Fine mapping of a psoriasis-susceptibility locus within the HLA class II region by using microsatellite markers in an association study of Japanese cases and controls.

BACKGROUND: The association between psoriasis and the HLA antigens encoded by the Major Histocompatibility Complex (MHC) genomic region is well known, but the role of the HLA class II region in susceptibility to psoriasis is unclear. OBJECTIVE: The purpose of this study is to map the psoriasis-susceptibility locus within the HLA class II region. METHODS: Three hundred seventy five unrelated Japanese patients with psoriasis vulgaris and 375 unrelated Japanese healthy controls were studied by an association analysis using 15 polymorphic microsatellite markers. RESULTS: Statistically significant differences were found at three microsatellite loci. The most significant association of psoriasis vulgaris with the microsatellite markers was found with DRA_CA (pc=0.0000135), the second with DQCARII (pc=0.0000840) and the third with G5_11525 (pc=0.0240). These significant microsatellite markers are in close vicinity to the DQA2, DQB1, DRB1, DRA and BTNL2 genes. CONCLUSION: The results suggest that there are psoriasis susceptibility genes located within the HLA class II region and therefore strongly support previous findings of a positive association between psoriasis and certain alleles of the DQB1 and DRB1 genes.

The role of NK cells in antitumor activity of dietary fucoidan from Undaria pinnatifida sporophylls (Mekabu).

Fucoidan from Mekabu (sporophyll of Undaria pinnatifida), a dietary alga, exerts antitumor activity possibly through enhancing the immune response. The present report describes the effects of dietary Mekabu fucoidan on the tumor growth of mouse A20 leukemia cells and on T cell-mediated immune responses in T cell receptor transgenic (DO-11 - 10 - Tg) mice. The animals were fed with a diet containing 1% Mekabu fucoidan (0.034 +/- 0.003 g/mouse/day) for 10 days and subcutaneously (s. c.) inoculated with A20 leukemia cells. Thereafter, the mice were fed with the diet containing fucoidan for 40 days. Mekabu fucoidan inhibited tumors by 65.4 %. We studied how the killer activities of T cell-mediated and natural killer (NK) cells are augmented in DO-11 - 10 mice fed with Mekabu fucoidan. The cytolytic activities of ovalbumin (OVA), which is specific against OVA-transfected A20 (OVA-A20) B lymphoma cells, and NK cells against YAC-1 were significantly enhanced in the mice fed with fucoidan compared with a basic diet. Thus, these findings suggested that Mekabu fucoidan mediates tumor destruction through Th1 cell and NK cell responses.

Identification and characterization of novel variants of the thioredoxin reductase 3 new transcript 1 TXNRD3NT1.

We have identified and characterized a new gene sequence, TXNRD3NT1, whose transcripts, corresponding to the EST AA430236, were found by Affymetrix DNA chip analysis to be significantly down regulated in affected psoriatic tissue. The full-length cDNA of TXNRD3NT1 was isolated and characterized by combining 5'- and 3'-RACE (rapid amplication of cDNA ends) with screening a keratinocyte cDNA library, designing appropriate PCR primers, cloning amplified products, sequencing, and sequence analysis. Because part of this gene overlaps the previously described thioredoxin reductase 3 (TXNRD3) gene, we have named it TXNRD3NT1 (TXNRD3 new transcript 1). The full-length TXNRD3NT1 cDNA has 1133 nucleotides with a 251-bp 3-UTRand 2 poly(A)signal variants and 2 poly (A) sites. The TXNRD3NT1 cDNA ORF encodes for 133 amino acids, with the first four residues coding for a tubulin-beta mRNA autoregulation signal. Mapping the cDNA nucleotide sequence to the human genome sequence revealed that the TXNRD3NT1 gene has 4 exons located on Chromosome 3, at position 3q21. Exons 1 and 2 of the TXNRD3NT1 gene overlap with exons 15 and 16 of the thioredoxin reductase 2 gene which has different ORFs to that of TXNRD3NT1. The translation initiation codon ATG was found in exon 3 of the TXNRD3NT1 gene. RT-PCR showed that the full-length variant of the TXNRD3NT1 gene was expressed in only four issues (pancreas, esophagus, bone marrow, and keratinocytes) of the 30 different tissues tested. In most other tissues, an aberrant and truncated form of the transcript (i.e., missing exon 3 and part of exon 4) was detected. The result of a preliminary association study between psoriasis and single microsatellite marker of the TXNRD3NT1 gene suggests that it may not be a significant genetic determinant of psoriasis. However, we cannot exclude the possibility that other sequence variants may still exist within the TXNRD3NT1 gene. Sequence analysis of the TXNRD3NT1 gene from 8 psoriasis patients and 8 healthy controls revealed a number of synonymous SNPs that may be useful markers for future disease association studies.

Identification, expression analysis and polymorphism of a novel RLTPR gene encoding a RGD motif, tropomodulin domain and proline/leucine-rich regions.

