Case Report: A Complex Case of Alloimmunisation and Transfusion Management in a 71-Year-Old Female

Introduction

Transfusion of red blood cells (RBCs) is a common lifesaving intervention.1 However, alloimmunisation against non-ABO antigens can complicate subsequent transfusions, leading to delays in finding compatible blood and increasing the risk of haemolytic transfusion reactions (HTRs).2,3 Alloantibodies, particularly those targeting the Rh and Kell systems, are clinically significant due to their high immunogenicity. The incidence of alloimmunisation is higher in populations with prior antigen exposure, such as transfusion-dependent patients.1 This report details the challenges of managing a transfusion in a patient with multiple alloantibodies in an emergency setting.

Case Report

Patient presentation: 71-year-old female presented to the emergency ward with severe anaemia (haemoglobin: 6.2 g/dL). Blood grouping, antibody screening, and crossmatching were initiated to facilitate the transfusion of two units of packed red blood cells (PRBCs).

Laboratory findings: The patient's laboratory findings indicated a blood group of A positive. The antibody screening results were positive, and crossmatching was incompatible with all tested units. Additionally, the direct antiglobulin test (DAT) was positive, and the autocontrol (A/C) also showed a positive result.

Antibody identification: Advanced serological workups, including solid-phase red cell adherence (SPRCA), revealed the presence of Anti-C and Anti-e antibodies. Elution studies confirmed these findings. Due to the high prevalence of C (87%) and e (98%) antigens in the Indian population, most donor units were incompatible.

Management

To identify compatible units, multiple panels (Cap R Ready ID, Panocell 16, and Panocell 10 enzyme panels) and extended crossmatching were performed. Eventually, two O Positive R2R2 units (C-, c+, e-, E+) were located and transfused successfully.

Discussion

Pathophysiology of alloimmunisation: Alloantibodies against RBC antigens develop after exposure to foreign antigens through transfusion, pregnancy, or organ transplantation. Anti-C and Anti-e antibodies belong to the Rh system, which is highly immunogenic. These antibodies can cause HTRs, complicating transfusion management and posing significant risks to patients.

Diagnostic challenges: The case highlights the critical role of antibody screening and identification in transfusion medicine:

1. Antibody screening: A sensitive test, such as SPRCA, is essential to detect clinically significant antibodies that may not be identified through crossmatching alone (Figure 1).1

Image of Capture-R Ready Screen strip.

• In a positive test, indicator red cells cannot move to the bottom of the well because Anti-IgG-IgG complexes are formed on the antigen surface of the immobilised red cell membrane layer.
• In a negative test, indicator red cells can move easily to the bottom of the well and form a red cell button.
• The degree of red cell adhesion to the monolayer is the key indicator of positive and negative reactions (Figure 1).

2. Elution studies: his procedure helped confirm the antibodies bound to the patient’s RBCs, ruling out additional alloantibodies.

3. Phenotyping: Recent transfusions made phenotyping of the patient’s RBCs unreliable, necessitating alternative approaches for antibody identification.

4. Panel testing: : Using multiple panels (e.g., Panocell 16, Panocell 10) enables the detection of antibodies with broad reactivity, as seen in this case of Anti-C and Anti-e (Figure 2 and Figure 3). 82 The Max Medical Journal March 2025

Figure 2: Antigram of Capture-R Ready Screen.

Figure 3: Antigram of Capture-R Ready-ID.