Patient With Rigidity and Fasciculations: Steroid-Responsive Presentation of Anti-IgLON5 Disease

An 82-year-old man presented with 2-year lasting widespread muscular fasciculations, cramps, and limb stiffness, with spontaneous movements in the right lower limb, unsteady gait (Video 1), and falls. Neurophysiologic studies disclosed signs of neuromuscular hyperexcitability. CSF analysis showed high tau protein concentration (543 pg/mL; reference values, <404) and unique-to-CSF oligoclonal bands. Serum and CSF anti-IgLON5 antibodies were positive (Figure 1). He carried the anti-IgLON5 disease-associated HLA-DRB1*10:01 allele.1 Brain MRI, thoracoabdominal CT, whole-body FDG-PET, and video-polysomnography were unremarkable. No sleep disturbances, bulbar symptoms, parkinsonism, or dementia were detected. Intravenous methylprednisolone (500 mg/d for 5 days), followed by oral benzodiazepines, prompted rapid functional recovery, with limb stiffness and gait improvement (Video 1), which persisted at 6-month follow-up. Anti-IgLON5 disease has progressive course and protean clinical presentations,2 representative, in our patient, for overlapping signs and symptoms of neuromuscular hyperexcitability and rigidity. Identification of rare phenotypes is important because prompt recognition and treatment can improve prognosis.

Detailed stratified GWAS analysis for severe COVID-19 in four European populations

Given the highly variable clinical phenotype of Coronavirus disease 2019 (COVID-19), a deeper analysis of the host genetic contribution to severe COVID-19 is important to improve our understanding of underlying disease mechanisms. Here, we describe an extended genome-wide association meta-analysis of a well-characterized cohort of 3255 COVID-19 patients with respiratory failure and 12 488 population controls from Italy, Spain, Norway and Germany/Austria, including stratified analyses based on age, sex and disease severity, as well as targeted analyses of chromosome Y haplotypes, the human leukocyte antigen region and the SARS-CoV-2 peptidome. By inversion imputation, we traced a reported association at 17q21.31 to a ~0.9-Mb inversion polymorphism that creates two highly differentiated haplotypes and characterized the potential effects of the inversion in detail. Our data, together with the 5th release of summary statistics from the COVID-19 Host Genetics Initiative including non-Caucasian individuals, also identified a new locus at 19q13.33, including NAPSA, a gene which is expressed primarily in alveolar cells responsible for gas exchange in the lung.

A fast and reliable method for detecting SNP rs67384697 (Hsa-miR-148a binding site) by a single run of allele-specific real-time PCR

Surface expression of human leukocyte antigen (HLA)-class I molecules is critical for modulating T/natural killer lymphocytes' effector functions. Among HLA molecules, HLA-C, the most recently evolved form of class I antigens, is subjected to both transcriptional and multiple post-transcriptional regulation mechanisms affecting its cell surface expression. Among the latter a region placed in the 3' untranslated region of HLA-C transcript contains the single nucleotide polymorphism (SNP) rs67384697 "G-ins/del" that has been found to be strictly associated with surface levels of HLA-C allomorphs because of the effect on the binding site of a microRNA (Hsa-miR-148a). Higher expression of HLA-C has been proved to influence HIV-1 infection via a better control of viremia and a slower disease progression. More importantly, the analysis of SNP rs67384697 "G-ins/del" combined with the evaluation of the HLA-Bw4/-Bw6 C1/C2 supratype, as well as the killer immunoglobulin-like receptor genetic asset, has proved to be pivotal in defining the status of Elite Controllers in the Caucasian population. Here we describe a new reliable and fast method of allele-specific real-time PCR to monitor the integrity/disruption of the binding site of the microRNA Hsa-miR-148a in a high-throughput format that can be easily applied to studies involving large cohorts of individuals.

