However, we did not detect antibodies against desmogleins. no patients with other IIMs did (p< 0.001). Skin eruption with ash-like scales was observed in four HMGCR-IMNM patients, and non-scaly reddish patches and lumps in the other four patients; accordingly, their skin manifestations were considered as other dermal diseases except for IIM. However, skin and muscle mass biopsies revealed the atypical skin conditions of patients with HMGCR-IMNM to have the same pathological background, created by Bcl-2-positive lymphocyte infiltrations. == Conclusions == HMGCR-IMNM patients frequently have atypical skin conditions of the neck and back. Skin biopsy specimens from these lesions showed the same Bcl-2-positive lymphocytic infiltrations as muscle mass biopsy specimens regardless of the different gross dermal Gw274150 findings. Thus, such atypical skin conditions may be suggestive for HMGCR-IMNM. == Supplementary Information == The online version contains supplementary material available at 10.1186/s12865-024-00622-2. Keywords:3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGCR), Immune-mediated necrotizing myopathy, Jessners lymphocytic infiltration of skin, Bcl-2 == Background == Idiopathic inflammatory myopathies (IIMs) are a rare group of autoimmune diseases that can cause chronic inflammation of skeletal muscle mass and/or organs, including the skin, joints, lungs, gastrointestinal tract, and heart. Muscle mass involvement may cause muscle mass weakness, and extramuscular manifestations may lead to life-threatening complications [1,2]. Immune-mediated necrotizing myopathy (IMNM) is an IIM characterized by predominant muscle mass fiber necrosis and regeneration with little inflammation [3,4]. It is frequently associated with anti-signal acknowledgement particle (anti-SRP) and anti-3-hydroxy-3-methyl-glutaryl-coenzyme A reductase (anti-HMGCR) autoantibodies [514]. These autoantibodies produce almost the same clinical and pathological manifestations, including proximal muscle mass weakness and a high serum CK value. Despite the presence of dermatomyositis (DM), patients with IMNM usually have no skin conditions or interstitial pneumonia [911]. Recently, several reports have indicated that skin conditions including DM-like skin rash, Jessner-Kanoff disease, and cutaneous lymphoma are not rare in patients with anti-HMGCR antibody-positive IMNM Rabbit Polyclonal to ATXN2 (HMGCR-IMNM) [1517]. However, the incidence and phenotype of skin conditions in such patients are not yet fully known because HMGCR-IMNM is usually included in polymyositis (PM) according to EULAR/ACR Classification Gw274150 Criteria [18]. HMGCR is an enzyme resident in the endoplasmic reticulum that catalyzes the rate-limiting step of cholesterol biosynthesis within the mevalonate pathway [19]. It can be competitively inhibited by statins [20], which are widely used to lower cholesterol levels. Previous studies have reported that statins induce apoptosis of Bcl-2-positive lymphoma cells [21]; recently, it has also become evident that statins have pleiotropic immunological effects including antigen-presenting cells and T cells [22,23] and can even prevent tumor development and T-cell lymphomas [2426]. Statins also inhibit beta chemokine receptor 4 [27], which is expressed in Th2 lymphocytes and is the key molecule of adult T-cell lymphoma and human T-cell leukemia computer virus type 1-associated myelopathy [28]. In contrast to statins, you will find no previous reports of anti-HMGCR antibody having an association with lymphomas or pleiotropic immunomodulatory effects. However, we previously reported dermal and muscular Bcl-2-positive lymphocytic infiltrations in patients with HMGCR-IMNM [29]. Some HMGCR-IMNM patients with Gw274150 skin conditions histologically showed lymphocytic inflammatory infiltrates with perivascular arrangement and accumulation, which were mainly composed of small lymphocytes with histiocytes [29]. As such, clarifying the dermal manifestation of HMGCR-IMNM could reveal characteristics of anti-HMGCR antibody-positive myopathy. Here we retrospectively examined 88 consecutive patients with IIM by focusing on skin condition and offered dermal manifestations of HMGCR-IMNM compared with other IIMs. Though patients with HMGCR-IMNM rarely showed DM-like rashes including heliotrope eyelids, Gottrons sign, and mechanics hands, about 40% offered skin conditions that were clinically and pathologically different from DM-like rashes. Our findings enable us to more easily distinguish HMGCR-IMNM from other IIMs and suggest that HMGCR-IMNM might have a unique pathomechanism. == Methods == == Study design and patients == This is a cross-sectional study of 100 consecutive Japanese patients with IIM. We retrospectively collected demographic information, symptoms, physical examination findings, and internal organ involvement. We included all adults diagnosed as having IIM and Gw274150 followed up at the National Hospital Business Kure Medical Center and Chugoku Malignancy Center from April 2015 through August 2022. The data for this study was analyzed in January 2023. Participants.