|Year : 2022 | Volume
| Issue : 1 | Page : 51-53
Cw alloimmunization in multitransfused thalassemic patients of North India: Prevalence and approach to transfusion
Sangeeta Pahuja1, Shivali Sehgal2, Geetika Sharma1, Jagdish Chandra3, Nupur Parakh3, Manisha Singh1, Ramvilash Yadav1
1 Department of Immunohematology and Blood Transfusion, Lady Hardinge Medical College, New Delhi, India
2 Department of Pathology, Hamdard Institute of Medical Sciences and Research, New Delhi, India
3 Department of Paediatrics, Lady Hardinge Medical College, New Delhi, India
|Date of Submission||27-Sep-2021|
|Date of Decision||21-Jan-2022|
|Date of Acceptance||21-Mar-2022|
|Date of Web Publication||29-Apr-2022|
Dr. Shivali Sehgal
Department of Pathology, Hamdard Institute of Medical Sciences and Research, New Delhi
Source of Support: None, Conflict of Interest: None
Background and Objectives: The C Willis or Cw antigen is a low-incidence antigen of Rh system. The antibody against the Cw antigen (anti-Cw) is an IgG antibody which may occur naturally or may be immune in nature. The identification of Cw antibody is important since it has the potential to cause hemolytic disease of the newborn as well as hemolytic transfusion reaction. This study was conducted with the aim of determining the prevalence of Cw antibody in multitransfused thalassemic patients enrolled in a Regional Blood Transfusion Center (RBTC) of North India. Methods: A retrospective descriptive observational study was conducted at the Department of Immunohematology and Blood Transfusion, LHMC and Associated Hospitals. All transfusion-dependent thalassemic (TDT) patients and non-TDT (NTDT) patients enrolled in the RBTC of the hospital till December 2018 were included in the study. Antibody screening was performed in all recipients before each transfusion. The prevalence of anti-Cw was estimated. Results: A total of 567 thalassemic patients (including TDT and NTDT) were registered in RBTC, LHMC till December 2018. On pretransfusion antibody screening and identification, 3 out of 567 thalassemic patients were found to have alloimmunization against Cw antigen. The prevalence of anti-Cw in multitransfused thalassemics was 0.53%. Conclusion: The prevalence of anti-Cw is variable in different populations and it is not a very commonly reported antibody in patients with thalassemia. One should be aware of the approach to transfusion in thalassemic patients who develop Cw alloimmunization.
Keywords: Cw alloimmunization, multitransfused, North India, thalassemics
|How to cite this article:|
Pahuja S, Sehgal S, Sharma G, Chandra J, Parakh N, Singh M, Yadav R. Cw alloimmunization in multitransfused thalassemic patients of North India: Prevalence and approach to transfusion. Glob J Transfus Med 2022;7:51-3
|How to cite this URL:|
Pahuja S, Sehgal S, Sharma G, Chandra J, Parakh N, Singh M, Yadav R. Cw alloimmunization in multitransfused thalassemic patients of North India: Prevalence and approach to transfusion. Glob J Transfus Med [serial online] 2022 [cited 2022 May 20];7:51-3. Available from: https://www.gjtmonline.com/text.asp?2022/7/1/51/344342
| Introduction|| |
The Rh blood group system was first brought to light by Levine and Stetson in 1939 when they described hemolytic transfusion reaction (HTR) in an obstetric patient after blood transfusion from her husband. Today, 61 Rh antigens have been characterized. The C Willis or Cw antigen is a low-incidence antigen of Rh system (Rh8) which results from single amino acid substitution (Gln41Arg), most often found on the RhCe protein. The antibody against the Cw antigen (anti-Cw) was first described in 1946. It may occur naturally or may be immune in nature. This is an IgG antibody which has the potential to cause hemolytic disease of the newborn (HDN) as well as HTR.
Aims and objective
This study was conducted with the aim of determining the prevalence of Cw antibody in multitransfused thalassemic patients including both transfusion-dependent thalassemic (TDT) as well as nontransfusion dependent thalassemic (NTDT) patients, enrolled in a Regional Blood Transfusion Center (RBTC) of North India.
| Materials and Methods|| |
This retrospective descriptive observational study was conducted at the Department of Immunohematology and Blood Transfusion, LHMC and Associated Hospitals. All TDT and NTDT patients enrolled in the RBTC of the hospital till December 2018 were included in the study.
As per the guidelines, antibody screening is done in all recipients before each transfusion. At our institute, screening is performed using Bio-Rad ID-Diacell I-II-III Asia (three-cell panel, Manufacturer: DiaMed GmbH, Switzerland). If positive, antibody identification is done using Bio-Rad ID-DiaPanel (11-cell panel, Manufacturer: DiaMed GmbH, Switzerland) to identify the specificity of the antibody and to assess the clinical significance.