High-resolution analysis of the HLA-A, -B, -C and -DRB1 alleles and national and regional haplotype frequencies based on 120 926 volunteers from the Italian Bone Marrow Donor Registry

HLA genes are highly polymorphic and structurally complex. They are located in the major histocompatibility complex (MHC) on chromosome 6, and the frequency of alleles and haplotypes varies widely among human populations. In this paper, we calculated the allele and haplotype frequencies using the HLA data of more than 120 000 Italian unrelated bone marrow donors enrolled in the national registry (IBMDR) and typed them with a high-resolution (HR) method for the HLA-A, -B, -C and -DRB1 alleles. The allele frequency data were obtained by manual counting; haplotype frequencies were calculated using the expectation maximisation (EM) algorithm. The total numbers of observed alleles were 226 for HLA-A, 343 for HLA-B, 201 for HLA-C and 210 for HLA-DRB1, which account for 5.4%, 6.7%, 5.2% and 8.5%, respectively, of each locus allele (IPD-IMGT/HLA Database Release 3.32, April 2018). The three most frequent Italian haplotypes were HLA-A*01:01~B*08:01~C*07:01~DRB1*03:01 (2.5%), A*02:01~B*18:01~C*07:01~DRB1*11:04 (1.1%) and A*30:01~B*13:02~C*06:02~DRB1*07:01 (1.1%). Moreover, for a relevant subset of the examined population (>100 000 individuals), the birthplace was available, and thus, we grouped the frequency data based on the corresponding Italian geographic areas, describing the HLA specificity of the Italian regional populations. The haplotype frequencies were also compared between national and regional data, and we observed remarkable differences in the regional haplotype frequencies, particularly in Sardinia. This study represents a valid tool to identify a more efficient haematopoietic stem cell unrelated donor recruitment and selection strategy, as well as for population genetic and HLA-disease association fields.

Identification of a novel HLA-C allele, C*02:10:03, in a Venezuelan patient

HLA-C*02:10:03 identified in a Venezuelan patient and characterized using next generation sequencing.

KIR3DS1-Mediated Recognition of HLA-*B51: Modulation of KIR3DS1 Responsiveness by Self HLA-B Allotypes and Effect on NK Cell Licensing

Several studies described an association between killer-cell immunoglobulin-like receptor (KIR)/HLA gene combinations and clinical outcomes in various diseases. In particular, an important combined role for KIR3DS1 and HLA-B Bw4-I80 in controlling viral infections and a higher protection against leukemic relapses in donor equipped with activating KIRs in haplo-HSCT has been described. Here, we show that KIR3DS1 mediates positive signals upon recognition of HLA-B*51 (Bw4-I80) surface molecules on target cells and that this activation occurs only in Bw4-I80^neg individuals, including those carrying particular KIR/HLA combination settings. In addition, killing of HLA-B*51 transfected target cells mediated by KIR3DS1⁺/NKG2A⁺ natural killer (NK) cell clones from Bw4-I80^neg donors could be partially inhibited by antibody-mediated masking of KIR3DS1. Interestingly, KIR3DS1-mediated recognition of HLA-B*51 could be better appreciated under experimental conditions in which the function of NKG2D was reduced by mAb-mediated blocking. This experimental approach may mimic the compromised function of NKG2D occurring in certain viral infections. We also show that, in KIR3DS1⁺/NKG2A⁺ NK cell clones derived from an HLA-B Bw4-T80 donor carrying 2 KIR3DS1 gene copy numbers, the positive signal generated by the engagement of KIR3DS1 by HLA-B*51 resulted in a more efficient killing of HLA-B*51-transfected target cells. Moreover, in these clones, a direct correlation between KIR3DS1 and NKG2D surface density was detected, while the expression of NKp46 was inversely correlated with that of KIR3DS1. Finally, we analyzed KIR3DS1⁺/NKG2A⁺ NK cell clones from a HLA-B Bw4^neg donor carrying cytoplasmic KIR3DL1. Although these clones expressed lower levels of surface KIR3DS1, they displayed responses comparable to those of NK cell clones derived from HLA-B Bw4^neg donors that expressed surface KIR3DL1. Altogether these data suggest that, in particular KIR/HLA combinations, KIR3DS1 may play a role in the process of human NK cell education.

