Efficacy of Low-Dose FK506 in the Treatment of Myasthenia gravis – A Randomized Pilot Study

To determine the efficacy of low-dose FK506 in the treatment of myasthenia gravis (MG), untreated de novo patients were randomly selected to receive treatment with (n = 18) or without (n = 16) FK506, and were evaluated for 1 year after treatment with limitation of daily dose of prednisolone. Low-dose FK506 reduced the duration of early-phase therapy in hospital (p < 0.05) and the need for combined therapy with plasmapheresis and high-dose intravenous methylprednisolone or high-dose intravenous methylprednisolone alone (p < 0.05). It also reduced the daily dose of prednisolone (p < 0.05) required to maintain minimal manifestations of MGFA postintervention status. None of the patients exhibited significant side effects up to 1 year after treatment. These findings suggest that low-dose FK506 is safe and efficacious for the treatment of de novo MG patients.

Overexpression of alpha7 nicotinic acetylcholine receptor prevents G1-arrest and DNA fragmentation in PC12 cells after hypoxia

We investigated the neuroprotective function of alpha7 nicotinic acetylcholine receptor (alpha7nAChR) after transient hypoxia (12 h) and reoxygenation (0-72 h), comparing rat pheochromocytoma (PC12) cells overexpressing FLAG-tagged alpha7nAChR (alpha7pCMV cells) and control PC12 cells (non-transfected or transfected with vector only) in medium with and without nicotine. Plasma membrane degradation in the early phase after hypoxia was inhibited in PC12 cells with nicotine, and more profoundly in alpha7pCMV cells with nicotine. Inhibition of DNA fragmentation in the late phase after hypoxia was most remarkable in alpha7pCMV cells with nicotine, but, surprisingly, it was more remarkable in alpha7pCMV cells without nicotine than in PC12 cells with nicotine. G1-arrest of the cell cycle, observed in control PC12 cells at 12 h after hypoxia, preceding DNA fragmentation, was not evident in alpha7pCMV cells, with or without nicotine. Furthermore, in alpha7pCMV cells with and without nicotine, the basal expression levels of total Akt were approximately 1.5-fold higher, and the up-regulation of Akt phosphorylated at Ser473 after hypoxia was strikingly enhanced, compared with control PC12 cells. These findings suggest that alpha7nAChR functions constitutively in PC12 cells, that its overexpression raises tolerance against G1-arrest and DNA fragmentation after hypoxia, and that it can be considered a candidate target for treatment against hypoxia-induced acute membrane degradation and delayed DNA fragmentation in neurons.

Dendritic cells in hyperplastic thymuses from patients with myasthenia gravis

To investigate the role of dendritic cells (DCs) in the hyperplastic myasthenia gravis (MG) thymus, we studied the frequency and distribution of three mature DC phenotypes (CD83(+)CD11c(+), CD86(+)CD11c(+), and HLA-DR(+)CD11c(+)) in samples from patients with MG whose symptoms dramatically improved following thymectomy and in non-MG control thymuses. In hyperplastic MG thymuses, mature DCs were much more numerous in nonmedullary areas, such as the subcapsular/outer cortex; around the germinal centers; and in extralobular connective tissue, particularly around blood vessels. Mature DCs strongly coexpressed CD44 and appeared to be components of a CD44-highly positive (CD44(high)) cell population migrating from the vascular system. Furthermore, in the hyperplastic MG thymus, the expression of secondary lymphoid-tissue chemokine (SLC) markedly increased especially around extralobular blood vessels, where the CD44(high) cell population accumulated. These findings suggest that DCs may migrate into the hyperplastic thymus from the vascular system via mechanisms that involve CD44 and SLC. DCs may present self-antigens, thereby promoting the priming and/or boosting of potentially autoreactive T cells against the acetylcholine receptor.

Effects of FK506 on myasthenia gravis patients with high interleukin-2 productivity in peripheral blood mononuclear cells

We compared the early effects of FK506 on clinical severity, interleukin-2 (IL-2) production by phytohemagglutinin-stimulated peripheral blood mononuclear cells (PBMs), and serum levels of acetylcholine receptor antibodies between myasthenia gravis (MG) patients with elevated (>1250 pg/ml, n = 9) or normal (<1250 pg/mL, n = 10) levels of PBM IL-2 production. Reduction in clinical severity and PBM IL-2 production were significantly greater in the patients with elevated IL-2 production than those with normal PBM IL-2 production in the first month of treatment.

