|Year : 2018 | Volume
| Issue : 2 | Page : 121-124
Optimization of blood safety through essential characterization of naturally occurring lewis antibody
Sudipta Sekhar Das, Ritam Chakrabarty
Department of Transfusion Medicine, Apollo Gleneagles Hospitals, Kolkata, West Bengal, India
|Date of Web Publication||24-Oct-2018|
Dr. Sudipta Sekhar Das
Department of Transfusion Medicine, Apollo Gleneagles Hospitals, Kolkata, West Bengal
Source of Support: None, Conflict of Interest: None
Background: Lewis (Le) antibodies are usually naturally occurring; however, they may be clinically significant, may be immunoglobulin G (IgG) type, and may cause hemolytic transfusion reactions. The present study depicts the clinical significance and detailed characterization of Le antibodies in blood donors and patient populations and their implication in safe blood transfusion. Materials and Methods: The prospective study included seven individuals who were detected with Le antibodies. Further investigations were performed for detailed characterization of these antibodies with regard to antibody type, thermal amplitude, titer, and enzyme study and secretor status of the individuals. Results: Of the 69,354 donors and patients subjected to antibody screening, anti-Lea was detected in 7 individuals with none having anti-Leb. All showed the Le (a−b−) phenotype with 4 individuals presenting with IgG anti-Lea optimally reacting at 37°C, with a highest titer of 32. Where all seven individuals were ABH secretors, however none revealed any Le substances. For patients requiring transfusion, compatible Lea antigen-negative red cell units were issued without any adverse events. Conclusions: As naturally occurring Le antibodies may be clinically significant and cause hemolytic transfusion reaction, therefore identification and detailed characterization of antibody in blood donor or recipient is very crucial to blood safety.
Keywords: Antibody identification, Lewis antibody, Lewis antigen, Lewis system, thermal amplitude
|How to cite this article:|
Das SS, Chakrabarty R. Optimization of blood safety through essential characterization of naturally occurring lewis antibody. Glob J Transfus Med 2018;3:121-4
|How to cite this URL:|
Das SS, Chakrabarty R. Optimization of blood safety through essential characterization of naturally occurring lewis antibody. Glob J Transfus Med [serial online] 2018 [cited 2019 Apr 18];3:121-4. Available from: http://www.gjtmonline.com/text.asp?2018/3/2/121/243921
| Introduction|| |
Lewis (Le) antigens are poorly developed at birth. They are produced by tissue cells and secreted into body fluids including plasma. They are then absorbed onto red cell membrane from plasma. There are three main Le phenotypes, namely Le (a+b−), Le (a−b+), and Le (a−b−). Le antibodies (anti-Lea and anti-Leb) are usually naturally occurring, predominantly of immunoglobulin (Ig) M (IgM) class and are generally produced by Le (a−b−) individuals. Anti-Lea is more commonly encountered than anti-Leb and may rarely be partially or entirely of IgG class following transfusions of Le antigen positive blood. These anti-Lea IgG antibodies often react at 37°C and Coombs phase and may cause hemolytic transfusion reactions. Here, we share our experience of encountering naturally occurring clinically significant anti-Le antibodies in blood donor and patient and importance of their characterization to ensure safe blood transfusion.,
| Materials and Methods|| |
The present prospective study from April 2013 to January 2018 comprises three blood donors and four patients who were detected with anti-Le antibody. Donor-clotted samples were initially subjected to mandatory antibody screening and subsequent antibody identification. Antibody screening in patients was performed as a part of mandatory pretransfusion testing. For all samples under the study, antibody screening and identifications were performed using column agglutination technique (CAT) and dedicated cell panels (Ortho-clinical diagnostics, Inc., Raritan, USA). Enhanced reactivity of antibody was studied using papain-treated panel cells (Ortho-Clinical Diagnostics, Inc., Raritan, USA). On confirmation of antibody, the following investigations were performed for detailed characterization:
- Le antigen typing of donors and patients using special antisera (BioRad/DiaMed, Cressier s/Morat, Switzerland)
- Direct antiglobulin test (DAT) using CAT
- Determination of thermal amplitude and titer of antibody using “pooled O red cells” carrying the corresponding antigen Le (a+b−),
- Determination of IgG class of Le antibody using dithiothreitol-treated serum,
- Saliva test to study secretor status.
Donor details were obtained from donor card and donor recalling for repeat sampling and confirmation. Patient details were obtained from patient file and personal communication.
| Results|| |
Of the 42067 donors and 27287 patients subjected to antibody screening, anti-Le antibody was detected in 3 (0.007%) donors and 4 (0.015%) patients with all expressing Le (a−b−) phenotypes. [Table 1] and [Table 2] describe the detailed characterization of Le antibodies in donors and patients, respectively. All antibodies detected were anti-Lea with only IgM anti-Lea observed in three individuals and both IgM and IgG type detected in another four. For all IgM anti-Lea, the titer range was 2–16 at 4°C and 2–4 at 22°C (room temperature). Titer range of IgM + IgG anti-Lea was 4–8 at 4°C, 2–8 at 22°C, and 2–32 at 37°C. High titer (32) IgG anti-Lea was detected in one patient with previous history of multiple transfusions. Saliva could be collected and tested from all individuals. All were ABH secretors with none having Le substances. For patients with clinically significant anti-Lea antibody who needed transfusions, crossmatch compatible, Lea negative, blood units were transfused without any adverse events.