An improved method for HLA-B and -C supratyping

A growing body of evidence links the analysis of the KIR genotype and the presence of their HLA-B and -C ligands to a wide repertoire of human diseases. We noticed that, using a panel of 184 Caucasoid donors, a limited number of HLA alleles were incorrectly supratyped by previously described pyrosequence-based assays. Here we describe a simple implementation of the reported methods that corrects all the discrepancies found with HLA-B and -C molecular typing and allows establishing a quick and high-throughput method for the determination of HLA-Bw4 I(80), Bw4T(80), Bw6 and HLA-C1 or -C2 supratype.

The distribution of KIR-HLA functional blocks is different from north to south of Italy

The killer cell immunoglobulin-like receptor (KIR)-human leukocyte antigen (HLA) interaction represents an example of genetic epistasis, where the concomitant presence of specific genes or alleles encoding receptor-ligand units is necessary for the activity of natural killer (NK) cells. Although KIR and HLA genes segregate independently, they co-evolved under environmental pressures to maintain particular KIR-HLA functional blocks for species survival. We investigated, in 270 Italian healthy individuals, the distribution of KIR and HLA polymorphisms in three climatic areas (from cold north to warm south), to verify their possible geographical stratification. We analyzed the presence of 13 KIR genes and genotyped KIR ligands belonging to HLA class I: HLA-C, HLA-B and HLA-A. We did not observe any genetic stratification for KIR genes and HLA-C ligands in Italy. By contrast, in a north-to-south direction, we found a decreasing trend for the HLA-A3 and HLA-A11 ligands (P = 0.012) and an increasing trend for the HLA-B ligands carrying the Bw4 epitope (P = 0.0003) and the Bw4 Ile80 epitope (P = 0.0005). The HLA-A and HLA-B KIR ligands were in negative linkage disequilibrium (correlation coefficient -0.1211), possibly as a consequence of their similar function in inhibiting NK cells. The distribution of the KIR-HLA functional blocks was different along Italy, as we observed a north-to-south ascending trend for KIR3DL1, when coupled with HLA-B Bw4 ligands (P = 0.0067) and with HLA-B Bw4 Ile80 (P = 0.0027), and a descending trend for KIR3DL2 when coupled with HLA-A3 and HLA-A11 ligands (P = 0.0044). Overall, people from South Italy preferentially use the KIR3DL1-HLA-B Bw4 functional unit, while those from the North Italy equally use both the KIR3DL2-HLA-A3/A11 and the KIR3DL1-HLA-B Bw4 functional units to fight infections. Thus, only KIR3DL receptors, which exert the unique role of microbial sensors through the specific D0 domain, and their cognate HLA-A and HLA-B ligands are selectively pressured in Italy according to geographical north-to-south distribution.

Acute graft-versus-host disease in pediatric allogeneic hematopoietic stem cell transplantation. Single-center experience during 10 yr

a-GvHD may complicate allogeneic HSCT. In this retrospective single-center study, we evaluated incidence and risk factors of a-GvHD in 197 consecutive allogeneic pediatric HSCTs applying Glucksberg and NIH a-GvHD classifications. Among 179 eligible transplants, the cumulative incidence of grade 0-I a-GvHD was 48% and grade II-IV was 52%. None of the considered variables significantly influenced the incidence of grade II-IV a-GvHD. Malignancy and myeloablation were associated with an increased risk of classic a-GvHD (p < 0.01). Seventy-two percentage of children are alive, with a significant difference in OS and TRM between grade 0 and I vs. grade II and IV a-GvHD; this observation was reproduced in the non-malignant setting, while only a disparity in TRM was evidenced in children with malignancy. In our experience, the incidence of a-GvHD was similar, regardless of donor type. Myeloablation and malignant disease represented the only risk factors for classic a-GvHD. Our results highlight the need for a better prevention of this complication in the non-malignant setting.