We describe the isolation and characterization of a full-length cDNA encoded by a gene that was significantly down-regulated in the affected skin of patients with psoriasis vulgaris. The cDNA was isolated from a keratinocyte cDNA library and its sequence was found to correspond to a hypothetical locus recorded in GenBank with the accession number . The nucleotide sequence of the full-length cDNA was found to have an open reading frame of 1365 amino acids and to span approximately 12 kb of genomic DNA with 39 exons on chromosome 16q22. The deduced amino acid sequence contains four distinct structural regions, an RGD motif, a leucine-rich repeat (LRR) region, a tropomodulin domain, and a proline-rich domain. The gene was consequently designated as RLTPR (RGD, leucine-rich repeat, tropomodulin and proline-rich containing protein). The RLTPR hypothetical protein has a functional domain organization similar to Acan125, a myosin-binding protein expressed by Acanthamoeba castellanni. RT-PCR with RLTPR PCR primers amplified products from cDNAs prepared from all of the 30 different tissues that we examined including thymus, spleen, colon, skin, skin keratinocytes, skin fibroblasts and fetal skin. During the course of screening the human keratinocyte cDNA library, some alternative splicing was also detected in three regions of the RLTPR gene. In addition, sequence analysis of the RLTPR genes from eight psoriasis patients and eight healthy controls revealed a number of synonymous and nonsynonymous SNPs that may be useful markers for future disease association studies.

A case of atypical benign fibrous histiocytoma.

A case of atypical benign fibrous histiocytoma is reported. A 62-year-old Japanese female visited our clinic because of an asymptomatic solitary lesion on the skin of the left leg. Physical examination revealed a polypoid mass lesion (2.5 x 2.3 x 1.8 cm) with central erosion. The lesion began with a 1 mm-sized papule and slowly enlarged over the 20 years. Clinical diagnosis was a malignant tumor such as dermatofibrosarcoma protuberans, atypical fibroxanthoma or adnexal tumors. Biopsy of the polypoid lesion was carried out. Histopathological examination revealed a polypoid lesion consisting of proliferation of fibroblast-like spindle cells in the dermis. Large atypical cells with pleomorphic nuclei were occasionally observed but mitotic figures were rare. From immunohistochemical results (CD68, Factor-XIII, MIB-1 labeling index), we diagnosed this case as "atypical benign fibrous histiocytoma (ABFH)". Clear distinction has not been made between ABFH, a variant of benign fibrous histiocytoma, and atypical fibroxanthoma, which is a variant of malignant fibrous histiocytoma. Here we report a case of ABFH with a diagnosis of the neoplasm.

hRDH-E2 gene polymorphisms, variable transcriptional start sites, and psoriasis.

hRDH-E2 is a member of the short-chain alcohol dehydrogenase/reductase (SDR) family that converts retinol to retinaldehyde as the first and rate-limiting step in the retinoic acid synthetic pathway. This pathway is critical for the maintenance of epidermal homeostasis in vivo. Previously, we reported that the mRNA levels of hRDH-E2 in psoriatic skin were elevated significantly compared with that in healthy individual skin and psoriatic unaffected skin. The gene encoding hRDH-E2 is located on Chromosome 8 close to a candidate region for psoriasis and therefore is a functional and positional candidate for this disorder. In the present study, the transcription start sites for hRDH-E2 gene transcription in the lung were found to be more upstream of those that were identified previously in keratinocytes. Consequently, differences in the nucleotide sequence were determined for all of the coding exons, untranslated regions, and at least 2850 bp of 5'-noncoding sequence of hRDH-E2 by direct sequencing of polymerase chain reaction (PCR)-amplified DNA samples obtained from 8 psoriatic patients and 8 healthy controls. One polymorphic microsatellite marker at the noncoding 3' end of the gene and six single nucleotide polymorphisms (SNPs) (three in the 5' flanking sequence, two in the coding sequence, and one in the intronic sequence) were identified. One of the SNPs was nonsynonymous in the second exon with an allelic variation between the amino acid sequences Arg and Trp. The microsatellite marker and the six SNPs were all genotyped in 100 Japanese psoriatic patients and 120 controls. However, there were no statistically significant differences in the genotype or allele frequency distributions between the cases and controls. On this basis, we conclude that the polymorphisms that we detected for the hRDH-E2 gene do not contribute to the etiology of psoriasis but may be important in diseases of other tissues.

Genetic association analysis using microsatellite markers in atopic dermatitis.

Atopic dermatitis (AD) is presumed to be influenced by genetic and environmental factors. In this study, 54 patients with AD were examined for disease association by the use of 12 microsatellite markers. Several significant associations were recognized in the alleles on chromosome 5, 7 and 11. AD genes were mapped near the FC epsilon RI beta gene (around D11S1314 locus) on chromosome 11, the IL4 gene cluster on chromosome 5 and the TCR gamma gene on chromosome 7. This distribution in close proximity to candidate loci for AD is very similar to that of atopic genes, therefore implying that an atopic trait is genetically responsible for the development of AD.