Transfusion-induced hemolysis in warm autoimmune hemolytic anemia with autoantibodies that have anti-e specificity: a case report and systematic review of the literature

Abstract

Warm autoimmune hemolytic anemia (wAIHA) is characterized by autoantibodies against proteins that comprise the Rh antigen system along with hemolysis. The presence of specific autoantibodies, especially autoantibodies with anti-e specificity, is rare. The pathophysiology, management, and outcomes in this condition, including with transfusion of e-antigen positive packed red blood cells (pRBCs), remain poorly understood. A 63-year-old woman presented with fatigue, jaundice, tea-colored urine, and dyspnea. She was diagnosed with wAIHA with anti-e specificity and developed worsening hemolysis after receiving a unit of e-antigen positive pRBCs with a drop in hemoglobin from 85 to 71 g/L. She achieved a complete response with a tapering course of prednisone and folate. We conducted a systematic review of the literature by searching MEDLINE, EMBASE, and Cochrane for articles on management of wAIHA with anti-e specificity published between 1946 and 2025. We identified eighteen cases of wAIHA mediated through autoantibodies with anti-e specificity, only one of which demonstrated hemolysis after transfusion with e-antigen positive pRBCs. Treatment with corticosteroids and rituximab was effective in many of these cases. This is the one of the few cases to demonstrate increased hemolysis after transfusion with e-antigen positive pRBCs in a patient with wAIHA and autoantibodies with anti-e specificity. In these patients, transfusion of e-antigen positive pRBCs should be avoided and if transfusion is necessary, it will be important to closely monitor for worsening hemolysis. Additionally, our case and those reported in the literature highlight the effectiveness of standard corticosteroid treatment for this rare type of wAIHA.

Keywords

anti-e antibody glucocorticoids red blood cells transfusion warm autoimmune hemolytic anemia

Introduction

Warm autoimmune hemolytic anemia (wAIHA) is a rare autoimmune disorder characterized by red cell destruction (hemolysis), which is primarily mediated by IgG autoantibodies, with or without complement involvement. This condition can be primary or associated with infections, autoimmune diseases, lymphoproliferative disorders, or solid tumors.¹ wAIHA is the most common of the autoimmune hemolytic anemia and its diagnosis is supported by the evidence of hemolysis (elevated lactate dehydrogenase (LDH), unconjugated bilirubin, reticulocytes, and decreased haptoglobin), and presence of autoantibodies. A peripheral blood smear may show spherocytosis. The presence of autoantibodies is detected by a positive direct antiglobulin test (DAT) for IgG and/or complement C3d.² Subsequent serologic eluate testing, which involves extracting the antibodies coating the red blood cell (RBC) surface and studying its specificity against a panel of reagent red cells, will show “pan-agglutination.” This is because IgG autoantibodies in wAIHA are usually directed against ubiquitous proteins that comprise the Rh antigen system.³

Specificity for a particular antigen is a rare finding on eluate testing in wAIHA,⁴ and the pathophysiology, management, and outcomes of these conditions are not well understood. Moreover, there is a notable lack of reports of patients with autoantibodies with anti-e specificity who received transfusion with e-antigen positive packed RBCs (pRBCs) to inform decision-making in this context. We report a case of a patient with wAIHA caused by autoantibodies with anti-e specificity, and describe outcomes following transfusion with e-antigen positive pRBCs, followed by a systematic review of the literature.

Case presentation

A 63-year-old woman presented with a 4-week history of fatigue, jaundice, and tea-colored urine, as well as progressive dyspnea over the prior several days. Medical history included fibromuscular dysplasia with prior vertebral artery dissection and associated transient ischemic attack, for which she was on apixaban. She had no previous blood transfusions but had two pregnancies over 30 years ago. On physical examination, she was jaundiced with no evidence of hepatosplenomegaly or lymphadenopathy.

