It has previously been shown that circulating Sezary cells respond in vitro to superantigenic staphylococcal exotoxins in a manner that is restricted by their Ylj usage. This study was conducted to examine whether cutaneous colonization with Staphylococcus aureus influences the activity ofthe skin lesions of Sezary syndrome, and whether S. aureus isolated from patients with Sezary syndrome stimulates circulating Sezary cells in vitro. Two patients with Sezary syndrome, whose skin was colonized with S. aureus. were treated with antibacterial agents, and the relation between the severity ofthe skin disease and the degree oi S. aureus colonization was assessed. In addition, the patients' peripheral blood mononuclear cells were cultured in the presence of mitomycin C-treated S. aureus or superantigenic staphylococcal toxins. The antibacterial treatment improved the skin disease, and eliminated S. aureus in both patients. In one patient, 98% of the peripheral blood mononuclear cells bore VQ2V/31 7 of the T-cell receptor, indicative of the presence of an extremely high percentage of circulating Sezary cells. The peripheral blood lymphocytes from this patient responded well in vitro to superantigenic staphylococcal enterotoxin (SE), but not to SEA or toxic shock syndrome toxin-1. or to mitomycin-treated S. aureus isolated from the same patient. Cutaneous colonization by S. aureus influences the disease activity of CTCL. possibly by activation of Sezary cells by bacterial superantigenic exoproteins.

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The USA300 clone, which produces Panton–Valentine leukocidin (PVL), is a major pathogenic community‐acquired methicillin‐resistant Staphylococcus aureus (CA‐MRSA) clone that causes intractable skin infections. Recently, PVL‐positive CA‐MRSA, including USA300 clones, have emerged in both communities and hospitals in Japan. To prevent an outbreak of PVL‐positive MRSA, infected patients should be treated with effective antimicrobial agents at community clinics. Herein, we investigate molecular epidemiological characteristics of PVL‐positive MRSA isolated from outpatients with skin and soft tissue infections (SSTI), which are common community‐onset infectious diseases. The detection rate of MRSA was 24.9% (362 strains) out of 1455 S. aureus strains isolated between 2013 and 2017. Among the MRSA strains, 15.5% (56 strains) were PVL‐positive strains and associated with deep‐seated skin infections. Molecular epidemiological analyses of PVL‐positive MRSA showed that USA300 was the predominant clone (53.6%, 30 strains) and was identified in Kanto (18 strains), Kagawa (nine strains), Tohoku (two strains) and Hokkaido (one strain). Notably, minocycline and fusidic acid were effective against all PVL‐positive MRSA strains. Hence, our data reveals the current status of PVL‐positive MRSA isolated from patients with SSTI in Japan. Continuous surveillance of CA‐MRSA is necessary to monitor latest prevalence rates and identify effective antimicrobial agents for PVL‐positive MRSA strains.

The role of cadherins in cutaneous biology has focused mainly on the classical cadherins, E- and P-cadherin. In this review, roles for cadherins in skin morphogenesis, keratinocyte differentiation, and cancer metastasis are discussed. E-cadherin is expressed on the surfaces of whole epidermal layer cells, and P-cadherin is expressed only on the surfaces of basal cells. Ultrastructural studies have shown that E-cadherin is distributed on the cytoplasmic membranes of keratinocytes with a condensation in the intercellular space of the desmosomes. During human skin development, P-cadherin expression is spatiotemporally controlled and closely related to the segregation of basal layers as well as to the arrangement of epidermal cells into eccrine ducts. In human skin diseases, E-cadherin expression is markedly reduced on the acantholytic cells of tissues in pemphigus and also in Darier's disease. Keratinocytes cultured in high calcium produce a much more intense immunofluorescence of intercellular E- and P-cadherin than do cells grown in low calcium. Ultrastructural studies show that E-cadherin on the cytoplasmic membrane of the keratinocytes is shifted to desmosomes under physiological conditions and therein expresses an adhesion function is association with other desmosomal cadherins. Cell adhesion molecules are now considered to play significant roles in the cellular connections of cancers and metastatic cells. Reduced expression of E-cadherin on invasive neoplastic cells has been demonstrated for cancers of the stomach, liver, breast, and several other organs. This reduced expression of E-cadherin is observed in squamous cell carcinoma and Paget's disease. Soluble E-cadherins in sera are elevated in various skin diseases, including bullous pemphigoid, pemphigus vulgaris and psoriasis, but not in patients with burns. Markedly high levels in soluble E-cadherin are demonstrated in patients with metastatic cancers.

The Ca2+‐dependent cell‐cell adhesion molecules, termed cadherins, are subdivided into several subclasses. E (epithelial)‐ and P (placental)‐cadherins are involved in the selective adhesion of epidermal cells. E‐cadherin is expressed on the cell surfaces of all epidermal layers and P‐cadherin is expressed only on the surfaces of basal cells. Ultrastructural studies have shown that E‐cadherin is distributed on the plasma membranes of keratinocytes with a condensation in the intercellular space of the desmosomes. During human skin development P‐cadherin expression is spatiotemporally controlled and closely related to the segregation of basal layers as well as to the arrangement of epidermal cells into eccrine ducts. In human skin diseases E‐cadherin expression is markedly reduced on the acantholytic cells of tissues in pemphigus and Darier's disease. Cell adhesion molecules are now considered to play a significant role in the cellular connections of cancer and metastatic cells. Reduced expression of E‐cadherin on invasive neoplastic cells has been demonstrated for cancers of the stomach, liver, breast, and several other organs. This reduced or unstable expression of E‐ and P‐cadherin is observed in squamous cell carcinoma, malignant melanoma, and Paget's disease, but cadherin expression is conserved in basal cell carcinoma. Keratinocytes cultured in high calcium produce much more intense immunofluorescence of intercellular E‐ and P‐cadherin than those cells grown in low calcium. E‐cadherins on the plasma membrane of the keratinocytes are shifted to desmosomes under physiological conditions, and therein may express an adhesion function in association with other desmosomal cadherins. Soluble E‐cadherins in sera are elevated in various skin diseases including bullous pemphigoid, pemphigus vulgaris, and psoriasis, but not in patients with burns. Markedly high levels in soluble E‐cadherin are demonstrated in patients with metastatic cancers. Microsc. Res. Tech. 38:343–352, 1997. © 1997 Wiley‐Liss, Inc.