Genetic insights into Tietz albinism-deafness syndrome: A new dominant-negative mutation in MITF

Tietz albinism-deafness syndrome (TADS) is a rare and severe manifestation of Waardenburg syndrome that is primarily linked to mutations in MITF. In this report, we present a case of TADS resulting from a novel c.637G>C mutation in MITF (p.Glu213Gln; GenBank Accession number: NM_000248). A 3-year-old girl presented with congenital generalized hypopigmentation of the hair, skin, and irides along with complete sensorineural hearing loss. Histopathological and electron microscopy investigations indicated that this variant did not alter the number of melanocytes in the skin but significantly impaired melanosome maturation within melanocytes. Comprehensive melanin analysis revealed marked reductions in both eumelanin (EM) and pheomelanin (PM) rather than changes in the EM-to-PM ratio observed in oculocutaneous albinism. We conducted an electrophoretic mobility shift assay to investigate the binding capability of the identified variant to DNA sequences containing the E-box motif along with other known variants (p.Arg217del and p.Glu213Asp). Remarkably, all three variants exhibited dominant-negative effects, thus providing novel insights into the pathogenesis of TADS. This study sheds light on the genetic mechanisms underlying TADS and offers a deeper understanding of this rare condition and its associated mutations in MITF.

Effects of empagliflozin on progression of chronic kidney disease: a prespecified secondary analysis from the empa-kidney trial

BACKGROUND

Sodium-glucose co-transporter-2 (SGLT2) inhibitors reduce progression of chronic kidney disease and the risk of cardiovascular morbidity and mortality in a wide range of patients. However, their effects on kidney disease progression in some patients with chronic kidney disease are unclear because few clinical kidney outcomes occurred among such patients in the completed trials. In particular, some guidelines stratify their level of recommendation about who should be treated with SGLT2 inhibitors based on diabetes status and albuminuria. We aimed to assess the effects of empagliflozin on progression of chronic kidney disease both overall and among specific types of participants in the EMPA-KIDNEY trial.

METHODS

EMPA-KIDNEY, a randomised, controlled, phase 3 trial, was conducted at 241 centres in eight countries (Canada, China, Germany, Italy, Japan, Malaysia, the UK, and the USA), and included individuals aged 18 years or older with an estimated glomerular filtration rate (eGFR) of 20 to less than 45 mL/min per 1·73 m2, or with an eGFR of 45 to less than 90 mL/min per 1·73 m2 with a urinary albumin-to-creatinine ratio (uACR) of 200 mg/g or higher. We explored the effects of 10 mg oral empagliflozin once daily versus placebo on the annualised rate of change in estimated glomerular filtration rate (eGFR slope), a tertiary outcome. We studied the acute slope (from randomisation to 2 months) and chronic slope (from 2 months onwards) separately, using shared parameter models to estimate the latter. Analyses were done in all randomly assigned participants by intention to treat. EMPA-KIDNEY is registered at ClinicalTrials.gov, NCT03594110.

FINDINGS

Between May 15, 2019, and April 16, 2021, 6609 participants were randomly assigned and then followed up for a median of 2·0 years (IQR 1·5-2·4). Prespecified subgroups of eGFR included 2282 (34·5%) participants with an eGFR of less than 30 mL/min per 1·73 m2, 2928 (44·3%) with an eGFR of 30 to less than 45 mL/min per 1·73 m2, and 1399 (21·2%) with an eGFR 45 mL/min per 1·73 m2 or higher. Prespecified subgroups of uACR included 1328 (20·1%) with a uACR of less than 30 mg/g, 1864 (28·2%) with a uACR of 30 to 300 mg/g, and 3417 (51·7%) with a uACR of more than 300 mg/g. Overall, allocation to empagliflozin caused an acute 2·12 mL/min per 1·73 m2 (95% CI 1·83-2·41) reduction in eGFR, equivalent to a 6% (5-6) dip in the first 2 months. After this, it halved the chronic slope from -2·75 to -1·37 mL/min per 1·73 m2 per year (relative difference 50%, 95% CI 42-58). The absolute and relative benefits of empagliflozin on the magnitude of the chronic slope varied significantly depending on diabetes status and baseline levels of eGFR and uACR. In particular, the absolute difference in chronic slopes was lower in patients with lower baseline uACR, but because this group progressed more slowly than those with higher uACR, this translated to a larger relative difference in chronic slopes in this group (86% [36-136] reduction in the chronic slope among those with baseline uACR <30 mg/g compared with a 29% [19-38] reduction for those with baseline uACR ≥2000 mg/g; ptrend<0·0001).

INTERPRETATION

Empagliflozin slowed the rate of progression of chronic kidney disease among all types of participant in the EMPA-KIDNEY trial, including those with little albuminuria. Albuminuria alone should not be used to determine whether to treat with an SGLT2 inhibitor.

FUNDING

Boehringer Ingelheim and Eli Lilly.

Impact of primary kidney disease on the effects of empagliflozin in patients with chronic kidney disease: secondary analyses of the EMPA-KIDNEY trial

BACKGROUND

The EMPA-KIDNEY trial showed that empagliflozin reduced the risk of the primary composite outcome of kidney disease progression or cardiovascular death in patients with chronic kidney disease mainly through slowing progression. We aimed to assess how effects of empagliflozin might differ by primary kidney disease across its broad population.

