Homeostatic Function of Dermokine in the Skin Barrier and Inflammation.

Dermokine is a chiefly skin-specific secreted glycoprotein localized in the upper epidermis, and its family consists of three splice variants in mice and five in humans. To investigate the pathophysiological impact of dermokine, we generated mice deficient for two (ßγ) or all dermokine isoforms (αßγ). Both variants, especially dermokine αßγ-deficient mice exhibited scale and wrinkle formation resembling ichthyosis accompanied by transepidermal water imbalance at the neonatal stage. Several dermokine αßγ-deficient mice died by postnatal day 21 when reared under low humidity. Moreover, the cornified envelope was vulnerable, and skin barrier lipid ceramides were reduced in the epidermis of dermokine αßγ-deficient mice. cDNA microarray and quantitative reverse transcriptase-PCR assays of the epidermis revealed the upregulation of small proline-rich protein and late cornified envelope family members, as well as antimicrobial peptides in the dermokine αßγ-deficient mice. These barrier gene signatures were similar to that seen in psoriasis, whereas recent studies demonstrated that congenital ichthyosis has gene profiles resembling psoriasis. In line with these findings, adult dermokine αßγ-deficient mice exhibited aggravated phenotypes in psoriasis-like dermatitis models but not in allergic dermatitis models. Dermokine may play a regulatory role in inflammatory dyskeratotic diseases, such as congenital ichthyosis and psoriasis, in the crosstalk between barrier dysfunction and inflammation.

Sublamina densa-type linear IgA bullous dermatosis with IgA autoantibodies specific for type VII collagen: a case report and clinicopathological review of 32 cases.

Linear IgA bullous dermatosis (LABD) is a rare autoimmune bullous disorder characterized by linear deposits of IgA at the basement membrane zone(BMZ) and/or by circulating IgA anti-BMZ antibodies. Comparing with other immuno-bullous diseases, LABD represents a heterogeneous disease entitywith diversity of pathogenic IgA autoantibodies to different hemidesmosomal antigens and an association with malignancies and occasional drug use. We herein present an 82-year-old Japanese man with LABD, whose indirect immunofluorescence using 1M NaCl-split skin showed positive staining for IgA at the dermal side alone. Fluorescence overlay antigen mapping using laser scanning confocal microscopy (FOAM-LSCM) was employed to examine the in vivo bound patient's IgA, which was specific for type VII collagen (COL7), a prominent antigen of the sublamina densa. One year later, he developed malignant lymphoma, suggesting the diagnosis of paraneoplastic LABD. We reviewed 32 cases of sublamina-densa type LABD with anti-COL7 IgA antibodies thus far reported in the literature to compare the clinicopathological characteristics of this rare disease variant and emphasize that COL7 is the main autoantigen in sublamina densa disease.

CD34-positive infantile myofibromatosis: Case report and review of hemangiopericytoma-like pattern tumors.

We describe a case of CD34-positive infantile myofibromatosis with hemangiopericytoma-like pattern. A 2-day-old Japanese boy presented with multiple hemispherical nodules on the extremities and back. There was a biphasic histological growth in the dermis, accompanied by a hemangiopericytoma-like pattern with antler-like branching vessels. Tumor cells were oval to spindle-shaped myoid cells with bland appearance. Immunohistochemically, vimentin, calponin and CD34 were positive, while α-smooth muscle actin, h-caldesmon, HHF35 and desmin were negative. Although CD34 was positive, the present case could be diagnosed as infantile myofibromatosis. Myopericytoma, myofibroma/myofibromatosis, glomus tumor, glomangiopericytoma and angioleiomyoma share a continuous spectrum of benign hemangiopericytoma-like pattern tumors. Myofibroma/myofibromatosis is nearly included in myopericytoma among pericytic (perivascular) tumors, and could be positive for CD34. Several immunohistochemical panels of smooth muscle markers are needed for the diagnosis of pericytic (perivascular) tumors.

Spindle cell squamous cell carcinoma not expressing stratified but simple epithelial cytokeratin: efficacy of simple epithelial cytokeratin immunoreactivity.

We present two cases of spindle cell squamous cell carcinoma, which were derived from solar keratosis and burn scar in two elderly Japanese patients, respectively. The tumors involved the whole dermis and subcutis in connection with the overlying epidermis. They were composed mainly of anaplastic spindle cells partially forming storiform patterns. The tumor cells were diffusely positive for vimentin and cytokeratin 8/18 (clone CAM5.2, simple epithelial cytokeratin), but negative for cytokeratin 1/5/10/14 (clone 34ßE12, stratified epithelial cytokeratin). Ultrastructural analysis of a patient demonstrated desmosomes and tonofilaments in the tumor cells. Although spindle cell squamous cell carcinoma is usually positive for vimentin, detailed cytokeratin profile is controversial. The present cases revealed immunohistochemistry not expressing stratified but simple epithelial cytokeratin and vimentin. We should be reminded of the efficacy of simple epithelial cytokeratin immunoreactivity in spindle cell squamous cell carcinoma.

