Introduction
Two principal subgroup of blood group A are A1 and A2 [1]. In Indian population frequency of A2 is 0.8% to 3.0% while frequency A2B is 0.6 – 1.4% [2, 3]. 22-26% of A2B individuals can have anti A1 antibodies which reacts at temperature below 25°C and do not pose problem in transfusion [1]. Subgroups of A can result in discrepancy in ABO blood grouping and haemolytic transfusion reactions are rare [1]. We report a case of A2B with anti A1 antibody reactive at 37°C, which was transfused with B group blood unit.
Case Report
A 42 year old male, weighing 65 kilograms, a known chronic alcoholic was admitted with severe upper abdominal pain. Imaging investigations revealed features of acute on chronic pancreatitis. During course of hospitalisation, he had massive upper gastrointestinal bleeding. He went into hypovolemia and was managed with intravenous fluids. His haemoglobin dropped to 3.5 gm/ dl, haematocrit value was 10.1% with a normal coagulation profile and the total serum protein was 6.2 gm/dl. Urgent blood demand was placed and blood specimen for crossmatch was collected before intravenous colloid infusion.
His specimen was processed as per laid down protocol for ‘urgent blood demand’. Initial rapid cell and serum grouping result revealed cell group- AB and serum group-B with Rh D positive. Simultaneously compatibility with two units of A1B Rh positive units was undertaken and an abbreviated crossmatch (immediate-spin, saline crossmatch) at room temperature (RT) was compatible, however 3+ agglutination was noted in low ionic strength saline (LISS)-Coombs gel agglutination card at 37°C in anti human globulin (AHG) phase of major crossmatch. Further compatibility test with four available A1B Rh units had same results. Back to basic, the blood group of the patient was repeated with ‘washed RBC’ by tube method; both cell and serum group was undertaken for cell group, anti A1 lectin was also incorporated in the test. Blood group reaction was confirmed macro and microscopically (Table 1). Presence of anti A1 was established by undertaking serum grouping with multiple A1 and O cells and one A2 cell. LISS-Coombs gel agglutination card for indirect Coombs test at 37°C revealed 4+ agglutination due to patients anti A1. The blood group of patient was confirmed as ‘A2B with anti A1 antibodies-RhD positive’. Next step was the compatibility test for transfusion of safe blood. Due to non-availability of A2B group blood unit, compatibility test with two units each of O Rh positive and B Rh positive was undertaken. Blood group O units had minor match problems as expected due to donor anti B, however, both B group blood units were found compatible. A decision to transfuse B units was taken. In total 6, 2 and 12 units of A1B, O and B Rh positive group blood units respectively were subjected for compatibility test. Result of compatibility test is presented in Table 2. B group units had two types of compatibility results due to absence and presence of anti A2 which was confirmed by using A1 and A2 cells.
Table 1.
Blood group of the patient
| Grouping | Cell Group | Serum Group | |||||||
|---|---|---|---|---|---|---|---|---|---|
| Test Substance | Anti A | Anti A1 | Anti B | Anti AB | Anti D | A1 Cells | A2 Cells | B Cells | O Cells |
| Test Result | 1 + | Negative | 3+ | 4+ | 3+ | 1 + | Negative | Negative | Negative |
Table 2.
Compatibility result with various blood donor units
| Donor Units | Major Match |
Minor Match |
||||
|---|---|---|---|---|---|---|
| Test- Temp | Saline- RT | AHG-370C |
Saline-RT | AHG-370C |
||
| Test Method | Tube | Tube | Gel | Tube | Tube | Gel |
| A1B RhD+ (6 units) | N | 1+ | 2-3+ | N | N | N |
| O Rh D+ (2 units) | N | N | N | 3+ | 3+ | 4+ |
| B RhD+ (9 units) | N | N | N | N | N | N |
| B RhD+ (3 units) | N | N | N | N | N | 1+ |
AHG- Anti human globulin. RT- Room temperature, N-Negative/Not agglutinated (compatible)
Patient was transfused with eight units of compatible B Rh positive blood over 36 hours. His haemoglobin rose to 8.9 gm/dl. He underwent endotherapy for variceal source in gastric fundus. Patient had haemoglobin of 11.4 and 10.6 gm/dl on 12th and 20th post transfusion days respectively. His direct and indirect Coombs test with R1R1, R2R2, rr screening cells were negative on pre-transfusion and post-transfusion first, 12th and 20th days. Patient recovered from acute illness.
