Cold versus warm autoimmune hemolytic anemia in diffuse large B cell lymphoma: pathogenic and therapeutic implications: a case series.

Introduction

Autoimmune hemolytic anemia (AIHA) is a rare hematologic disorder characterized by a positive direct antiglobulin test (DAT). Clinically, AIHA presents with varying degrees of anemia, jaundice, and reticulocytosis [ 1 , 2 ].AIHA is classified into cold agglutinin syndrome (CAS) and warm autoimmune hemolytic anemia (WAIHA) [ 3 ]. CAS is mediated by IgM cold antibodies that bind erythrocyte surface antigens, activating the classical complement pathway and causing intravascular hemolysis. WAIHA is driven by IgG warm antibodies that bind red blood cells and promote their phagocytosis by splenic macrophages via Fcγ receptors. It is characterized by chronic anemia and jaundice, with DAT predominantly positive for IgG and without notable temperature dependence [ 4 ].

As the most common aggressive nonHodgkin lymphoma in adults [ 5 ], diffuse large B cell lymphoma (DLBCL) [ 6 ] has clinical attention for its association with autoimmune hemolytic anemia (AIHA) [ 7 ]. Approximately 10%–15% of AIHA cases are secondary to lymphoproliferative disorders, clonal tumor cells secrete pathogenic antibodies, which directly bind to erythrocyte antigens and trigger hemolysis [ 8 ]; second, the tumor microenvironment leads to immune dysregulation, activating polyclonal B cells to produce immunoglobulin G (IgG) warm antibodies or promoting excessive macrophage activation, thereby enhancing red blood cell destruction [ 9 ]. Clinically, this association often manifests as AIHA being the initial presentation of DLBCL.

DLBCL associated with CAS-DLBCL and WAIHA-DLBCL differ clinical phenotype, pathological features, and therapeutic response [ 10 ]. CAS-DLBCL patients typically present with high-titer cold agglutinins and monoclonal IgM proteins, with imaging showing deep lymphadenopathy, Such cases respond rapidly to therapy because the pathogenic antibodies are directly produced by CD20 + tumor clones. Patients with WAIHA-DLBCL exhibit polyclonal IgG elevation. reflecting IgG antibody-mediated extravascular hemolysis. This subtype responds poorly to corticosteroids and requires adequate chemotherapy to control tumor burden and concurrently reduce splenic erythrocyte destruction.Although the clinical features of the two subtypes are being recognized, controversies remain in current research. In terms of pathogenesis, the high incidence of BCL6 gene amplification in CAS-DLBCL and BCL2/BCL6 co-amplification in WAIHA-DLBCL [ 11 ] suggest the involvement of distinct oncogenic pathways in immune dysregulation. There is a lack of consensus on lymphoma screening strategies for patients with AIHA. The clinical significance of parameters such as the degree of LDH elevation, the threshold for lymph node short-axis diameter, and the nature of splenic nodules still requires validation in large-scale cohorts. Regarding treatment strategies, whether patients with CAS-DLBCL—particularly those at high risk—would benefit from combining rituximab with chemotherapy to improve prognosis remains uncertain. Similarly, for patients with WAIHA-DLBCL with splenomegaly, whether adjuvant splenic radiotherapy could reduce hemolysis lacks high-level evidence to support its use.

This study analyzes two cases of diffuse large B cell lymphoma (DLBCL) initially presenting as cold agglutinin syndrome (CAS) and warm autoimmune hemolytic anemia (WAIHA). By systematically comparing their clinical phenotypes, pathological characteristics, molecular alterations, and therapeutic responses, identify key distinguishing features of antibody subtype-associated DLBCL and establish a “triad screening model” comprising refractory hemolysis, cytopenia, and lymphatic/splenic involvement.

