Sex: M
Vaccine: COVID19
Symptoms: Physical examination, Platelet count, Reticulocyte count, Serum ferritin, Urine analysis
Clinical narrative: cold agglutinin hemolytic anemia (CAHA); The initial case was missing the following minimum criteria: Literature report: No adverse effect. Upon receipt of follow-up information on 27Jun2025, this case now contains all required information to be considered valid.  This is a literature report.  A 56-year-old male patient received BNT162b2 (COVID-19 VACCINE NOS MANUFACTURER UNKNOWN), as dose number unknown (booster), single (Batch/Lot number: unknown) for covid-19 immunisation. The patient's relevant medical history included: "vitiligo" (ongoing); "Graves' disease" (ongoing); "diabetes mellitus" (ongoing); "hospital" (ongoing). The patient's concomitant medications were not reported. Vaccination history included: COVID-19 VACCINE (DOSE NUMBER UNKNOWN; MANUFACTURER UNKNOWN), for COVID-19 immunisation. The following information was reported: COLD TYPE HAEMOLYTIC ANAEMIA (medically significant), outcome "unknown", described as "cold agglutinin hemolytic anemia (CAHA)". Clinical course: A 56-year-old male with a past medical history of vitiligo, Graves' disease, and diabetes mellitus presented to the hospital with symptoms of lethargy, loss of appetite, night sweats, and 10-lb weight loss for 1 month. The patient reported that the onset of the above-mentioned symptoms started within a week of the mRNA booster vaccine for COVID-19. The physical exam was remarkable for pallor and jaundice. Laboratory workup revealed leukocytosis (White blood cell count 24 K/uL), anemia (Hemoglobin 8.0 g/dL), thrombocytosis (platelets 554 K/uL), mild transaminitis (alanine aminotransferase 88, aspartate aminotransferase 164, alkaline phosphatase 273), and hyperbilirubinemia (total bilirubin 11.2 mg/dL, direct bilirubin 8.3 mg/dL). Haptoglobin was <7.75 mg/dL, reticulocyte count was elevated (30.59%), and lactate dehydrogenase was 1423 U/L, all suggestive of hemolysis (Table 1). Acute phase reactants were elevated (C- reactive protein 14 mg/dL, ferritin 944 ng/mL). The direct antiglobulin test was positive for complement component 3 (C3) but negative for immunoglobulin G (IgG), a serologic pattern consistent with CAHA. Flow cytometry showed a high CD4/ CD8 positive T-Cell ratio of 17.23. Computed tomography (CT) of the abdomen and pelvis revealed hepatosplenomegaly with isolated lymphadenopathy in the porta hepatis (Figure 1). Further evaluation, including lymph node biopsy, demonstrated a mixed lymphoid population with occasional large atypical lymphoid cells. Bone marrow biopsy revealed hypercellular marrow (70-80%) with trilineage hematopoiesis and approximately 10% involvement by atypical large CD20+, BCL2+, BCL6+ atypical B-cells, negative for CD10, MUM1, CD30, P53, and Cyclin D1. CMYC expression was equivocal (~30%). FISH analysis demonstrated complex chromosomal abnormalities with polysomy in a small subset (2%) of cells, below the diagnostic threshold but supportive of cytogenetic instability. Flow cytometry showed no blast proliferation or aberrant myeloid markers. B-cells comprised 2.01% of marrow cells. Liver biopsy showed infiltration by large atypical lymphoid cells, consistent with involvement by the patient's DLBCL. These histopathologic and immunophenotypic findings, along with the liver biopsy showing infiltration by large atypical lymphoid cells, collectively confirm the diagnosis of DLBCL. Broad-spectrum antibiotics were initiated for possible infection but later discontinued following negative infectious workup, including blood culture, urinalysis, and respiratory and urine cultures. The patient was started on prednisone (1 mg/kg) for hemolytic anemia. Lack of laboratory improvement with steroid therapy further supported the diagnosis of CAHA. Patient's hemoglobin dropped to 6.9 g/dl during hospitalization and required 1 unit of packed red blood cells transfusion. He was later discharged in stable condition with plans for oncology follow-up to initiate treatment for DLBCL; however, specific details regarding the appointment or the intended oncology provider were unavailable, suggesting he may have sought care elsewhere.  Therapeutic measures were taken as a result of cold type haemolytic anaemia.; Sender's Comments: There is not a reasonable possibility that the reported event cold agglutinin hemolytic anemia was related to the suspect product event most likely due to patient underlying contributory factors. The impact of this report on the benefit-risk profile of the Pfizer product and on the conduct of the study is evaluated as part of Pfizer procedures for safety evaluation, including the review and analysis of aggregate data for adverse events. Any safety concern identified as part of this review, as well as any appropriate action in response, will be promptly notified to regulatory authorities, Ethics Committees, and Investigators, as appropriate.