Strategy for genetic analysis in hereditary neuropathy

Inherited neuropathies are a heterogeneous group of slowly progressive disorders affecting either motor, sensory, and/or autonomic nerves. Peripheral neuropathy may be the major component of a disease such as Charcot-Marie-Tooth disease or a feature of a more complex multisystemic disease involving the central nervous system and other organs. The goal of this review is to provide the clinical clues orientating the genetic diagnosis in a patient with inherited peripheral neuropathy. This review focuses on primary inherited neuropathies, amyloidosis, inherited metabolic diseases, while detailing clinical, neurophysiological and potential treatment of these diseases.

P11.66.A Immune checkpoint inhibitors related peripheral nerve disorders: clinical and electrophysiological particularities

Background

The immune-checkpoint inhibitors (ICIs) announced a new era in cancer treatment allowing long-term survival in advanced cancers. However, immune related adverse events impose treatment limitations being one of the main challenges when dealing with ICI treated patients. Neurologic toxicities have unique presentations and can progress rapidly, requiring prompt recognition. Among them, ICI-related peripheral nerve disorders are highly heterogeneous, profoundly debilitating, and insufficiently explored.

Material and Methods

We reviewed the clinical and electrodiagnostic features of a retrospective cohort of patients hospitalized in our centre for ICI related neuropathies. We applied the EFNS 2021 electrodiagnostic criteria for neuropathies and we researched the outcome according to the treatment received.

Results

We included 16 patients: 4 men and 12 women, median age 61 years (31-72) treated by anti-PD1 monotherapy (10) or antiCTLA4-antiPD1 combination (6). Median delay from ICIs initiation to neuropathy symptoms was 58,5 days (4 cycles), it seemed lower in combination group (median 33,5 days vs 81,5 days in monotherapy patients p=0,02). Half of patients presented with concurrent non-neurological irAE. CSF was inflammatory in 56% of cases, pleocytosis was seen in 57% of these. Cranial nerve involvement was rare (3/16) the most frequent phenotype was demyelinating polyneuropathy fulfilling EFNS 2021 EMG criteria in 10 cases. The other 6 presented with non-length dependent sensory neuropathy, (3) dysautonomic neuropathy (1) or sensory motor neuropathy with incomplete EFNS 2021 EMG criteria (2). ICI treatment was stopped, and steroids were the first line of treatment for all patients. However, 12/16 patients received additional iv immunoglobulin. Supplementary immunomodulation (cyclophosphamide, tocilizumab) was required in 2 cases. 75% of patients improved within a median of 4.5 months, median decrease in mRS was 2 points. Noteworthy, the rechallenge by antiPD1 monotherapy was proposed in 4 patients with a single neuropathy relapse.

Conclusion

Our series expand the knowledge on the clinical and electrophysiological phenotype of ICI related neuropathies improving their recognition in clinical practice. Moreover, our findings argue for the benefit of adding iv immunoglobulin to steroids as a first line treatment for different phenotypes of ICI related neuropathies.

Comparison of Lewis-Sumner syndrome with chronic inflammatory demyelinating polyradiculoneuropathy patients in a tertiary care centre

BACKGROUND AND PURPOSE

Whether the Lewis-Sumner syndrome (L-SS) is a distinct entity from other types of chronic inflammatory demyelinating polyradiculoneuropathy (CIDP-ot) remains controversial.

METHOD

The clinical/electrophysiological characteristics and long-term outcomes of 45 L-SS and 35 CIDP-ot patients were retrospectively compared.

RESULTS

The CIDP-ot group was composed of 11 patients with a typical CIDP, 17 with a pure sensory form, four with a distal form and three with a pure motor form. In the L-SS group, asymmetric (P < 0.001) and monomelic involvement (P = 0.04) of the upper limbs (P < 0.001) was significantly more frequent; paucisymptomatic forms (Overall Neuropathy Limitations Scale ≤ 1) were less frequent (P < 0.001); electroneuromyography showed that conduction block in intermediate nerve segments was the main demyelinating feature, with frequent F-wave abnormalities on nerves without conduction block (44%). Long-term prognosis was globally poorer in the L-SS group with more frequent aggravation during treatment (P = 0.02), less frequent treatment withdrawal (P = 0.03) and longer time to achieve successful withdrawal (39 vs. 15 months).

CONCLUSIONS

Our study suggests that L-SS patients have a less favourable therapeutic response rate and long-term outcomes. Rapid differentiation of L-SS from other forms of CIDP is important in order to anticipate a more complicated disease course management, with from one side the inefficacy or even harmfulness of corticosteroids and from the other side a difficult weaning procedure. A prospective study is necessary to confirm these results.

