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Transfusion May 2024A life-threatening anaphylactic shock can occur if a patient with undiagnosed immunoglobulin A (IgA) deficiency (i.e., IgA levels <500 ng/mL) receives IgA-containing...
BACKGROUND
A life-threatening anaphylactic shock can occur if a patient with undiagnosed immunoglobulin A (IgA) deficiency (i.e., IgA levels <500 ng/mL) receives IgA-containing blood, hence the need for a rapid, point-of-care (POC) method for IgA deficiency screening. Enzyme-linked immunosorbent assay (ELISA) is routinely used to detect IgA, but this method requires trained specialists and ≥24 h to obtain a result. We developed a surface plasmon resonance (SPR)-based protocol to identify IgA-deficient patients or donors within 1 h.
MATERIALS AND METHODS
The SPR sensor relies on the detection of IgAs captured by primary antibodies adsorbed on the SPR chip and quantified with secondary antibodies. The sensor was calibrated from 0 to 2000 ng/mL in buffer, IgA-depleted human serum, and plasma samples from IgA-deficient individuals. A critical concentration of 500 ng/mL was set for IgA deficiency. The optimized sensor was then tested on eight plasma samples with known IgA status (determined by ELISA), including five with IgA deficiency and three with normal IgA levels.
RESULTS
The limit of detection was estimated at 30 ng/mL in buffer and 400 ng/mL in diluted plasma. The results obtained fully agreed with ELISA among the eight plasma samples tested. The protocol distinguished IgA-deficient from normal samples, even for samples with an IgA concentration closer to critical concentration.
DISCUSSION
In conclusion, we developed a reliable POC assay for the quantification of IgA in plasma. This test may permit POC testing at blood drives and centralized centers to maintain reserves of IgA-deficient blood and in-hospital testing of blood recipients.
Topics: Humans; Surface Plasmon Resonance; Immunoglobulin A; IgA Deficiency; Enzyme-Linked Immunosorbent Assay
PubMed: 38591151
DOI: 10.1111/trf.17818 -
Immunogenetics Jun 2024X-linked hyper-immunoglobulin M (X-HIGM) syndrome and autosomal recessive hyper-immunoglobulin E syndrome (HIES) are rare inborn errors of immunity characterized by...
X-linked hyper-immunoglobulin M (X-HIGM) syndrome and autosomal recessive hyper-immunoglobulin E syndrome (HIES) are rare inborn errors of immunity characterized by recurrent infections due to immune system impairment. In this study, we identified a novel hemizygous CD40 ligand (CD40L) mutation and compound heterozygous dedicator of cytokinesis-8 (DOCK8) mutations in two Han Chinese families with X-HIGM and HIES, respectively. We aimed to investigate the association between their genotypes and phenotypes. Genomic DNA was extracted from peripheral blood samples obtained from the families. Whole exome sequencing and Sanger sequencing were performed to identify and verify pathogenic variants in the two families. Clinical analyses of the probands were also performed. A novel hemizygous mutation of CD40L in exon 2 (c.257delA) was identified in the first proband, resulting in the substitution of glycine with glutamic acid at codon 86 of the protein. This leads to premature termination of translation at downstream codon 9 (p.E86Gfs*9). Sanger sequencing confirmed that the variant was inherited from the mother. The second proband carried two novel compound heterozygous mutations in DOCK8: one at exon 14 (c.1546C > G) inherited from the father, and the other at intron 41 (c.5355 + 6C > T; splicing) inherited from the mother. This study enhances our understanding of the pathogenetic mutation spectrum of CD40L and DOCK8 genes, facilitating the prenatal diagnosis of X-HIGM and HIES and enabling timely treatment of patients.
Topics: Humans; Male; Guanine Nucleotide Exchange Factors; CD40 Ligand; Pedigree; Female; Mutation; Heterozygote; Job Syndrome; Hyper-IgM Immunodeficiency Syndrome, Type 1; Asian People; Child; Child, Preschool; China; Exome Sequencing; East Asian People
PubMed: 38587548
DOI: 10.1007/s00251-024-01340-0 -
Cells Feb 2024Selective IgA deficiency (SIgAD) is the most common form and common variable immunodeficiency (CVID) is the most symptomatic form of predominant antibody deficiency....
Selective IgA deficiency (SIgAD) is the most common form and common variable immunodeficiency (CVID) is the most symptomatic form of predominant antibody deficiency. Despite differences in the clinical picture, a similar genetic background is suggested. A common feature of both disorders is the occurrence of autoimmune conditions. Regulatory T cells (T) are the major immune cell type that maintains autoimmune tolerance. As the different types of abnormalities of T cells have been associated with autoimmune disorders in primary immunodeficiency (PID) patients, in our study we aimed to analyze the gene expression profiles of T cells in CVID and SIgAD patients compared to age-matched healthy controls. The transcriptome-wide gene profiling was performed by microarray technology. As a result, we analyzed and visualized gene expression patterns of isolated population of T cells. We showed the differences at the gene level between patients with and without autoimmunizations. Our findings suggest that the gene signatures of T cells isolated from SIgAD and CVID patients differ from age-matched healthy controls and from each other, presenting transcriptional profiles enriched in innate immune or Th response, respectively. The occurrence of autoimmunity in both types of PID is associated with down-regulation of class I IFNs signaling pathways. In summary, our findings improve our understanding of T dysfunctions in patients with common PIDs and associated autoimmunity.