Case report

Case 1: CAS combined with DLBCL

We report a case of a 29-year-old Han male patient. On 17 October 2024, he presented to the First Affiliated Hospital of Anhui Medical University with complaints of fatigue and palpitations for 2 weeks. A complete blood count revealed: white blood cell count of 4.12 × 10 9 /L, hemoglobin of 76 g/L, platelet count of 315 × 10 9 /L, and reticulocyte percentage of 15.26%. Biochemical tests showed: total bilirubin of 55.6 µmol/L, direct bilirubin of 18 µmol/L, indirect bilirubin of 37.6 µmol/L, and lactate dehydrogenase of 835 U/L. Tests for iron metabolism, urinalysis, and a panel of 10 autoantibodies showed no abnormalities. Both the direct antiglobulin test and blood typing yielded indeterminate results. The patient was diagnosed with hemolytic anemia and treated with oral prednisone acetate at a dose of 15 mg (three times daily). He was subsequently monitored with intermittent blood tests, and the steroid dosage was gradually tapered. On 8 February 2025, the patient returned to our hospital due to worsening fatigue and palpitations, along with chest tightness and shortness of breath, which intensified upon exertion.

Physical examination

The patient was alert and oriented, exhibited signs of severe anemia, and had mild scleral icterus. No enlargement of superficial lymph nodes was detected. Cardiopulmonary auscultation revealed no abnormalities. The liver and spleen were not palpable below the costal margin. No edema of the lower limbs or neurological abnormalities were observed.

Laboratory examinations

Complete blood count: white blood cell count 12.12 × 10 9 /L, red blood cell count of 1.55 × 10 12 /L, hemoglobin of 58 g/L, platelet count of 497 × 10 9 /L, reticulocyte percentage of 13.15%, and absolute reticulocyte count of 0.2038 × 10 12 /L. Liver function tests: total bilirubin of 99.1 µmol/L, direct bilirubin of 10.7 µmol/L, indirect bilirubin of 88.4 µmol/L, and lactate dehydrogenase (LDH) of 707 U/L. Immunoglobulin and complement panel: IgM of 5.02 g/L, complement C4 of 0.03 g/L. Cold agglutinin titer at 4 °C was 1:2048. Pretransfusion immunological screening showed blood type A, RhD-positive, with a positive irregular antibody screen. Coombs test: direct antiglobulin test (DAT) positive (C3d positive), indirect antiglobulin test (IAT) also positive. Serum immunofixation electrophoresis and serum protein electrophoresis revealed a monoclonal immunoglobulin of the IgM-K type with an M-protein band present; M-protein concentration was 3.26 g/L. Urine immunofixation electrophoresis and urine protein quantification showed a κ light chain precipitation band and M-protein band, with an M-protein level of 254.93 mg/24 hours. Serum free light chain analysis: serum free κ light chain 15.7 mg/L, serum free λ light chain 22.10 mg/L, with a κ/λ ratio of 0.71. Autoantibody panel (16 items): antinuclear antibody (ANA) positive, granular pattern at a titer of 1:100; all other items negative. No abnormalities were found in PNH clone detection, coagulation profile, urinalysis, respiratory pathogen panel (8 items), Epstein–Barr virus (EBV) DNA, cytomegalovirus (CMV) DNA, thyroid function panel (T3, T4, TSH), antiphospholipid antibodies, ANCA testing, β2-microglobulin, immunoglobulin subclass panel, thyroid antibodies, or fecal occult blood test. Bone marrow cytology: active proliferation of nucleated cells, granulocyte-to-erythroid ratio 0.51:1. Granulocytic lineage: cells at various stages displayed mostly normal morphology with some eosinophils observed. Erythroid lineage: elevated proportion of cells at all stages, with generally normal morphology of erythroblasts and anisocytosis among mature red blood cells. Lymphocyte proportion was decreased, with otherwise normal morphology. A total of 15 megakaryocytes were observed, including 5 platelet-producing megakaryocytes, 11 granular megakaryocytes, and 2 naked nuclei. Scattered platelets were also seen. Bone marrow immunophenotyping: no evidence of acute leukemia, high-risk myelodysplastic syndromes (MDS), lymphoma, or multiple myeloma-related immunophenotypic abnormalities. A significant relative increase in nucleated red blood cells was noted. Bone marrow biopsy: no increase in blasts or lymphocytes; few megakaryocytes were observed. Erythroid hyperplasia was mildly increased. The lab results were presented in Table 1 . Table 1 Lab results of case 1 Test item Result Unit White blood cell count 12.12 10⁹/L Red blood cell count 1.55 10 12 /L Hemoglobin 58 g/L Platelet count 497 10⁹/L Reticulocyte percentage 13.15 % Absolute reticulocyte count 0.2038 10 12 /L Liver function tests Total bilirubin 99.1 µmol/L Direct bilirubin 10.7 µmol/L Indirect bilirubin 88.4 µmol/L Lactate dehydrogenase (LDH) 707 U/L Immunoglobulin and complement panel IgM 5.02 g/L Complement C4 0.03 g/L