Dual role for Id2 in chemical carcinogen-induced skin tumorigenesis.

Inhibitor of DNA binding 2 (Id2) is a negative regulator of basic helix-loop-helix transcription factors and is involved in the control of cellular differentiation and proliferation. By using a two-step chemical carcinogenesis protocol, we evaluated the role of Id2 in skin tumor formation in mice. Twenty weeks after the initiation, the number of tumors formed in the Id2(-/-) mice was 3.5-fold higher than that in their wild-type littermates, whereas the diameter of tumors in the Id2(-/-) mice was about half of that of the tumors in the wild-type mice. In the Id2(-/-) mice, epidermal gammadelta T cells, which play a key role in immunosurveillance against skin tumor development, were barely detectable. Although histological analyses demonstrated no apparent difference in tumor cell type, tumor vessel formation or apoptosis, the proportion of proliferating cells was reduced in the tumors in the Id2(-/-) mice compared with those in the wild-type mice. In the wild-type mice, the expression of Id2 was enhanced in skin tumors compared with that in ear epidermal cells. Biochemical analysis demonstrated that cyclin D1 was reduced at the protein level in the tumors in the Id2(-/-) mice, whereas other factors such as cyclin E and p27 were not altered significantly. Our results reveal that Id2 plays a dual role in skin tumorigenesis by suppressing tumor development through the establishment of epidermal gammadelta T cell-mediated skin immunosurveillance and by promoting tumor cell proliferation via the control of the cyclin D1 protein level.

Primary cutaneous signet ring cell carcinoma expressing cytokeratin 20 immunoreactivity.

Primary cutaneous signet ring cell carcinoma (PCSRCC) is a very unusual but distinctive clinicopathologic entity that can simulate metastatic adenocarcinomas. It is defined as a diffuse malignant epithelial neoplasia localized in the dermis and subcutis without epidermal involvement, showing variable amounts of signet ring cells, without evidence of visceral adenocarcinoma. We present 2 cases of PCSRCC, which involved eyelids and axilla respectively. Despite thorough systemic workup, primary sources could not be demonstrated in either case. The tumor cells are positive for gross cystic disease fluid protein 15 in addition to a variety of glandular markers. Furthermore, both cases were immunostained with cytokeratin 20 (CK20). In conclusion, we report 2 cases of PCSRCC expressing CK20 immunoreactivity. CK20-positive primary cutaneous tumors should include PCSRCC in addition to Merkel cell carcinoma.

Dominant expression of CXCR3 is associated with induced expression of IP-10 at hapten-challenged sites of murine contact hypersensitivity: a possible role for interferon-gamma-producing CD8(+) T cells in IP-10 expression.

Murine contact hypersensitivity is elicited as a consequence of immunologic reactions triggered by skin-applied antigen, interactions among Langerhans cells, T cells, keratinocytes and mast cells, and a variety of chemokines generated by cellular interactions. In this study, we sensitized and challenged BALB/c mice with hapten, dinitrofluorobenzene or picryl chloride, and examined the expressions of mRNA for chemokines and their receptors by reverse transcription-polymerase chain reaction in the skin of elicited earlobes. CXC chemokines, IP-10 and Mig, were transcribed 24-48 h after challenge. This was associated with the expression of their agonistic receptor CXCR3, while mRNA for TARC and MDC, and their receptor CCR4 were not detected. Since CXCR3 and CCR4 are expressed preferentially on types 1 (Th1/Tc1) and 2 (Th2) T cells, respectively, the results suggested that the former type of T cells predominantly infiltrate at the elicited sites. Immune lymph node cells of the sensitized mice also expressed mRNA for CXCR3 but not CCR4 with concomitant transcription of interferon-gamma (IFN-gamma) but not interleukin-4 subsequent to challenge. The percentage of lymph node CD8(+) T cells was increased from 16% in naive mice to 30-50% in hapten-challenged mice, and in the immune lymph nodes, CD8(+) cells were the major source of IFN-gamma compared to CD4(+) cells. Since IFN-gamma is known to stimulate keratinocytes to produce IP-10 and Mig, it is suggested that these IFN-gamma-producing CD8(+) T cells enhance the production of these chemokines, thereby functioning as not only the effector cells but also the cytokine source to sustain the challenge reaction.