case_images: PMC10861374_01
case_images: Peripheral blood smear on admission shows red blood cell agglutination (A, May Giemsa staining; magnification x200). Bone marrow smear on admission shows a high number of erythroblasts and red blood cell agglutination (B, May Giemsa staining; magnification x200). Histopathological examination reveals an elevated erythroblast count and absence of lymphoid cell infiltration (C, Hematoxylin and Eosin staining; magnification x200). Immunohistochemical staining reveals the absence of distinct clusters of CD20-positive cells (D, magnification x200) or CD3-positive cells (E, magnification x200). Immunohistochemical staining for IgM indicates few lymphocytes positive for IgM (F, magnification x200). Flow cytometric evaluation of the bone marrow reveals that a B-cell population did not harbor immunoglobulin light-chain restriction (G).
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case_images: PMC10861374_01_jslrt-63-246-g001.jpg
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case_images: A peripheral blood smear showed red blood cell agglutination (Fig. 1A), and cold agglutinin was identified at a titer of 512, which was compatible with the diagnosis of CAD. Bone marrow aspiration showed increased erythroblasts with no evidence of lymphoproliferative disorder (Fig. 1B). Histopathological findings demonstrated an increase in erythroblast cells without lymphocyte clustering (Fig. 1C). Immunohistochemistry staining indicated the absence of CD20-positive or CD3-positive cell infiltration in the bone marrow (Fig. 1D and E), and no evidence of monoclonal IgM production was observed (Fig. 1F). Flow cytometric analysis confirmed the absence of immunoglobulin light-chain restriction in the B cell population (Fig. 1G).
case_images: Clinical course and laboratory findings after admission. Arrows indicate times of SARS-CoV-2 mRNA vaccination. PSL: prednisolone.
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case_images: PMC10861374_01_jslrt-63-246-g002.jpg
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case_images: His hemolytic parameters gradually improved, and prednisolone was tapered off; however, his hemoglobin level did not reach the normal range (Fig. 2). Pfizer-BioNTech BNT162b2 bivalent SARS-CoV-2 mRNA vaccination, the patient presented with fatigue and dark urine at our hospital. Physical examination revealed conjunctival icterus, and laboratory findings revealed a hemoglobin level of 8.6 g/dL, high reticulocyte count, and elevated bilirubin levels, consistent with the exacerbation of hemolytic anemia (Fig. 2). Sutimlimab infusion stabilized his blood counts, improving hemoglobin levels (Fig. 2), while Raynaud's phenomenon was still present. Notably, he had no complaints of fatigue after the fifth vaccination, and laboratory findings showed no evidence of hemolysis (Fig. 2).