New insights into orthostatic hypotension in multiple system atrophy: a European multicentre cohort study

OBJECTIVES

Orthostatic hypotension (OH) is a key feature of multiple system atrophy (MSA), a fatal progressive neurodegenerative disorder associated with autonomic failure, parkinsonism and ataxia. This study aims (1) to determine the clinical spectrum of OH in a large European cohort of patients with MSA and (2) to investigate whether a prolonged postural challenge increases the sensitivity to detect OH in MSA.

METHODS

Assessment of OH during a 10 min orthostatic test in 349 patients with MSA from seven centres of the European MSA-Study Group (age: 63.6 ± 8.8 years; disease duration: 4.2 ± 2.6 years). Assessment of a possible relationship between OH and MSA subtype (P with predominant parkinsonism or C with predominant cerebellar ataxia), Unified MSA Rating Scale (UMSARS) scores and drug intake.

RESULTS

187 patients (54%) had moderate (> 20 mm Hg (systolic blood pressure (SBP)) and/or > 10 mm Hg (diastolic blood pressure (DBP)) or severe OH (> 30 mm Hg (SBP) and/or > 15 mm Hg (DBP)) within 3 min and 250 patients (72%) within 10 min. OH magnitude was significantly associated with disease severity (UMSARS I, II and IV), orthostatic symptoms (UMSARS I) and supine hypertension. OH severity was not associated with MSA subtype. Drug intake did not differ according to OH magnitude except for antihypertensive drugs being less frequently, and antihypotensive drugs more frequently, prescribed in severe OH.

CONCLUSIONS

This is the largest study of OH in patients with MSA. Our data suggest that the sensitivity to pick up OH increases substantially by a prolonged 10 min orthostatic challenge. These results will help to improve OH management and the design of future clinical trials.

[Werner's syndrome]

BACKGROUND

Werner's syndrome associates early aging in young adults, small height, cataract, glucose intolerance, hypogonadism, skin ulcers, vascular calcifications and osteoporosis.

CASE REPORT

We report a new case of Werner's syndrome in a 34-year-old man with suggestive alterations of the skin and endocrine anomalies in addition to hypospadias, urethral stenosis, bilateral mega-ureter and chronic renal failure.

DISCUSSION

The diagnosis of Werner's syndrome in our patient was unquestionable because of the clinical presentation and the familial context. However, the urology anomalies have not been reported in this syndrome. A simple coincidence cannot be excluded.

Intraluminal water increases expression of plasmid DNA in rat lung

Effective gene delivery to specific organs is a major goal for human gene therapy. The lung's structure allows instillation of agents into the airspaces, directly adjacent to the lung epithelium. We hypothesized that the airspace instillation of hypotonic solutions would increase the permeability of the lung epithelium and increase DNA uptake. This hypothesis was tested by instilling plasmid DNA (p4241) encoding the luciferase gene in isotonic and hypotonic solutions. The highest luciferase expression in the lung was achieved after the instillation of this plasmid DNA in distilled water. Aerosolization of water just before the instillation of the plasmid DNA also enhanced the expression level of luciferase in the lung. In addition, an intralobar instillation of the plasmid DNA in water significantly increased the luciferase expression, suggesting that the instillation of the plasmid over a smaller surface area increased expression. Levels of expression could be measured for 3 days. Water increases the permeability of lung epithelial cells transiently and/or enhances gene expression and can be used to achieve gene expression in the lung airspaces for short intervals without toxicity.

Cationic liposome-mediated intravenous gene delivery

Systemic gene transfer provides new opportunities for the analysis of gene function and gene regulation in vivo, as well as for human gene therapy. We used the chloramphenicol acetyltransferase reporter gene to examine several parameters important for the development of efficient, cationic liposome-mediated, intravenous (IV) gene transfer in mice. We then demonstrated that this approach can produce high level expression of biologically important genes. Specifically, we assessed the relationship of expression vector design to the level of systemic gene expression produced, and compared transfection levels produced by intravenously injecting DNA alone versus DNA-liposome complexes. We found that both the position of the heterologous intron, and the promoter element used in the expression plasmid, significantly affected the level of systemic gene expression produced. Although intravenous injection of plasmid DNA alone transfected every tissue analyzed, liposome-mediated delivery was much more efficient. We also established that repeated i.v. injection of DNA-liposome complexes produced high level systemic transfection. The second injection of DNA-liposome complexes produced levels of gene expression at least as high as those following a single i.v. injection. Thus, unlike some viral vectors, a neutralizing host-immune response does not limit re-expression, following reinjection of DNA-liposome complexes. Finally, we showed that the expression vectors which produced the highest levels of chloramphenicol acetyltransferase reporter gene expression could also produce high level expression of two colony stimulating factor genes in mice. Specifically, i.v. injection of liposomes complexed to expression vectors into which we had inserted either the murine granulocyte-macrophage-colony stimulating factor cDNA or the human granulocyte-CSF cDNA, produced circulating levels of the corresponding colony stimulating factor gene product comparable to levels which have been shown previously to be both biologically and therapeutically significant.

