Assessment of mRNA Vaccine Immunogenicity in Solid Organ Transplant Recipients.

Background and Objectives: Solid organ transplant (SOT) recipients have a higher risk of suffering from severe Coronavirus (COVID-19) compared to the general population. Studies have shown impaired immunogenicity of mRNA vaccines in this high-risk population; thus, SOT recipients have been prioritized globally for primary and booster doses. Materials and Methods: We analyzed 144 SOT recipients who had previously received two doses of BNT162b2 or mRNA1273 vaccine, and who were subsequently vaccinated with a booster dose of the mRNA1273 vaccine. Humoral and cellular immune responses were measured 1 and 3 months after the second dose, and 1 month after the third dose. Results: One month after the second dose, 33.6% (45/134) of patients displayed a positive antibody response with a median (25th, 75th) antibody titer of 9 (7, 161) AU/mL. Three months after the second dose, 41.8% (56/134) tested positive with a median (25th, 75th) antibody titer of 18 (7, 251) AU/mL. After the booster dose, the seropositivity rate increased to 69.4% (93/134), with a median (25th, 75th) titer of 966 (10, 8027) AU/mL. The specific SARS-CoV-2 T-cell response was assessed in 44 randomly selected recipients 3 months after the second dose, and 11.4% (5/44) of them had a positive response. Following the third dose, 42% (21/50) tested positive. Side effects after the third dose were mild, with pain at the injection site being the most frequent adverse effect, reported by 73.4% of the recipients. Conclusion: Our study shows a mild delayed increase in antibody titer, three months after primary vaccination compared to one month after. It also shows a robust augmentation of humoral and specific T-cell responses after the booster dose, as well as the safety and tolerability of the mRNA vaccines in SOT recipients.

Transthyretin (Pro24Ser) variant amyloidosis: A case report of the first patient in Greece.

OBJECTIVE: Transthyretin cardiac amyloidosis (ATTR-CA) is a rare and potentially fatal disease caused by the accumulation of insoluble transthyretin (TTR) amyloid fibrils in the heart. The symptoms of ATTR-CA are often non-specific, often leading to underdiagnosis. Early diagnosis and treatment have a significant impact on disease progression and mortality. CASE PRESENTATION: In this case we report a 73-year-old male presented with dyspnea on exertion. The patient had a medical history of peripheral neuropathy, bilateral carpal tunnel syndrome, spinal fusion, and a family history of coronary artery disease. Upon his presentation at the Cardiology department, cardiac echo study revealed left and right ventricular hypertrophy with pulmonary hypertension, diastolic dysfunction and a restrictive pattern. Because of the high probability of amyloidosis, the patient underwent a technetium-99m-3,3-diphosphono-1,2-propanodicarboxylic acid (99mTc-DPD) bone scintigraphic study, which confirmed the diagnosis of ATTR-CA. Transthyretin gene sequencing analysis revealed the rare p. Pro24Ser pathogenic variant. Final diagnosis was ATTR-CA associated with the proline replaced by serine at position 24 (Pro24Ser) TTR variant, which is rare and only a few cases have been reported worldwide. The patient was treated with tafamidis and inotersen and followed up. CONCLUSION: This case highlights the importance of considering amyloidosis as a differential diagnosis for non-specific symptoms and the need for early diagnosis and management of ATTR-CA.

KCNE2 gene mutation and Brugada syndrome.

KCNE2 gene mutations have been associated with atrial fibrillation, long QT syndrome, Brugada syndrome and unexplained sudden cardiac death. Herein, we describe a case of Brugada syndrome carrying an heterozygous variant in the KCNE2 gene [NM_172201.2:c.161 T > C, p.(Met54Thr, M54T)]. Gain of function of the Ito current possibly explains the Brugada ECG phenotype in this case.

A novel variant of RyR2 gene in a family misdiagnosed as congenital long QT syndrome: The importance of genetic testing.

Catecholaminergic polymorphic ventricular tachycardia (CPVT) and Long-QT syndrome (LQTS) are two distinct entities with similar clinical presentation and management but different clinical course. In this study, we present two family members presented with aborted sudden cardiac death (SCD) that was attributed to CPVT. The CPVT may be underrecognized in SCD victims and a diagnosis of "atypical LQTS" may warrant consideration of CPVT and analysis of RyR2 if the standard cardiac channel gene screen for LQTS is negative. Although the management of both channelopathies is quite common the clinical outcomes are different, with CPVT displaying a more malignant clinical course.