Imaging studies

Contrast-enhanced CT of the chest, abdomen, and pelvis revealed multiple enlarged lymph nodes in the retroperitoneum, mesenteric vessels, and bilateral iliac vascular regions, with the largest short axis measuring 30 mm. The spleen was of normal size, and no hepatic lesions were detected. Ultrasound of superficial lymph nodes showed lymphadenopathy in bilateral cervical and axillary regions. The left axillary lymph node (34 × 14 mm) exhibited abnormal structure, loss of the hilum, and abundant blood flow signals.

Pathology and immunohistochemistry

On 11 March 2025, a biopsy of the left cervical lymph node was performed. Pathology indicated diffuse large B cell lymphoma (DLBCL), nongerminal center B cell type (Non-GCB). Immunohistochemical analysis showed the following profile: CD20 (+), PAX-5 (+), Bcl-6 (+), MUM-1 (+, approximately 60% of cells), CD10 (−), Bcl-2 (+, approximately 50% of cells), C-myc (+, approximately 40% of cells), CD3 (−), CD5 (−), CD30 (−), ALK (−), and Ki-67 (+, approximately 80% of cells). In situ hybridization for Epstein–Barr virus (EBER-ISH) was negative. Given the positivity for C-myc (~40%) and Bcl-2 (~50%) in this case, fluorescence in situ hybridization (FISH) was conducted, revealing no BCL6 or BCL2 gene rearrangements and no MYC gene translocation. The patient was definitively diagnosed with diffuse large B cell lymphoma, nongerminal center B cell subtype, double-expressor phenotype, Ann Arbor stage IIIA, and classified as high-risk with an age-adjusted International Prognostic Index (aaIPI) score of 3 (Fig. 1 A–D). Fig. 1 Pathological features of lymph node specimens. A – D Biopsy of the left cervical lymph node from a 29-year-old Han male patient, indicating diffuse large B cell lymphoma (DLBCL), nongerminal center B cell type: A Hematoxylin-eosin staining × 40; B Hematoxylin-eosin staining × 400; C Immunohistochemistry staining showing positivity for CD20; D Immunohistochemistry staining showing positivity for Ki67. E – H Excision of the left inguinal lymph node from a 37-year-old Han female patient, indicating a hematopoietic and lymphoid system tumor: E Hematoxylin-eosin staining × 40; F Hematoxylin-eosin staining × 400; G Immunohistochemistry staining showing positivity for CD20; H Immunohistochemistry staining showing positivity for Ki67

Treatment plan

After admission, the patient was initially treated with prednisone but showed poor response. Blood typing could not be determined, and antiglobulin testing failed. The transfusion department reported cold agglutination at 4 °C in the patient’s blood specimen. Rituximab 100 mg was subsequently administered intravenously once weekly for four doses to eliminate abnormal B cell clones. Following definitive diagnosis of DLBCL, the patient received chemotherapy with the Pola-R-CHP regimen: polatuzumab vedotin 1.8 mg/kg on day 0, rituximab 375 mg/m 2 on day 1, cyclophosphamide 750 mg/m 2 on day 2, doxorubicin 50 mg/m 2 on day 2, and 100 mg of prednisone on days 2–6. Each cycle was administered every 3 weeks for a total of three cycles.