Discussion
A1 and A2 are major subgroups of Blood group A. Both subgroup cells react with anti A lectin, however anti A1 lectin differentiate them as it does not react with A2 cells. The blood group A2 and A2B are extremely rare blood groups which can cause discrepancy in ABO blood grouping [1]. At times ABO discrepancy leads to haemolytic transfusion reaction, hence it is necessary to include anti A1 lectin in blood group test protocol. 1-8% of A2 individuals and 22-26% of A2B individuals are have anti A1 [1]. The higher percentage of anti A1 in A2B is attributed to *R101 allele which is present in 41% of A2B individuals as against 1% in A2 group [4]. Anti- A1 has thermal range of up to 25°C because of which it is clinically not significant. In fact, published cases that have reported clinically significant anti-A1 antibody are in patients who had undergone cardiac surgery using cold cardioplegia [5, 6]. Cases of anti A1 reactive at 37°C leading to transfusion reactions are rare [7, 8].
In our case anti A1 was reactive at 37°C and transfusion with A2B group units would have been ideal but it was not available. Transfusion of O group red cell is also recommended in these recipients [1], but blood component facility was not available. We did not transfuse O group whole blood units as we anticipated anti B in plasma of O whole blood units leading to haemolytic transfusion reactions considering large volume transfusion requirements [1]. The only choice left was transfusion of B group units. In majority of B positive cases primary anti A is anti A1 however primary anti A2 can be encountered [1]. Nine out of twelve of cross matched units had only anti-A1 while three had both primary anti A1 and anti A2 antibodies. It is well known that anti-A in B blood group donors generally have primary anti A1 and occasionally anti A2 [1]. In management of this case, the importance of blood grouping and AHG phase in compatibility test has been highlighted [1]. The successful transfusion of B group ‘Whole Blood’ units to the recipient of blood group A2B with anti A1 antibody reactive at 37°C in management of life threatening condition makes this case rare.
Conflicts of Interest
None identified
References
- 1.Brecher ME, editor. Technical Manual 14th Edition. American Association of Blood Banks; Bethesda, Maryland: 2002. [Google Scholar]
- 2.Gauniyal M. The Study of Blood Group A1A2BO and Rh among the Brahmins of Mussoorie, Uttaranchal. Anthropologist. 2006;8:53–54. [Google Scholar]
- 3.Das PK, Nair SC, Harris VK. Distribution of ABO and Rh-D blood groups among blood donors in a tertiary care centre in South India. Trop Doct. 2001;31:47–48. doi: 10.1177/004947550103100121. [DOI] [PubMed] [Google Scholar]
- 4.Ogasawara K, Yabe R, Uchikawa M. Different alleles cause an imbalance in A2 and A2B phenotypes of the ABO blood group. Vox Sang. 1998;74:242–247. [PubMed] [Google Scholar]
- 5.McManigal S, Sims KL. Intravascular hemolysis secondary to ABO incompatible platelet products. An under recognized transfusion reaction. Am J Clin Pathol. 1999;111:202–206. doi: 10.1093/ajcp/111.2.202. [DOI] [PubMed] [Google Scholar]
- 6.Sulochana PV, Sathyabhama S, Mathai J, Devi KS. Clinically significant autoantibodies: A case report. Indian J Pathol Microbiol. 2003;46:246–247. [PubMed] [Google Scholar]
- 7.Northoff H, Wolpl A, Sugg U. An unusual sample of irregular anti-A1, probably causing an early delayed transfusion reaction. Blut. 1986;52:317–322. doi: 10.1007/BF00320795. [DOI] [PubMed] [Google Scholar]
- 8.Brecher ME, Moore SB, Reisner RK, Rakela J, Krom RA. Delayed hemolysis resulting from anti-A1 after liver transplantation. Am J Clin Pathol. 1989;91:232–258. doi: 10.1093/ajcp/91.2.232. [DOI] [PubMed] [Google Scholar]