A case report of recessive restrictive cardiomyopathy caused by a novel mutation in cardiac troponin I (TNNI3).

BACKGROUND: Restrictive cardiomyopathy is a rare cardiac disease, for which several genes including TNNT2, MYPN, FLNC and TNNI3 have been associated with its familial form. CASE PRESENTATION: Here we describe a female proband with a severely manifested restrictive phenotype leading to heart transplantation at the age of 41, who was found homozygous for the novel TNNI3 mutation: NM_000363.4:c.586G > C, p.(Asp196His). Her parents were third-degree cousins originating from a small village and although they were found heterozygous for the same variant they displayed no symptoms of the disease. Her older sister who was also found heterozygous was asymptomatic. Her twin sister and her brother who were homozygous for the same variant displayed a restrictive and a hypertrophic phenotype, respectively. Their children are all carriers of the mutation and remain asymptomatic until the age of 21. CONCLUSION: These observations point to a recessive mode of inheritance reported for the first time for this combination of gene/disease.

Phenotypic Heterogeneity within Members of a Family Carrying the Same RBM20 Mutation R634W.

OBJECTIVE: We present the genotypic and phenotypic characterization of a family displaying dilated cardiomyopathy (DCM). METHODS: The proband and his relatives underwent full cardiological assessment. Genetic analysis of the proband was performed with the use of next-generation sequencing technology. RESULTS: In this study, we present 6 members of a family carrying the RBM20 mutation NM_001134363.2:c.1900C>T. The proband was initially diagnosed with DCM at the age of 18 years and received an implantable cardioverter defibrillator (ICD) due to ventricular arrhythmias. His brother, carrier of the mutation, has been diagnosed with borderline left ventricular function. The mutation was shown to be of paternal origin, but their father remains asymptomatic with a mild DCM, while his electrocardiogram at the initial evaluation showed a right bundle branch block pattern. The mutation was also detected in the index case's aunt who was resuscitated from sudden cardiac death. Her echocardiography revealed early stages of DCM and a bicuspid aortic valve. Her children are both carriers of the mutation. Her daughter is unaffected, but her son has an ICD implanted due to sustained ventricular tachycardia and presents early signs of DCM. CONCLUSION: Our findings are the first report of co-segregation of the mutation in 6 family members, supporting its pathogenic role.

Viral induction of AID is independent of the interferon and the Toll-like receptor signaling pathways but requires NF-kappaB.

Activation-induced cytidine deaminase (AID) is expressed in germinal centers of lymphoid organs during immunoglobulin diversification, in bone marrow B cells after infection with Abelson murine leukemia retrovirus (Ab-MLV), and in human B cells after infection by hepatitis C virus. To understand how viruses signal AID induction in the host we asked whether the AID response was abrogated in cells deficient in the interferon pathway or in signaling via the Toll-like receptors. Here we show that AID is not an interferon responsive gene and abrogation of Toll-like receptor signaling does not diminish the AID response. However, we found that NF-kappaB was required for expression of virally induced AID. Since NF-kappaB binds and activates the AID promoter, these results mechanistically link viral infection with AID transcription. Thus, induction of AID by viruses could be the result of several signaling pathways that culminate in NF-kappaB activation, underscoring the versatility of this host defense program.

Regulation of AID expression in the immune response.

The B cell-specific enzyme activation-induced cytidine deaminase (AID) has been shown to be essential for isotype switching and affinity maturation of antibody genes during the immune response. Conversely, AID activity has also been linked to autoimmunity and tumorigenesis. Determining how AID expression is regulated in vivo is therefore central to understanding its role in health and disease. Here we use phylogenetic footprinting and high-resolution histone acetylation mapping to accurately demarcate AID gene regulatory boundaries. Based on this strategy, we identify a novel, positive regulatory element required for AID transcription. Furthermore, we generate two AID indicator mouse strains using bacterial artificial chromosomes that faithfully recapitulate endogenous AID expression. The first strain uses a green fluorescent protein reporter to identify B cells that actively express AID during the immune response. In the second strain, AID transcription affects the permanent expression of a yellow fluorescent protein reporter in post-germinal center and terminally differentiated lymphocytes. We demonstrate the usefulness of these novel strains by resolving recent contradictory observations on AID expression during B cell ontogeny.