Outcome and follow-up

After the third cycle of chemotherapy, the patient’s fatigue and cyanosis significantly improved. Hemoglobin increased to 111 g/L, reticulocyte percentage decreased from 13.15% to 2.66%, indirect bilirubin declined to 10.8 µmol/L, and lactate dehydrogenase dropped to 410 U/L. Cold agglutinin titer at 4 °C decreased to 1:64. Follow-up contrast-enhanced CT after three cycles showed all lymph nodes with short-axis diameters less than 10 mm, confirming partial remission (PR). The patient is currently under ongoing treatment and regular follow-up.

Case 2: WAIHA combined with DLBCL

We also report the case of a 37-year-old Han female patient who began experiencing dizziness and fatigue without obvious cause more than 5 years ago, with symptoms worsening upon exertion. She was diagnosed with warm autoimmune hemolytic anemia (WAIHA) at a local hospital, and initially responded well to corticosteroid therapy. In August 2023, her symptoms recurred, and she subsequently received prednisone, cyclophosphamide, and rituximab treatment, during which her hemoglobin (Hb) level remained around 80 g/L. On 20 August 2024, owing to worsening dizziness and fatigue, she presented to our hospital. Complete blood count revealed: white blood cell count of 2.51 × 10 9 /L, hemoglobin of 53 g/L, and platelet count of 66 × 10 9 /L. Biochemistry showed total protein of 58.4 g/L, total bilirubin of 73.3 µmol/L, and unconjugated bilirubin of 73.0 µmol/L. She was again diagnosed with hemolytic anemia and received 20 mg of intravenous immunoglobulin (IG) daily for two days, along with folic acid and vitamin B12 supplementation, transfusion of washed red blood cells, and antimicrobial therapy with meropenem plus levofloxacin. On 31 March 2025, she was re-admitted with “dizziness and generalized fatigue for more than 5 years, worsened for 1 week.”

Physical examination

The patient was alert and oriented, with features of severe anemia. Mild scleral icterus was observed. There were no petechiae on the skin or mucosa. No superficial lymphadenopathy was palpable. No tenderness over the sternum. Cardiopulmonary examination was unremarkable. The abdomen was soft; the spleen was palpable 2 cm below the left costal margin without tenderness; the liver was not palpable below the costal margin. No edema was noted in either lower limb.

Laboratory examinations

Complete blood count showed: white blood cell count of 1.00 × 10 9 /L, red blood cell count of 1.92 × 10 12 /L, hemoglobin of 55 g/L, platelet count of 88 × 10 9 /L, reticulocyte percentage of 13.34%, and absolute reticulocyte count of 0.2228 × 10 12 /L. Biochemistry: total bilirubin of 85.5 µmol/L, direct bilirubin of 8.9 µmol/L, indirect bilirubin of 76.6 µmol/L, and lactate dehydrogenase (LDH) of 505 U/L. Coagulation panel: prothrombin time was 12.3 seconds, activated partial thromboplastin time was 30.8 seconds, fibrinogen was 4.55 g/L, D-dimer was 0.85 µg/mL, and fibrin degradation products were 4.9 µg/mL. Pretransfusion immunological testing showed blood type O RhD positive, with a positive irregular antibody screen. The direct antiglobulin test was positive (IgG positive), and the indirect antiglobulin test was also positive. Immunoglobulins and complement levels, serum immunofixation electrophoresis, serum protein electrophoresis, serum free light chain assay, paroxysmal nocturnal hemoglobinuria (PNH) clone detection, extended immunologic panel, routine urinalysis, and stool routine with occult blood test showed no significant abnormalities. Bone marrow cytology revealed active nucleated cell proliferation with a granulocyte-to-erythroid ratio of 1.48:1. Granulocytic lineage showed morphologically normal cells at various stages and presence of eosinophils. The erythroid lineage displayed a slightly elevated proportion of late erythroblasts with overall normal morphology. Mature erythrocytes were anisocytotic. Lymphocyte ratio was within normal range with unremarkable morphology. A total of 219 megakaryocytes were observed across the smear, including 25 classified cells: 3 promegakaryocytes, 8 platelet-producing megakaryocytes, 13 granular megakaryocytes, and 1 naked nucleus. Platelets were seen scattered and in clusters, with a relatively abundant count. Bone marrow immunophenotyping showed no evidence of acute leukemia, high-risk myelodysplastic syndromes (MDS), lymphoma, or plasma cell myeloma-associated immunophenotypic abnormalities. Bone marrow biopsy revealed no increase in B lymphocytes. The lab results were presented in Table 2 . Table 2 Lab results of case 2 Test item Result Unit White blood cell count 1.00 10⁹/L Red blood cell count 1.92 10 12 /L Hemoglobin 55 g/L Platelet count 88 10⁹/L Reticulocyte percentage 13.34 % Absolute reticulocyte count 0.2228 10 12 /L Biochemistry Total bilirubin 85.5 µmol/L Direct bilirubin 8.9 µmol/L Indirect bilirubin 76.6 µmol/L Lactate dehydrogenase (LDH) 505 U/L Coagulation panel Prothrombin time 12.3 s Activated partial thromboplastin time 30.8 s Fibrinogen 4.55 g/L D-dimer 0.85 µg/mL Fibrin degradation products 4.9 µg/mL