Topics: Child; Humans; Autoimmune Diseases; Common Variable Immunodeficiency; IgA Deficiency; T-Lymphocytes, Regulatory; Transcriptome
PubMed: 38474381
DOI: 10.3390/cells13050417 -
Journal of Clinical Immunology Feb 2024B cells and their secreted antibodies are fundamental for host-defense against pathogens. The generation of high-affinity class switched antibodies results from both...
B cells and their secreted antibodies are fundamental for host-defense against pathogens. The generation of high-affinity class switched antibodies results from both somatic hypermutation (SHM) of the immunoglobulin (Ig) variable region genes of the B-cell receptor and class switch recombination (CSR) which alters the Ig heavy chain constant region. Both of these processes are initiated by the enzyme activation-induced cytidine deaminase (AID), encoded by AICDA. Deleterious variants in AICDA are causal of hyper-IgM syndrome type 2 (HIGM2), a B-cell intrinsic primary immunodeficiency characterised by recurrent infections and low serum IgG and IgA levels. Biallelic variants affecting exons 2, 3 or 4 of AICDA have been identified that impair both CSR and SHM in patients with autosomal recessive HIGM2. Interestingly, B cells from patients with autosomal dominant HIGM2, caused by heterozygous variants (V186X, R190X) located in AICDA exon 5 encoding the nuclear export signal (NES) domain, show abolished CSR but variable SHM. We herein report the immunological and functional phenotype of two related patients presenting with common variable immunodeficiency who were found to have a novel heterozygous variant in AICDA (L189X). This variant led to a truncated AID protein lacking the last 10 amino acids of the NES at the C-terminal domain. Interestingly, patients' B cells carrying the L189X variant exhibited not only greatly impaired CSR but also SHM in vivo, as well as CSR and production of IgG and IgA in vitro. Our findings demonstrate that the NES domain of AID can be essential for SHM, as well as for CSR, thereby refining the correlation between AICDA genotype and SHM phenotype as well as broadening our understanding of the pathophysiology of HIGM disorders.
Topics: Humans; Cytidine Deaminase; Hyper-IgM Immunodeficiency Syndrome; Immunoglobulin A; Immunoglobulin Class Switching; Immunoglobulin G; Phenotype; Somatic Hypermutation, Immunoglobulin
PubMed: 38363477
DOI: 10.1007/s10875-024-01665-1 -
Journal of Clinical Immunology Feb 2024
Review
Topics: Humans; Hyper-IgM Immunodeficiency Syndrome; Heterozygote
PubMed: 38363450
DOI: 10.1007/s10875-024-01666-0 -
Journal of Gastrointestinal and Liver... Dec 2023Celiac disease is a common gastroenterological illness. Current diagnostics of the disease are based on serological markers and histology of duodenal biopsies. Hitherto,... (Review)
Review
Celiac disease is a common gastroenterological illness. Current diagnostics of the disease are based on serological markers and histology of duodenal biopsies. Hitherto, a strict gluten-free diet is the only effective treatment and is necessary for good control of the disease. Serological tests in current use have very high specificity and sensitivity for diagnostics, but in follow-up they have some limitations. Their levels do not accurately reflect mucosal healing, and they are unable to detect minimal transgressions in the diet. This problem is significant in patients with IgA deficiency, and there exist no robust follow-up tools for monitoring these patients' adherence to treatment. For their follow-up, we currently use IgG-based tests, and these antibodies persist for a long time even when a patient has stopped consuming gluten. More accurate and specific biomarkers are definitely needed. Adherence to a gluten-free diet is essential not only for intestinal mucosa healing and alleviation of symptoms but also for preventing complications associated with celiac disease. Here, we summarize current evidence regarding noninvasive biomarkers potentially useful for follow-up not only of patients with IgA deficiency but for all patients with celiac disease. We describe several very promising biomarkers with potential to be part of clinical practice in the near future.
Topics: Humans; Celiac Disease; Follow-Up Studies; IgA Deficiency; Glutens; Diet, Gluten-Free; Biomarkers; Immunoglobulin A
PubMed: 38147608
DOI: 10.15403/jgld-4926 -
Journal of Clinical Immunology Dec 2023Inherited deficiencies of CD40 and CD40 ligand (CD40L) reflect the crucial immunological functions of CD40-CD40L interaction/signaling. Although numerous studies have...