Increased expression of alpha7 nAChR after transient hypoxia in PC12 cells

We examined the effects of transient (6 h) hypoxia on nicotinic acetylcholine receptor (nAChR) subunit alpha7 expression in cultured PC12 cells, using RT-PCR and cytochemistry for alpha-bungarotoxin (alphaBTX) binding sites. The relative amount of alpha7 subunit mRNA compared with that before hypoxia decreased to 84% immediately after hypoxia, but then began to increase at 6 h after hypoxia, reaching 171% at 12 h. After this point, it decreased again to 81% at 48 h. Until 6 h after hypoxia, cells appeared to shorten their neurites and form aggregates, without any accompanying remarkable change in alphaBTX binding sites compared with before hypoxia. However, at 12 h and 24 h after hypoxia, alphaBTX binding sites remarkably increased, whereafter cells resumed outgrowth of their neurites at 24-48 h. These findings suggested that nAChR subunit alpha7 was upregulated in both mRNA and protein levels in response to transient hypoxia/reoxygenation in PC12 cells.

The difference between IgM and IgG antibody prevalence in different serological assays for COVID-19; lessons from the examination of healthcare workers

OBJECTIVES

The objective of this study was to investigate the differences between the results of two serology assays for detection of COVID-19 among medical staff, who are at higher risks of infection.

METHODS

The immunochromatography (ICG) rapid test kit and the chemiluminescence immunoassay (CLIA) quantitative antibody test were performed. The differences in IgM and IgG antibody prevalence in different serological assays were descriptively analyzed.

RESULTS

A total of 637 participants were included in this research. Two staff were IgM positive in the CLIA quantitative antibody test (cutoff value: 10 AU/ml) of 51 staff who were IgM positive in the rapid test kit. Six staff were IgG positive in the CLIA quantitative antibody test of 56 staff who were IgG positive in the rapid test kit. The proportion of antibody positive staff differed greatly between the rapid test kit and the CLIA quantitative antibody test.

CONCLUSIONS

There was a vast difference in the proportions of IgG and IgM antibody positive staff in the rapid test kit and the CLIA quantitative antibody test results. The results from the only rapid test kit might have to be interpreted with caution. Further studies to evaluate antibody testing accuracy are required to promote the understanding of each assay's characteristics and determine their purposes in each community.

Over-expression of alpha7 nicotinic acetylcholine receptor induces sustained ERK phosphorylation and N-cadherin expression in PC12 cells

Over-expression of alpha7 nicotinic acetylcholine receptor (alpha7nAChR) in PC12 cells, independent of agonistic stimulation, induces marked neurite outgrowth and high capacity for migration and adherence (differentiation-like transformation), and increases tolerance against cell damage. In the present study, we investigated the effects of alpha7nAChR over-expression and nicotine on ERK phosphorylation and N-cadherin expression by comparing 3 groups of cells: PC12 cells transfected with alpha7 subunit cDNA (alpha7pCMV cells); untransfected PC12 cells exposed to 50 microM nicotine (PC12 cells+nicotine); and PC12 cells transfected with vector only (pCMV cells). alpha7 subunit protein was detected in alpha7pCMV cells at 24 to 72 h after transfection. alpha7pCMV cells exhibited sustained expression of phospho-ERKs (p42 and p44) at 24 to 72 h after transfection, and differentiation-like transformation at 72 h after transfection. PC12 cells+nicotine exhibited transient expression of phospho-ERKs at 48 h after addition of nicotine, but did not exhibit differentiation-like transformation. Neither ERK phosphorylation nor differentiation-like transformation was observed in pCMV cells. Expression of surface N-cadherin increased at 72 h after transfection on alpha7pCMV cells, but did not increase on PC12 cells+nicotine or pCMV cells. These findings suggest that, in PC12 cells, over-expression of alpha7nAChR induces sustained activation of ERK, which probably promotes N-cadherin expression and differentiation-like transformation.

Interleukin-2 production by peripheral blood mononuclear cells from patients with myasthenia gravis

We examined interleukin-2 (IL-2) production by phytohemagglutinin (PHA)-stimulated peripheral blood mononuclear cells (PBMs) from 75 untreated myasthenia gravis (MG) patients and 48 control patients. Patients with MG consisted of those with elevated PBM IL-2 production (>1,250 pg/ml; mean + 2SD of the controls) (n = 29, 39%) and those with normal PBM IL-2 production (<1,250 pg/ml) (n = 46, 61%). Significant characteristics of patients with elevated PBM IL-2 production included elevated serum levels of anti-acetylcholine receptor antibodies, severe generalized symptoms, thymic hyperplasia, and marked effects of thymectomy (p < 0.05). These findings suggest that elevated PBM IL-2 production can reflect functional abnormalities of T cells in some patients with MG, and that PBM IL-2 production should be considered as a candidate target of therapy.