| Discussion|| |
Anti-Lea was detected during the routine mandatory antibody screen in the donors. These donors were healthy, young with no history of blood transfusions, or pregnancy. Naturally occurring low-titer anti-Lea of IgG type was detected in two of the three donors who revealed the antibody even after 6-month follow-up. A 37-year-old male donor had low-titer anti-Lea of IgM type optimally reactive at 4°C and 22°C. Plasma products prepared from these donations were discarded as per the departmental protocol. In an Indian blood donor study, Kahar et al. observed that Le (a−b+) was the most common phenotype with 65.22% frequency, and this finding was comparable to other previous studies.,, With no Le (a+b+) phenotype observed in the study, interestingly Le (a−b−) was found in 18.26%, which was higher than that reported for Whites (6%).,, Lack of inheritance of Le gene (lele) leads to expression of the Le (a−b−) phenotype and is much more common in blacks (22%). In the current study, out of the 42067 donors screened for antibody, anti-Lea was detected in three donors and this may be attributed to the high frequency of Le (a−b−) phenotype in Indian blood donor population. This observation reveals the importance of mandatory donor antibody screening and judicious use of blood components prepared from these collections.
Le antibodies are usually naturally occurring; however, those reacting at 37°C and Coombs phase should not be ignored because they may cause significant posttransfusion in vivo hemolysis. Primarily being IgM type, these hemolysins may activate complement and cause in vivo or in vitro hemolysis. This may explain the anemia with reticulocytosis, elevated lactate dehydrogenase, and positive DAT (C3d) in a 33-year-old unmarried female patient. Quite frequently, Le antibodies are found in the sera of pregnant women; however, none of the female cases under the study were pregnant. A 29-year-old female with chronic iron deficiency anemia had a history (>1 year) of several episodes of the whole blood transfusions elsewhere. This might have triggered the formation of high-titer IgG anti-Lea in a case of preexisting naturally occurring IgM or low-titer IgG anti-Lea. Clinical insignificance of Le antibodies has been observed by previous workers because of their neutralization by Le substances present in the plasma of Le (a−b+) and Le (a+b−) individuals. In addition, other factors such as loss of red cell Le antigens into the plasma, lack of reactivity at 37°C and Coombs phase, IgM nature of antibody and incapability of crossing placenta, and poor antigen development at birth contribute to the clinical insignificance of Le antibody., However, both anti-Lea and anti-Leb have been implicated in cases of mild hemolytic disease of newborn.,
Like Le, there are other cold-reacting antibodies that at times react at 37°C and cause serological difficulties and at times untoward adverse events. Where the present study detected 7 (0.01%) Le antibodies in 69354-screened individuals with 57% of them clinically significant, Makroo et al. found 4 (0.008%) individuals with antibodies directed against Le system, of which 50% were clinically significant IgG antibodies. Mladenovic, on the other hand, reported a high prevalence of clinically significant Le antibodies, where 71 of 76 detected anti-Lea and 7of 25 anti-Leb were of IgG type. Likewise, other authors have reported varying prevalence of Le antibodies in their studies.,,
Saliva test could be performed in all individuals, where none revealed Lea or Leb substances, but all were found to be ABH secretors. These findings were in accordance with observation mentioned in the literature., In all individuals, the reactivity of anti-Lea was found to be enhanced by papain-treated panel cells. Anti-Leb is uncommon, weaker than anti-Lea, usually an IgM agglutinin with no complement fixation property. Where none of the individuals under the present study presented anti-Leb, however Makroo et al. found two of the four Le antibodies as anti-Leb.
For both the patients carrying IgG anti-Lea, incompatible crossmatches were observed. Where the former patient with cholelithiasis showed an incompatible reactivity of 1+ to 2+, high incompatible reactivity (4+) was observed in the patient suffering from iron deficiency anemia. This might be attributed to the high-titer IgG anti-Lea in the later patient. Patients with clinically significant anti-Lea antibody were transfused Lea antigen-negative compatible red cell units without any adverse events. Where the surgical patient with cholelithiasis did not require blood transfusion, the one suffering from iron deficiency anemia received 2 units of compatible red cells with posttransfusion hemoglobin (Hb) value of 8.7 g/dL. Another female patient who received blood transfusion was diagnosed as “anemia under evaluation.” Since she carried anti-Lea antibody of IgM type optimally reacting at lower temperature (4°C–22°C), no incompatibility was noticed during crossmatching. She received 2 units of red cell, which were not screened for Lea antigen, and achieved a posttransfusion Hb of 8 g/dL.
| Conclusions|| |
We conclude that identification and characterization of any antibody in donor or recipient sample is very crucial to blood safety. Naturally occurring Le antibodies may be clinically significant and at times cause hemolytic transfusion reaction, so their detailed characterization with regard to thermal amplitude and titer is important. All patients with clinically significant Le antibodies should receive compatible Le antigen-negative red cell units to optimize the therapeutic transfusion benefit. However, for patients having only IgM type, low-thermal amplitude Le antibody, with no incompatibility at Coombs phase, antigen typing of donor red cell units may be omitted. This will further help in inventory and cost management of the transfusion services.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Table 1], [Table 2]