METHODS

EMPA-KIDNEY, a randomised, controlled, phase 3 trial, was conducted at 241 centres in eight countries (Canada, China, Germany, Italy, Japan, Malaysia, the UK, and the USA). Patients were eligible if their estimated glomerular filtration rate (eGFR) was 20 to less than 45 mL/min per 1·73 m2, or 45 to less than 90 mL/min per 1·73 m2 with a urinary albumin-to-creatinine ratio (uACR) of 200 mg/g or higher at screening. They were randomly assigned (1:1) to 10 mg oral empagliflozin once daily or matching placebo. Effects on kidney disease progression (defined as a sustained ≥40% eGFR decline from randomisation, end-stage kidney disease, a sustained eGFR below 10 mL/min per 1·73 m2, or death from kidney failure) were assessed using prespecified Cox models, and eGFR slope analyses used shared parameter models. Subgroup comparisons were performed by including relevant interaction terms in models. EMPA-KIDNEY is registered with ClinicalTrials.gov, NCT03594110.

FINDINGS

Between May 15, 2019, and April 16, 2021, 6609 participants were randomly assigned and followed up for a median of 2·0 years (IQR 1·5-2·4). Prespecified subgroupings by primary kidney disease included 2057 (31·1%) participants with diabetic kidney disease, 1669 (25·3%) with glomerular disease, 1445 (21·9%) with hypertensive or renovascular disease, and 1438 (21·8%) with other or unknown causes. Kidney disease progression occurred in 384 (11·6%) of 3304 patients in the empagliflozin group and 504 (15·2%) of 3305 patients in the placebo group (hazard ratio 0·71 [95% CI 0·62-0·81]), with no evidence that the relative effect size varied significantly by primary kidney disease (pheterogeneity=0·62). The between-group difference in chronic eGFR slopes (ie, from 2 months to final follow-up) was 1·37 mL/min per 1·73 m2 per year (95% CI 1·16-1·59), representing a 50% (42-58) reduction in the rate of chronic eGFR decline. This relative effect of empagliflozin on chronic eGFR slope was similar in analyses by different primary kidney diseases, including in explorations by type of glomerular disease and diabetes (p values for heterogeneity all >0·1).

INTERPRETATION

In a broad range of patients with chronic kidney disease at risk of progression, including a wide range of non-diabetic causes of chronic kidney disease, empagliflozin reduced risk of kidney disease progression. Relative effect sizes were broadly similar irrespective of the cause of primary kidney disease, suggesting that SGLT2 inhibitors should be part of a standard of care to minimise risk of kidney failure in chronic kidney disease.

FUNDING

Boehringer Ingelheim, Eli Lilly, and UK Medical Research Council.

Rational design of a JAK1-selective siRNA inhibitor for the modulation of autoimmunity in the skin

Inhibition of Janus kinase (JAK) family enzymes is a popular strategy for treating inflammatory and autoimmune skin diseases. In the clinic, small molecule JAK inhibitors show distinct efficacy and safety profiles, likely reflecting variable selectivity for JAK subtypes. Absolute JAK subtype selectivity has not yet been achieved. Here, we rationally design small interfering RNAs (siRNAs) that offer sequence-specific gene silencing of JAK1, narrowing the spectrum of action on JAK-dependent cytokine signaling to maintain efficacy and improve safety. Our fully chemically modified siRNA supports efficient silencing of JAK1 expression in human skin explant and modulation of JAK1-dependent inflammatory signaling. A single injection into mouse skin enables five weeks of duration of effect. In a mouse model of vitiligo, local administration of the JAK1 siRNA significantly reduces skin infiltration of autoreactive CD8+ T cells and prevents epidermal depigmentation. This work establishes a path toward siRNA treatments as a new class of therapeutic modality for inflammatory and autoimmune skin diseases.

Pulmonary manifestation of inflammatory bowel disease: Two case reports

Pulmonary involvement associated with inflammatory bowel disease (IBD) are a rare extraintestinal manifestation (EIM) of inflammatory bowel disease (IBD), we herein presented two cases. Case 1: 53-year-old man with Crohn's disease treated with mesalazine and azathioprine. Pulmonary nodular shadows were incidentally detected on chest imaging, and revealed granulomas through transbronchial lung biopsy. Case 2: 68-year-old man with ulcerative colitis treated with mesalazine. He presented with fever and respiratory symptoms, and chest imaging showed multiple nodular infiltrates. He was diagnosed with organizing pneumonia by lung biopsy. Both cases were diagnosed to have pulmonary involvement associated with inflammatory bowel disease (IBD) according to multidisciplinary examination including positron emission tomography-computed tomography (FDG-PET) and pathological test. Pulmonary manifestations with IBD may not always require discontinuation of drugs or additional use of steroids or immunosuppressants.