The conundrum of HLA-DRB1*14:01/*14:54 and HLA-DRB3*02:01/*02:02 mismatches in unrelated hematopoietic SCT

Uncertainty still exists on the role of polymorphisms outside the HLA-DRB1 binding site or inside the HLA-DRB3 binding groove in unrelated hematopoietic SCT (HSCT). The ideal model to solve the conundrum consists of the transplants mismatched for HLA-DRB1*14:01/*14:54 and/or for HLA-DRB3*02:01/*02:02. A task force was set up in Italy to recruit transplanted pairs defined as HLA-DRB1*14:01 before 2006, the year crucial for the proper definition of the HLA-DRB1*14:54 allele in molecular biology. Out of 2723 unrelated pairs, 189 transplanted in Italy from 1995 to 2006 were HLA-DRB1*14:01 positive; 103/189 pairs with good historical DNA were retyped for HLA-DRB1*14 and HLA-DRB3 at-high resolution level; 31/103 pairs had HLA-DRB1*14 and/or HLA-DRB3 mismatched; 99/103, having complete clinical data, underwent statistical analysis for OS, TRM, disease-free survival and acute and chronic GvHD. No significant involvement of HLA-DRB1*14:01/*14:54 or HLA-DRB3*02:01/*02:02 mismatches was found, either alone or combined. Our findings suggest that disparities at exon 3 of the HLA-DRB1 gene seem unlikely to influence the outcome after HSCT. The same may be envisaged for HLA-DRB3(*)02:01 and (*)02:02 alleles which, although differing in the Ag binding site, seem unable to modulate an appreciable immune response in an HSCT setting.

Patients with paroxysmal nocturnal hemoglobinuria have a high frequency of peripheral-blood T cells expressing activating isoforms of inhibiting superfamily receptors

Patients with paroxysmal nocturnal hemoglobinuria (PNH) have a large clonal population of blood cells deriving from hematopoietic stem cells (HSCs) deficient in glycosylphosphatidylinositol (GPI)-anchored surface molecules. A current model postulates that PNH arises through negative selection against normal HSCs exerted by autoreactive T cells, whereas PNH HSCs escape damage. We have investigated the inhibitory receptor superfamily (IRS) system in 13 patients with PNH. We found a slight increase in the proportion of T cells expressing IRS. In contrast to what applies to healthy donors, the engagement of IRS molecules on T cells from patients with PNH elicited a powerful cytolytic activity in a redirected killing assay, indicating that these IRSs belong to the activating type. This was confirmed by clonal analysis: 50% of IRS+ T-cell clones in patients with PNH were of the activating type, while only 5% were of the activating type in healthy donors. Moreover, the ligation of IRS induces (1) production of tumor necrosis factor alpha (TNF-alpha) and interferon gamma (IFN-gamma) and (2) brisk cytolytic activity against cells bearing appropriate IRS counter-ligands. In addition, these IRS+ T cells show natural killer (NK)-like cytolytic activity to which GPI- cells were less sensitive than GPI+ cells. Thus, T cells with NK-like features, expressing the activating isoforms of IRS, may include effector cells involved in the pathogenesis of PNH.

Prevalence of DRB1*01 and DRB1*04 alleles in a group of patients with rheumatoid arthritis living in Liguria

A major component of genetic susceptibility to rheumatoid arthritis (RA) appears to be explained by inheritance of HLA-DRB1 alleles. Multiple HLA-DRB1 alleles (DRB1*0401, *0404, *0405, *0408, *0101, *102, *1001 and *1402) encoding a shared epitope at amino acid positions 70-74 are associated with susceptibility to RA. There is ethnic variation in the clinical expression of RA and in both the frequency and type of HLA-DRB1 alleles carrying the shared epitope. We evaluated the prevalence of the alleles of HLA-DRB1 locus encoding for SE in 42 outpatients with RA attending the Rheumatology Center of the University of Genoa, Bruzzone Institute, and living in Liguria. A control group was composed of Italian marrow donors. DNA genotyping was performed using a low-resolution polymerase chain reaction technique for characterization of the families of HLA-DRB1 alleles for each of the 42 patients studied. Subsequently, subjects with *01 and *04 haplotype were tested with high-resolution HLA-DRB 1 typing to characterize the *01 and *04 alleles. No statistically significant differences were found in the prevalence of RA-associated single alleles *01 and *04 in the study group or in the control group. In contrast, the sum of susceptibility *04 alleles studied by resolution typing was strongly related to RA in the study group in comparison with the control group.

