Alloimmunization against platelets, granulocytes and erythrocytes in multi-transfused patients in Iranian population

Presence of antibodies against HLA class I and class II molecules in children before and after allo-HSCT. Alloantibodies before and after HSCT

A severe complication of allogeneic hematopoietic stem cell transplantation (HSCT) is graft failure (GF). Among others, donor-specific anti-HLA antibodies (DSA) are associated with graft rejection after allogeneic or haploidentical transplantation in adults. Knowledge of DSA and pediatric recipients is limited. Hence, we aimed to generate more information about the presence of DSA (pre- and post-HSCT) and the clinical outcomes (graft rejection and poor function) in children. We identified DSA in 27% of the patients. We observed a higher frequency (50%) of DSA-bearing patients with a benign disease diagnosis than those diagnosed with leukemia (16.66%). We observed graft rejection in one patient (with DSA against two alleles of HLA class I molecules) and poor function in three recipients during the first 30 days after HSCT in the absence of DSA. The presence of donor and nondonor HLA-specific antibodies decreased substantially after transplantation. After the transplant, we identified two patients with DSA specific for HLA class I molecules (independent of clinical relevance), and four recipients showed PGF in the absence of DSA. We were unable to establish any association between the presence of DSA and a clinical outcome: graft failure or prevalence of viral infection.

Red blood cell alloimmunization in Iran: A Comprehensive review of the literature

BACKGROUND:

Alloimmunization is an immune response against foreign antigens which introduced into the body through transfusion, pregnancy, or transplantation. This phenomenon is a big challenge in patients, which require regular transfusions. In the current study, we tried to have a comprehensive review on the status of alloimmunization in Iran. For this purpose, we searched for papers investigating alloimmunization in transfusion-dependent patients and also in patients with no regular transfusions who are candidate for surgery or who need blood.

METHODS:

We searched PubMed, Google Scholar, SID, and MAGIRAN databases using the following keywords: “blood transfusion,” “alloimmunization,” “alloantibodies,” “irregular antibodies,” “red cell antibodies,” and “Iran.” No limitation for the date of publication and language of the papers was defined. All the identified records were then screened for the relevance and duplication.

RESULTS:

A total of 22 papers were included in this study. All of the studies were conducted from 1999 to 2016 and providing alloimmunization data from different cities all over of Iran. In general, the results showed that the most prevalent alloantibodies are anti-Kell (anti-K antigen) and anti-Rh system, mainly anti-E, anti-D, anti-C, and anti-c.

CONCLUSION:

Anti-Kell and anti-Rh antibodies are the most prevalent antibodies responsible for alloimmunization in Iranian population.

Pattern of distribution of 35 red cell antigens in regular voluntary blood donors of South Gujarat, India

BACKGROUND

Extended phenotyping is one of the important method of reducing red cell alloimmunisation. Extended phenotyping of red cells from voluntary donors have many uses in addition to its application in population genetics. As there was very little data extended phenotyping on a cohort of Indian Voluntary blood donors this project was undertaken.

STUDY DESIGN & METHODOLOGY

200 regular voluntary blood donors having 'O' blood group were included for red cell antigen typing of Rh (D,C,E,c,e), Kell (K, k, Kp^a, Kp^b), Duffy (Fy^a, Fy^b), Kidd (Jk^a, Jk^b), Lewis(Le^a, Le^b), P(P1), MNS (M, N,S,s), and Lutheran (Lu^a, Lu^b), Colton (Co^a, Co^b), Diago (Dia^a, Wr^a), V^w and Xg^a antigens using conventional antisera provided by DIAGAST. Calculations of antigen and phenotypes frequencies were expressed as percentages.

RESULTS

Out of 200 'O' group blood donors, 96.5% were Rh D and 2.5% were K positive. Amongst Rh antigens, e was the most common (100%) followed by D, C (91.0%), c (50.5%) and E (16.5%) with DCe/DCe (R1R1, 48.0%) being the most common phenotype. In Kell blood group system, we found k antigen to be 100% and a rare phenotype Kp (a + b+) was found in 1% of the donors. For Kidd and Duffy blood group systems, Jk (a + b+) and Fy (a + b-) were the most common phenotypes (39.0% and 64.0%, respectively). In the MNS blood group system, M + N+ (67.5%) and S + s+(43.5%) were the most common phenotypes. There were antigens like C^w(3.5%), K(2.3%), Kp^a(1.2%), In^a(1.0%), V^w(1.2%), Co^a(4.5%), Co^b(1%), Lu^a(1.75%), Di^a+(1.2%), and Wr^a+(0.6%) with frequency < 5% in the donor population.

CONCLUSION

Extensively antigen phenotypes group 'O' red cells showed significant variation with other population from India as well as with Caucasian and black population. Extensive phenotyping 'O' group regular blood donors of red cell antigens is very useful to prepare in-house red cell panels for identification of alloantibodies.

Red blood cell alloimmunization among hospitalized patients: transfusion reactions and low alloantibody identification rate

Background

Unexpected red blood cell alloantibodies can cause hemolytic transfusion reactions. In this study, the prevalence of alloimmunization, the rate of identification of alloantibodies and the rate of blood transfusion reactions among transfused patients were identified in a clinical emergency hospital in Brazil.

Methods

Transfusions and clinical records of patients who had a positive indirect antiglobulin test between January and December 2013 were analyzed.

Results

Of 1169 patients who received blood transfusions, 28 had positive indirect antiglobulin tests, with one patient having two positive tests at different times, resulting in 29 positive tests during the period of this study. Alloantibodies were identified in 58.6% (17/29) of the cases. In 27.5% (8/29), identification was inconclusive and it was not possible to confirm alloimmunization. The rate of red blood cell alloimmunization was 1.71% (21/1169). Of 21 cases of alloimmunization, four (19%) were unidentified due to an unusual agglutination profile. All identified alloantibodies were clinically significant (10/17 anti-Rh, 5/17 anti-Kell and 2/17 anti-MNS). In two patients who had positive indirect antiglobulin tests, one had an unidentified alloantibody, and the other had an inconclusive test and developed a hemolytic transfusion reaction.

Conclusion

The prevalence of clinically important red blood cell alloantibodies and hemolytic transfusion reactions among patients with unidentified alloantibodies suggests that specific laboratory techniques should be performed to identify alloantibodies in cases of pan-reactivity or autoantibodies to improve transfusion safety.