Painless thyroiditis mimicking relapse of hyperthyroidism during or after potassium iodide or thionamide therapy for Graves' disease resulting in remission

The diagnosis of painless thyroiditis (PT) during antithyroid drug (ATD) treatment of Graves' disease (GD) is difficult. We evaluated the thyroidal radioactive iodine uptake (RAIU) in 100 patients with relapsed thyrotoxicosis during or after careful ATD treatment. The RAIU was <5%/5 h in 35 patients (35%) (Group A - PT), 5%-15%/5 h in 6 patients (6%) (Group B - indefinite) and >15%/5 h in 59 patients (59%) (Group C - relapsed GD [rGD]). TSH receptor antibody (TBII) was positive in 4 (11.4%), 3 (50.0%) and 39 (only 66.1%) patients in Groups A, B and C, respectively. In Group A, the serum fT₄ level spontaneously normalized after 35 (26-56) days, sometimes followed by transient hypothyroidism, confirming the diagnosis of PT. Nineteen (54.3%) had been treated with potassium iodide, and PT frequently occurred ironically when the ATD dosage was reduced. PT repeatedly occurred in nine patients. All went into remission smoothly or developed hypothyroidism, except one patient with strongly positive TBII who developed rGD after the resolution of PT (PT on GD). In 10 (50%) of 20 patients with negative TBII despite rGD in Group C, TBII became positive afterwards. In conclusion, it is important to recognize that PT can occur in the clinical course of GD, resulting in frequent remission despite relapse of PT. The thyroid function reflects the balance between the stimulating TBII activity and the responsiveness of the thyroid tissue (sometimes unresponsive and other times autostimulated). The RAIU is still a valuable tool in cases of ambiguous thyrotoxicosis.

Activation of the NLRP1 inflammasome in human keratinocytes by the dsDNA mimetic poly(dA:dT)

The accrual of cytosolic DNA leads to transcription of type I IFNs, proteolytic maturation of the IL-1 family of cytokines, and pyroptotic cell death. Caspase-1 cleaves pro-IL1β to generate mature bioactive cytokine and gasdermin D which facilitates IL-1 release and pyroptotic cell death. Absent in melanoma-2 (AIM2) is a sensor of dsDNA leading to caspase-1 activation, although in human monocytes, cGAS-STING acting upstream of NLRP3 mediates the dsDNA-activated inflammasome response. In healthy human keratinocytes, AIM2 is not expressed yet caspase-1 is activated by the synthetic dsDNA mimetic poly(dA:dT). Here, we show that this response is not mediated by either AIM2 or the cGAS-STING-NLRP3 pathway and is instead dependent on NLRP1. Poly(dA:dT) is unique in its ability to activate NLRP1, as conventional linear dsDNAs fail to elicit NLRP1 activation. DsRNA was recently shown to activate NLRP1 and prior work has shown that poly(dA:dT) is transcribed into an RNA intermediate that stimulates the RNA sensor RIG-I. However, poly(dA:dT)-dependent RNA intermediates are insufficient to activate NLRP1. Instead, poly(dA:dT) results in oxidative nucleic acid damage and cellular stress, events which activate MAP3 kinases including ZAKα that converge on p38 to activate NLRP1. Collectively, this work defines a new activator of NLRP1, broadening our understanding of sensors that recognize poly(dA:dT) and advances the understanding of the immunostimulatory potential of this potent adjuvant.

Pulmonary and Intestinal Involvement in a Patient with Myeloperoxidase-specific Antineutrophil Cytoplasmic Antibody-positive Hermansky-Pudlak Syndrome

A 26-year-old Japanese woman was admitted with a 1-month history of diarrhea, a high fever for a few days, and exacerbation of dyspnea. She was treated with an antifibrotic drug and long-term oxygen therapy for Hermansky-Pudlak syndrome-related pulmonary fibrosis. New ground-glass attenuation appeared on chest computed tomography (CT), and a colon biopsy showed an inflammatory cell accumulation with a high titer of myeloperoxidase (MPO)-specific anti-neutrophil cytoplasmic antibodies (ANCA). Systemic inflammation related to MPO-ANCA titer elevation was suspected. Steroid pulse therapy and intravenous cyclophosphamide improved chest CT findings and diarrhea. Therefore, immunosuppressant treatment should be considered for systemic inflammation related to MPO-ANCA.

Iodide-sensitive Graves' hyperthyroidism and the strategy for resistant or escaped patients during potassium iodide treatment

The effectiveness of potassium iodide (KI) (100 mg/day) was evaluated in 504 untreated patients with Graves' hyperthyroidism (GD). Initial response to KI within 180 days, the effect of additional methylmercaptoimidazole (MMI) or radioactive iodine (RI) in resistant or escaped patients, and long-term prognosis were evaluated. Serum fT₄ levels became low or normal in 422 patients (83.7%, KI-sensitive group) without serious side effects. Among these patients, serum TSH levels became high (n = 92, hypothyroid) or normal (n = 78) in 170 patients (33.7%) (KI-sensitive with a recovered TSH response, Group A), but remained suppressed in 252 patients (50.0%) (KI-sensitive with TSH suppression, Group B). Serum fT₄ levels decreased but remained high in 82 patients (16.3%) (KI-resistant, Group C). Older patients, or those with small goiter and mild GD were more KI-sensitive with a recovered TSH response than others. Escape from KI effect occurred in 0%, 36% and 82% in Group A, B and C, respectively. Patients in Group B and C were successfully treated with additional low-dosage MMI or RI. After 2-23 years' treatment (n = 429), remission (including possible remission) and spontaneous hypothyroidism were significantly more frequent in Group A (74.3% and 11.1%, respectively,) than in Groups B (46.3% and 2.8%, respectively) or C (53.6% and 1.5%, respectively) (p < 0.0001). In conclusion, a high KI sensitivity with a recovered TSH response was observed in about a third of the patients in GD associated with a better prognosis. Additional MMI or RI therapy was effective in escaped or KI-resistant patients with suppressed TSH level.