Investigations revealed macrocytic anemia with a hemoglobin of 74 g/L (reference interval (RI) 115–160 g/L; baseline hemoglobin was 140 g/L 3 years prior) and mean corpuscular volume of 115.7 fL (RI 80–100 fL), leukocytes 10.3 × 10⁹/L (RI 4–10 × 10⁹/L), and platelets 287 × 10⁹/L (RI 150–400 10⁹/L). LDH was 1453 U/L (RI <214 U/L), haptoglobin <0.10 g/L (RI 0.3–2.0 g/L), reticulocytes 338 × 10⁹/L (RI 10–100 × 10⁹/L), total bilirubin 73 μmol/L (RI <21 μmol/L), and unconjugated bilirubin 61 μmol/L. Her vitamin B12 level was 328 pmol/L (RI 133–675 pmol/L). Folate levels were not measured. Her peripheral blood smear showed evidence of spherocytosis and polychromasia (Figure 1). Her polyspecific DAT was positive followed by monospecific DAT that was positive for IgG only and serologic eluate testing showed the presence of an autoantibody with anti-e specificity. The patient was phenotyped and was found to be e-antigen positive. Other investigations showed a creatinine 71 μmol/L (RI 55–100 μmol/L), international normalized ratio 1.0 (RI 0.1–1.1) and activated partial thromboplastin time 22 s (RI 20–29 s). Her liver enzymes, quantitative immunoglobulins, and serum-free light chain assay results were within normal limits. Her serum protein electrophoresis showed no evidence of a monoclonal protein. Her thyroid-stimulating hormone was 1.32 mIU/L (RI 0.27–4.20 mIU/L). Serologies for human immunodeficiency virus, hepatitis B, hepatitis C, cytomegalovirus, and Epstein–Barr virus were negative. Autoimmune markers, including complement levels, rheumatoid factor, antinuclear antibody, and antineutrophil cytoplasmic antibodies, were within reference intervals. Her iron panel did not show evidence of iron deficiency with a ferritin of 581 ug/L (RI 30–327.8 μg/L), transferrin saturation 76.4% (RI 11%–56%), serum iron 35 μmol/L (RI 7.0–26.0 μmol/L), and unsaturated iron-binding capacity 10.8 μmol/L (24.2–70.1 μmol/L). Initial laboratory values are summarized in Table 1.

Figure 1.

Peripheral blood smear, 50X objective lens magnification, Wright–Giemsa stain. A: spherocytes and B: polychromasia.

Table 1.

Summary of initial laboratory values.

Biochemical marker	Laboratory value	Reference range
Hemoglobin	74 g/L (baseline 140 g/L)	115–160 g/L
MCV	115.7 fL	80–100 fL
Leukocytes	10.3 × 10⁹/L	4–10 × 10⁹/L
Platelets	287 × 10⁹/L	287 × 10⁹/L
LDH	1453 U/L	1453 U/L
Haptoglobin	<0.10 g/L	0.3–2.0 g/L
Reticulocytes	338 × 10⁹/L	10–100 × 10⁹/L
Total bilirubin	73 μmol/L	<21 μmol/L
Unconjugated bilirubin	61 μmol/L	N/A
Vitamin B12	328 pmol/L	133–675 pmol/L
C3 (pre-transfusion)	1.00 g/L	N/A
C4 (pretransfusion)	0.27 g/L	N/A
Creatinine	71 μmol/L	55–100 μmol/L
INR	1.0	0.1–1.1
aPTT	22.0 s	20–29 s
TSH	1.32 mIU/L	0.27–4.20 mIU/L
Ferritin	581 μg/L	30–327.8 ug/L
Transferrin saturation	76.4%	11%–56%
Serum iron	35 μmol/L	7.0–26.0 μmol/L
UIBC	10.8 μmol/L	24.2–70.1 μmol/L

aPTT, activated partial thromboplastin time; C3, complement component 3; C4, complement component 4; INR, internationalized normalized ratio; LDH, lactate dehydrogenase; MCV, mean corpuscular volume; N/A, not applicable; TSH, thyroid-stimulating hormone; UIBC, unsaturated iron binding capacity.

Computerized tomography scan of the chest, abdomen, and pelvis did not show any evidence of lymphadenopathy, organomegaly, or evidence of malignancy. Flow cytometry of the peripheral blood did not show any evidence of a B-cell lymphoproliferative disorder. Given the macrocytic anemia and the patient’s age, we did consider myelodysplasia on the differential diagnosis; however, we did not perform a bone marrow aspiration and biopsy given that we had more likely explanations for her clinical presentation (i.e., wAIHA and macrocytosis secondary to alcohol use). There were no dysplastic features on her peripheral blood film.

