[A case of dermatomyositis positive for anti-nuclear matrix protein 2 antibody without dermatologic symptoms].

We report a 47-year-old woman who presented with progressive myalgia, weakness in the proximal limbs, and dysphagia for a month and a half. No skin rash was observed on admission. Examination of MRI data suggested inflammatory changes in the proximal limbs and trunk muscles. Biopsy specimens from the left biceps muscle showed no perifascicular atrophy, but immunohistochemical staining revealed the presence of myxovirus resistance protein A (MxA) in myofibers, strongly suggesting dermatomyositis (DM). In addition, her serum was positive for anti-nuclear matrix protein 2 (anti-NXP-2) antibody, which is reportedly useful as a marker of DM without skin lesions. Her symptoms gradually improved upon intravenous methylprednisolone pulse therapy in conjunction with oral prednisolone, oral tacrolimus, and intravenous immunoglobulin therapy. Our findings suggest that in cases where inflammatory muscle disease is suspected, anti-NXP-2 antibody analyses should be considered for precise diagnosis, even if there are no dermatological symptoms.

Renal cell carcinoma with central nervous system demyelination caused by nivolumab.

INTRODUCTION: Central nervous system demyelination caused by immune checkpoint inhibitors is a very rare condition. CASE PRESENTATION: A 65-year-old man who received nivolumab for renal cell carcinoma developed abnormal behavior, such as disagreeable speech and sudden anger. Brain-enhanced magnetic resonance imaging revealed multiple lesions with partial contrast effects in the cerebral white matter. We tentatively diagnosed demyelination caused by nivolumab, and performed steroid pulse therapy twice. After that, his symptoms improved. For the next 2 years, his symptoms did not recur, nor did his cancer progress. CONCLUSION: Demyelination caused by immune checkpoint inhibitors can be fatal and requires early diagnosis and treatment.

Association of Dermatomyositis Sine Dermatitis With Anti-Nuclear Matrix Protein 2 Autoantibodies.

Importance: Reports on dermatomyositis (DM) sine dermatitis (DMSD) are scarce, and the concept of the disease has not been widely accepted. Objective: To confirm the existence of DMSD, determine its prevalence, and characterize its serologic features. Design, Setting, and Participants: This is a cohort study that reviewed clinical information, laboratory data, and muscle pathology slides from January 2009 to August 2019. We further assessed the follow-up data of 14 patients with DMSD. The median (interquartile range) follow-up period was 34 (16-64) months. Muscle biopsy samples, along with clinical information and laboratory data, were sent to a referral center for muscle diseases in Japan for diagnosis. Of patients whose myopathologic diagnosis was made at the National Center of Neurology and Psychiatry between January 2009 and August 2019, 199 patients were eligible for inclusion. These patients underwent full investigation for DM-specific autoantibodies (against transcriptional intermediary factor γ, Mi-2, melanoma differentiation-associated gene 5, nuclear matrix protein 2 [NXP-2], and small ubiquitin-like modifier activating enzyme ); however, 17 patients were excluded because their muscle fibers did not express myxovirus resistance protein A, a sensitive and specific marker of DM muscle pathology. Main Outcomes and Measures: Diagnosis of DMSD was based on the absence of a skin rash at the time of muscle biopsy. Results: Of the 182 patients, 93 were women (51%) and 46 were children (25%) (<18 years). Fourteen patients (8%) had DMSD and none were clinically diagnosed with DM. Among the 14 patients with DMSD, 12 (86%) were positive for anti-NXP-2 autoantibodies, while the remaining 2 were positive for anti-transcriptional intermediary factor γ and anti-Mi-2 autoantibodies, respectively. Only 28% of patients (47 of 168) with a skin rash were positive for anti-NXP-2 autoantibodies, indicating a significant association between anti-NXP-2 autoantibodies and DMSD (86% [12 of 14] vs 28% [47 of 168]; P < .001). This association was also supported by multivariable models adjusted for disease duration (odds ratio, 126.47; 95% CI, 11.42-1400.64; P < .001). Conclusions and Relevance: Dermatomyositis sine dermatitis does exist and accounts for 8% of patients with DM confirmed with muscle biopsy. Dermatomyositis sine dermatitis is significantly associated with anti-NXP-2 autoantibodies, which contrasts with anti-MDA5 DM, which is typically clinically amyopathic in presentation. It is essential to distinguish DMSD from other types of myositis because DM-specific therapies that are currently under development, including Janus kinase inhibitors, may be effective for DMSD.

A case of central nervous system relapse in acute promyelocytic leukemia.

A 70-year-old woman who have achieved complete remission (CR) of acute promyelocytic leukemia (APL) with all-trans retinoic acid and chemotherapy presented with abnormal sensation in the right lateral thigh and the bilateral legs. In addition, neurological examination revealed weakness of the left shoulder abduction, the right hand, and the bilateral lower limbs. Atypical promyelocytes were detected in the cerebrospinal fluid, in spite of normal finding in the peripheral blood smear. Magnetic resonance imaging showed gadolinium-enhanced multiple intradural/extramedullary lesions in the whole spine. Nerve conduction studies of the right limbs revealed sensorimotor conduction abnormalities, conspicuously in the posterior tibial and sural nerves. As a result, she was diagnosed as having intrathecal relapse of APL, associated with multiple mononeuropathy. The neurological symptoms were completely disappeared by intrathecal chemotherapy and whole-spine radiotherapy, suggesting that the neuropathy was possibly caused by meningeal infiltration affecting multiple spinal nerve roots. Since extramedullary or intrathecal relapse is extremely rare in APL compared with other types of leukemia, precise neurological evaluations and suitable treatment should be performed immediately, when APL patients with CR manifest some neurological symptoms.

Hepatoma-derived growth factor is a neurotrophic factor harbored in the nucleus.

Hepatoma-derived growth factor (HDGF) is a heparin-binding proliferating factor originally isolated from conditioned medium of the hepatoma-derived cell line HuH-7. HDGF has greatest homology in an amino acid sequence with high mobility group 1 (HMG1), which has been characterized as a DNA-binding, inflammatory, and potent neurite outgrowth molecule. HDGF is reported to be widely expressed and act as a growth factor in many kinds of cells. However, it has not been investigated in the nervous system. Here, we show by Western blot analysis that HDGF is present in the mouse brain from the embryonic period until adulthood. In situ hybridization and immunohistochemical analyses revealed that HDGF was expressed mainly in neurons, and HDGF protein was localized to the nucleus. HDGF and high mobility group 1 were secreted under physiological conditions and released extracellularly in necrotic conditions. Furthermore, we showed that exogenously supplied HDGF had a neurotrophic effect and was able to partially prevent the cell death of neurons in which endogenous HDGF was suppressed. Therefore, we propose that HDGF is a novel type of neurotrophic factor, on account of its localization in the nucleus and its potential to function in an autocrine manner under both physiological and pathological conditions throughout life.