Establishment of an immunoglobulin�A?deficient blood donor registry with a simple in-house screening enzyme-linked immunosorbent assay

The association of IgA deficiency on infection rate, self-perceived health, and levels of C-reactive protein in healthy blood donors

The clinical importance of immunoglobulin A (IgA) deficiency in otherwise healthy individuals is not well described. We aimed to investigate the self-reported mental and physical health and the risk of infection in IgA-deficient blood donors compared to healthy control blood donors. Infectious events, recorded in public health registries either as prescriptions filled of any antimicrobial medicine or as hospital infections, were compared between 177 IgA-deficient blood donors and 1770 control blood donors. A subset of the IgA-deficient donors were further characterized by self-reported health (Short Form-12, n = 28) and circulating C-reactive protein (CRP) (n = 10). IgA-deficient individuals had lower self-reported mental health (p = 0.01) and higher CRP (p < 0.05). A strong trend was found regarding prescription of antimicrobial medicine (hazard ratio = 1.19, p = 0.05). No association was found with hospital infections (hazard ratio = 1.02, p = 0.95) or self-reported physical health (p = 0.86). IgA-deficient blood donors have impaired self-reported mental health, enhanced inflammation and possibly an increased risk of infection. Despite these findings, this study does not provide sufficient evidence to warrant specific health precautions for donors with IgA deficiency.

An acute transfusion reaction

We present the case of a 67-year-old man who suffered an acute anaphylactic reaction during red cell transfusion due to the presence of anti-IgA antibodies. The incidence and clinical relevance of anti-IgA antibodies in IgA deficiency is reviewed, and the wider investigation and management of acute transfusion reactions is also discussed. This case highlights the need to consider the potential risks of blood component transfusion against the purported benefit.

The higher frequency of IgA deficiency among Swedish twins is not explained by HLA haplotypes

Serum immunoglobulin A (IgA) concentrations were determined in 12 600 adult Swedish twins, applying a high-throughput reverse-phase protein microarray technique. The prevalence of IgA deficiency (IgAD) was found to be 1:241 in monozygotic (MZ) twins and 1:198 in dizygotic (DZ) twins. Hence, the prevalence in twins is markedly elevated as compared with the normal Swedish adult population (1:600). The twins did not show a difference in the frequency of HLA haplotypes in comparison with almost 40 000 healthy Swedish controls. As expected, the risk-conveying HLA alleles A*01, B*08 and DRB1*01 were overrepresented among the IgAD twins and were also associated with significantly lower mean serum IgA concentrations in the twin cohort. In contrast, significantly higher mean IgA concentrations were found among individuals carrying the protective HLA alleles B*07 and DRB1*15. Exome sequencing data from two MZ twin pairs discordant for the deficiency showed no differences between the siblings. Model fitting analyses derived a heritability of 35% and indicate that genetic influences are modestly important for IgAD. The probandwise concordance rates for IgAD were found to be 31% for MZ and 13% for DZ twins.

Long-Term Treatment and Transfusion of Normal Blood Components Following Tolerance Induction in Patients with Anti-IgA Anaphylactic Reactions

BACKGROUND

In general, patients with significant anti-Ig-A do not tolerate intravenous (i.v.) administration of normal blood products. Here, we present our experiences in the induction of immune tolerance (IIT) and long-term treatment in a series of such patients affected in such a way. The question whether blood components from IgA-deficient donors are required will be discussed.

METHODS

Ten adult patients (4 females and 6 males; age ranging from 36 to 75 years) with anti-IgA were included in this study. All patients required long-term treatment with blood components. One patient had IgA deficiency and paroxysmal nocturnal hemoglobinuria (PNH), and all other patients had common variable immunodeficiency (CVID). The particle gel immunoassay was used for the detection of anti-IgA. Immune tolerance to IgA was induced by controlled subcutaneous (s.c.) and/or i.v. infusions of IgG preparations.

RESULTS

Prior to IIT, anti-IgA was detectable in plasma samples of all patients and significantly diminished or abolished by controlled s.c. and/or i.v. infusions of IgG. Multiple transfusions with normal blood components could be repeatedly performed with the patient suffering from PNH without any complications. As long as i.v. IgG (IVIgG) infusions were consequently administered as individually required (intervals 2-8 weeks), none of the patients developed reactions during observation (up to 10 years). However, interruption of treatment and re-exposure to IVIgG resulted in adverse reactions.

CONCLUSION

Patients with significant anti-IgA can be safely desensitized and tolerate long-term IgG substitutions independent of the IgA concentration of the used blood component.

