Search

Objective: To determine serologic characteristics, frequency, phenotype, paraneoplastic associations, and electrodiagnostic and histopathologic features accompanying contactin-1 autoimmunity., Methods: Archived sera known to produce synaptic tissue-based immunofluorescence patterns were reevaluated, and contactin-1 specificity was confirmed by recombinant protein assays. Screening of 233 chronic/relapsing demyelinating neuropathies for additional cases was performed., Results: We identified 10 contactin-1 IgG seropositive cases. Frequency of contactin-1 immunoglobulin (Ig) G among tested Mayo Clinic chronic/relapsing demyelinating neuropathies was 2%. Sensory predominant presentations (n = 9, 90%), neuropathic pain (n = 6, 60%), and subacute progression (n = 5, 50%) were commonly encountered among contactin-1 neuropathies. Two patients had chronic immune sensory polyradiculopathy-like phenotype at presentation. Electrodiagnostic studies were consistent with demyelination (slowed conduction velocities and/or prolonged distal latencies) without conduction block. Markedly elevated CSF protein (median 222 mg/dL, range 69-960 mg/dL), thickening/gadolinium enhancement of nerve roots (4/5), and subperineural edema on nerve biopsy (4/4) were other characteristic features. Three cases were diagnosed with paraneoplastic demyelinating neuropathies (thymoma, n = 1; breast cancer, n = 1; plasmacytoma, n = 1). Four of the 9 patients treated with IV immunoglobulin demonstrated initial clinical improvement, but the favorable response was sustained in only 1 case (median follow-up, 60 months). Sustained clinical stabilization or improvement was observed among 3 of the 6 cases in whom second-line therapies (rituximab, cyclophosphamide, and azathioprine) were used., Conclusion: Contactin-1 IgG has a distinct sensory predominant presentation commonly associated with neuropathic pain, with demyelinating changes on electrophysiologic studies. A paraneoplastic cause should be considered. Testing of contactin-1 IgG among cases with similar presentations may guide immunotherapy selection, especially second-line immunotherapy consideration., (Copyright © 2020 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of the American Academy of Neurology.)

We here describe the development and validation of IMMUNO-COV™, a high-throughput clinical test to quantitatively measure SARS-CoV-2-neutralizing antibodies, the specific subset of anti-SARS-CoV-2 antibodies that block viral infection. The test measures the capacity of serum or purified antibodies to neutralize a recombinant Vesicular Stomatitis Virus (VSV) encoding the SARS-CoV-2 spike glycoprotein. This recombinant virus (VSV-SARS-CoV-2-S-Δ19CT) induces fusion in Vero cell monolayers, which is detected as luciferase signal using a dual split protein (DSP) reporter system. VSV-SARS-CoV-2-S-Δ19CT infection was blocked by monoclonal α-SARS-CoV-2-spike antibodies and by plasma or serum from SARS-CoV-2 convalescing individuals. The assay exhibited 100% specificity in validation tests, and across all tests zero false positives were detected. In blinded analyses of 230 serum samples, only two unexpected results were observed based on available clinical data. We observed a perfect correlation between results from our assay and 80 samples that were also assayed using a commercially available ELISA. To quantify the magnitude of the anti-viral response, we generated a calibration curve by adding stepped concentrations of α-SARS-CoV-2-spike monoclonal antibody to pooled SARS-CoV-2 seronegative serum. Using the calibration curve and a single optimal 1:100 serum test dilution, we reliably measured neutralizing antibody levels in each test sample. Virus neutralization units (VNUs) calculated from the assay correlated closely (p < 0.0001) with PRNT EC50 values determined by plaque reduction neutralization test against a clinical isolate of SARS-CoV-2. Taken together, these results demonstrate that the IMMUNO-COV™ assay accurately quantitates SARS-CoV-2 neutralizing antibodies in human sera and therefore is a potentially valuable addition to the currently available serological tests. The assay can provide vital information for comparing immune responses to the various SARS-CoV-2 vaccines that are currently in development, or for evaluating donor eligibility in convalescent plasma therapy studies.

