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PubMed1983

Selective IgA deficiency in blood donors.

The frequency of selective IgA deficiency was determined in a healthy population of 6,240 blood donors. Screening for IgA deficiency was performed by double-diffusion analysis in agarose gel. Confirmation testing was performed with the more sensitive passive hemagglutination inhibition assay. Prevalence of IgA deficiency, characterized by a serum level of below 50 mg/L, was 0.30% (1 in 328), which is the highest prevalence of selective IgA deficiency reported in a healthy population. Antibodies to IgA were detected in sera of 36.8% of the blood donors with selective IgA deficiency, which also is the highest prevalence of anti-IgA antibodies reported in any previous study. The literature on IgA deficiency in healthy populations is reviewed. Current concepts in treatment of IgA-deficient patients requiring blood products are described.

Adolescent↗
PubMed1982

Autologous mixed lymphocyte reaction in man. VIII. Deficiency of autologous mixed lymphocyte reaction in patients with selective IgA deficiency.

Autologous mixed lymphocyte reaction (AMLR) between T and non-T cells was studied in 12 patients with selective IgA deficiency. Seven of 12 patients demonstrated significantly (P less than 0.05) lower AMLR when compared to simultaneously studied age and sex matched controls. In the allogeneic MLR, T cells from patients responded normally to control non-T cells; however, non-T cells from patients were poor stimulators against normal responder T cells when compared to allogeneic MLR between different normal controls. The deficient AMLR in selective IgA deficiency further supports abnormal immune regulation and might explain the increased incidence of autoimmune phenomena and autoimmune diseases associated with selective IgA deficiency.

Adolescent↗
PubMed1992

Involvement of both HLA and Ig heavy chain haplotypes in human IgA deficiency.

Immunoglobulin-A deficiency (IgA-D) is the most common human Ig class deficiency with an estimated frequency of approximately 1 in 500 in the Swedish population. We investigated the immunoglobulin heavy chain constant region gene segments (IGHC) in 103 individuals with IgA-D and the immunoglobulin heavy chain variable region gene segments (IGHV) in 20 of these, in order to identify a possible molecular basis of the defect. No deletions of IGHV gene segments of the VH2, VH5, and VH6 families or the IGHG genes were observed. In the IGHC, there were, however, differences in the restriction fragment length polymorphism frequencies of IGHG genes where the Bam HI haplotype "H2" [IGHGP, 10 kilobases (kb), IGHG2, 25 kb; and IGHG4, 9.0 kb] was overrepresented. The mean serum levels of IgG4 and IgE were significantly lower in individuals (both IgA-D subjects and healthy controls) homozygous for the H2 haplotype than in individuals homozygous for the H1 haplotype (IGHGP, 8.8 kb, IGHG2, 13.5 kb, and IGHG4, 9.4 kb). IgA-D subjects homozygous for HLA DQB1*0201 (DQw2), a marker that has previously been reported to show a strong association with IgA deficiency, showed a similar reduction of serum levels of IgG4 and IgE as compared with DQB1*0201 negative IgA-D subjects. These findings suggest that the two loci found to be associated with IgA deficiency may act via a common pathway.

Blotting, Southern↗
PubMed2000

Immunoglobulin A (IgA) deficiency and alternative celiac disease-associated antibodies in sera submitted to a reference laboratory for endomysial IgA testing.

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). To evaluate the impact of IgA deficiency on serologic detection of CD in a reference laboratory setting, IgA levels were measured in 510 consecutive serum specimens submitted for testing for EMA; 510 consecutive serum specimens submitted for Helicobacter pylori IgG testing served as a gastrointestinal symptom control group. The frequency of IgA deficiency was significantly higher among the specimens submitted for testing for EMA (5.1%) than among the specimens from the symptom control group (1.4%). Three subsets of sera from the group of specimens submitted for testing for EMA were then tested by additional serologic assays for CD; these subsets were EMA-positive sera (n = 25), EMA-negative, IgA-deficient sera (n = 26), and control sera (from EMA-negative, IgA-nondeficient patients age matched to IgA-deficient patients; n = 26). The proportions of EMA-positive sera positive by other assays for CD were 92% for transglutaminase IgA (TG-IgA), 80% for gliadin IgA, 84% for gliadin IgG, 60% for endomysial IgG (EMG), and 32% for transglutaminase IgG (TG-IgG). Very low proportions (0 to 8%) of IgA-deficient sera and control sera were positive for TG-IgA, gliadin IgA, EMG, and TG-IgG. Eight of 26 (31%) IgA-deficient serum samples were positive for gliadin IgG, whereas 3 of 26 (12%) control serum samples were positive for gliadin IgG, but this difference was not statistically significant. Physicians supplied clinical data for 18 of 26 patients with IgA deficiency; only 4 patients had undergone small-bowel biopsy, and 0 of 4 patients showed villous atrophy. These findings show that IgA deficiency is found more frequently among sera submitted for testing for EMA in a reference laboratory setting, but there was no clear-cut serologic or clinical evidence of CD in EMA-negative, IgA-deficient patients.