A case of Graves' disease presenting with internal ophthalmoplegia during methylmercaptoimidazole treatment

A 28-year-old Japanese woman positive for TSH receptor antibody and anti-nuclear antibody complained of difficulty seeing nearby objects, severe throbbing retro-orbital pain, diplopia, blepharoptosis and upward gaze palsy when she became hypothyroid during treatment with 30 mg methylmercaptoimidazole for Graves' hyperthyroidism. Brain magnetic resonance imaging revealed slightly swollen bilateral inferior rectus muscles, suggesting the external ophthalmoplegia due to the muscle pathology commonly encountered in Graves' disease. The retro-orbital pain was associated with marked accommodation failure and the pupillary abnormalities. The left and/or right eye showed intermittent, asymmetric and fluctuating mydriasis, being unresponsive to ordinary light but slowly responsive to strong sunlight and slowly responsive in a dark room. During the 5-year period, mydriasis was observed 9 times on both sides, 11 times only on the right side and 4 times only on the left side. Internal ophthalmoplegia with tonic pupils and accommodation failure affecting both the pupillary sphincter muscle and ciliary muscle due to damage to the parasympathetic outflow to these muscles was suggested. Autoimmune mechanism and/or the mechanism underlying channelopathy affecting the ciliary ganglion or short ciliary nerves might be responsible for this fluctuating complication. This very rare panophthalmopathy affecting both external and internal muscles occurred when the patient was suffering from iatrogenic hypothyroidism during the 30 mg methylmercaptimidazole treatment for Graves' disease.

Acute respiratory failure due to Aspergillus niger infection with acute fibrinous and organazing pneumonia: A case report

A 59-year-old woman complaining of wet cough, hemoptysis, slight fever, anorexia, and malaise was admitted to hospital with suspected lobar pneumonia. She received treatment for myocardial infarction and deep venous thrombosis caused by familial protein C deficiency. Rapid deterioration due to respiratory failure occurred despite intensive care with broad-spectrum antibiotics. At a later date, sputum examination revealed the presence of Aspergillus niger. Based on clinical and autopsy findings, she was diagnosed with acute respiratory failure due to pulmonary aspergillosis with acute fibrinous and organizing pneumonia. This is the first reported case of pulmonary aspergillosis with acute fibrinous and organizing pneumonia complicated by calcium oxalate resulting from Aspergillus niger infection, leading to severe inflammation and tissue injury in the lungs.

Impact of a SLC24A5 variant on the retinal pigment epithelium of a Japanese patient with oculocutaneous albinism type 6

Oculocutaneous albinism (OCA) 6 is a non-syndromic type of OCA that has distinct ocular symptoms and variable cutaneous hypopigmentation. The causative gene of OCA6 is SLC24A5, which encodes NCKX5, a K⁺ -dependent Na⁺ /Ca²⁺ exchanger 5. NCKX5 is involved in the maturation of melanosomes, but its function is still unclear. In this study, we characterized a Japanese patient with OCA6. Genetic analysis revealed compound heterozygous variants in SLC24A5, c.590 + 1dupG, and c.598G>A (p.G200R). To clarify the functional significance of the missense variant, we generated a knock-in (KI) mouse model carrying the mouse homolog of the G200R variant using the CRISPR/Cas9 system. Chemical analysis showed decreased amounts of eumelanin in the hair and skin of KI mice, while levels of benzothiazine units in pheomelanin were significantly increased in their hair. Retinal pigment was also decreased in KI mice. Notably, a histopathologic study revealed a significant pigment loss in the retinal pigment epithelium (RPE) but not in the choroid. Immunohistochemically, the expression of NCKX5 in the RPE was decreased but was maintained in the choroid of KI mice. These findings could explain the difference in phenotypic severity between eye symptoms and hypopigmentation in the skin/hair.

AIM2 regulates anti-tumor immunity and is a viable therapeutic target for melanoma

The STING and absent in melanoma 2 (AIM2) pathways are activated by the presence of cytosolic DNA, and STING agonists enhance immunotherapeutic responses. Here, we show that dendritic cell (DC) expression of AIM2 within human melanoma correlates with poor prognosis and, in contrast to STING, AIM2 exerts an immunosuppressive effect within the melanoma microenvironment. Vaccination with AIM2-deficient DCs improves the efficacy of both adoptive T cell therapy and anti–PD-1 immunotherapy for “cold tumors,” which exhibit poor therapeutic responses. This effect did not depend on prolonged survival of vaccinated DCs, but on tumor-derived DNA that activates STING-dependent type I IFN secretion and subsequent production of CXCL10 to recruit CD8⁺ T cells. Additionally, loss of AIM2-dependent IL-1β and IL-18 processing enhanced the treatment response further by limiting the recruitment of regulatory T cells. Finally, AIM2 siRNA-treated mouse DCs in vivo and human DCs in vitro enhanced similar anti-tumor immune responses. Thus, targeting AIM2 in tumor-infiltrating DCs is a promising new treatment strategy for melanoma.

