Introduction:

Thalassemia (βeta / E-βeta) affects 2-3% of Eastern-Indian population. This huge health burden is managed by transfusion & supportive care due to paucity of curative treatment. Regular transfusions burden already overwhelmed blood banks, health-care infrastructure & patients' families (compromising working days and distant travel).

Rate of alloantibody (4-50%) & autoantibody (10-30%) formation in thalassemia patients following usually matched RBC transfusion is well documented. Majority receive usually matched (non-phenotype) RBC causing alloantibody & autoantibody formation causing increased transfusion requirement and complications.

With is background, aim of this study is to assess the outcome of phenotypically-matched RBC transfusion in previously and newly diagnosed thalassemia patients.

Objective:

  • To estimate the presence of alloantibody & autoantibody in previously diagnosed patients receiving usually matched RBC transfusion and in newly diagnosed receiving phenotypically-matched RBC transfusion.

  • To assess transfusion requirement & iron-overload in previously diagnosed patients.

Material and methods:

Total 81cases (calculated sample size) enrolled into 2 groups. Group-1: 41 previously diagnosed patients on usually matched RBC transfusion, Group-2: 40 newly diagnosed patients on phenotypically-matched RBC transfusion. Post-enrolment both groups received phenotypically-matched RBC transfusion for 6 months. Baseline haemoglobin, direct Coomb's test for autoantibody detection, indirect Coomb's test for alloantibody screening, specific antibody identification by 11 cell panel kit in screening positive cases were done. Limited RBC phenotype (C,c,E,e,kell) detected by commercially available kit. Iron overload assessed by three monthly serum ferritin estimation

Inclusion criteria:

  • Age: >1yr - < 40 yrs

  • Previously diagnosed thalassemia patients on usually matched RBC transfusion atleast for 6 months enrolled under group-1.

  • Newly diagnosed thalassemia patients not yet received RBC transfusion >1 unit enrolled under group-2

Exclusion criteria:

  • Pregnant women & other hemoglobinopathies

Results:

Group 1-

Female-58.5%, Male-41.5%. Beta-thalassemia major-78%, E-βeta-22%. TDT-85.4%, NTDT-14.6%.

  • RBC phenotype: C-68.3%, c-36.6%, E-2.4%, e-65.9%, kell-2.4% (of patients).

  • alloantibody screening positive-17%, DCT positive at baseline-9.8%. Alloantibody positive patients developed clinically significant erythrocyte alloantibodies particularly against anti-C (40%), anti-c (20%), anti- E (20 %), anti-e (20%), anti-jkb (20%)

  • 4% patients(n=1) autoantibody and 2.4% alloantibody positive after 6 months of enrolment.

  • Mean transfusion requirement 6 months before & after enrolment 93±5.84 and 6.47±4.13 respectively (p<0.0001).

  • Mean hemoglobin 6 months before & after enrolment 6.77±18 and 7.43±1.07 respectively (p<0.003).

  • Mean ferritin 6 months before & after enrolment 58±872 & 1164.95±625.52 (p=0.004).

Group 2-

Female-37.8%, male-62.2%. TDT-75.7%, NTDT-24.3%. Beta thalassaemia major-55%, E-β-45%.

RBC phenotype: C-81.1%, c-45.9%, E-10.8%, e-97.3%

  • Alloantibody screening positive-5.4% and no DCT positive cases at baseline. Alloantibody positive patients developed clinically significant erythrocyte alloantibodies (50%) particularly against anti -c and e.

  • After 6 months of enrolment, no alloantibody & autoantibody detected.

  • Mean haemoglobin at baseline and 6 months after enrolment 4± 1.02 & 7.77±1.19 respectively (p=.016).

Summary & Conclusion:

  • Use of limited phenotype-matched RBC in previously diagnosed patients can reduce already developed antibody and significant reduction in alloantibody (17 % to 2.4%, p value <0.05) & autoantibody (9.8 % to 2.4 %, p value <0.05) in group-1. Reduction in alloantibody (5.4% to 0 %) in group-2.

  • Phenotype matched RBC transfusion & pretransfusion screening is cost effective, feasible approach needs to be ensured when transfusion strategy is planned for all thalassemia patients irrespective of their antibody status.

Limitation:

Larger sample size necessary to reach consensus solution in resource constrained countries.

Disclosures

No relevant conflicts of interest to declare.

This content is only available as a PDF.
2024
Sign in via your Institution