In vivo gene delivery. Efficient transfection of T lymphocytes in adult mice

We have demonstrated that a single intraperitoneal injection of cationic liposomes complexed to a chloramphenicol acetyltransferase (CAT) gene expression plasmid can transfect the majority of splenic Thy 1.2+ T lymphocytes, as well as significant numbers of bone marrow-derived hematopoietic cells, in adult mice. CAT activity was detected in the spleen for at least 2 weeks, and there was no evidence of treatment-related toxicity. Some degree of tissue-specific transgene expression was achieved by varying the cationic lipid used.

Systemic gene expression after intravenous DNA delivery into adult mice

Direct gene transfer into adult animals resulting in generalized or tissue-specific expression would facilitate rapid analysis of transgene effects and allow precise in vivo manipulation of biologic processes at the molecular level. A single intravenous injection of expression plasmid:cationic liposome complexes into adult mice efficiently transfected virtually all tissues. In addition to vascular endothelial cells, most of the extravascular parenchymal cells present in many tissues including the lung, spleen, lymph nodes, and bone marrow expressed the transgene without any apparent treatment-related toxicity. The transgene was still expressed in large numbers of cells in multiple tissues for at least 9 weeks after a single injection. Expression could be targeted to specific tissues and cell types, depending on the promoter element used.

Aerosol gene delivery in vivo

The ability to express transgenes selectively within the lung will greatly facilitate the development of gene therapy for a variety of human diseases. We have demonstrated that aerosol administration of a chloramphenicol acetyltransferase (CAT) expression plasmid complexed to cationic liposomes produces high-level, lung-specific CAT gene expression in mice in vivo. Significant levels of CAT activity are seen in the lungs for at least 21 days following aerosolization. In situ immunostaining for intracellular CAT protein reveals that the majority of airway epithelial and alveolar lining cells are transfected in vivo. Histological analyses show no apparent treatment-related damage. These results have important implications for the development of human gene therapy.

Prolonged transgene expression in rodent lung cells

We tested the efficiency of several different cationic liposome formulations, complexed to one of two different chloramphenicol acetyltransferase (CAT) reporter plasmids, in transfecting freshly isolated, highly purified rat lung alveolar type II cells, alveolar macrophages, and three different human lung carcinoma cell lines, as well as NIH 3T3 cells, a rapidly dividing, transformed mouse fibroblast line. Our results demonstrated that several different cationic liposome formulations can mediate high-level CAT gene expression in all the cell types tested. Electron microscopic analysis confirmed that cationic liposome-DNA complexes are avidly bound and internalized by lung cells. The time course of expression of transfected genes in nontransformed cell types with low mitotic indices, such as type II cells, is poorly characterized. NIH 3T3 cells expressed maximal CAT activity by day 4 following transfection, with virtual disappearance of activity by day 11. Conversely, type II cells expressed maximal CAT activity between days 5 and 11, and CAT activity was still clearly present 35 days after transfection. Southern blot analysis of DNA isolated from transfected type II cells revealed that the CAT gene was largely present in an extrachromosomal form, rather than integrated into genomic DNA. These observations indicate that following cationic liposome-mediated transfection, rat alveolar type II cells (the majority of which do not divide in culture) can express transfected genes for prolonged periods, apparently mediated by expression of the transgene in an episomal form.

Lipofection does not require the removal of serum

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Biodistribution, tissue reaction, and lung retention of pentamidine aerosolized as three different salts

Aerosolized pentamidine isoethionate is retained in the lung and appears to prevent Pneumocystis carinii pneumonia (PCP) in many AIDS patients. We evaluated alternative formulations of pentamidine that might reduce the airway irritation associated with aerosolized pentamidine isoethionate. Specifically, we assessed the biodistribution, histologic response, and lung retention of the isoethionate, gluconate, and lactate salts of pentamidine after aerosol administration to mice. For each of the three aerosolized salts tested, greater than 50% of the pentamidine initially recovered from the lungs after one dose was still retained there 14 days later. Thus, significant levels of pentamidine, aerosolized as three different salts, are retained in the lung for at least 2 wk after a single dose. The three salts of pentamidine each produced high lung to extrapulmonary drug ratios, the converse of that produced by intravenous injection of pentamidine isoethionate. At very high aerosol doses, the ability of the lung to retain pentamidine appeared saturable. Even aerosolized daily for 2 wk at very high doses, none of the three pentamidine salts produced histologic evidence of organ toxicity. A Phase 1 trial of aerosolized pentamidine gluconate in AIDS-PCP patients is now in progress to determine if this approach can reduce airway irritation.