Gaining Insight into Vitiligo Genetics through the Lens of a Large Epidemiologic Study

Several epidemiologic studies and GWASs have implicated genetic factors in the pathogenesis of vitiligo. The report by Kim et al. (2020) describes a prospective cohort study from Korea that has the greatest statistical power to date in addressing the epidemiology of vitiligo inheritance. The authors reported the incidence risk ratios in individuals whose first-degree relatives or spouses are affected, providing clear evidence that both genetic and nongenetic factors influence the pathogenesis of vitiligo.

Hemodilution Impacts Assessment of Thyroid Status before and after Hemodialysis in Patients with End-Stage Renal Disease

BACKGROUND

To elucidate the role of hemodilution in the alteration of thyroid hormone levels in end-stage renal disease (ESRD), we compared thyroid function before and after hemodialysis (HD).

METHODS

Twenty-three male ESRD patients (age <65 years) with either chronic glomerulonephritis (CGN) or diabetic nephropathy (DN), who were enrolled between June 2019 and August 2019, were included in the study. The free thyroxine (fT4), free tri-iodothyronine (fT3), and thyroid-stimulating hormone (TSH), thyroxine-binding globulin (TBG), and thyroglobulin (Tg), measured before and after HD in 12 patients with CGN (48.7 ± 11.8 years [mean ± standard deviation]) and 11 patients with DN (57.6 ± 6.5 years), were compared with 45 healthy controls (52.5 ± 11.9 years).

RESULTS

The fT4, fT3, and TBG were significantly low before HD and increased in parallel with an increase in hematocrit and albumin after HD in both ESRD subgroups. The TSH was high before HD and decreased significantly after HD, while Tg remained almost unchanged. In DN, the fT4 levels were nearly identical, while fT3 was lower with slightly higher TSH, compared with CGN. The TSH/fT4 ratios before HD were significantly higher in both subgroups, and the fT3/fT4 ratios after HD were significantly lower in DN than the control.

CONCLUSIONS

Our findings suggest that the low fT4 and fT3 levels found in ESRD are due to hemodilution before HD, resulting in a slightly higher TSH level but almost unchanged Tg level, and that DN is associated with decreased T4-to-T3 conversion.

Benford's Law and COVID-19 reporting

Trust in the reported data of contagious diseases in real time is important for policy makers. Media and politicians have cast doubt on Chinese reported data on COVID-19 cases. We find Chinese confirmed infections match the distribution expected in Benford's Law and are similar to that seen in the U.S. and Italy. We identify a more likely candidate for problems in the policy making process: Poor multilateral data sharing on testing and sampling.

Five novel mutations in SASH1 contribute to lentiginous phenotypes in Japanese families

SASH1 has been reported as a causal gene of lentiginous phenotypes with and without heredity, including an autosomal dominant type characterized by lentigines predominantly on sun-exposed areas such as the face and limbs. Recently, cases of dyschromatosis with SASH1 mutations have been reported worldwide; however, only one case has been reported from Japan. Here, we analyzed six Japanese patients who characteristically showed many lentigines on sun-exposed areas, using next-generation sequencing. We identified five novel heterozygous mutations in SASH1 (p.I586M, p.S531Y, p.R644W, p.T525R, and p.S516I) in our patients and their families. The p.R644W substitution identified in two unrelated families was the first mutation located in the sterile alpha motif 1 (SAM1) domain. The degree and location of the lentigines were variable across individuals, even if they shared the same SASH1 mutation. All mutations were predicted to be deleterious by six different algorithms used to evaluate the functional impact of a variation. In addition, immunohistopathological findings and RNA sequencing results suggested that SASH1 mutations were associated with an increase in the number of melanocytes, acceleration of melanogenesis, and upregulated hair keratin expression.

Current landscape of Oculocutaneous Albinism in Japan

Oculocutaneous albinism (OCA), which is roughly divided into non-syndromic and syndromic OCA, is a group of autosomal recessive disorders caused by mutations in genes associated with pigmentation. Patients with OCA have hypopigmentation and ocular manifestations such as photophobia, amblyopia, and nystagmus. Hermansky-Pudlak syndrome (HPS), the most common syndromic OCA, is characterized by the additional features of a bleeding tendency and other critical systemic comorbidities such as pulmonary fibrosis and immunodeficiency. NGS-based gene analyses have identified several new causative genes for OCA and have detected rare subtypes of OCA with high accuracy including Japanese patients. In our survey of 190 Japanese OCA patients/families, OCA4 is the most common subtype (25.3%) followed by OCA1 (20.0%), HPS1 (14.7%), and OCA2 (8.4%). Similar to the A481T variant in OCA2, which is associated with a mild form of OCA2 and skin color variation, the c.-492_489delAATG variant located in the promoter region of SLC45A2 has been uniquely identified in Japanese patients with a mild form of OCA4. Further, rare OCA subtypes, including OCA3, HPS2, HPS3, HPS4, HPS5, HPS6, and HPS9, have also been identified in Japanese patients. The clinical characteristics and underlying molecular mechanisms of each subtype of OCA are concisely summarized in this review.

