Cytokine-release syndrome in patients with B-cell chronic lymphocytic leukemia and high lymphocyte counts after treatment with an anti-CD20 monoclonal antibody (rituximab, IDEC-C2B8)

Blood. 1999 Oct 1;94(7):2217-24.


Eleven patients with relapsed fludarabine-resistant B-cell chronic lymphocytic leukemia (CLL) or leukemic variants of low-grade B-cell non-Hodgkin's lymphoma (NHL) were treated with the chimeric monoclonal anti-CD20 antibody rituximab (IDEC-C2B8). Peripheral lymphocyte counts at baseline varied from 0.2 to 294.3 x 10(9)/L. During the first rituximab infusion, patients with lymphocyte counts exceeding 50.0 x 10(9)/L experienced a severe cytokine-release syndrome. Ninety minutes after onset of the infusion, serum levels of tumor necrosis factor-alpha (TNF-alpha) and interleukin-6 (IL-6) peaked in all patients. Elevated cytokine levels during treatment were associated with clinical symptoms, including fever, chills, nausea, vomiting, hypotension, and dyspnea. Lymphocyte and platelet counts dropped to 50% to 75% of baseline values within 12 hours after the onset of the infusion. Simultaneously, there was a 5-fold to 10-fold increase of liver enzymes, d-dimers, and lactate dehydrogenase (LDH), as well as a prolongation of the prothrombin time. Frequency and severity of first-dose adverse events were dependent on the number of circulating tumor cells at baseline: patients with lymphocyte counts greater than 50.0 x 10(9)/L experienced significantly more adverse events of National Cancer Institute (NCI) grade III/IV toxicity than patients with less than 50.0 x 10(9)/L peripheral tumor cells (P = .0017). Due to massive side effects in the first patient treated with 375 mg/m(2) in 1 day, a fractionated dosing schedule was used in all subsequent patients with application of 50 mg rituximab on day 1, 150 mg on day 2, and the rest of the 375 mg/m(2) dose on day 3. While the patient with the leukemic variant of the mantle-cell NHL achieved a complete remission (9 months+) after treatment with 4 x 375 mg/m(2) rituximab, efficacy in patients with relapsed fludarabine-resistant B-CLL was poor: 1 partial remission, 7 cases of stable disease, and 1 progressive disease were observed in 9 evaluable patients with CLL. On the basis of these data, different infusion schedules and/or combination regimens with chemotherapeutic drugs to reduce tumor burden before treatment with rituximab will have to be evaluated.

Publication types

  • Clinical Trial

MeSH terms

  • Adult
  • Aged
  • Antibodies, Monoclonal / adverse effects*
  • Antibodies, Monoclonal, Murine-Derived
  • Antigens, CD20 / immunology
  • Antineoplastic Agents / adverse effects*
  • Cytokines / blood*
  • Female
  • Humans
  • Interleukin-6 / blood
  • Leukemia, Lymphocytic, Chronic, B-Cell / immunology
  • Leukemia, Lymphocytic, Chronic, B-Cell / pathology
  • Leukemia, Lymphocytic, Chronic, B-Cell / therapy*
  • Liver Function Tests
  • Lymphocyte Count*
  • Lymphoma, Mantle-Cell / immunology
  • Lymphoma, Mantle-Cell / therapy
  • Male
  • Middle Aged
  • Neoplasm Staging
  • Platelet Count
  • Rituximab
  • Syndrome
  • Tumor Necrosis Factor-alpha / physiology


  • Antibodies, Monoclonal
  • Antibodies, Monoclonal, Murine-Derived
  • Antigens, CD20
  • Antineoplastic Agents
  • Cytokines
  • Interleukin-6
  • Tumor Necrosis Factor-alpha
  • Rituximab