A truncating variant altering the extreme C-terminal region of desmoplakin (DSP) suggests the crucial functional role of the region: a case report study.

BACKGROUND: Homozygous truncating mutations located in the C-terminal region of the desmoplakin gene (DSP) are known to mainly cause Carvajal syndrome, an autosomal recessive syndromic form of arrhythmogenic cardiomyopathy with an extra-cardiac cutaneous phenotype. CASE PRESENTATION: Here we describe a female proband with a documented arrhythmogenic left ventricular cardiomyopathy and a syncopal episode at the age of 13, who was found homozygous for the novel DSP variant: NM_004415.4:c.8586delC, p.(Ser2863Hisfs*20) at the extreme C-terminal region of the protein, just 8 amino acids upstream the stop codon. She did not have any of the typical dermatological symptoms that characterize Carvajal syndrome. Her brother had died suddenly at the age of 18 during exercise and was found homozygous for the same variant at the post-mortem, while their parents were heterozygous. The region of origin of both parents was the same geographic area of Greece, but they were not aware of any common ancestor. Detailed clinical examination revealed that the mother displayed a mild arrhythmic phenotype, while the father was asymptomatic. CONCLUSION: These observations pinpoint to a significant functional role of the extreme C-terminal tail of the protein.

Immunogenicity of the Two mRNA SARS-CoV-2 Vaccines in a Large Cohort of Dialysis Patients.

Chronic kidney disease patients, especially those on hemodialysis, are at the highest risk of a severe course and death from COVID-19. Moreover, they appear to have suboptimal response in both cellular and humoral immunity after vaccination. The present study investigated humoral and cellular response and safety after two doses of either of the two authorized mRNA vaccines in a cohort of 310 patients on maintenance dialysis. The antibody response rate was 94.5%, with a median (25th, 75th) antibody titer of 3478 (1236, 8141) AU/mL. Only mild adverse effects were observed. Only vaccine type was independently associated with immunogenicity. Α statistically significant difference in favor of mRNA1273 versus BNT162b2 vaccine was observed. Antibody positivity (100% vs. 94.3%, p < 0.001), median (25th, 75th) antibody levels: 9499 (6118, 20,780) AU/mL vs. 3269 (1220, 7807) AU/mL (p < 0.001). Among the 65 patients tested for T-cell response, 27 (41.5%) had a positive one with a median (25th, 75th) antibody titer of 6007 (3405, 12,068) AU/mL, while 38 with no T-cell response presented a lower median (25th, 75th) antibody titer of 1744 (850, 4176) AU/mL (p < 0.001). Both mRNA vaccines are safe for dialysis patients and can trigger humoral and cellular responses, although with lower titers than those that have been reported to healthy individuals.

RBM20 mutation and ventricular arrhythmias in a young patient with dilated cardiomyopathy: a case report.

Gene mutations in RBM20 have been identified in a minority of familial and sporadic dilated cardiomyopathy cases. Recent studies of carriers of RBM20 mutations not only highlight the aforementioned association with dilated cardiomyopathy but also indicate a link with increased incidence of ventricular arrhythmias. Herein we describe a case of 17-year-old female patient with dilated cardiomyopathy carrying a p.(Arg634Trp) RBM20 mutation and presenting with frequent premature ventricular contractions and episodes of non-sustained ventricular tachycardia.

A new phenotype of severe dilated cardiomyopathy associated with a mutation in the LAMP2 gene previously known to cause hypertrophic cardiomyopathy in the context of Danon disease.