NKT-associated markers and perforin in hyperplastic thymuses from patients with Myasthenia gravis

Immunohistochemical expression of natural killer T (NKT) cell-associated markers (Valpha24 and CD56) and perforin in relation to CD44-highly positive (CD44(high)) cells was studied in hyperplastic thymuses from patients with myasthenia gravis (MG) whose symptoms dramatically improved after thymectomy and compared with non-MG control thymuses. In the control thymuses, Valpha24-positive (Valpha24(+)) and CD56-positive (CD56(+)) cells were sparsely distributed in the medullary area only. In contrast, in hyperplastic MG thymus, Valpha24(+) and CD56(+) cells were more frequent in connective tissue, appeared to have penetrated the thymic parenchyma, and most coexpressed CD44(high). Perforin-positive cells were not present in the control thymus, but were in the connective tissue and perilobular cortical areas in the hyperplastic MG thymus. Most of these perforin-positive cells were CD44(high) and were located near blood vessels. They appeared to have migrated directly from the vascular system and penetrated the thymic parenchyma. Some perforin-positive cells coexpressed Valpha24, CD56, or both. These findings suggest that in this particular type of MG thymus, NKT-like cells may have increased via a CD44- and perforin-mediated mechanism, leading to an imbalance in the immune system that favored an antibody-mediated autoimmunity against the acetylcholine receptor.

Mental distress in a clinical nurse due to a false-positive COVID-19 antibody test result during the COVID-19 epidemic in Japan: A case report

This study suggests the importance of instituting accompanying measures to prevent potential negative mental and social impacts on people receiving false-positive results.

Hypoxic condition interferes with phosphorylation of Akt at Thr(308) in cultured rat pheochromocytoma-12 cells

Phosphorylation of Akt induced under hypoxic or ischemic conditions has been reported only for residue Ser(473). We examined whether Akt can be phosphorylated at Thr(308), another phosphorylation site on Akt, and can exhibit neuroprotective effects under conditions of hypoxia/reoxygenation, comparing pheochromocytoma-12 (PC12) cells transfected with constitutively active Akt (Myr-pCMV cells) and those transfected with pCMV vector only (pCMV cells). Expression levels of Akt phosphorylated at Ser(473) were 2.1-fold higher in Myr-pCMV cells compared with pCMV cells, before the onset of hypoxia, which were increased transiently during hypoxia, and then decreased gradually during reoxygenation. In contrast, Akt phosphorylated at Thr(308) was not detected in pCMV cells under any conditions but was expressed in Myr-pCMV cells prior to hypoxia, followed by an immediate decrease during hypoxia and a further decline during reoxygenation. However, G1-arrest of the cell cycle observed at 12 h after hypoxia in pCMV cells was prevented in Myr-pCMV cells. These findings suggest that hypoxia activates Akt by phosphorylation at Ser(473) only, which is sufficient to elicit a neuroprotective function against hypoxic neuronal damage.

Seroprevalence of SARS-CoV-2 antibodies among hospital staff in rural Central Fukushima, Japan: A historical cohort study

Performing a cohort-based SARS-CoV-2 antibody assay is crucial for understanding infection status and future decision-making. The objective of this study was to examine consecutive antibody seroprevalence changes among hospital staff, a high-risk population. A two-time survey was performed in May and October 2020 for 545 hospital staff to investigate the changes in the results of the rapid kit test and chemiluminescence immunoassay (CLIA). The seroprevalence of each assay was summarized at both the survey periods. The proportion of seropositive individuals in the CLIA for each survey period and the number of confirmed COVID-19 cases in Central Fukushima were then compared. We chose 515 participants for the analysis. The proportion of IgM seroprevalence in CLIA increased from 0.19% in May to 0.39% in October, and IgG seroprevalence decreased from 0.97% in May to 0.39% in October. The proportion of IgM seroprevalence in the rapid kit test decreased from 7.96% in May to 3.50% in October, and IgG seroprevalence decreased from 7.77% in May to 2.14% in October.

The IgG and IgM antibody seroprevalence among hospital staff in rural Central Fukushima decreased; the seroprevalence among hospital staff was consistent with the number of confirmed COVID-19 cases in the Central Fukushima area. Although it is difficult to interpret the results of the antibody assay in a population with a low prior probability, constant follow-up surveys of antibody titers among hospital staff had several merits in obtaining a set of criteria regarding the accuracy of measures against COVID-19 and estimating the COVID-19 infection status among hospital staff.