Unrelated donor marrow transplantation: an update of the experience of the Italian Bone Marrow Group (GITMO)

BACKGROUND AND OBJECTIVES

Unrelated donor bone marrow transplant (UD-BMT) has become an attractive alternative source of hematopoietic cells for patients lacking a matched sibling. The aim of this paper was to report on results of the 696 UD BMTs performed in 31 Italian institutions during the first 10 years of activity of the Italian Bone Marrow Donor Registry (IBMDR).

EVIDENCE AND INFORMATION SOURCES

In 1989 the Italian Bone Marrow Transplant Group (GITMO) established the IBMDR to facilitate donor search and marrow procurement for patients lacking an HLA identical sibling. By end of December 1999, 260,000 HLA-A, B typed volunteer donors had been cumulatively registered and 2,620 searches had been activated for Italian patients. At least one HLA-A, B, DRB1 matched donor was found for 54% of the patients and 696 UD BMTs were performed. In 50% of cases the donor was found in the IBMDR and in 50% in 15 other Registries. The average time from search activation to transplant was 6 months for disease other than CML. For CML it was 14 months. Actuarial 12-month transplant-related mortality (TRM) was 68% in patients grafted between 1979 and 1992 and 44% for patients grafted after 1993. Twenty-eight per cent of patients developed grade III or IV acute GvHD and 24% developed extensive chronic GvHD. The rate of disease free survival at three years was 57% for patients with 1st chronic phase CML, 37% for patients with 1st or 2nd CR ALL, 31% for AML or MDS patients 18 years of age and 54% for patients with inborn errors.

PERSPECTIVES

We conclude that the IBMDR has benefited a substantial number of patients lacking a matched sibling and has facilitated the recruitment of UDs into the international donor pool. The long time required for the search is the major obstacle to the success of this programme. This suggests that early transplant and a decrease in TRM could further improve these encouraging results.

Unrelated donor marrow transplantation: an update of the experience of the Italian Bone Marrow Transplant Group (GITMO)

Unrelated donor bone marrow transplant (UD-BMT) has become an attractive alternative source of hematopoietic cells for patients lacking a matched sibling. The aim of this paper was to report on results of the 696 UD BMTs performed in 31 Italian institutions during the first 10 years of activity of the Italian Bone Marrow Donor Registry (IBMDR). In 1989 the Italian Bone Marrow Transplant Group (GITMO) established the IBMDR to facilitate donor search and marrow procurement for patients lacking an HLA identical sibling. By end of December 1999, 260,000 HLA-A, B typed volunteer donors had been cumulatively registered and 2,620 searches had been activated for Italian patients. At least one HLA-A, B, DRB1 matched donor was found for 54% of the patients and 696 UD BMTs were performed. In 50% of cases the donor was found in the IBMDR and in 50% in 15 other Registries. The average time from search activation to transplant was 6 months for disease other than CML. For CML it was 14 months. Actuarial 12-month transplant-related mortality (TRM) was 68% in patients grafted between 1979 and 1992 and 44% for patients grafted after 1993. Twenty-eight per cent of patients developed grade III or IV acute GvHD and 24% developed extensive chronic GvHD. The rate of disease free survival at three years was 57% for patients with 1st chronic phase CML, 37% for patients with 1st or 2nd CR ALL, 31% for AML or MDS patients < or = 18 years of age and 54% for patients with inborn errors. We conclude that the IBMDR has benefited a substantial number of patients lacking a matched sibling and has facilitated the recruitment of UDs into the international donor pool. The long time required for the search is the major obstacle to the success of this programme. This suggests that early transplant and a decrease in TRM could further improve these encouraging results.

[The Italian Registry of Bone Marrow Donors]

Following a synthetic statement of the scientific, genetic and practical assumptions of the bone marrow transplantation (BMT) from marrow unrelated donor (MUD), which, in turn, have represented the basis for the establishment of the Italian Bone Marrow Donor Registry (IBMDR), the paper reports the registry activity on 30 November 1998. At that date, Italian volunteers were 232,876, number which put the IBMDR as the fourth registry all over the world and as the third in Europe. The mean age of the donors is 34 years, and this means that IBMDR is one of the youngest among international registries. Using Italian donors, 426 BMT, altogether, have been performed, (248 for Italian patients and 178 for foreign patients). Donor search activations performed by national and international transplant centres have been, at the same date, 5729 (1821 for Italian patients and 3908 for foreign patients). Operating standards and guidelines for all centres participating in the IBMDR are reported in this issue.