Adolescent↗
PubMed1978

Gammaglobulin treatment and anti-IgA antibodies in IgA-deficient patients.

Antibodies to IgA may cause severe anaphylactic reactions during blood transfusions. Tests for anti-IgA antibodies were carried out on six patients with IgA deficiency (five of whom also had hypogammaglobulinaemia) who had received continuous gammaglobullin treatment for chronic or recurrent infections for three to eight years. Three patients had minute amounts of IgA, and three had none (less than 0.01 microgram/ml). Only one patient had anti-IgA. Her antibody titre did not change during treatment. No patient had any untoward effects of treatment, which relieved the symptoms of infection in every case. IgA determinations should be performed by more accurate methods than radial immunodiffusion when evaluating the risks of giving gammaglobulin to patients with hypogammaglobulinaemia and IgA deficiency. Probably the stimulus provided by intramuscular gammaglobulin in such patients is insufficient for the formation of anti-IgA antibody.

Adult↗
PubMed1994

Molecular analysis of IgA deficiency. Evidence for impaired switching to IgA.

The most common form of primary immunodeficiency is IgA deficiency (IgAD). However, the molecular basis of this disease remains elusive. Therefore, to address this issue we made a systematic analysis of the molecular events leading to IgA production. B lymphocytes that produce IgA have undergone somatic rearrangement that joins the switch (S) mu to S alpha region with deletion of the intervening sequences. Examination of the resulting S mu/S alpha junctions in unstimulated PBMC from IgAD patients by nested primer PCR revealed a significant decrease in the number of the S mu/S alpha fragments. To obtain the antisense primers to generate the S mu/S alpha fragments, we sequenced the human S alpha 1 and the downstream region extending to the C alpha 1 locus. Similar to previously reported switch sequences, we also found the S alpha 1 to be predominantly composed of pentameric repeats GAGCT and GGGCT. The decrease in the number of S mu/S alpha fragments is consistent with a profound decrease in the C alpha membrane mRNA expression in unstimulated PBMC, as well as in the C alpha mRNA levels and IgA production in PWM-stimulated PBMC. Sequence analysis of the switch junctions from IgA-producing cell lines, control donors, and an IgAD patient showed direct joining in 8 of 9 cases examined. TGF-beta 1, previously shown to be the switch factor for human and mouse IgA, was also examined. No difference in the TGF-beta 1 mRNA levels in unstimulated PBMC between the control subjects and the IgAD patients were detected. Our findings indicate that the failure to switch to IgA-producing B lymphocytes, or an impaired survival of such cells, may be an important molecular mechanism in IgAD.

Animals↗
PubMed1983

Anti-IgA in selective IgA deficiency. In vitro effects and Ig subclass pattern of human anti-IgA.

Anti-IgA antibodies were found in 14 of 33 (42%) IgA-deficient donors. In healthy IgA-deficient blood donors anti-IgA appeared associated with the presence of HLA DR3. The antibodies were mainly of the IgG1 and, in high-titred sera, IgG4 subclasses. Sera containing high-titred anti-IgA selectively impaired IgA synthesis in vitro as induced by direct and indirect polyclonal B-cell activators. These antibodies may play a role in the pathogenesis and/or the maintenance of IgA deficiency.

Antibodies, Anti-Idiotypic↗
PubMed2006

Do we need to measure total serum IgA to exclude IgA deficiency in coeliac disease?

