Monoclonal antibodies (mAbs) are increasingly used in treatment protocols for chronic lymphocytic leukemia (CLL). Here we determined (i) the extent of antibody-dependent cellular cytotoxicity (ADCC) of four different mAbs against primary CLL cells, (ii) whether ADCC correlates with antigen density on CLL cells, and (iii) whether allogeneic natural killer (NK) cells display superior ADCC than autologous. Effector cells for ADCC were (i) NK-92 cells not expressing FcR, (ii) NK-92 cells transfected with a high-affinity Fc receptor, (iii) autologous NK cells from patients with CLL, (iv) allogeneic NK cells. Results suggest that ADCC contributes to killing of CLL cells by anti-CD20 antibodies (rituximab and veltuzumab), whereas mAbs against CD22 (epratuzumab) and CD23 (lumiliximab) showed minimal ADCC. The magnitude of anti-CD20 mediated ADCC did not correlate with antigen density of CD20. ADCC was not influenced by the FcR genotype expressed by autologous NK cells. Allogeneic NK cells were superior to autologous NK cells in killing primary CLL cells.

Chemotherapy used to treat lymphoma can cause severe neutropenia. Risk models have identified factors that predict neutropenia across all chemotherapy cycles. We used clinical information obtained during pretreatment evaluation to develop a predictive model for severe neutropenia in the first cycle of cyclophosphamide, doxorubicin, vincristine and prednisone (CHOP) chemotherapy. This case series study included lymphoma patients receiving CHOP chemotherapy with or without rituximab who did not receive pre-emptive hematopoietic growth factor. Risk factors for neutropenia were identified from previously published models and included age >or=65 years, hypoalbuminemia, renal/cardiovascular disease, anemia, abnormal bone marrow and increased lactate dehydrogenase (LDH). A composite score equal to the number of pretreatment risk factors was used to predict severe neutropenia in cycle 1. Fifty-three percent of patients (47 of 89) had severe neutropenia, with 70% of first episodes occurring during cycle 1. Eighty-two percent of first-cycle, severe neutropenia events occurred in patients >or=65-years-old. In univariate analysis, age >or=65 years and increased baseline LDH were significantly associated with increased risk for severe neutropenia in cycle 1. In logistic regression modeling, the probability of severe neutropenia in cycle 1 increased as the number of pretreatment risk factors increased, with a one-unit increase in risk score resulting in a 2.3-fold increase in severe neutropenia. The study results suggest that data obtained before initiating CHOP-based chemotherapy can be used to identify those patients who are at risk for severe neutropenia in cycle 1. If validated, our model could be used to identify patients who would benefit from early use of growth factors.

A patient had adult T-cell leukemia-lymphoma in the unusual setting of coinfection with human immunodeficiency virus type 1 (HIV-1) and human T-cell lymphotropic virus type I (HTLV-I). The leukemic cells were CD4 positive and showed clonal genetic rearrangement of the T-cell receptor complex. Cytogenetic analysis showed three clonal karyotypic abnormalities: trisomy 3 and two translocations [t(1;15), (X;1)]. The patient was seropositive for HIV and HTLV-I; HTLV-I and HIV-1 DNA sequences were detected in peripheral blood leukocytes by the polymerase chain reaction. The HTLV-I sequences were detected in a relatively high proportion of mononuclear cells (at least 1 in 30 cells), whereas HIV-1 sequences were detected in a smaller proportion of cells (at least 1 in 3000 cells). Clinical remission was achieved after chemotherapy. There was a decrease in the proportion of HTLV-I positive mononuclear cells (at least 1 in 1000 cells), whereas the proportion of HIV-1 positive cells was relatively unchanged (at least 1 in 1000 cells). Adult T-cell leukemia-lymphoma in the setting of HIV coinfection may become increasingly common because asymptomatic retroviral coinfections are frequent.

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