Backgrounds: Patients with celiac disease (CeD) carry the major histocompatibility complex class II, HLA-DQ2 or DQ8 haplotype; the absence of these haplotypes excludes a diagnosis of CeD. While the most common and highest risk HLA haplotypes in CeD have been established, the risk profiles of the less common and equivocal HLA haplotypes need further refinement. The aim of this study was to use a large national patient cohort to further stratify the risk gradient of HLA-DQ haplotypes., Methods: The study cohort included 24,339 adult patients with suspected CeD and immunoglobulin (Ig)A sufficiency (total IgA ≥ 70 mg/dL) whose samples were assessed at Mayo Clinic Laboratories for HLA-DQ genotyping, total IgA, and tissue transglutaminase (tTG)-IgA. Data from a subset of the patients who had duodenal biopsies were analyzed to determine the risk gradient of CeD. Logistic regression models were used to evaluate the risk gradient and to calculate odds ratios (ORs) for being positive to CeD serology according to different HLA-DQ2 and DQ8 heterodimers., Results: Of the 24,339 patients, 55% (n = 13,456) expressed HLA-DQ2 or DQ8 heterodimers. Compared with patients who had non-permissive HLA-DQ heterodimers, patients who had HLA-DQ2 homozygosity (HLA-DQ2.5/DQ2.5, HLA-DQ2.5/DQ2.2, or HLA-DQ2.2/DQ2.2) showed increased odds for tTG-IgA positivity (OR = 96.9; 95% CI, 58.3-147.9). Interestingly, the odds for patients who were compound heterozygous for HLA-DQ2.5 and HLA-DQ8 were similar to those for HLA-DQ2.5 heterozygotes. However, a single HLA-DQ2.2 haplotype (without HLA-DQ8, DQ2.2 heterozygous) was not associated with tTG-IgA positivity. These findings were confirmed in a subset of patients (n = 738) who had duodenal biopsies performed in addition to CeD serologic testing., Discussion: This large national reference laboratory cohort study demonstrated that HLA-DQ2.2 heterozygous is not associated with positive tTG-IgA serology, suggesting the reclassification of this haplotype as non-permissive for CeD., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 American Society for Histocompatibility and Immunogenetics. Published by Elsevier Inc. All rights reserved.)

Objective: To define the clinicopathologic features of amphiphysin-immunoglobulin G (IgG)-mediated neuropathy., Methods: Patients examined at our institution from January 1, 1995, to September 30, 2018, with amphiphysin-IgG by indirect immunofluorescence and Western blot, were reviewed. Their phenotypes were compared to cases of coexisting collapsin response-mediator protein-5 (CRMP5)-IgG or anti-neuronal nuclear antibody type 1 (ANNA1-IgG) and CRMP5-IgG autoimmunity. Improvement in modified Rankin Scale (mRS) (≥1) on follow-up was considered a favorable outcome. Amphiphysin RNA expression was assessed in healthy nerves., Results: Fifty-three amphiphysin-IgG-positive cases were identified. Of 33 (60%) patients with neuropathy, 21 had amphiphysin-IgG alone, and 12 had coexisting autoantibodies (ANNA1-IgG, n = 8; CRMP5-IgG, n = 2; ANNA1-IgG and CRMP5-IgG, n = 2). The neuropathies in isolated amphiphysin-IgG autoimmunity included polyradiculoneuropathy (62%), diffuse sensory neuronopathy (35%), and facial neuropathy with gastroparesis (3%). Among these, pain (80%), breast cancer (63%), and CNS (57%) involvements commonly coexisted, and neuropathy frequently prompted breast cancer diagnosis (76%). Stiff-person spectrum disorder was the most common CNS accompaniment (45%). Nerve biopsies showed axonal loss (n = 6/6), subperineurial edema (n = 4/6), and CD4 predominant inflammation (n = 2/6). Median mRS score at last follow-up was 3.5; 58% of patients were immunotherapy-responsive. Patients with amphiphysin-IgG alone had more favorable immunotherapy response than patients with CRMP5-IgG polyneuropathy (n = 45) (44% vs 16%, p = 0.028, odds ratio 4.2, 95% confidence interval 1.1 to 15.5). Only 1/9 (11%) patients with amphiphysin-IgG with coexisting CRMP5-IgG or ANNA1-IgG had immunotherapy response. RNA amphiphysin expression occurred at low levels in nerve., Conclusion: Amphiphysin-IgG autoimmune neuropathy has a recognizable phenotype, is frequently immune responsive, and can prompt early diagnosis of breast cancer., (© 2019 American Academy of Neurology.)

Fibrillary GN (FGN) is a rare primary glomerular disease. Histologic and histochemical features of FGN overlap with those of other glomerular diseases, and no unique histologic biomarkers for diagnosing FGN have been identified. We analyzed the proteomic content of glomeruli in patient biopsy specimens and detected DnaJ heat shock protein family (Hsp40) member B9 (DNAJB9) as the fourth most abundant protein in FGN glomeruli. Compared with amyloidosis glomeruli, FGN glomeruli exhibited a >6-fold overexpression of DNAJB9 protein. Sanger sequencing and protein sequence coverage maps showed that the DNAJB9 protein deposited in FGN glomeruli did not have any major sequence or structural alterations. Notably, we detected DNAJB9 in all patients with FGN but not in healthy glomeruli or in 19 types of non-FGN glomerular diseases. We also observed the codeposition of DNAJB9 and Ig- γ Overall, these findings indicate that DNAJB9 is an FGN marker with 100% sensitivity and 100% specificity. The magnitude and specificity of DNAJB9 overabundance in FGN also suggests that this protein has a role in FGN pathogenesis. With this evidence, we propose that DNAJB9 is a strong biomarker for rapid diagnosis of FGN in renal biopsy specimens., (Copyright © 2018 by the American Society of Nephrology.)