BACKGROUND: Screening for IgA deficiency in patients with coeliac disease is essential because of the increased incidence of IgA deficiency associated with the disease, which usually relies on the estimation of IgA levels in each case. AIM: To devise a method of excluding IgA deficiency without measuring total serum IgA in each case. MATERIALS AND METHODS: The optical density readings on enzyme-linked immunosorbent assay (ELISA) of 608 routine samples received for tissue transglutaminase (TTG) antibody testing for coeliac disease were compared with their total IgA concentrations. Dilution experiments were also carried out to ensure linear relationships between optical density on ELISA and IgA concentrations and to compare the sensitivities for TTG and endomysium antibodies in TTG-positive samples. RESULTS AND DISCUSSION: A clear relationship was shown between total IgA concentration and TTG optical density readings by ELISA. To ensure a positive TTG result if antibodies are present, it was possible to recommend an optical density level above which all samples have sufficient IgA. Samples with optical density <0.05 should be investigated further by estimating total IgA and, if low, samples should be subjected to immunofluorescence microscopy testing for IgA and IgG endomysium antibodies. CONCLUSIONS: An easier, more cost-effective and practical way of excluding IgA deficiency in the investigation on coeliac disease is reported.

Autoantibodies↗
PubMed1983

Persistent and transient IgA deficiency in juvenile rheumatoid arthritis.

Twenty-five children with serum IgA levels of less than 0.1 g/l (below the 2.5% confidence limit at 2 years of age) were found among approximately 350 cases of juvenile rheumatoid arthritis (JRA). During follow-up, 10 of them proved to have persistent IgA deficiency, 13 were classified as having transient IgA deficiency, and 2 had consistently low serum IgA. Transient IgA deficiency occurred during treatment, in 9 cases with gold and in 2 with antimalarials. The gold-induced IgA deficiency usually developed abruptly soon after institution of gold therapy, and its duration varied from a few months (4 cases) to several years (3 cases). In 6 cases a low IgA level has returned to normal despite continuing gold therapy. In half the patients with persistent IgA deficiency the course has been mild and oligoarticular, and after a mean duration of 8.8 years only one has active disease. In contrast, in the patients with transient IgA deficiency the disease was characterized by early onset (mean age 3.0 years), a polyarticular course (10/13) and prolonged activity (7/13, mean duration 9.6 years). Coeliac disease was diagnosed in 2 patients, both with persistent IgA deficiency.

Antimalarials↗
PubMed1982

Low molecular weight IgM in selective IgA deficiency.

Thirty-nine persons with selective IgA deficiency were studied. These comprised 27 subjects found by population screening and 12 by other means. Low molecular weight (LMW) serum IgM was sought in 28 of the 39 persons. Nine of the 28 (32%) had LMW IgM detectable by a sensitive gel filtration technique. Of 17 patients discovered by screening, five (29%) had LMW IgM. In the nine positive persons, LMW IgM constituted up to 17% of the total serum IgM concentration. Eight of the nine IgA deficient persons with LMW IgM, had clinical disease while associated disease in the entire IgA deficient population was less frequent. Serum immune complexes were demonstrated in five of seven subjects with LMW IgM using a C1q-dependent radioimmunoassay; four of these had immune complex associated disorders, three with polyarthritis and one with glomerulonephritis. Because circulating immune complexes are frequently detected in IgA deficient persons without disease, it is proposed that the presence of LMW serum IgM in IgA deficiency may be associated with disease due to the formation of specific pathogenic immune complexes.

Adolescent↗
PubMed1985

Gm allotypes in IgA deficiency.

Gm phenotypes were examined in 90 Swedish IgA-deficient (less than 0.05 g/litre of serum IgA) donors and 40 normal first and second degree relatives of six of these donors. The G1m1,2, G3m5 and Km1 frequency in the group of IgA-deficient donors did not differ from that found in the normal population. Among the relatives, HLA and/or Gm identical normal sibs were observed. Anti-IgA antibodies were present in 29 of the IgA-deficient donors and anti-IgG in seven. No association between the two was found. A statistically significant association between the G1m-2 phenotype and the presence of anti-IgA antibodies was observed. When subdivided according to HLA type, a non-random distribution of Gm phenotypes was seen in HLA-B8/DR3 positive individuals with anti-IgA antibodies (HLA-B8/DR3 being the haplotype associated with IgA deficiency). These data suggest an association between IgA deficiency, anti-IgA and the studied Gm allotypes.