PURPOSE
Inherited deficiencies of CD40 and CD40 ligand (CD40L) reflect the crucial immunological functions of CD40-CD40L interaction/signaling. Although numerous studies have provided a detailed description of CD40L deficiency, reports of CD40 deficiency are scarce. Herein, we describe the characteristics of all reported patients with CD40 deficiency.
METHODS
The PubMed, Embase and Web of Science databases were searched for relevant literature published till 7th August 2023. Study deduplication and identification of relevant reports was performed using the online PICO Portal. The data were extracted using a pre-designed data extraction form and the SPSS software was used for analysis.
RESULTS
Systematic literature review revealed 40 unique patients with CD40 deficiency. Respiratory tract and gastrointestinal infections were the predominant clinical manifestations (observed in 93% and 57% patients, respectively). Sclerosing cholangitis has been reported in nearly one-third of patients. Cryptosporidium sp. (29%) and Pneumocystis jirovecii (21%) were the most common microbes identified. Very low to undetectable IgG levels and severely reduced/absent switch memory B cells were observed in all patients tested/reported. Elevated IgM levels were observed in 69% patients. Overall, splice-site and missense variants were the most common (36% and 32%, respectively) molecular defects identified. All patients were managed with immunoglobulin replacement therapy and antimicrobial prophylaxis was utilized in a subset. Hematopoietic stem cell transplantation (HSCT) has been performed in 45% patients (curative outcome observed in 73% of these patients). Overall, a fatal outcome was reported in 21% patients.
CONCLUSIONS
We provide a comprehensive description of all important aspects of CD40 deficiency. HSCT is a promising curative treatment option for CD40 deficiency.
Topics: Humans; CD40 Ligand; Cryptosporidiosis; Cryptosporidium; Hyper-IgM Immunodeficiency Syndrome; Immunologic Deficiency Syndromes; CD40 Antigens; Immunoglobulin M; Lymphopenia
PubMed: 38129705
DOI: 10.1007/s10875-023-01633-1 -
Nature Communications Dec 2023Immunoglobulin A (IgA) is acknowledged to play a role in the defence of the mucosal barrier by coating microorganisms. Surprisingly, IgA-deficient humans exhibit few...
Immunoglobulin A (IgA) is acknowledged to play a role in the defence of the mucosal barrier by coating microorganisms. Surprisingly, IgA-deficient humans exhibit few infection-related complications, raising the question if the more specific IgG may help IgM in compensating for the lack of IgA. Here we employ a cohort of IgA-deficient humans, each paired with IgA-sufficient household members, to investigate multi-Ig bacterial coating. In IgA-deficient humans, IgM alone, and together with IgG, recapitulate coating of most bacterial families, despite an overall 3.6-fold lower Ig-coating. Bacterial IgG coating is dominated by IgG1 and IgG4. Single-IgG2 bacterial coating is sparse and linked to enhanced Escherichia coli load and TNF-α. Although single-IgG2 coating is 1.6-fold more prevalent in IgA deficiency than in healthy controls, it is 2-fold less prevalent than in inflammatory bowel disease. Altogether we demonstrate that IgG assists IgM in coating of most bacterial families in the absence of IgA and identify single-IgG2 bacterial coating as an inflammatory marker.
Topics: Humans; Bacteria; Escherichia coli; IgA Deficiency; Immunoglobulin A; Immunoglobulin G; Immunoglobulin M
PubMed: 38065985
DOI: 10.1038/s41467-023-44007-2 -
Journal of Pediatric Health Care :... 2024This case describes a four-month-old male who was admitted to the pediatric intensive care unit for acute respiratory failure in the setting of a co-infection requiring...
Use of Metagenomic Next-Generation Sequencing in the Identification of Pneumocystis Jiroveci Pneumonia in a Previously Healthy Infant Diagnosed With X-Linked Hyper-IgM Syndrome.
This case describes a four-month-old male who was admitted to the pediatric intensive care unit for acute respiratory failure in the setting of a co-infection requiring increased ventilatory support. Immunodeficiency workup demonstrated poor vaccination response and low immunoglobulin titers. mNGS via Karius® test was positive for Pneumocystis jiroveci (PJP), Parvovirus, and Bocavirus. The patient was successfully treated with trimethoprim-sulfamethoxazole and prednisone. Genetic workup via Invitae panel confirmed that the patient had X-linked Hyper-IgM Syndrome. Use of mNGS can help with early identification of pathogens that conventional testing does not detect, even in patients not already identified as immunocompromised.
Topics: Humans; Male; Pneumonia, Pneumocystis; Pneumocystis carinii; Infant; Hyper-IgM Immunodeficiency Syndrome, Type 1; High-Throughput Nucleotide Sequencing; Metagenomics; Trimethoprim, Sulfamethoxazole Drug Combination
PubMed: 38032574
DOI: 10.1016/j.pedhc.2023.09.009