The patient was diagnosed with wAIHA with anti-e specificity. Due to the patient’s worsening symptoms of dyspnea and palpitations and hemoglobin of 61 g/L, after discussion between patient, consulting hematologist, and blood bank, the decision was made to transfuse the patient 1 unit of available pRBCs, which were e-antigen positive. This decision was also supported by prior cases that reported response to e-antigen positive pRBC transfusion without hemolysis.⁵ She received ABO and D compatible blood (donor AB and D positive and recipient AB and D positive). Her hemoglobin transiently improved to 85 g/L posttransfusion, but then rapidly fell to 71 g/L in less than 24 h. No other causes of hemolysis such as infections, new medications, or microangiopathic hemolysis were identified. After the transfusion, her hemolytic markers worsened with increases in total bilirubin, LDH, and reticulocytes by 23 μmol/L, 258 U/L, and 225 × 10⁹/L, respectively. She did not receive any other transfusions in hospital and was started on prednisone 1 mg/kg daily and folic acid 5 mg daily. Within 6 weeks, her hemoglobin increased to 142 g/L and remained elevated up to the last follow-up bloodwork 6 months later. Her hemolytic parameters all normalized with hemoglobin 145 g/L, MCV 95.2 fL, and reticulocyte count of 37 × 10⁹/L. She did not require any second-line therapies for wAIHA, such as rituximab. The trajectory of her hemoglobin ad LDH level is depicted in Figure 2.

Figure 2.

Trajectory of hemoglobin (solid line) and LDH (dotted line) from time of prednisone and folate initiation, measured in days. The green line indicates time of e-antigen pRBC transfusion. Left Y-axis—hemoglobin (g/L) and right Y-axis—LDH (U/L). The hemoglobin rose from 61 to 85 g/L, but then fell down to 75 and 71 g/L in less than 24 h. The LDH rose from 1424 to 1786 U/L in the same timeframe.

Discussion

wAIHA is a rare acquired disorder characterized by IgG-mediated autoantibody destruction of one’s own RBCs. Autoantibodies in wAIHA typically show broad reactivity against Rh antigens; however, specificity for a particular antigen can occur in rare cases.^3,4 Given that there have been less than forty cases of wAIHA with specific autoantibodies reported in the literature, there is limited evidence available regarding optimal management—specifically the efficacy and safety of transfusion—for these variants of wAIHA.

Our systematic review of the literature involved searching MEDLINE, EMBASE, and Cochrane between 1946 and 2025 for key terms “autoantibodies,” “anti-e,” “mimicking specificity,” “Rh-specificity,” and “wAIHA.” Data regarding clinical presentation, treatment, and outcomes after transfusion, were extracted. Exclusion criteria were as follows: (1) cases not explicitly examining patients with autoantibodies that have anti-e specificity and (2) cases where patients did not receive a blood transfusion. The systematic review flowchart is shown in Figure 3. We identified eighteen patient cases of wAIHA published in the literature due to an autoantibody with anti-e specificity (Table 2). Our case demonstrates that hemolysis can occur after receiving e-antigen positive blood for patients with wAIHA and an autoantibody with anti-e specificity, which was only reported in one of the eighteen prior cases. Specifically, our patient had a 14 g/L drop in her hemoglobin with worsening hemolysis after receiving 1 unit of e-antigen positive pRBCs. Additionally, our patient achieved a complete response prednisone and folic acid without the need for second-line treatments.

Figure 3.

Systematic review flowchart.

Table 2.

Summary of case reports of wAIHA with an autoantibody that had anti-e specificity.

Study	Number of cases	Patient (age/sex)	Blood transfusions and hemolysis	Medications used	Clinical course + outcomes
Yun et al.⁵	1	62 F	Received 1 unit of pRBCs (e-antigen positive) with no hemolytic reaction	None reported	Hb increased from 63 to 74 g/L posttransfusion
Datta et al.⁴	1	12 M	Received 4 units of pRBCs (e-antigen negative) with no hemolytic reaction	- Methylprednisolone 30 mg/kg × 3 days - Rituximab 375 mg/m² × 1 dose	- Hb rose from 62 to 36 g/L after initial 2 units of pRBCs - Hb ultimately rose to 81 g/L after treatment with methylprednisolone, rituximab, and two more units of pRBCs
Subramaniyan⁶	2	- 77 F - 49 F	Both patients received 1 unit of pRBCs (e-antigen negative) with no hemolytic reaction	Prednisolone 1 mg/kg/day (duration not reported)	- 77 F: Hb rose from 50 to 62 g/L post-transfusion. DAT negative and antibody screen negative at 4-month follow-up - 49 F: Hb rose from 62 to 70 g/L post-transfusion. DAT negative and antibody screen negative at 6-month follow-up
Jang et al.⁷	10	- 70 F: anti-C + e - 32 F: anti-C + e - 60 F: anti-C + e - 6 M: anti-C + e - 74 M: anti-C + e - 7 F: anti- C + e - 69 M: anti-e - 23 M: anti-e - 17 F: anti-e - 81 F: anti-e	Some patients transfused with “least incompatible pRBC units,” but specific patients not reported. No evidence of hemolysis	Not reported	No evidence of acute or delayed hemolytic reaction
Dong et al.⁸	1	60 F	- Received 1 unit of pRBCs (e-antigen negative) with no significant increment in hemoglobin - Received 1 unit of pRBCs (e-antigen positive) with significant increment in hemoglobin (~15 g/L)	Glucocorticoids (type and duration not specified)	Hb ultimately rose by ~15 g/L after transfusion with e-antigen negative pRBC. No further hemolytic reaction
Castellino et al.⁹	3	- 5 F - 16 F - 17 M	- 5 F: Transfused 3 units of pRBCs. No hemolysis present - 16 F: Transfused 341 units of pRBCs. No hemolysis present - 17 M: Transfused 28 units of pRBCs. Hemolysis present	Some patients treated with corticosteroids, but specific patients and duration of treatment not reported	Resolution of hemolysis + negative DAT in some patients. Specific patients not reported

