A 63-year-old female was admitted to our department with a complaint of abdominal pain on January 8, 2020, and blood routine test showed pancytopenia (WBC 1.8×109/L, Hb 82g/L and PLT 14×109/L). The patient recalled that, three months ago, she suffered from gingival bleeding for four days, but did not take it seriously after healing. Besides moderate anemia and subcutaneous bleeding, she also had multiple enlarged lymph nodes in retroperitoneum, hepatic portal area and pelvic cavity, as well as splenomegaly, as observed by abdominal computerized tomography (CT). Further examinations showed an extremely high ratio of CD19 positive cells (17.63%) in the peripheral blood. Hence, we screened for B cell originated disorders. Histopathology result showed 4% small lymphocytes and occasional lymphoplasmacytic cells in bone marrow aspiration, and there was an active proliferation of megakaryocytes (approximately 126/slide) with dysmaturity (only 9% were plate-producing). The immunophenotype of this abnormal population was positive for CD19, CD20, CD22, CD79b, CD200, sIgM and κ light chain, weak expression of CD25 and negative for CD103, CD10, CD5, CD11c, CD23, CD27, CD56, CD43, FMC-7, CD38, λ light chain, and CD138, which indicated an abnormal clonal mature B cell population. The next generation sequencing (NGS) indicated positive for MYD88 L265p mutation (c.794T > C). There was also a clonal IgM in serum (total IgM 7.65 g/L, immunoelectrophoresis showed positive for IgM and κ light chain). These clinical data supported the diagnosis of WM. In addition, the detection of Coombs’ (both direct anti-globulin test and indirect antiglobulin test), CD55/CD59, lactate dehydrogenase (LDH) showed negative.
Given the ITP-like manifestation in bone marrow morphology, a dexamethasone containing chemotherapy (BRD: Bortezomib 2 mg weekly×4, DXM 20 mg weekly×4 and Rituximab 375 mg/m2 monthly) was initiated. The platelet counts increased to normal after the first two rounds of DXM, but decreased to 12×109/L after the third dose of DXM, and became refractory to platelet transfusion (Fig. 1). The platelet count was maintained at 1–2×109/L, and the patient did not respond to second round continued dose of DXM (20 mg qd for 4 days). The patient refused further chemotherapy, and accepted ITP-based treatment including methylprednisolone (12 mg qd), intravenous immunoglobulin (IVIG, 20 g qd×4), recombinant human thrombopoietin (TPO, 15,000U qd), and TPO receptor agonist (Eltrombopag 75 mg qd) subsequently, but remained unresponsive to all these treatment. Rituximab was continued during the course (500 mg qw×3) considering the primary WM disease (Fig. 2).
During the management of refractory thrombocytopenia, the patient suffered from severe hemolytic anemia (hemoglobin decreased from 104 g/L to 41 g/L), with increased serum indirect bilirubin (IBIL maximum was 119.7 µmol/L), LDH (maximum was 559U/L) and reticulocyte (maximum was 25.25%) (Fig. 3). The cold agglutinating titer is under 1:4, while the direct anti-globulin test (DAT) was positive for IgG and C3. And the Anti-nuclear antibody (ANA), Ham’s, Rous test, as well as ADAMST13 activity and Flare test (PNH) showed normal. To further distinguish whether the hemolysis originated from the primary disease (WM) or was drug-induced, we tested the polymorphism of FcγR. The results showed that the patient was FcγRⅡα 131H/R and FcγRⅢα 158F/V (Fig. 4), which indicated that the hemolysis may not have developed from the progression of WM4. Eltrombopag was highly suspected as the cause of hemolysis, since it was initiated 10 days before the onset of hemolysis, but no published evidence was available for its withdrawal regardless of its potential benefit in platelet recovery. Given the patient’s refusal of chemotherapy, we finally started ibrutinib with her informed consent after explaining the high risk of hemorrhage, accompanied by continuous eltrombopag daily and IVIG twice a week. Five days later, the platelet count increased significantly to 15×109/L, but hemolysis did not improved within 15 days, and even got worse. The dosage of ibrutinib was increased from 140 mg to 420 mg per day, and the platelet count continuously increased to around 25×109/L. With decreased risk of hemorrhage, eltrombopag was withdrawn, and the hemolysis stopped immediately (indicators improved every day). IBIL, LDH and absolute value of reticulocyte decreased to almost normal within 10 days, and the hemoglobinn recovered in 50 days (Fig. 5). The patient continued the ibrutinib maintenance therapy for three months, and achieved very good partial remission (VGPR), with normal IgM, hemogram and stable disease.