Imaging studies

Hepatobiliary, pancreatic, and splenic ultrasound revealed splenomegaly (spleen thickness 77 mm, 24 mm below the costal margin) with multiple nodules. Noncontrast and contrast-enhanced CT of the entire abdomen showed multiple splenic nodules, multiple enlarged retroperitoneal lymph nodes (short-axis diameter 15–20 mm), a hypodense nodule in the left hepatic lobe (follow-up recommended), and a right renal cyst. Superficial lymph node ultrasound demonstrated abnormal enlargement of bilateral cervical, submandibular, supraclavicular, axillary, and inguinal lymph nodes (maximum short-axis diameter 12 mm), with partial loss of hilar structure.

Pathology and immunohistochemistry

On 11 March 2025, a biopsy of the left cervical lymph node was performed. Pathology indicated diffuse large B cell lymphoma (DLBCL), nongerminal center B cell type (Non-GCB). Immunohistochemical analysis showed the following profile: CD20 (+), PAX-5 (+), Bcl-6 (+), MUM-1 (+, approximately 60% of cells), CD10 (−), Bcl-2 (+, approximately 50% of cells), C-myc (+, approximately 40% of cells), CD3 (−), CD5 (−), CD30 (−), ALK (−), and Ki-67 (+, approximately 80% of cells). In situ hybridization for Epstein–Barr virus (EBER-ISH) was negative. Given the positivity for C-myc (~40%) and Bcl-2 (~50%) in this case, fluorescence in situ hybridization (FISH) was conducted, revealing no BCL6 or BCL2 gene rearrangements and no MYC gene translocation. The patient was definitively diagnosed with diffuse large B cell lymphoma, nongerminal center B cell subtype, double-expressor phenotype, Ann Arbor stage IIIA, and classified as high-risk with an age-adjusted International Prognostic Index (aaIPI) score of 3 (Fig. 1 A–D).

Treatment plan

After admission, the patient received intravenous human immunoglobulin (20 g/day for 7 days) to ameliorate hemolytic anemia, granulocyte colony-stimulating factor to elevate white blood cell counts, cefoperazone-sulbactam for infection prophylaxis, and washed red blood cell transfusions to correct anemia. Upon DLBCL diagnosis, Pola-R-CHP chemotherapy was initiated: polatuzumab vedotin 1.8 mg/kg on day 0, rituximab 375 mg/m 2 on day 1, cyclophosphamide 750 mg/m 2 on day 2, doxorubicin 50 mg/m 2 on day 2, and prednisone 100 mg on days 2–6, administered every 3 weeks for two cycles.