Danon disease is a rare X-linked cardiac and skeletal muscle disorder with multisystem clinical manifestations. Genetic defects at the lysosome-associated membrane 2 protein (LAMP2) are the cause of the disorder. Due to the rarity of the disease, there is limited progress in understanding the correlation between genotype and phenotype, and explaining the large variability of the clinical features of the disease. In this study, we report two patients, twin sisters, referred to our hospital for end stage heart failure due to dilated cardiomyopathy, requiring heart transplant evaluation. Genetic analysis, using targeted next generation sequencing, showed that the proband carried a LAMP2 missense variant, c.928G > A. The mutation was also detected in her twin sister by sanger sequencing. This variant has already been reported by other investigators and was correlated with the clinical triad of Danon disease i.e. hypertrophic cardiomyopathy, mental retardation and peripheral myopathy. The new phenotype of dilated cardiomyopathy associated with this mutation, confirms the phenotypic heterogeneity of the particular mutation, as well as of Danon disease.

Holt-Oram Syndrome in a Patient with Crohn's Disease: a Rare Case Report and Literature Review.

INTRODUCTION: Holt-Oram syndrome (HOS) is an uncommon autosomal dominant disorder defined by congenital cardiac defects, some anatomical deformities in the upper limb and conduction abnormalities. Sequence alteration of TBX5 gene located on chromosome 12 has associated with HOS. CASE REPORT: We present the case of a 26-year-old female with known upper limb alteration and ventricular septal defect who later in life developed Crohn's disease. CONCLUSION: To the best of our knowledge association of Holt-Oram syndrome with Crohn's disease has not been reported in literature before. Therefore, a possible genetic connection between Holt-Oram syndrome and Crohn's disease remains to be determined.

The regulation of somatic hypermutation.

Somatic hypermutation and class switch recombination cause genetic alterations in immunoglobulin (Ig) genes, which underlie the generation of the secondary antibody repertoire in B lymphocytes. Both processes require activation-induced cytidine deaminase (AID), whose mechanism of action in not yet known in detail, but which mediates the accumulation of point mutations in the Ig locus. This highly mutagenic process must be tightly controlled, and multiple levels of regulation might exist. Recent experiments show that AID deaminates deoxycytidine to deoxyuridine in single-stranded DNA. This mutagenic event is targeted to actively transcribed sequences, and the specificity of deamination might be related to the chromatin structure of the transcription complex.

cDNA cloning, characterization, and developmental expression of the 20S proteasome alpha5 subunit in the Mediterranean fruit fly Ceratitis capitata.

In the present study, we report the cDNA cloning, characterization, and developmental expression of the 20S proteasome alpha5 subunit from the Mediterranean fruit fly Ceratitis capitata (medfly). Using an RT-PCR fragment that corresponds to the amino-terminal region of the Drosophila melanogaster 20S proteasome alpha5 subunit, we isolated a 987-bp cDNA that encodes the complete coding region of the medfly ortholog, which was named CcPSMA5. CcPSMA5 consists of 241 amino acids and has a predicted molecular weight of 26.4 kDa and pI 4.75. Comparison of the CcPSMA5 amino acid sequence with the sequences of all known 20S proteasome alpha5 subunits from different organisms indicated that the medfly 20S proteasome alpha5 subunit has the strongest homology to that of Drosophila. In situ hybridization showed that the CcPSMA5 gene is mapped in the region 44B of chromosome 4. Northern blot hybridization analysis showed that the CcPSMA5 mRNA has a size of approximately 1.2 kb. High levels of the CcPSMA5 mRNA were detected in freshly laid eggs, indicating that they were maternally deposited. The mRNA expression pattern during medfly development suggests that the CcPSMA5 gene is upregulated before mid-embryogenesis and at the onset of metamorphosis.

A role for activation-induced cytidine deaminase in the host response against a transforming retrovirus.

Activation-induced cytidine deaminase (AID) is specifically expressed in the germinal centers of lymphoid organs, where it initiates targeted hypermutation of variable regions of immunoglobulin genes in response to stimulation by antigen. Ectopic expression of AID, however, mediates generalized hypermutation in eukaryotes and prokaryotes. Here, we present evidence that AID is induced outside the germinal center in response to infection by the Abelson murine leukemia virus. The genotoxic activity of virally induced AID resulted in checkpoint kinase-1 (chk1) phosphorylation and ultimately restricted the proliferation of the infected cell. At the same time, it induced NKG2D ligand upregulation, which alerts the immune system to the presence of virally transformed cells. Hence, in addition to its known function in immunoglobulin diversification, AID is active in innate defense against a transforming retrovirus.