The pattern of lung injury induced after pulmonary exposure to tumor necrosis factor-alpha depends on the route of administration

TNF-alpha is a protein elaborated by monocytes and macrophages in response to endotoxin. The in vivo consequences of TNF-alpha elaboration have been examined extensively after intravenous administration of TNF-alpha. Substantially less is known about the effects of TNF-alpha that may be generated locally by resident tissue phagocytes. We investigated the direct effects of TNF-alpha on lung tissue by administering large amounts of human TNF-alpha directly to the lung, either as an aerosol or as an intratracheal bolus. Rats were exposed to an aerosol containing several concentrations of TNF-alpha, resulting in retention of significant quantities of TNF-alpha. The histologic response to inhaled TNF-alpha was characterized by adherence of leukocytes to venular endothelium, endothelial cell disruption, and bronchovascular edema. After aerosol administration, however, there was no evidence of alveolar inflammation or edema. In contrast, intravenous administration of large amounts of human TNF-alpha, at a dose that produced a lung content of TNF-alpha similar to that produced after high-concentration aerosol exposure, resulted in severe alveolar injury and edema. Intravenous administration of TNF-alpha did not result in the bronchovascular changes seen after inhalation. To ensure that sufficient quantities of TNF-alpha were being delivered to the lung, TNF-alpha was given as an intratracheal bolus to rats. This led to measurable absorption, but the spectrum and severity of lung injury was similar to the group that received TNF-alpha as an aerosol. We conclude that in rats, the pulmonary response to the injurious effects of TNF-alpha differ, depending on whether the TNF-alpha is delivered to the air or blood side of the alveolar capillary barrier.

Lymphocyte proliferative responses to soluble and liposome-conjugated envelope peptides of HIV-1

The proliferation of lymphocytes from HIV-seronegative (HIV Ab-) and seropositive (HIV Ab+) individuals in response to two synthetic peptide epitopes of HIV envelope glycoproteins (ENVgp) was evaluated as an index of cell-mediated immunity in infected individuals. All HIV Ab- and most HIV Ab+ individuals' lymphocytes failed to proliferate in primary cultures in response to the two soluble HIV ENVgp peptides, ENVP346 and ENVP466 even in the presence of rIL-2. After stimulation with liposome-conjugates of ENVP346 or ENVP466 and soluble rIL-2, however, CD4 lymphocytes from some HIV Ab+ individuals were able to proliferate. Significantly higher frequencies of rIL-2-augmented proliferative responses to liposome-conjugated ENVP346 or ENVP466 were observed in HIV Ab+ asymptomatic individuals as compared to patients with AIDS-related conditions or AIDS. These studies indicate that the conjugation of HIV peptides or proteins to liposomes and stimulation with rIL-2 may enhance cell-mediated responses to these peptides.

Lymphocyte proliferative responses to soluble and liposome-conjugated envelope peptides of HIV-1

The proliferation of lymphocytes from HIV-seronegative (HIV Ab-) and seropositive (HIV Ab+) individuals in response to two synthetic peptide epitopes of HIV envelope glycoproteins (ENVgp) was evaluated as an index of cell-mediated immunity in infected individuals. All HIV Ab- and most HIV Ab+ individuals' lymphocytes failed to proliferate in primary cultures in response to the two soluble HIV ENVgp peptides, ENVP346 and ENVP466 even in the presence of rIL-2. After stimulation with liposome-conjugates of ENVP346 or ENVP466 and soluble rIL-2, however, CD4 lymphocytes from some HIV Ab+ individuals were able to proliferate. Significantly higher frequencies of rIL-2-augmented proliferative responses to liposome-conjugated ENVP346 or ENVP466 were observed in HIV Ab+ asymptomatic individuals as compared to patients with AIDS-related conditions or AIDS. These studies indicate that the conjugation of HIV peptides or proteins to liposomes and stimulation with rIL-2 may enhance cell-mediated responses to these peptides.

Fulminant puerperal sepsis associated with aplastic anemia: the case for prophylactic antibiotic therapy

Fulminant puerperal sepsis due to Clostridium perfringens occurred in a primiparous 19-year-old woman who developed aplastic anemia during pregnancy. Although the risk of infectious complications among pregnant women with compromised host defenses has not been accurately determined, it appears to be increased, particularly in patients with granulocytopenia. It therefore seems reasonable to give antibiotic prophylaxis during the intrapartum period to immunosuppressed women who come to term. Consideration of the bacterial pathogens most likely to cause acute endometritis in the early puerperium has led us to recommend a short course (72 hours) of penicillin G, 4 million units q4h, and gentamicin, 1,5 mg/kg q8h, as an appropriate regimen for such patients.