Evaluation of particle gel immunoassays for the detection of severe immunoglobulin A deficiency and anti-human immunoglobulin A antibodies

BACKGROUND

Immunoglobulin A (IgA)-deficient patients with anti-IgA (Ab) require transfusions using blood components with less than 0.05 mg IgA/dL as they are known to be safe for these patients. Identification of severely IgA-deficient (IgA SD) donors involved preliminary screening by the Ouchterlony double immunodiffusion assay followed by confirmatory testing at the required level of sensitivity for IgA and Ab at an external reference laboratory. Two in vitro particle gel immunoassays (ID-PaGIA IgA deficiency test and anti-IgA test) were also evaluated for their suitability in identifying IgA SD individuals and determining their Ab status.

STUDY DESIGN AND METHODS

Samples from 198 donors and 36 patients, subjected to confirmatory testing for IgA SD and Ab over a 2-year period, were also evaluated using the ID-PaGIA kits.

RESULTS

DiaMed test sensitivity and specificity for detection of IgA SD in donors was 98% whereas for Ab, test sensitivity was 91% at a specificity of 94%. In patients, sensitivity was 94% for IgA SD and 67% for Ab, both tests at a specificity of 100%.

CONCLUSIONS

The ID-PaGIA IgA deficiency test was a sensitive and specific tool for identifying IgA SD donors or patients. Sensitivity of the Ab test was high for donors but reduced for patients and of high specificity in both groups. Further studies with patients are needed to confirm this latter observation. Implementation of these tests would make it possible to supply appropriate products from IgA SD donors to prevent anaphylactic transfusion reactions in patients.

Allergic transfusion reactions from blood components donated by IgA-deficient donors with and without anti-IgA: a comparative retrospective study

BACKGROUND AND OBJECTIVES

IgA deficiency is common (1/500) and up to 40% of affected individuals will develop anti-IgA. A few studies suggested that passive transfusion of anti-IgA was not associated with an increased risk of allergic reactions. This study was designed to assess the safety of transfusing blood components containing anti-IgA.

MATERIALS AND METHODS

IgA-deficient blood donors with and without anti-IgA were identified from Héma-Québec's (HQ) computerized database. IgA deficiency was confirmed by an ELISA method and the presence of anti-IgA by a passive hemagglutination assay. Blood donations from IgA-deficient donors issued to hospitals between March 1999 and December 2004 were retrieved. Medical charts of recipients were reviewed for the occurrence of a suspected transfusion reaction. Presence and nature of transfusion reactions were assessed blindly by an adjudicating committee.

RESULTS

A total of 323 IgA-deficient blood products were issued by HQ to 55 hospitals. Of these, 48 agreed to participate [315 blood products (97.5%)]. A total of 272 products were transfused: 174 contained anti-IgA, and 98 did not. Only two minor allergic reactions occurred in each group. Incidence of allergic reactions was 1.15% in the anti-IgA group and 2.04% in the group without anti-IgA (P = 0.91). There was no anaphylactic reaction in either group.

CONCLUSIONS

This study indicates that the proportion of allergic reactions does not appear to be greater in recipients of blood components containing anti-IgA compared to recipients of non-anti-IgA-containing components. Allowing donations from IgA-deficient donors with anti-IgA may therefore be contemplated.

Screening of Canadian Blood Services donors for severe immunoglobulin A deficiency

BACKGROUND

Immunoglobulin A (IgA)-deficient patients with antibodies to IgA require transfusions with IgA-deficient blood components to either avoid or reduce the frequency of serious adverse reactions. To supply compatible blood components for these individuals, the Canadian Blood Services (CBS) National Testing Laboratory must initially screen and subsequently identify, after confirmatory testing at the American Red Cross (ARC), donors severely deficient in IgA (<0.05 mg/dL).

STUDY DESIGN AND METHODS

The Ouchterlony double immunodiffusion assay was used as an initial screen at CBS to identify IgA-deficient donors (test sensitivity 2-4 mg/dL). Sample aliquots from these donors were then sent to the ARC for confirmatory testing using an enzyme-linked immunosorbent assay method for severe IgA deficiency (<0.05 mg/dL) and a passive hemagglutination assay to detect anti-IgA.

RESULTS

From November 2007 to December 2008, of 54,594 samples screened initially at CBS there were 137 samples (0.251%) identified as possibly IgA deficient. Of these 137, there were 100 reports returned from ARC confirming severe IgA deficiency in 65 donors (25 female, 40 male) without detectable anti-IgA and in 35 donors (18 female, 17 male) with anti-IgA. The remaining 37 donors had IgA levels of more than 0.05 mg/dL.

CONCLUSION

Results from the ARC confirmed a frequency of 1 in 546 in the CBS' blood donor population for severe IgA deficiency (<0.05 mg/dL), 1 in 840 for those without anti-IgA, and 1 in 1560 for those with antibody. Donors repeatedly confirmed as severely IgA deficient without anti-IgA were considered eligible for the CBS IgA-deficient donor registry program.