Expression of discoidin domain receptor 1 and E-cadherin in epidermis affects melanocyte behavior in rhododendrol-induced leukoderma mouse model

Vitiligo is a depigmentation disease characterized by gradual loss of melanin and melanocytes from the epidermis. The mechanism of melanocyte loss is not yet known. In this report, we showed that the expression of discoidin domain receptor 1 and E-cadherin, known adhesion molecules, was variable or absent in the epidermis of rhododendrol-induced leukoderma (RDIL) mice during the depigmentation process. Our findings suggest that melanocyte damage by rhododendrol promotes reduction of adhesion molecules not only in melanocytes but also in keratinocytes, and this is associated with the detachment of melanocytes from the basal layer.

Clinical experience of treating Graves' hyperthyroidism complicated with malignancy-The possible role of potassium iodide for avoiding the risk of thionamide-associated neutropenia

The treatment of Graves' hyperthyroidism (GD) complicated with malignancy is challenging, as anti-thyroid thionamide drugs (ATDs) and anti-cancer chemotherapy are both associated with a risk of neutropenia. Treatment with conventional ATDs, radioactive iodine (RAI) or potassium iodide (KI) was attempted in 8 patients with malignancy (34-80 years of age; 2 males and 6 females) in whom GD had been fortuitously diagnosed during a detailed systematic examination. Three patients requiring surgery were initially treated conventionally with methylmercaptoimidazole (MMI), MMI and KI or RAI (group A; one patient each). The patients became euthyroid on days 17-31 and underwent surgery on days 25-47. RAI therapy was administered to one patient after surgery. The patients were then treated with KI during chemotherapy. Five other patients who did not require surgery were initially treated with 100 mg KI monotherapy (group B). The serum free T₄ level declined immediately in all of these patients, and they became euthyroid on days 7-18, remaining almost entirely euthyroid for more than 120 days. Anti-cancer chemotherapy was successfully completed for three of the patients while taking KI, despite the patients experiencing repeated episodes of anti-cancer chemotherapy-induced neutropenia. Our present findings suggest that, in patients with GD and malignancy, MMI + KI or RAI may be required if immediate surgery is scheduled, but KI monotherapy may be worth trying, if anti-cancer chemotherapy is scheduled, thus avoiding the possibility of thionamide-induced neutropenia.

Genome-wide association study identifies CDH13 as a susceptibility gene for rhododendrol-induced leukoderma

Racemic RS-4-(4-hydroxyphenyl)-2-butanol (rhododendrol; trade name: Rhododenol [RD]), which is used in topical skin-lightening cosmetics, was unexpectedly reported in Japan to induce leukoderma or vitiligo called RD-induced leukoderma (RIL) after repeated application. To our knowledge, no studies have investigated chemical-induced vitiligo pathogenesis on a genome-wide scale. Here, we conducted a genome-wide association study (GWAS) for 147 cases and 112 controls. CDH13, encoding a glycosylphosphatidylinositol-anchored protein called T-cadherin (T-cad), was identified as the strongest RIL susceptibility gene. RD sensitivity was remarkably increased by T-cad knockdown in cultured normal human melanocytes. Furthermore, we confirmed tyrosinase upregulation and downregulation of the anti-apoptotic molecules (BCL-2 and BCL-XL), suggesting that T-cad is associated with RD via tyrosinase or apoptotic pathway regulation. Finally, monobenzyl ether of hydroquinone sensitivity also tended to increase with T-cad knockdown, suggesting that the T-cad could be a candidate susceptibility gene for RIL and other chemical-induced vitiligo forms. This is the first GWAS for chemical-induced vitiligo, and it could be a useful model for studying the disease's genetic aspects.

P1554AEFFECT OF HAEMODILUTION ON THYROID FUNCTION BEFORE AND AFTER HAEMODIALYSIS IN PATIENT WITH END-STAGE RENAL DISEASE

Background and Aims

To study the factors involved in the low thyroid hormones in end - stage renal disease (ESRD), we compared thyroid function before and after hemodialysis (HD).

Method

The serum free thyroxine (fT4), free triiodothyronine (fT3), and thyroid - simulating hormone (TSH), thyroxine binding globulin (TBG) and thyroglobulin (Tg) levels were measured before and after HD in 12 patients with chronic glomerulonephritis (CGN, age; 48.7 ± 11.8 [mean ± SD]) and 11 patients with diabetic nephropathy (DN, age; 57.6 ± 6.5), comparing with controls (n = 13, age; 40.9 ± 11.3).

