Moore PS, Said JW, Knowles DM. Kaposi’s sarcoma-associated herpesvirus-like DNA sequences in AIDS-related body cavity-based lymphomas. N Engl J Med 1995; 332: 1186-91.
Epidermal mast cells in atopic dermatitis participate in the IgE-mediated immediate hypersensitivity reaction by releasing mediators that include histamine, prostaglandins, leukotrienes, and neutral proteases. Such cells have been identified in the epithelium of the nasal mucosa of patients with allergic rhinitis’ and in the epithelium of the intestinal mucosa of normal subjects.2 Although mast cells have been identified in the connective tissue of the skin, they have not been observed in the epidermis, even in patients with atopic dermatitis. We examined skin from ten patients with atopic dermatitis, four males and six females, aged 10 to 32 years (mean 21-5), who were attending our hospital clinic. Mean duration of disease was 8-6 years. Disease was in the active state in all patients, who were receiving no corticosteroids either systemically or topically. As controls, we studied eight healthy volunteers, four males and four females, aged 12 to 45 years (mean 26-4). Informed consent was obtained from each participant. Specimens of skin were obtained from non-involved skin of the upper arm of each subject. Each specimen was cut into four blocks to be processed for light and electron microscopy. One block was conventionally fixed with formaldehyde, one was fixed with Carnoy’s fixative (ethanol, chloroform, and acetic acid), and one was quick-frozen in liquid nitrogen for immunohistochemical study. The remaining block was fixed with glutaraldehyde and osmium tetroxide, and processed for electronmicroscopy. Criteria for identifying mast cells were: metachromatic response to staining with toluidine blue; positive immunoreaction for antihuman mast-cell tryptase monoclonal antibody (MAB1222; Chemicon International, Temecula, CA); and typical ultrastructural features observed on electron microscopy. We observed mast cells in the epidermis (as well as the dermis) of three of the ten skin specimens from patients with atopic dermatitis fixed with Carnoy’s, but in none of the conventionally fixed specimens. Observations by immunohistochemistry (not shown) and electronmicroscopy confirmed the findings. In all specimens, mast cells were seen in the dermal connective tissue, particularly around the capillaries. Special fixation and staining are required to observe mast cells in the epidermis. These cells are a source of the cytokines that recruit and activate the inflammatory cells SIR-Mast cells
Figure: Light (a) and
electron (b) micrographs showing the of mast cells in the epidermis of a patient with atopic presence dermatitis Mast cells are displaced in the basal layer of the epidermal processes (rete pegs). The cells are identified by a, metachromasia with toluidine blue, and b, intracytoplasmic granules and microvilli on their plasma membrane. Bar=1 µ.
involved in the allergic reactionTheir presence may explain the initiation of the late-phase inflammatory response in the skin of patients with atopic dermatitis. *Shuhei Imayama, Yosaburo Shibata, Yoshiaki Hori Departments of Dermatology and Anatomy, Faculty of Medicine, Kyushu University, Fukuoka 812-82, Japan 1
2 3
Igarashi Y, Goldrich MS, Kaliner MA, Irani AMA, Schwartz LB, White MV. Quantitation of inflammatory cells in the nasal mucosa of patients with allergic rhinitis and normal subjects. J Allergy Clin Immunol 1995; 95: 716-25. Atkins FM. Intestinal mucosal mast cells. Ann Allergy 1987; 59: 44-53. Horsmanheimo L, Harvima LT, Jarvikalho A, Harvima RJ, Naukkarinen A, Horsmanheimo M. Mast cells are one major source of interleukin-4 in atopic dermatitis. Br J Dermatol 1994; 131: 348-53. 1559