Dysgammaglobulinemia↗
PubMedDate not supplied

[IgA deficiency in pediatrics].

To evaluate the IgA deficiency we have considered 368 children, admitted to "Day hospital" for different pathologies: 64 of them had serum IgA levels lower than the normal values for their age according to Ellis and Robbin. The age of the children with this deficiency was included from 4 months up to 8 years: 39 were boys, 25 were girls. In 54 cases the IgA deficiency was "partial" that is: the IgA value found out was lower than the normal for the age, but higher than 5 mg%. In 10 cases the IgA deficiency was "severe" (the IgA value was lower than 5 mg%). Six cases, among the 29 ones with intestinal diseases, had a severe deficiency, whereas among the 22 cases with respiratory diseases 3 had a "severe" deficiency. The 2 patients with urinary disease had a partial deficiency; only one case of the remaining 11 with different pathologies had a "severe" deficiency. Among the carriers of serum IgA deficiency an high incidence of chronic pathology has been found out (83%). Nevertheless the percentage of IgA deficiency extrapolated from the all case histories doesn't differ very much (64 cases among 368 = 17.39%) considering only those patients with chronic relapsing pathology (53 cases among 275 = 18.2%). Therefore it seems that the IgA deficiency could be considered a chronicizing factor in the examinated pathology even if in few cases. Anyway the frequency of IgA deficiency has reached major values (29/54; 45.3%) in the patients with enteric diseases. The frequency of IgA deficiency is smaller but still important in those patients with respiratory diseases (22/64: 34.3%).(ABSTRACT TRUNCATED AT 250 WORDS)

Age Factors↗
PubMed1996

Prevalence and diagnosis of celiac disease in IgA-deficient children.

BACKGROUND: Reported frequencies of celiac disease in selective IgA deficiency in childhood vary widely and this is probably due to the different characteristics of the patients studied and to the different criteria used for intestinal biopsy: all patients or only those with symptoms of malabsorption. Diagnosis of celiac disease is of considerable importance in IgA deficiency because of its increased frequency and also because avoidance of dietary gluten permits elimination of the symptoms and complications of celiac disease. OBJECTIVES: To obtain a more reliable estimate of the incidence of celiac disease in childhood IgA deficiency jejunal biopsies were performed in 65 consecutively diagnosed IgA-deficient children whose parents consented. Some clinical and laboratory parameters including IgA-antigliadin and IgG-antigliadin antibodies were evaluated to predict their usefulness in selecting IgA-deficient patients for intestinal biopsy. METHODS: All IgA-deficient patients had serum IgA levels below 5 mg/dL and salivary IgA below 0.5 mg/dL. Jejunal biopsy was performed using a peroral Watson capsule and IgA-antigliadin and IgG-antigliadin antibodies were performed by an ELISA assay. RESULTS: Biopsy findings of severe villous atrophy permitted diagnosis of celiac disease in 7.7% (5/65 children). IgG-antigliadin antibody levels, elevated in 16 patients including all five celiacs, were the best parameter for predicting celiac disease and gave no false negatives. CONCLUSIONS: The 7.7% frequency of celiac disease observed in these IgA-deficient children is about 20 times higher than in the general Italian population, and the lowest among the studies biopsying all patients; this is probably attributable to the presence of a substantial proportion of healthy children (20/65) and very few (2/65) with autoimmune disorders. The elevated sensitivity and negative-predictive value of IgG-antigliadin antibodies lead us to suggest that positive IgG-antigliadin antibodies can be used to select IgA-deficient children for jejunal biopsy with a very low probability of missing celiac disease while allowing a drastic reduction in the number of biopsies performed.

Adolescent↗
PubMed1995

IgA deficiency and psoriasis: relevance of IgA in the pathogenesis of psoriasis.

A psoriatic patient with absolute deficiency of IgA is reported. The manifestations of psoriasis appeared at the age of 6 months and proved to be resistant to various treatments. The present case report and the data available in the literature on IgA and psoriasis all converge on the hypothesis that IgA is a systemic factor which belongs to the 'off switches' of the psoriatic process.

Adult↗
PubMed1986

IgG subclass deficiency in children with IgA deficiency presenting with recurrent or severe respiratory infections.