Results

The serum fT4, fT3 and TBG levels were low before HD but increased almost in parallel with the increase in hematocrit and albumin levels after HD in both ESRD groups. The serum TSH level was high before HD but decreased after HD and Tg level remained almost unchanged. In DN, serum fT4 levels was almost the same, but fT3 levels was lower with slightly higher TSH level, compared with CGN.

Conclusion

Significantly lower fT4, fT3 and TBG levels in ESRD before HD seemed to be due to hemodilution and almost corrected after HD. The TSH level was promptly normalized with elevated fT4, and Tg levels remained unchanged probably due to the balance between corrected hemodilution and rapid response to decreased TSH stimulation. It may better to evaluate thyroid function after HD in ESRD. Accelerated senile changes were suggested in DN.

Novel AP3B1 compound heterozygous mutations in a Japanese patient with Hermansky-Pudlak syndrome type 2

Hermansky-Pudlak syndrome type 2 (HPS2) is an extremely rare autosomal recessive inherited disease characterized by partial oculocutaneous albinism (OCA), bleeding diathesis due to a storage pool deficiency and immunodeficiency. The disorder is caused by disruption of the adapter protein 3 complex, which is involved in impaired intracellular vesicle transport. Here, we report the first case of a 1-year-old girl with HPS2 in Asia. She had no specific symptoms other than OCA and neutropenia. We analyzed her platelet function using transmission electron microscopy and a platelet aggregation test, cytotoxic degranulation assay of her natural killer (NK) cells and bleeding time, the results of which led to the diagnosis of HPS2. Although her NK-cell cytotoxic degranulation was impaired, she had not developed signs of hemophagocytic lymphohistiocytosis (HLH) or fibrosing lung disease. Molecular genetic analyses showed novel heterozygous mutations (c.188T>A [p.M63K] and c.2546>A [p.L849X]) in AP3B1. When examining patients with OCA, blood tests should be performed to confirm neutrophil count, bleeding time and platelet agglutination. When HPS2 is suspected, detailed immunological tests should be considered, and attention should be paid to HLH and pulmonary lesions immediately and over the long term.

Axillary lymph-node metabolic activity assessment on 18F-FDG-PET/CT in rheumatoid arthritis patients treated with biologic therapies

Objective: Recent studies have provided new insights into the role of lymph nodes (LNs) in rheumatoid arthritis (RA). The aim of this study was to evaluate the metabolic activity of the axillary LNs in relation to that of the upper limb joints and the clinical assessment of disease activity in RA patients treated with biologic therapies.Method: ¹⁸F-fluorodeoxyglucose-positron emission tomography/computed tomography (¹⁸F-FDG-PET/CT) scans were acquired for 64 patients with RA at baseline and after 6 months of biologic therapy, and the patients' clinical status was evaluated. The maximum standardized uptake value (SUV_max), metabolic active volume, and total lesion glycolysis (TLG) were used to assess glucose metabolism in the LNs and 12 joints. Clinical evaluations included serum markers and the Disease Activity Score based on 28-joint count-erythrocyte sedimentation rate (DAS28-ESR).Results: Changes in the SUV_max and TLG for the axillary LNs correlated significantly with those of the ipsilateral wrist joints. There was a positive correlation between the changes in the three metabolic parameters of the axillary LNs and the changes in disease activity after treatment. After 6 months of biologic therapy, all metabolic parameters for the axillary LNs in patients with a DAS28-ESR < 3.2 were significantly lower than those of patients with a DAS28-ESR ≥ 3.2.Conclusion: A relationship between the glucose metabolism of the axillary LNs and the ipsilateral wrist joints was demonstrated by the ¹⁸F-FDG-PET/CT parameters. The metabolic activity and active volume of axillary LNs may reflect the therapeutic response to the biologic treatment of RA.

The long-term follow-up of patients with thionamide-treated Graves' hyperthyroidism

Since there have been few reports on the long-term prognosis of Graves' hyperthyroidism, the prognosis of 549 Graves' hyperthyroidism patients initially treated with thionamide and followed for >8 (range: 8.6-36.4) years was studied, evaluating the change in the TSH binding inhibitor immunoglobulin activity (TBII). The distribution of the time required for the first disappearance of TBII was normal after logarithmic conversion, and the mean ± 2 SD was 1.5 (0.3-8.1) years. TBII became negative once within 5 years in 78.9% of patients. However, TBII re-elevation was observed in 47.8% of this group (fluctuating type). Remission was observed in 88.9% of the non-fluctuating type (smooth remission) and 37.2% of the fluctuating type patients. TBII remained positive for >5 years in 21.1% (smoldering type) of patients, with remission observed in only 19.8% of patients. Final remission was observed in 301 (54.8%) patients; the median time to remission was 6.8 (interquartile range: 4.0-10.9) years. A longer time until normalization of TBII and higher final thyroid weight were associated with a poor prognosis. Spontaneous hypothyroidism was observed in 6.0% of patients, independent of the TBII change. Our findings suggest that remission of Graves' hyperthyroidism mostly occurred after 4-11 years treatment. While predicting the prognosis before therapy was difficult, the clinical course may suggest a better prognosis if TBII disappears within five years without TBII fluctuation or enlargement of the goiter. Patients may safely wait more than five years to undergo ablative therapy if they hope to avoid permanent hypothyroidism.

