Disease relevance of IgA Deficiency

• TACI is mutant in common variable immunodeficiency and IgA deficiency [1].
• As there is an association between selective IgA deficiency and certain autoimmune diseases, it is possible that this immunodeficiency contributed to the development of PBC in the patient in whom the two diseases coexisted [2].
• Letter: Selective IgA deficiency and idiopathic thrombocytopenic purpura [3].
• Use of low concentrations of human IgA anti-tissue transglutaminase to rule out selective IgA deficiency in patients with suspected celiac disease [4].
• In two patients, one with systemic lupus erythematosus and the other having asthma with nephrotic syndrome, the diagnosis of IgA deficiency was suggested by the complete absence of IgA on the renal biopsy [5].

High impact information on IgA Deficiency

• In addition, the mean IgE concentration was significantly elevated in patients with selective IgA deficiency, many of whom were atopic, and in those with the Wiskott-Aldrich syndrome [6].
• We looked at 4 patients with severe and unusual infections in whom MBP gene mutations were the only identified cause of immunodeficiency and one patient with combined MBP and IgA deficiency [7].
• The only case that was missed had selective IgA deficiency and was positive for IgG-class reticulin antibodies [8].
• Captopril-induced IgA deficiency [9].
• In the third generation, one member died of PBC, and a second individual has both symptomatic PBC and selective immunoglobulin A (IgA) deficiency, an association not previously reported [2].

Chemical compound and disease context of IgA Deficiency

• IgA deficiency, epilepsy, and phenytoin treatment [10].
• Letter: Selective IgA deficiency [11].
• One of them had selective IgA deficiency and no antibody response to pneumococcal polysaccharide immunisation, and the other had a subnormal percentage of T lymphocytes in peripheral blood [12].
• Twelve of 19 patients with common variable immunodeficiency (63%, P less than 0.001) and 9 of 16 patients with IgA deficiency (56%, P less than 0.01) had rare C2 alleles and/or C4A and 21-hydroxylase A deletions, whereas these gene features were seen in only 5 of 34 healthy individuals (15%) in the control group [13].
• We speculate that neither steroid therapy nor an isolated serum IgA deficiency in the presence of secretory IgA discovered after her recovery predisposed her to sinopulmonary disease [14].

Biological context of IgA Deficiency

• Nine of 11 patients with C4A deletion had an HLA haplotype consistent with the MHC supratype HLA-A1, Cw7, B8, C4AQ0, C4B1, BfS, DR3 previously found to be associated with IgA deficiency [13].
• Fine-scale mapping at IGAD1 and genome-wide genetic linkage analysis implicate HLA-DQ/DR as a major susceptibility locus in selective IgA deficiency and common variable immunodeficiency [15].
• Most patients with IgA deficiency had either infection, atopy or autoimmunity [16].
• Moreover, impaired neutrophil chemotaxis was found in some patients with selective IgA deficiency (five cases) or immotile cilia syndrome (seven cases) [17].
• As clearly suggested by investigation of families, the findings could be attributed to high prevalence of the extended major histocompatibility complex (MHC) haplotype [HLA-A1, B8, C4AQ0, C4B1, BfS, DR3] in IgA deficiency [18].

Anatomical context of IgA Deficiency

• Altered expression of lymphocyte Fc alpha receptor in selective IgA deficiency and IgA nephropathy [19].
• A patient with IgA deficiency presented with classical rheumatoid arthritis (RA) and subsequently, features of multiple other connective tissue diseases (CTD) [20].
• Bacterial lipopolysaccharide induces long-lasting IgA deficiency concurrently with features of polyclonal B cell activation in normal and in lupus-prone mice [21].
• In contrast to normal adult cells, blood MNC from the nine children with IgA deficiency and age-matched controls (2-17 years) yielded more IgG1 than IgG2 plasma cells in both control and LPS cultures, while the pattern of response to PWM was similar in all groups (gamma 1 greater than gamma 2) [22].
• The results of this study of SC, alpha 1-AT, lysozyme and esterase may indicate that IgA deficiency is not related to a defect in enterocyte transport of immunoglobulins and confirms previously reported findings indicating the lymphoid B-cell compartment to be altered [23].

Gene context of IgA Deficiency

• Apart from elevated production of TNF-alpha, no other abnormalities in cytokine synthesis in selective IgA deficiency were observed [24].
• Patients with serologic abnormalities (e.g., partial IgA deficiency, partial IgG subclass deficiency) produced more IL-2 and IL-4 than did other patients [25].
• The findings were also consistent with possible overrepresentation of other MHC haplotypes with aberrant C4 gene organization in IgA deficiency [18].
• In the present study we determined the HLA-A, B and DR antigenic and haplotypic frequencies in unrelated Brazilian Caucasian paediatric patients with IgA deficiency (IgA-D) [26].
• Homozygosity rate for the gene loci DRB1 and DQB1 was increased in IgA deficiency [27].

Analytical, diagnostic and therapeutic context of IgA Deficiency

• Nine children with IgA deficiency were studied in order to evaluate by the immunoperoxidase technique the behaviour of secretory component (SC), alpha 1-antitrypsin (alpha 1-AT), lysozyme and esterase in biopsies of intestinal mucosa [23].
• Although in a larger series of control patients the specificity for the human IgA tissue transglutaminase enzyme linked immunosorbent assay might fall below 100%, in our opinion this is currently the serological method of choice in identifying patients with coeliac disease in the absence of IgA deficiency [28].
• Immunoglobulin A (IgA) deficiency occurs more frequently in patients with celiac disease (CD) than in the general population and can lead to false-negative results in the best serologic test for CD, endomysial IgA (EMA) [29].

References