Alterations of von Hippel-Lindau (VHL), succinate dehydrogenase (SDHX), and TMEM127 have been associated with the development of pheochromocytomas (PCs) and paragangliomas (PGLs) and are also associated with the development of renal neoplasms. This study involved 2 primary renal PGL and 12 cases of PC/PGL with associated renal neoplasia with a mean follow up of 74 months. Germline VHL and SDHX mutation status was obtained from the medical record. Immunohistochemistry for SDHB and mutation analysis for TMEM127 was performed, in addition to analysis of The Cancer Genome Atlas datasets for SDHX and TMEM127 mutated renal cell carcinomas (RCCs). The spectrum of renal neoplasia included clear cell and tubulocystic and papillary RCC, as well as a case of multiple papillary adenomas. Three patients had metastatic PC/PGL and three patients had VHL syndrome. Previously unreported TMEM127 alterations were identified in two patients, both without evidence of VHL syndrome or SDH-deficiency, and were classified as variants of uncertain significance. Primary renal PGL and neoplasia was associated with about 2% of 710 cases of PC/PGL. These were diagnosed concurrently or on average 27 months prior to the PC/PGL, and most were low-grade, low-stage clear cell RCCs. Up to half of patients with PC/PGL and renal neoplasia had VHL syndrome, SDH deficiency, or alterations in TMEM127. One (of three) case of metastatic PC/PGL had SDHB mutation and loss of SDHB by immunohistochemistry. The other two cases had retained SDHB expression.

Lysozyme amyloidosis (ALys) is a rare form of hereditary amyloidosis that typically manifests with renal impairment, gastrointestinal (GI) symptoms, and sicca syndrome, whereas cardiac involvement is exceedingly rare and neuropathy has not been reported. Here, we describe a 40-year-old man with renal impairment, cardiac and GI symptoms, and peripheral neuropathy. Renal biopsy specimen analysis revealed amyloidosis with extensive involvement of glomeruli, vessels, and medulla. Amyloid was also detected in the GI tract. Echocardiographic and electrocardiographic findings were consistent with cardiac involvement. Proteomic analysis of Congo red-positive renal and GI amyloid deposits detected abundant lysozyme C protein. DNA sequencing of the lysozyme gene in the patient and his mother detected a heterozygous c.305T>C alteration in exon 3, which causes a leucine to serine substitution at codon 102 (Human Genome Variation Society nomenclature: p.Leu102Ser; legacy designation: L84S). We also detected the mutant peptide in the proband's renal and GI amyloid deposits. PolyPhen analysis predicted that the mutation damages the encoded protein. Molecular dynamics simulations suggested that the pathogenesis of ALys p.Leu102Ser is mediated by shifting the position of the central β-hairpin coordinated with an antiparallel motion of the C-terminal helix, which may alter the native-state structural ensemble of the molecule, leading to aggregation-prone intermediates., (Copyright © 2017 by the American Society of Nephrology.)

Established guidelines from the International Myeloma Working Group recommend diagnostic screening for patients suspected of plasma cell proliferative disease using protein electrophoresis (PEL), free light chain measurements and immunofixation electrophoresis (IFE) of serum and urine in certain cases. Plasma cell proliferative disorders are generally classified as monoclonal gammopathies given most are associated with the excess secretion of a monoclonal immunoglobulin or M-protein. In clinical practice, the M-protein is detected in a patients' serum by the appearance of a distinct protein band migrating within regions typically occupied by immunoglobulins. Given each M-protein is comprised by a sequence of amino acids pre-defined by somatic recombination unique to each clonal plasma cell, the molecular mass of the M-protein can act as a surrogate marker. We established a mass spectrometry based method to assign molecular mass to the immunoglobulin light chain of the M-protein and used this to detect the presence of M-proteins. Our method first enriches serum for immunoglobulins, followed by reduction to separate light chains from heavy chains, followed by microflow LC-ESI-Q-TOF MS. The multiply charged light chain ions are converted to their molecular mass and reconstructed peak area calculations are used for quantification. Using this method, we term "monoclonal immunoglobulin Rapid Accurate Molecular Mass" or miRAMM, the presence of M-proteins can be reliably detected with superior sensitivity compared to current gel-based PEL and IFE techniques., (Copyright © 2015. Published by Elsevier Inc.)

A defining feature of many cancers is deregulated translational control. Typically, this occurs at the level of recruitment of the 40S ribosomes to the 5'-cap of cellular messenger RNAs (mRNAs), the rate-limiting step of protein synthesis, which is controlled by the heterotrimeric eukaryotic initiation complex eIF4F. Thus, eIF4F in particular, and translation initiation in general, represent an exploitable vulnerability and unique opportunity for therapeutic intervention in many transformed cells. In this article, we discuss the development, mode of action and biological activity of a number of small-molecule inhibitors that interrupt PI3K/mTOR signaling control of eIF4F assembly, as well as compounds that more directly block eIF4F activity.