Transfusion Management in a Bleeding Patient with Rare H-deficient Blood Group Variant

Dear Editor,

A 29-year-old primigravida, diagnosed with ruptured ectopic pregnancy presented to the emergency with dizziness, tachypnoea and haemoglobin of 5.9 g/dL. Record tracing of her antenatal check-up showed that the blood group was O RhD positive. She had no previous history of transfusion. Urgent request for two units of packed red cells was sent to the blood centre. Initially, the ABO and RhD grouping was performed using tube methods and showed discrepancy between forward and reverse grouping. After excluding sampling, technical and transcription error, the test was repeated by column agglutination technology for confirmation, but the results were still similar (Fig. 1). The O cells that were used in reverse grouping showed 4 + agglutination in both the methods. Further testing of red cells using anti-H lectin (Tulip Diagnostics, Goa, India) showed no agglutination. The direct antiglobulin test was negative. Antibody screening was performed at 37⁰ C with panel-cells (ID-Diacell I-II-III, Bio-Rad, Switzerland) which was found negative along with a negative autocontrol. There was no time to perform saliva study in this case for determination of the secretor status. Thus, the patient’s RBC was phenotyped with polyclonal anti-Le^a and anti-Le^b antisera and it was found to be Le (a–b+). Based on these observations, her blood group was considered as O para-Bombay phenotype (Oh-secretor). There was no H-deficient packed RBC available in transfusion service inventory and only her husband was available who had a blood group of A RhD positive. Furthermore, it was not possible to call any donor from the rare blood group registry considering the rapid clinical deterioration of the patient. Therefore, an alternative approach was taken. Random cross matches were performed with O Rh D positive red cells along with determination of the specificity of the antibodies in the patient’s serum by checking the reactions with group O cord cells at room temperature as well as at 4⁰ C (Table 1). The antibody was suggestive of anti-IH as the serum did not react with group O cord cells which lack I antigens but carry H antigens. Also, all units were found compatible after the AHG crossmatch at 37⁰ C excluding presence of a clinically significant anti-H antibody with wider thermal amplitude. Finally, she was transfused with four units of group O RhD positive RBCs within the next 24 h and underwent an exploratory laparotomy. There was satisfactory increment of Hb without any transfusion reaction and she was discharged a week after in haemodynamically stable condition.

Fig. 1.

Results of blood grouping by column agglutination technology

Table 1.

Investigation results

Test	Result	Interpretation
Cell grouping (Forward grouping)
Anti-A	0	Oh, RhD positive
Anti-B	0	(H-deficient variant)
Anti-A,B	0
Anti-A1 lectin	0
Anti-H lectin	0
Anti-D	4+
Serum grouping (Reverse grouping)
A1 cell	4+	Anti-H and/or IH present
A2 cell	3+	reacting up to 220 C
B cell	4+
O cell at 220 C	4+
O cell at 40 C	4+
O cell at 370 C	0
Direct antiglobulin test (DAT)	0	Negative
Antibody screening	0	Negative
(3-cell panel)
Autocontrol	0	Negative
Anti-Lewis-a (polyclonal)	0	Le (a–b+), suggestive of
Anti-Lewis-b (polyclonal)	2+	a secretor
Oi cord cells at 220 C	0	Anti-IH
Oi cord cells at 40 C	0
Cross-matching with OH, RhD positive red cells (six units)	0	All compatible

The para-Bombay phenotype is a rare red blood cell phenotype characterised by the lack of ABH antigens on red blood cells, but ABH substances can be found in saliva [1]. Two α-1,2 fucosyltransferases synthesise H antigen. α2Fuc-T1 (coded by FUT1) determines the expression of H antigen on red blood cells while α2Fuc-T2 (coded by FUT2) is expressed in non-erythroid tissues [2]. Based on previous studies, the incidence of the Bombay phenotype in our population ranges from 1:7000 to 1:10,000 [3]. But the exact incidence of para-Bombay phenotype is not known in the Indian population. Para-Bombay individuals usually have anti-H and/or anti-IH in their plasma. These antibodies have wide thermal amplitude reacting predominantly at 4◦C to 22◦C [4]. These individuals should be strictly transfused with H-deficient red cells if anti-H/anti-IH is reacting up to 37⁰ C. However, for patients with anti-H/anti-IH not reacting at 37⁰ C, in case of unavailability of the para-Bombay blood group, AHG compatible ABO identical red cells can be considered for transfusion [5].

In summary, transfusion in para-bombay still remains a blind spot and thermal amplitude of anti-H or anti-IH is an important factor for guiding the transfusion in such cases.

Electronic Supplementary Material

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