Candesartan prevents angiotensin II-induced facilitation of hypoxic neuronal damage through PKCdelta inhibition

To investigate the role of protein kinase Cdelta (PKCdelta) in angiotensin II-induced facilitation mechanisms of hypoxic neuronal damage and whether candesartan, an AT1 receptor antagonist, can suppress these mechanisms, we performed in vitro experiments which were free from vascular components using PC12 cells under hypoxic (12 h)/reoxygenation (0-48 h) conditions. Angiotensin II apparently increased the basal expression level of PKCdelta phosphorylated at Ser(643) before hypoxia, promoted the cleavage of PKCdelta to its catalytic fragment, and fostered the progression of DNA fragmentation after hypoxia. Candesartan inhibited both phosphorylation and cleavage of PKCdelta and suppressed the angiotensin II-induced facilitation of DNA fragmentation under hypoxic/reoxygenation conditions. However, PD123319, an AT2 receptor antagonist, influenced neither PKCdelta nor the angiotensin II-induced facilitation of DNA fragmentation. Furthermore, in PC12 cells expressing the ATP-binding mutant of PKCdelta (PKCdelta(K376R)) acting as a dominant-negative protein, both phosphorylation and cleavage of PKCdelta were attenuated and DNA fragmentation was markedly suppressed regardless of the presence of angiotensin II. These findings suggest that angiotensin II-induced facilitation of DNA fragmentation under hypoxic conditions is mediated by PKCdelta, and the mechanisms can be suppressed by the candesartan mediated blockade of the AT1 receptor.

[Case of herpes zoster associated Guillain-Barré syndrome with a relapse of eruptions after intravenous immunoglobulin therapy]

A 77-year-old woman developed progressive dysesthesia, hypesthesia and weakness in four extremities immediately after improvement of herpes zoster in the left Th10 dermatome area. Examination of the cerebrospinal fluid (CSF) showed an increase in protein concentrations. Evidence of demyelinating polyneuropathy was demonstrated by nerve conduction studies. Her hypesthesia and weakness in the extremities were gradually improved following intravenous immunoglobulin therapy (IVIg). Varicella zoster virus (VZV) titer levels in CSF well correlated both with neurological symptoms and CSF protein concentrations. VZV DNA in the CSF was not detectable. These findings suggested autoimmune Guillain-Barré syndrome (GBS) associated with herpes zoster. An interesting finding in the present patient is that one day after the completion of IVIg, when the neurological symptoms in the extremities were apparently ameliorating, the herpes zoster eruptions again emerged in the left L3 dermatome area. By treatment with intravenous acyclovir, the vesicular eruptions were improved. We assume that IVIg might suppress the immune response against VZV and promote the recurrence of eruptions.

Abstract WP32: Pathological Examination of Thrombus Components in Patients Undergoing Endovascular Thrombectomy

Introduction: Histopathological analysis of the thrombi, which was retrieved from stroke patients with large-vessel occlusion during mechanical thrombectomy, may provide information about underlying pathologies. It is likely that the size of the thrombi differ between stent retriever and aspiration catheter.

Objective: This study aimed to evaluate the thrombus composition and its association with radiological findings, stroke subtypes, and reperfusion times.

Methods: From June 2014 to August 2016, 51 patients were treated at our hospital by mechanical thrombectomy using stent retriever and/or aspiration catheter. The received thrombi were subjected to semi-quantitative analysis to quantify red blood cells, platelet, and/or fibrin in the overall area. We divided the patients into two groups according to the predominant composition of the thrombus: red thrombus group or white thrombus group. These two groups were compared with respect to imaging, clinical, and neurointerventional data.

Results: Histopathological analysis of retrieved thrombus from 44 patients with acute stroke due to internal carotid artery, middle cerebral artery, or basilar artery occlusion was performed. There were no significant changes with respect to the time from onset to reperfusion, time from puncture to reperfusion, and type of atrial fibrillation (paroxysmal or persistent). Postoperative stenotic lesion was significantly higher in patients with white thrombi than in those with red thrombi (83% vs 19%, p = 0.001). Preoperative susceptibility vessel sign on magnetic resonance imaging correlated with the proportion of red thrombi than with that of white thrombi (59% vs 33%, p = 0.04). The maximum diameter of thrombi was significantly larger in the combination Penumbra aspiration catheter group compared with that in the non-combination group (9.2 ± 3.7 vs 5.3 ± 4.7mm, p < 0.001).

Conclusion: Histological thrombus features vary significantly according to the underlying cause and may help to differentiate between large-artery atherosclerosis and cerebral embolism. Aspiration first pass technique could retrieve a large thrombus.

[A case with hepatitis A-associated Guillain-Barre syndrome and elevated serum anti-sulfatide antibody]

A 59-year-old man developed progressive sensory dullness and muscle weakness in the extremities, facial palsy on the left side, and hoarseness 4 days after the onset of acute hepatitis A. Vibration and joint sensation in the extremities were severely affected. Anti-sulfatide IgM antibody level was initially elevated in serum, but diminished along with amelioration of the symptoms following intravenous immunoglobulin therapy. Anti-sulfatide antibody may be involved in the pathogenesis of the present patient with hepatitis A-associated Guillain-Barré syndrome. This is probably the first case of hepatitis A associated Guillain-Barré syndrome with which elevated serum anti-sulfatide antibody was found.