Outcome and follow-up

After the second chemotherapy cycle, the patient exhibited significant improvement in fatigue and jaundice. Hemoglobin levels gradually increased to 75 g/L, reticulocyte percentage decreased to 6.72%, indirect bilirubin dropped to 12.6 μmol/L, and lactate dehydrogenase declined to 257 U/L. Post-two-cycle CT re-examination showed a 50% reduction in splenic nodules, with enlarged lymph nodes measuring < 10 mm in short-axis diameter. The patient remains under regular follow-up.

Discussion

Clonal tumor cells secreted IgM-κ cold antibodies, directly activating the classical complement pathway. This led to C3d deposition and intravascular hemolysis, establishing a direct “tumor-antibody-erythrocyte” attack axis [ 12 ]. This monoclonal antibody secretion pattern closely correlates with BCL6 gene amplification observed in 50% of CAS-DLBCL cases [ 13 ], suggesting that BCL6 dysregulation may drive B cell differentiation toward IgM-secreting plasma cells.

The WAIHA case exhibited no detectable monoclonal protein but showed elevated levels of IL-6 and IL-10. These cytokines activated polyclonal B cells, inducing IgG antibody production mediated erythrophagocytosis by splenic macrophages. CAS primarily exhibited C3d deposition (DAT anti-C3d positive), whereas WAIHA was characterized by IgG binding (DAT anti-IgG positive), aligning with the established theory that cold antibodies rely on complement activation, while warm antibodies depend on macrophage-mediated destruction [ 14 ].

Notably, both cases were classified as nonGCB DLBCL [ 15 ] but displayed molecular heterogeneity. The CAS case featured isolated BCL6 amplification, whereas the WAIHA case demonstrated BCL2/BCL6 amplification. This divergence may relate to distinct antibody production mechanisms—BCL6 dysregulation may promote B cell differentiation into IgM-secreting plasmablasts, whereas BCL2 overexpression prolongs the survival of IgG-producing plasma cells. Cold antibody-mediated AIHA is often monoclonal, while warm antibody-associated AIHA arises from polyclonal immune dysregulation.

WAIHA patients present with chronic progressive anemia accompanied by splenomegaly and intrasplenic nodules, reflecting IgG antibody-mediated extravascular hemolysis and tumor infiltration in the spleen. Laboratory findings reveal a clear biochemical distinction: CAS exhibits an IgM monoclonal spike, while WAIHA shows polyclonal IgG elevation. Additionally, cold agglutinin titers and DAT typing (anti-C3d versus anti-IgG) provide direct evidence for mechanistic differentiation.

This study proposes a triad screening model of “refractory hemolysis + cytopenia + lymph node/spleen involvement”: when AIHA patients show resistance to conventional immunotherapy, Hb < 60 g/L with platelets < 100 × 10 9 /L, or imaging reveals deep lymph nodes with a short-axis diameter > 1.5 cm or splenic nodules, immediate lymphoma screening should be initiated. Lymph node biopsy combined with immunohistochemistry and FISH testing is crucial for definitive diagnosis, while pre-warmed blood typing can eliminate interference from CAS cold antibodies.

The difference in treatment response stems directly from the distinct mechanisms of antibody production. Patients with CAS-DLBCL treated with rituximab plus polatuzumab vedotin achieved rapid hemolysis resolution within 2 weeks,This “targeting antibody-secreting cells” strategy[ 16 ] is more mechanistically precise than traditional R-CHOP. Conversely, WAIHA-DLBCL patients relied on R-CHOP for tumor burden control, with hemolysis resolution paralleling lymphoma regression, confirming that hemolysis in this subtype results from tumor-associated immune dysregulation, requiring suppression of abnormal B cell proliferation and cytokine storms for remission. In transfusion management, CAS patients require blood pre-warmed to 37 °C to prevent cold antibody agglutination, while patients with WAIHA benefit from washed red blood cells to reduce complement-mediated hemolysis, highlighting the importance of subtype-specific supportive care.