Unrelated donor marrow transplantation for inborn errors

From December 1989 to December 1997 40 children aged 1 year to 19 years with inborn errors other than severe combined immunodeficiencies underwent unrelated donor (UD) bone marrow transplantation (BMT) in one of 10 institutions of the Italian Bone Marrow Transplant Group participating in this program. The diseases leading to BMT included Fanconi Anemia (10), Thalassemia (8), Wiskott Aldrich syndrome (5), haemophagocytic lymphohystiocytosis (6), osteopetrosis (3), storage diseases (6), Chediak Higashi syndrome (1), Schwachman syndrome (1). Thirty-three pairs were A, B, DRB1 matched. Three pairs were one antigen mismatched and one pair was two antigens mismatched. The remaining three pairs lacked information on molecular biology. Twelve children underwent a preparative regimen including radiotherapy. The remaining 28 children were conditioned with a chemotherapy regimen which included Busulfan. GvHD disease prophylaxis included CSA and MTX alone (9) or associated with ALG (17) or in vivo Campath 1G (12). The remaining two children received CSA alone. Thirty-five children showed donor engraftment; three children with thalassemia and one with osteopetrosis failed to engraft. Five children developed secondary graft failure. Actuarial 5 year disease-free survival was 62%; grade III-IV acute GvHD developed in seven of 38 evaluable children (18%); chronic GvHD developed in seven of 27 evaluable children (26%). We confirm that Wiskott Aldrich syndrome, HLH, and osteopetrosis represent an absolute indication for UD-BMT. Prognosis of UD-BMT for FA could improve in children grafted in an early phase, but a better preparative regimen has to be identified. UD-BMT in thalassemia is acceptable only in a restricted subset of patients selected for poor compliance to therapy.

Unrelated donor marrow transplantation: initial experience of the Italian bone marrow transplant group (GITMO)

From 1 September 1988 to 30 September 1993, a search for an unrelated donor (URD) was started for 633 Italian patients. Eighty-five of them (13%) were transplanted. Despite the introduction of more strict criteria for the selection of compatible donors, the percentage of patients who reached transplant increased significantly after December 1992. For patients who started a search before and after January 1993, respectively the probability of transplant by 8 and 16 months from search activation was 4 and 10%, compared to 22 and 37% (P = 0.0001). The average intervals between search activation and graft were 15 and 8 months respectively, for the first and second group (P = 0.0001). Data of 75 consecutive transplants performed up to March 1994 were analyzed. Actuarial 2-year survival was 15% for patients grafted before 1992 and 40% for those grafted after January 1992. In this latter period, survival of patients with malignant and non-malignant disorders was 32 and 67%, respectively. In univariate analysis, patients younger than 16 years (P = 0.01), patients grafted after 1992 (P = 0.01) and patients receiving the marrow from a 6-antigen matched donor (P = 0.01) showed a higher survival probability. Multivariate analysis did not show any difference, probably due to the low number of patients and to short follow-up. The adoption of stricter and more accurate HLA-matching criteria and the consequent reduction of deaths related to acute GVHD were the main reasons for the improvement of survival observed in patients grafted after 1992.

Muscarinic inhibition of endogenous glutamate release from rat hippocampus synaptosomes

The effects of acetylcholine (ACh) on the depolarization-evoked release of endogenous glutamic acid (Glu) have been studied using synaptosomes prepared from rat hippocampus and depolarized in superfusion with 15 mM KCl. Acetylcholine inhibited Glu release in a concentration-dependent way. The natural agonist was particularly effective causing 50% inhibition of Glu release at 10 microM in the absence of acetylcholinesterase (AChE) inhibitors. The inhibitory effect of ACh on the K+-evoked release of Glu was antagonized by the selective muscarinic receptor antagonist atropine but not by the nicotinic receptor antagonist mecamylamine. The data represent the first demonstration that muscarinic receptors located on Glu axon terminals in rat hippocampus may modulate the release of Glu.