Psoriasis is a chronic inflammatory skin disease characterized by raised, well-demarcated, erythematous plaques and can significantly impair a patient's quality of life. 1,2 Recent advances in genetic analysis technology have revealed the contribution of the HLA-C locus to psoriasis. 3,4 Along with loci relating to the major histocompatibility complex (MHC), genome-wide association studies (GWAS) for psoriasis and psoriatic arthritis have revealed loci relating to immunological genes. Thus, psoriasis develops on the background of susceptibility to immunological challenges. Hematopoietic stem cell transplantation (HSCT) is a treatment for hematologic tumors and immunodeficiency diseases. HLA mismatch transplantations are occasionally performed and can result in HLA haplotype changes after transplantation. Given that the HLA loci are associated with the genetic background of psoriasis, there is a possibility that psoriasis may be induced or exacerbated if this change in HLA haplotypes occurs. In this study, we retrospectively investigated 378 pediatric patients who had undergone HSCT and

Psoriasis is a chronic inflammatory skin disease that affects approximately 2%-3% of the world's population and below 0.5% of the Asian population. [1][2][3][4] As the molecular pathology of psoriasis is elucidated, biologics, which selectively block certain molecules in inflammatory cascades, have proved their great effect and impact not only on psoriasis treatment but also on the quality of life of patients. Antibodies against tumor necrosis factor alpha (TNF) were the first series of biologics applied for psoriasis. Infliximab (IFX), a chimeric monoclonal antibody

Ectopic extramammary Paget’s disease (EMPD) is a rare variant of EMPD that develops in nonapocrine regions. Since reports about ectopic EMPD are limited, little is known about the biological and immunological background of ectopic EMPD. In this report, we present a case of ectopic EMPD on the lower abdomen that expressed RANKL but lacked the expression of MMP7. As we previously reported, Paget’s cells express RANKL and MMP7, release soluble RANKL in the tumor microenvironment, and stimulate tumor-associated macrophages to produce tumor-loading factors in conventional EMPD. In our present case, both CCL5-expressing cells and MMP25-bearing cells were lacking, whereas substantial numbers of CCL5-expressing cells and MMP25-bearing cells were found in conventional EMPD. Our case suggested that the lack of MMP7 on Paget’s cells might be one of the possible explanations for the biology of ectopic EMPD.