DAT, direct antiglobulin test; Hb, hemoglobin; pRBC, packed red blood cell; wAIHA, warm autoimmune hemolytic anemia.

Our case contrasts prior reports in the literature. Yun et al. reported a patient with a DAT positive for IgG and autoantibodies with e-antigen specificity who received 1 unit of e-antigen positive blood with no evidence of hemolysis and a rise in hemoglobin from 63 to 74 g/L after the transfusion.⁵ The e-antigen pRBC unit was given before an antibody identification test identified that the patient had an autoantibody with e-antigen specificity. Datta et al. reported on a 12-year-old male patient with a history of Immune Thrombocytopenic Purpura (ITP) on maintenance glucocorticoid therapy who presented with signs and symptoms of hemolysis.⁴ He was diagnosed with wAIHA and was later found to have an autoantibody with mimicking anti-e specificity. He was given 2 units of e-antigen negative pRBCs and his hemoglobin increased from 36 to 62 g/L. Ultimately, his hemoglobin was 81 g/L 1 week after admission during which he was treated with methylprednisolone for 3 days, given one dose of rituximab, and treated with two more units of e-antigen negative pRBCs. Furthermore, Subramaniyan reported on two patients who had evidence of hemolysis, a DAT positive for IgG (with one of the two patients also testing positive for C3d), as well as the presence of autoantibodies with anti-e specificity.⁶ Both patients were transfused 1 unit of e-antigen negative pRBCs; hemoglobin counts rose by 12 g/L for the first patient and 8 g/L for the second patient. Additionally, both of these patients were successfully treated with prednisolone 1 mg/kg daily, although the duration and degree of hemoglobin rise were not clear. The DAT and antibody screens were negative four months later for the first patient and 6 months later for the second patient. Moreover, Jang et al. reported on 10 patients who had autoantibodies with anti-e specificity, 6 of whom had concurrent autoantibodies with anti-C specificity.⁷ No severe acute or delayed hemolytic reactions were observed after transfusions with the least incompatible RBCs. It is unclear whether these patients were also treated with glucocorticoids.

Interestingly, Dong et al. reported on a patient with an autoantibody mimicking anti-e specificity.⁸ This patient demonstrated a poor transfusion response when given e-antigen positive pRBCs despite the use of glucocorticoids. When the patient was given e-antigen negative pRBCs, their hemoglobin incremented appropriately. These results are similar to our case report findings and further highlight the importance of having an appropriate transfusion strategy when treating patients with wAIHA and autoantibodies mimicking anti-e specificity. However, there are notable differences between the patient presented by Dong et al. and our patient case. Specifically, the autoantibody in our study did not demonstrate pan-agglutination. Furthermore, we also demonstrate that our patient responded well to standard corticosteroid and folic acid treatment like most regular cases of wAIHA. Additionally, our study is novel because we show direct evidence of posttransfusion hemolysis (i.e., rising LDH, bilirubin, reticulocytes) coinciding with a drop in hemoglobin, which was not specifically explained in the article by Dong et al.

The mechanism of specific autoantibody formation is not well understood. Similar to regular wAIHA, the basic pathophysiology of hemolysis posttransfusion involves IgG autoantibodies with particular specificities binding to their respective antigens on RBC membranes, which leads to the signaling of macrophages, phagocytosis, and extra-vascular hemolysis.² Interestingly, Castellino et al. described three cases of pediatric patients with sickle cell disease in which autoantibodies with anti-e specificity were formed after transfusion with pRBCs.⁹ These patients received a median of 24 units of pRBCs prior to autoantibody formation. One of these patients had evidence of clinically significant hemolysis with both IgG and C3d identified on their DAT. Likewise, Aygun et al. reported that warm autoantibodies developed in 8% of pediatric patients and 9.7% of adult patients with sickle cell disease after receiving blood transfusions.¹⁰ The mean number of pRBC units transfused per patient was 23.8 and 23.3 in pediatric and adult patients, respectively. The majority of these patients had underlying alloantibodies prior to autoantibody formation. These findings suggest that receiving multiple transfusions can be a risk factor for autoantibody formation. However, our patient had never received blood transfusions in the past. Ultimately, the role of repeat blood transfusions and underlying alloantibodies in warm autoantibody formation remains poorly understood and warrants further investigation.