Identification of anti-Cw requires the reagent red blood cells (RBCs) panel which includes Cw antigen-positive RBCs and allows exclusion of other clinically significant alloantibodies in result interpretation. In cases with anti-Cw antibody, antigen profiling of the red cells for Cw antigen was performed using monoclonal anti-Cw serum (Manufacturer: Bio-Rad Medical Diagnostics GmbH, Germany).
| Results|| |
A total of 567 thalassemic patients (including TDT and NTDT) were registered in RBTC, LHMC till December 2018. On pretransfusion antibody screening and identification, 3 out of 567 thalassemic patients were found to have alloimmunization against Cw antigen. Thus, the prevalence of anti-Cw antibody in multitransfused thalassemia patients in our center was 0.53% [Table 1].
|Table 1: Details of multitransfused thalassemic patients who developed Cw antigen|
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Rh and Kell profiles of these patients are shown in [Table 2]. In all three patients, antibody screening by three-cell panel in Coombs phase at 370C revealed positivity in the first cell. On performing, antibody identification by 11-cell panel in Coombs phase at 370C, the first cell was positive. There was no diminution of the reaction with papain. Since only a single cell in the panel had Cw antigen-positive RBCs, confirmation of the presence of anti-Cw was obtained by testing the serum with three different lots of antibody screening or identification panels. On antigen profiling of the red cells of all three patients, Cw antigen was negative.
|Table 2: Rh Kell profile of the three multitransfused thalassemic patients who developed Cw antigen|
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These patients were thereafter transfused with Cw negative and indirect antiglobulin test (IAT) crossmatch compatible blood. On follow-up after repeated transfusions with Cw negative blood, antibody titers declined and became serologically undetectable in two out of three cases [Table 1]. The third case shows 1 + reaction with Cw positive cells.
| Discussion|| |
Anti-Cw was first described by Callender and Race in a multitransfused patient (DCe/DCe) with systemic lupus erythematosus who had been transfused DCe/DCe Cw + red cells.
Identification of anti-Cw is important because of its potential in causing mild-to-severe HTRs as well as mild-to-moderate HDN.,,, Anti-Cw antibody is an IgG antibody which may be seen in combination with other antibodies to RBCs. In fact, it can be easily missed if it coexists with anti-D.
The Cw, Cx, and MAR antigens are encoded by alleles at the CC locus of the Rh system. Cw and Cx are low-frequency antigens which are antithetical to the high-frequency antigen MAR. Anti-Cw may show dosage that is, it reacts more strongly with cells from individuals who are homozygous for Cw antigen. This emphasizes the significance of antibody screening for all patients (particularly multitransfused groups) as it may be missed on crossmatch if antigen is in the heterozygous form.
Cw antigen is a low-prevalence antigen. It is found in about 2% of the Caucsian and is very rare in African-Americans., The frequency in North Indian donors has been previously reported to be 1.2%. It varies from 1% in African-Americans to around 9% in Latvians.,
The incidence of anti-Cw is variable in different populations. Bowman et al. reported an incidence of 0.1% of anti-Cw in pregnant females. HDN was reported in 2% of the babies whose mothers had been alloimmunized with anti-Cw. Jain et al. reported the antibody in a young female in North India. Bujandric and Grujic described anti-Cw in two patients of chronic renal failure on dialysis.
The prevalence of anti-Cw in multitransfused thalassemics was 0.53% in our study. Anti-Cw is not a very commonly reported antibody in thalassemic patients. Datta et al. did not come across any Cw alloantibody in their cohort of 500 thalassemic patients from East India. Similarly, Elhence et al. did not observe any anti-Cw in their study of 280 thalassemic patients of Northern India. Singer et al. did not find anti-Cw in any of the 64 multitransfused TDT patients of predominantly Asian descent. Furthermore, Cheng et al. did not report any anti-Cw in 382 Chinese thalassemic major patients. No anti-Cw was reported by Thompson et al. in their study of 697 thalassemic patients from 28 institutions of North America and the United Kingdom. However, El-Beshlawy et al. found anti-Cw in 11 out of a total of 200 thalassemic patients in Egypt. Ethnic differences and homogeneity of population can explain the differences in alloimmunization status in different geographical areas.
If Cw antigen is not represented in the antibody screening panel, these antibodies can remain undetected. Therefore, alloantibody screening panels should include Cw positive cells since they may not be as infrequent as they are thought to be and can result in clinically significant HDN and HTR.
If anti-Cw is identified during pregnancy, titers and follow-up should be done as per the guidelines to avoid HDN. In addition, physicians must be aware that the occurrence of anti-Cw can lead to serious transfusion complications.
Thalassemic patients who develop anti-Cw should ideally receive Cw negative RBCs after IAT crossmatch. Since Cw is a low-prevalence antigen, Cw antigen-negative blood is readily available. Even after the antibody becomes undetectable serologically, these patients should continue receiving Cw antigen-negative blood.
Cw antisera are expensive and not readily available in all blood banks. If the patient is known to have Cw antibody and testing with Cw antisera is not feasible, red cells compatible by IAT at 370C can be transfused.,
Providing compatible blood for transfusion in patients with antibodies to low-incidence antigens is not a problem, however, the identification of the same is necessary to assess their potential in causing HDN and HTR. In addition, these antibodies may complicate the detection of other clinically significant antibodies in multitransfused patients.
| Conclusion|| |
It is important to be aware of Cw antibody since it can lead to serious transfusion complications or HDN. The Cw antigen should be included in all the antibody screening panels. Furthermore, heterozygous antigen may get missed by crossmatch alone due to the dosage phenomenon. Patients with anti-Cw should be counseled regarding the potential of the antibody to cause HDN and HTR. Ideally, all patients with anti-Cw should be given a bio-passport or an antibody card mentioning the same since they might be negative on repeat testing but may develop a reaction if given Cw positive blood.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Table 1], [Table 2]