A group of 22 children presenting with recurrent or severe respiratory tract infections who had low IgA levels (more than 2 SD below the mean for age) were examined for IgG subclass deficiency. Patients were screened for possible defects in neutrophil chemotaxis, bactericidal, fungicidal, and quantitative iodination activity, as well as for complement function. The majority of the patients showed IgG subclass levels below the mean for age. Nine of the children showed definite IgG subclass deficiency and at least two showed definite deficiency of more than one IgG subclass. The predominant subclass deficiency was found to be IgG1. While nine children showed IgG4 levels below the level detectable by the technique used, it is not possible to assess whether these patients are deficient in this isotype since some healthy subjects also give values below the level of detection. Most of the patients who had very low (1-6 mg/dl) or undetectable (less than 1 mg/dl) levels of serum IgA did not show IgG subclass deficiencies, while IgG subclass deficiencies were common among those with borderline low IgA levels (slightly more than 2 SD below the mean for age). Nine children showed total IgG levels close to 2 SD below mean for age, and at least six of these showed IgG subclass deficiency. The result suggests that patients with recurrent and/or severe respiratory infections who have borderline IgA and IgG levels may have IgG subclass deficiencies and if they do could benefit from immunoglobulin therapy.

Blood Bactericidal Activity↗
PubMedDate not supplied

Evolution of IgA deficiency to IgG subclass deficiency and common variable immunodeficiency.

FIRST REPORT: male child with repeated pulmonary infections from the age of 4 months. He was diagnosed as IgA deficiency (undetectable IgA levels) at the age of 3 years, when he presented repeated bouts of pneumonia and tonsillitis. Several immunologic evaluations were made between the ages of 4 months and 8 years. At 8 years and 9 months, the diagnosis of IgA deficiency was confirmed, and associated IgG2 and IgG4 deficiency (29.0 mg/dl y 0.01 mg/dl) with normal total IgG serum level was found. With the administration of intravenous gammaglobulin, the lung infections remitted and the subsequent clinical course has been uneventful up to now. SECOND REPORT: a boy with repeated infections since the age of 2 months. IgA deficiency was diagnosed at 1 year 7 months (undetectable serum IgA levels). At age 51/2 years, his clinical course worsened and more serious infections appeared. A new immunologic study revealed IgA deficiency associated with CD4 cell deficiency (432 cells/mm3) and normal CD3, CD19, and CD8 levels. Despite intensive antibiotic treatment and care, the child died. The findings suggest an association of IgA deficiency and common variable immunodeficiency.

Common Variable Immunodeficiency↗
PubMedDate not supplied

Compensatory levels of salivary IgM anti-Streptococcus mutans antibodies in IgA-deficient patients.

The protective role of salivary IgA in dental caries has not been completely demonstrated, so, in order to elucidate this point, we evaluated 15 totally and partially IgA-deficient children in terms of the following variables: dental caries indexes, bacterial plaques, number of Streptococcus mutans and Lactobacillus in the saliva, and titers of IgA, IgG and IgM anti-Streptococcus mutans antibodies in the saliva. Age-matched healthy children served as the control group. IgA-deficient children showed caries scores lower than those of the healthy children; in addition, no statistical difference was found between amount of dental plaque and numbers of the bacteria in saliva. The totally IgA-deficient children presented IgM in levels much higher than the healthy children (p < 0.05). These data could indicate a compensation for the IgA deficiency by IgM.

Antibodies, Bacterial↗
PubMed1981

[IgA deficiency in the dermatologic clinic. Frequency, clinical relevance, diagnosis and therapy].

Eight of 400 (2%) unselected dermatological patients showed an IgA deficiency in their serum. Two had a complete and four an isolated deficiency of serum IgA. In three patients the IgA deficiency was combined with a deficiency of another immunoglobulin (antibody deficiency syndrome), and twice with a cellular immunodeficiency. An elevated IgE level was found in the serum of one patient. Most patients with IgA deficiency had recurrent infections of the skin and mucous membranes, or the dermatoses were caused secondarily by an inflammatory process of the latter. In contrast to the deficiency of serum IgA the concentration of secretory IgA in the saliva was normal. The immunotherapy of serum IgA deficiency depended on the existence or absence of associated immunological disorders: in case of isolated IgA deficiency substitution with enriched IgA, in antibody deficiency syndrome with gamma globulin and in combined humoral and cellular immune deficiency with additional therapy with transfer factor.

Dysgammaglobulinemia↗