Overall, including our case, there are nineteen cases to date of wAIHA with autoantibodies that have anti-e specificity. Only one of the aforementioned case reports showed increased hemolysis after receiving e-antigen positive blood. However, our patient had clear evidence of worsening hemolysis posttransfusion without other causes. Baruah et al. demonstrated that 98% of blood donors in a single cohort in North-Eastern India are e-antigen positive, which poses a challenge for obtaining e-antigen negative blood for patients with wAIHA and autoantibodies with anti-e specificity.¹¹ Our patient achieved a complete response after being on prednisone 1 mg/kg daily and folic acid that was sustained. Responses to standard therapies for wAIHA, including steroids and rituximab, were demonstrated in three of the other eighteen cases as well.

Limitations

Regarding limitations of our study, complement levels were not tested after blood transfusion. This is an important point to mention given that wAIHA is caused by increased erythrocyte destruction by IgG autoantibodies, with or without complement activation. Furthermore, the direct mechanism of autoantibody with anti-e specificity formation is not well understood. As explained above, receiving multiple blood transfusions and thus being exposed to several alloantibodies is a risk factor for developing autoantibodies with particular specificities, but it is not a sufficient explanation as our patient had never received a blood transfusion in the past. Having more information regarding antibody titers, antibody affinities, temperature range of reactivity, and crossmatch compatibility results would provide a more comprehensive clinical picture and are all areas for future research. As we did not have antibody titers available, we have provided a table summarizing the agglutination strength of the eluate against ee, Ee, and EE red cells (Table 3).

Table 3.

Eluate agglutination strength against EE, Ee, and ee red cells.

Red cell panels	Red cell type	Reaction
Panel 1
1	ee	2+
2	ee	2+
3	EE	0
4	ee	2+
5	ee	2+
6	Ee	1+
7	ee	2+
8	ee	2+
9	ee	2+
10	ee	2+
11	ee	2+
Panel 2
Select cell 1	EE	0
Select cell 1	EE	0
Select cell 1	EE	0

Conclusion

Warm autoimmune hemolysis mediated through autoantibodies with Rh antigen specificity is extremely rare with less than 40 cases reported in the literature and eighteen cases with autoantibodies that have anti-e specificity. Providing blood transfusions for patients with autoantibodies that have anti-e specificity can be challenging as the vast majority of blood donors are e-antigen positive. To our knowledge, our case is one of the few to demonstrate hemolysis after transfusion with e-antigen positive blood. In these patients, transfusion of e-antigen positive pRBCs should be avoided and if transfusion is necessary, especially in urgent/emergent situations, it is important to transfuse the most compatible (previously called least incompatible) pRBC units available and closely monitor for worsening hemolysis. Additionally, our case and those reported in the literature highlight the effectiveness of standard treatments for this rare type of wAIHA. Future research directions include examining the frequency and degree of hemolysis after transfusion with phenotype matched pRBC units, assessing the response rate to corticosteroid therapy and rituximab, and evaluating factors that increase the likelihood of both developing specific warm autoantibodies and hemolyzing posttransfusion.

Supplemental Material

sj-docx-1-tah-10.1177_20406207251410168 – Supplemental material for Transfusion-induced hemolysis in warm autoimmune hemolytic anemia with autoantibodies that have anti-e specificity: a case report and systematic review of the literature

Supplemental material, sj-docx-1-tah-10.1177_20406207251410168 for Transfusion-induced hemolysis in warm autoimmune hemolytic anemia with autoantibodies that have anti-e specificity: a case report and systematic review of the literature by Faramarz Jabbari-Zadeh, Ortenc Hoxha, Alan Gob, Ziad Solh, Benjamin Chin-Yee and Cyrus C. Hsia in Therapeutic Advances in Hematology

Footnotes

Acknowledgements

None.

Declarations

ORCID iDs

Faramarz Jabbari-Zadeh

Cyrus C. Hsia

Supplemental material

Supplemental material for this article is available online.

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