|Year : 2018 | Volume
| Issue : 1 | Page : 72-74
One case many learnings: A case of blood group discrepancy along with multiple alloantibodies
Samrat Thapa, Latha Jagannathan, Ankit Mathur, TV Kumar Reddy, Santanu Chakraborty
Deaprtment of Transfusion Medicine, Rotary Bangalore-TTK Blood Bank, Bangalore Medical Services Trust, Bengaluru, Karnataka, India
|Date of Web Publication||5-Apr-2018|
Dr. Samrat Thapa
Deaprtment of Transfusion Medicine, Rotary Bangalore-TTK Blood Bank, Bangalore Medical Services Trust, Bengaluru, Karnataka
Source of Support: None, Conflict of Interest: None
Routinely, Immunohematology Reference Testing Center receives samples with blood group discrepancy, presence of allo/autoantibodies, positive direct antiglobulin test (DAT), etc. We are presenting a case in which we not only resolved blood group discrepancy but also identified multiple alloantibodies reacting at different phases. A tricenarian female patient was diagnosed with chronic anemia with hemoglobin level below 7 g/dl. The patient had a history of blood transfusion and pregnancy as well. On blood grouping, the patient's forward grouping was “AB” and reverse was “O.” Indirect antiglobulin test was found to be positive while DAT and autocontrol were negative. After complete investigation, patient blood group was confirmed to be subgroup of AB along with anti-A1 antibody. Furthermore, a cold-reacting alloantibody with high thermal amplitude was detected along with one warm-reacting alloantibody.
Keywords: Blood subgroups, cold-reacting alloantibody, high thermal amplitude
|How to cite this article:|
Thapa S, Jagannathan L, Mathur A, Reddy TK, Chakraborty S. One case many learnings: A case of blood group discrepancy along with multiple alloantibodies. Glob J Transfus Med 2018;3:72-4
|How to cite this URL:|
Thapa S, Jagannathan L, Mathur A, Reddy TK, Chakraborty S. One case many learnings: A case of blood group discrepancy along with multiple alloantibodies. Glob J Transfus Med [serial online] 2018 [cited 2019 Mar 20];3:72-4. Available from: http://www.gjtmonline.com/text.asp?2018/3/1/72/229331
| Introduction|| |
Immunohematology Reference Testing Center (RTC) assists referring hospitals in resolving serological problems and locating compatible blood products when requested. Routinely, RTC receives sample for resolution of blood group discrepancy, antibody screening and identification, investigation of positive direct antiglobulin test (DAT), etc. This is one of atypical cases where RTC confirmed not only a blood subgroup but also detected multiple alloantibodies: one cold reacting with high thermal amplitude and another a low frequent and warm reacting.
Antibodies have optimum temperature for its reactivity. Reactivity in a certain phase will help to determine whether the antibody is cold reacting (IgM) or warm reacting (IgG). It will also help to distinguish between antibodies that are clinically significant and not significant. Any red blood cell antibody that binds its target antigen best at levels below body temperature (37°C) is commonly referred to as a “cold antibody” in contrasts to “warm antibodies” that reacts best at or near body temperature.
“Cold” or IgM antibodies typically react at immediate spin, room temperature, and sometimes at 37°C phases. These antibodies are usually clinically insignificant because they do not cause red blood cell destruction if antigen-positive donor red blood cells are transfused. When the crossmatch is performed, the antibody activity often has to be avoided to find serologically compatible blood. The specificities of cold-reacting antibody are anti-Le a, anti-Le b, anti-M, anti-N, and anti-P1. The antibody is usually identified by noting reactions at immediate spin (IS) that may not carry through to the antihuman globulin (AHG) phase although 37°C reactions are sometimes seen.
On the other hand, “warm” or IgG antibodies typically react at 37°C as well as AHG phase. These antibodies are clinically significant because they react best at body temperature.
| Case Report|| |
A 37-year-old female patient was diagnosed with chronic anemia, and the hemoglobin level at the time of admission was 6.5 gm/dl. The patient had a history of blood transfusion and pregnancy as well. Sample was received at RTC requesting for resolution of blood group discrepancy as well as antibody identification. On blood grouping, the patient's forward grouping was “AB” and reverse was “O” as shown in [Table 1]. The patient's indirect antiglobulin test was found to be positive while DAT and autocontrol were negative. Anti-AB antisera gave positive reaction while anti-A1 lectin was found to be negative confirming A2B group.
On screening patient's sera with 3-cell panel (SURGISCREEN Reagent Cells, Ortho-Clinical Diagnostics) by column agglutination technique (CAT), panagglutination was observed with varying grade of reaction. Identification of alloantibody was done using 11-cell identification panel (Panel A Resolve, Ortho-Clinical Diagnostics) by CAT which again gave panagglutination with varying grade of reaction. The patient's sera were retested with the same identification panel by tube method at three different phases, i.e. room temperature (IS), 37°C, and AHG as shown in [Table 2]. In IS phase, 11-cell panel was negative only for two cells, pattern clearly suggesting of anti-P1 antibody. In AHG phase, 2 cells were strongly reactive suggesting of anti-E antibody. Phenotyping of the patient's red blood cells was negative for both P1 and E confirming the presence of their corresponding antibody.
|Table 2: Patient serum's reaction grading with donor cells at different phases|
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Furthermore, to confirm the presence of anti-A1 antibody, reverse grouping was done with A2 cells which was negative for P1 antigen.
| Discussion|| |
Various studies done within Indian population shows that more than 64% of Indian population have P1 antigen., In the presence of cold-reacting antibody against such high-frequency antigen, not only can detection of IgG alloantibodies be difficult but also circumstances are much more strenuous if anti-A1 has to be confirmed.
When the observed pattern of reactive and nonreactive tests does not fit that of a single antibody, it is recommended to check the reactivity in different testing phases. Enzyme treatment of ribosome-binding site reagents has also been employed to resolve many cases of multiple antibodies which works by enhancing the reactivity of some antibody specificities while eliminating the reactivity of others.
Neutralization technique is another tool to inhibit the reactivity of certain antibodies using soluble antigen which will neutralize the antibody by occupying its antigen binding sites. In our case, soluble P1 antigen can be isolated from many sources such as hydatid cyst fluid, pigeon, and turtledove egg whites. Thus, obtained soluble antigen can be added to serum sample and incubated at room temperature. The neutralized serum is then tested against identification panel where anti-P1 reactivity will be inhibited and anti-E pattern is easily recognized.
On the other hand, the same neutralized serum can also be used for reverse typing where there will be no more anti-P1 interference with A1 cell, A2 cell, and B cell and hence if anti-A1 antibody present will be identified effortlessly.
However, the presence of an IgG component and high thermal amplitude of anti-P1 cannot be ignored and requires crossmatch compatible (with A2, O, or B group) as well as P-antigen-negative (if reacting weakly at 37°C or AHG phase of testing) and E-antigen-negative red blood cells to be transfused to the recipient.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Table 1], [Table 2]