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Inherited Defects in Immune Defenses Leading to Pulmonary Disease
Published in Stephen D. Litwin, Genetic Determinants of Pulmonary Disease, 2020
It is not clear whether selective IgA deficiency is inherited. Most cases occur sporadically. In 106 relatives of 34 selective IgA-deficient individuals, Buckley found only seven affected first-degree relatives including one family in which IgA was missing in three generations [99]. On the other hand, study of selected families has resulted in suggested monogenic inheritance in some instances [104-106], Nell et al. studied 13 IgA-deficient persons in five families. He concluded that three families showed autosomal recessive inheritance and two families showed autosomal dominant inheritance [104]. Stocker concluded that IgA deficiency was transmitted as an autosomal dominant trait in a family with four affected members [105]. Douglas et al. examined a family with three IgA-deficient and one hypogammaglobulinemic member and concluded that the normal parents ruled out dominant inheritance [106]. van Loghem used IgA allotypic markers to gather evidence against a structural gene defect [107], If monogenic mechanisms are involved in this disorder, they probably are restricted to a few cases or they are masked by variable expressivity of the gene.
Mucosal manifestations of immunodeficiencies
Published in Phillip D. Smith, Richard S. Blumberg, Thomas T. MacDonald, Principles of Mucosal Immunology, 2020
Scott Snapper, Jodie Ouahed, Luigi D. Notarangelo
Approximately one-third of adult individuals with IgA deficiency suffer from recurrent infections of the respiratory tract. Most of these infections are of viral origin and tend to be clinically mild. An increased incidence of pseudocroup (due to parainfluenza virus) has been observed in infants with IgA deficiency. Bacterial infections are less common and are predominantly due to Haemophilus influenzae and Streptococcus pneumoniae. Bronchiectasis and chronic lung damage have been rarely observed.
Infections
Published in C. Simon Herrington, Muir's Textbook of Pathology, 2020
Only a minority of those patients with Giardia sp. are symptomatic. They have abdominal pain and diarrhoea of varying severity; a proportion may also suffer from malabsorption. Children and those with IgA deficiency are particularly susceptible.
Therapeutic antibodies for COVID-19: is a new age of IgM, IgA and bispecific antibodies coming?
Published in mAbs, 2022
Jingjing Zhang, Han Zhang, Litao Sun
In 2020, the first human IgA mAb against SARS-CoV-2, named mAb362, was developed.125 In particular, mAb362 showed cross-reactivity against the RBD of both SARS-CoV-1 and SARS-CoV-2, and competitively blocked ACE2 receptor binding. Notably, mAb362 as mIgA, dIgA and sIgA showed significantly enhanced potency in neutralizing SARS-CoV-2 pseudovirus compared to the IgG isotype. The most potent mAb362 sIgA also neutralized authentic SARS-CoV-2, whereas the IgG isotype did not, indicating effective mucosal immunity of sIgA antibodies against SARS-CoV-2 (Table 3). Interestingly, in patients with Selective IgA Deficiency (SID), the lack of neutralizing anti-SARS-CoV-2 IgA and sIgA antibodies represents a possible cause of COVID-19 severity, vaccine failure and prolonged viral shedding,130 emphasizing the importance of IgA antibodies in mucosal immune responses upon SARS-CoV-2 infection.
The First Iranian Cohort of Pediatric Patients with Activated Phosphoinositide 3-Kinase-δ (PI3Kδ) Syndrome (APDS)
Published in Immunological Investigations, 2022
Saba Fekrvand, Samaneh Delavari, Zahra Chavoshzadeh, Roya Sherkat, Seyed Alireza Mahdaviani, Mahnaz Sadeghi Shabestari, Gholamreza Azizi, Mohammad Taghi Arzanian, Bibi Shahin Shamsian, Shabnam Eskandarzadeh, Narges Eslami, William Rae, Antonio Condino-Neto, Javad Mohammadi, Hassan Abolhassani, Reza Yazdani, Asghar Aghamohammadi
1. Hyper IgM (HIgM) characterized by normal or increased serum level of IgM along with decreased serum level of IgA and IgG; 2. Hypogammaglobulinemia characterized by decreased serum levels of at least one of IgG, IgA or IgM serum levels; 3. Agammaglobulinemia characterized by serum IgG level below 200 mg/dl in infants aged <12 months and 500 mg/dl in children aged >12 months or normal IgG levels with IgA and IgM below 2 standard deviations (SD) and 4. IgA deficiency (IgAD) characterized by serum levels of IgG and IgM within the age- and sex-matched reference values but IgA below 2SD. Hypogammaglobulinemia, agammaglobulinemia and IgAD profiles were equally frequent among APDS1 group (all in two patients, 33.3%), while HIgM (five patients, 55.6%) followed by hypogammaglobulinemia (three patients, 33.3%) and IgAD (one patient, 11.1%) were the more common profiles among APDS2 patients. Median absolute counts of all lymphocyte subsets as well as the median of all Ig levels including IgG and IgA (except IgM) were lower in patients with APDS2 than APDS1 group, although these differences were not significant.
Role of microbiota and related metabolites in gastrointestinal tract barrier function in NAFLD
Published in Tissue Barriers, 2021
Maria Victoria Fernandez-Cantos, Diego Garcia-Morena, Valeria Iannone, Hani El-Nezami, Marjukka Kolehmainen, Oscar P. Kuipers
Inside the mucus, SIgAs are the main immunoglobulins secreted on the intestinal mucosal surface and contribute to maintaining the homeostasis in the intestine. SIgAs are produced by plasma cells inside the mucosa, transported by the polymeric Ig receptor (pIgR) inside IECs and secreted into the lumen. SIgAs are able to neutralize invading microorganisms mainly interfering with the microbial adherence to IECs by forming intraluminal immune complexes. This process, defined as immune exclusion, prevents colonization and damage to IECs. SIgAs can also neutralize the invading pathogens that penetrate inside the lamina propria of the mucosa.53In addition, SIgAs are able to modulate the microbiota composition participating in the maintenance of GI tract homeostasis.54 And, their importance in GI tract has been shown in activation-induced cytidine deaminase (AID) deficient mice in which the SIgAs production is lacking due to the missing switch from Immunoglobulin M (IgM) to IgA. In the intestine of these mice an hyperplasia of lymphoid follicles has been observed suggesting that SIgAs are essential in preventing hyper-stimulation of the mucosal immune system.55 Despite the importance of SIgA in the GI tract, individuals with IgA deficiency do not present specific symptoms. This could be explained as a compensatory mechanism by an increased production of IgM observed in the intestine of these individuals.56 But it has been also reported that individuals with IgA deficiency could suffer from pulmonary infections, allergies and GI tract disorders.57