Molecular prognostic markers provide a basis for stratified management. BCL6 single amplification in CAS cases suggests intermediate-risk prognosis, whereas BCL2/BCL6 co-amplification in WAIHA cases may correlate with prolonged remission. Systematic treatment details are presented in Table 3 . Table 3 Comparison table of key features between cold antibody-type and warm antibody-type diffuse large B-cell lymphoma (DLBCL)-associated autoimmune hemolytic anemia (AIHA) Category of features Specific indicators Cold antibody-type DLBCL (CAS-DLBCL) Warm antibody-type DLBCL (WAIHA-DLBCL) Antibody-related Antibody type Monoclonal IgM-κ cold antibodies Polyclonal IgG warm antibodies Mechanism of antibody secretion Secreted directly by clonal tumor cells, associated with BCL6 gene amplification Induced by IL-6/IL-10-activated polyclonal B cells Hemolysis mechanism Primary pathway Activates the classical complement pathway, leading to C3d deposition and intravascular hemolysis Dependent on splenic macrophage-mediated erythrophagocytosis (extravascular hemolysis) DAT result Anti-C3d positive Anti-IgG positive Molecular characteristics Genetic abnormalities Isolated BCL6 amplification BCL2/BCL6 co-amplification DLBCL subtype Non-GCB type Non-GCB type Clinical and Laboratory Manifestations Main symptoms – Chronic progressive anemia with splenomegaly and intrasplenic nodules Serum protein features IgM monoclonal spike Polyclonal IgG elevation Specific tests Elevated cold agglutinin titers – Treatment-related First-line regimen Rituximab plus polatuzumab vedotin (targeting antibody-secreting cells) R-CHOP regimen (controlling tumor burden and abnormal B cell proliferation) Treatment response Rapid resolution of hemolysis within 2 weeks Resolution of hemolysis parallels lymphoma regression Transfusion management Blood prewarmed to 37 °C required to avoid cold antibody agglutination Washed red blood cells preferred to reduce complement-mediated hemolysis Prognostic Implications Significance of molecular markers Isolated BCL6 amplification suggests intermediate-risk prognosis BCL2/BCL6 co-amplification may correlate with prolonged remission

The single-center, small-sample nature of this study may limit the generalizability of its conclusions. Future multicenter cohort studies are needed to establish screening thresholds for indicators, as well as to validate whether BCL2/BCL6 co-amplification serves as an independent prognostic factor in WAIHA-DLBCL. Mechanistically, the NF-κB pathway in IgM monoclonal antibody secretion and IL-6/IL-10 antagonists in WAIHA may open new avenues for precision treatment.

Conclusion

DLBCL-associated AIHA is not a homogeneous disease. The significant heterogeneity between CAS and WAIHA subtypes—in antibody mechanisms, clinical phenotypes, and treatment responses—necessitates a multidimensional diagnostic strategy integrating serological (antibody type/titer), imaging (lymph node/spleen characteristics), and molecular pathological (BCL2/BCL6 status) data. The triad screening model and mechanism-guided treatment approach proposed in this study provide a clinical framework for the early identification and precise intervention of this rare disease. Further elucidation of the molecular basis of tumor–immune interactions will be crucial for improving patient outcomes in the future.

Publisher’s Note

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Zhiye Zhang and Xingxing Yu contributed equally to this work.

Acknowledgements

Thanks to all authors for their contributions to this article.

Author contributions

Tianwen Gao: investigation, funding acquisition, project administration. Zhiye Zhang, Jingjing Li, and Tianwen Gao: writing—review and editing—and writing—original draft. Xingxing Yu: data curation and conceptualization.

Funding

This work was supported by Anhui Medical University Institutional Research Fund (2022xkj212).

Availability of data and materials

Not application.

Declarations

Ethics approval and consent to participate

Not applicable.

Consent for publication

Written informed consent was obtained from the patient for publication of this case report and any accompanying images. A copy of the written consent is available for review by the Editor-in-Chief of this journal.

Competing interests

The authors declare no conflicts of interest.

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