Intralymphatic histiocytosis in a patient with lung adenocarcinoma treated with pembrolizumab: a case report

Background

Pembrolizumab, an anti-programmed cell death-1 protein monoclonal antibody, is effective for patients with advanced non-small-cell lung cancer. However, immune checkpoint inhibitors such as pembrolizumab induce various immune-related adverse events, involving the lung, liver, gastrointestinal, endocrine system, and skin. Intralymphatic histiocytosis (ILH) is a rare, chronic cutaneous disorder with a reactive inflammatory component, which often occurs in patients with rheumatoid arthritis.

Case presentation

We present a 67-year-old man with lung adenocarcinoma who developed ILH associated with pembrolizumab treatment. He was treated with palliative thoracic radiotherapy for superior vena cava syndrome. Subsequently, he received four cycles of pembrolizumab. Approximately 2.5 months after the initiation of pembrolizumab, he developed erythema on the trunk of his body. Based on findings of skin biopsies, he was diagnosed with pembrolizumab-induced ILH. Moreover, the upregulation of tumor necrosis factor-α was observed during pembrolizumab therapy.

Conclusions

This is the first report of ILH induced by pembrolizumab in a patient with lung adenocarcinoma.

Metyrapone-responsive ectopic ACTH-secreting pheochromocytoma with a vicious cycle via a glucocorticoid-driven positive-feedback mechanism

In ectopic ACTH-secreting pheochromocytoma, combined ACTH-driven hypercortisolemia and hypercatecholaminemia are serious conditions, which can be fatal if not diagnosed and managed appropriately, especially when glucocorticoid-driven positive feedback is suggested with a high ACTH/cortisol ratio. A 46-year-old man presented with headache, rapid weight loss, hyperhidrosis, severe hypertension and hyperglycemia without typical Cushingoid appearance. Endocrinological examinations demonstrated elevated plasma and urine catecholamines, serum cortisol and plasma ACTH. Moreover, his ACTH/cortisol ratio and catecholamine levels were extremely high, suggesting catecholamine-dominant ACTH-secreting pheochromocytoma. Computed tomography revealed a large right adrenal tumor. ¹⁸F-FDG positron emission tomography showed uptake in the area of the adrenal tumor, while ¹²³I-metaiodobenzylguanidine scintigraphy showed no accumulation. His plasma ACTH level paradoxically became elevated after a dexamethasone suppression test. After metyrapone administration, not only serum cortisol but also plasma ACTH levels were exponentially decreased almost in parallel, suggesting a glucocorticoid-driven positive-feedback regulation in this rapidly exacerbated ectopic ACTH-producing pheochromocytoma. Interestingly enough, plasma catecholamine levels were also decreased by metyrapone, although they remained extremely high. He became severely dehydrated due to hypoadrenalism requiring hydrocortisone supplementation. His clinical signs and symptoms were improved, and right adrenalectomy was performed uneventfully, resulting in complete remission of pheochromocytoma and Cushing's syndrome. A glucocorticoid-driven positive-feedback regulation in this ectopic ACTH-secreting pheochromocytoma created a vicious cycle with rapid exacerbation of both hypercortisolemia and hypercatecholaminemia with extremely elevated plasma ACTH level. Metyrapone was clinically effective to stop this vicious cycle; nonetheless, great care must be taken to avoid hypoadrenalism especially when hypercatecholaminemia remained.

Peptidylarginine deiminase is involved in maintaining the cornified oral mucosa of rats

BACKGROUND AND OBJECTIVE

Epithelial cells derived from different regions exhibit marked differences in their differentiation capacity, allowing them to provide a suitable protective barrier. We aimed to clarify the role of peptidylarginine deiminase (PAD) in modifying the key epidermal proteins filaggrin (FLG) and keratin 1 (K1) during stratification of the rat palate and buccal mucosa.

MATERIAL AND METHODS

We performed immunofluorescence, immunoblotting, PAD activity assays and 2-dimensional electrophoresis, and developed an organotypic culture model.

RESULTS

PAD1 expression was highest in the palate, whereas PAD2, PAD3 and PAD4 expression was highest in the skin, suggesting the tissue-specific expression of PAD isozymes that leads to differences in calcium dependency. Immunoblotting showed that the FLG monomer, as well as its degradation products and precursor (proFLG), were most abundantly expressed in the skin but had low expression in the palate, whereas only faint proFLG expression was detected in the buccal mucosa. FLG and K1 were colocalized with PAD1 and were likely to be citrullinated in the cornified layers of the skin; this colocalization was not detected on the palatal surface, and dot-like presence of proFLG that might be citrullinated and that of PAD1 were found in the granules of the palate. Organotypic models derived from the rat palate revealed that PAD inhibition reduced the breakdown of FLG, increased its association with K1 together with epithelial compaction, and decreased permeability in a dye permeability assay. Conversely, PAD stimulation had the opposite effects.

CONCLUSION

Citrullination is likely a protein modification that plays an important role in maintaining the structure and function of oral cornified mucosa in a way that is distinctly different from that of the skin.