Obinutuzumab induces depletion of NK cells in patients with chronic lymphocytic leukemia.

AIM: Obinutuzumab induces NK cell antibody-dependent cell-mediated cytotoxicity. OBJECTIVE: Investigate the effects on the human immune system after obinutuzumab monotherapy treatment in patients with chronic lymphocytic leukemia (CLL). METHOD: To evaluate these effects, we analyzed the distribution of CD4+ and CD8+ T cells, B cells and NK cells in the peripheral blood of eight CLL patients who were treated with obinutuzumab in monotherapy. The distribution of peripheral blood lymphocytes was examined prior to each dose of obinutuzumab and 24-72 h after the first 1000 mg complete dose (cycle 1 day 2). We also repeated measurements 3 months after the last obinutuzumab dose. In total we obtained ten samples of each patient. Analyses were performed by flow cytometry with monoclonal antibodies against CD3, CD4, CD8, CD19 and CD56+. RESULTS: After the first 1000 mg obinutuzumab infusion (cycle 1 day 2), CD4+ T cells and CD8+ T cells were significantly decreased in peripheral blood compared with prior to therapy. This reduction in the CD4+ T cells persisted after six cycles of obinutuzumab (1235 cells/µl basal vs 662 cells/µl after six cycles, p ≤ 0.05), but not in CD8+ T cells (987 cells/µl basal vs 837 cells/µl after six cycles). Interestingly, we also observed significant differences in the NK cell compartment after the first 1000 mg drug infusion (490 cells/µl basal vs 23 cells/µl postinfusion, p ≤ 0.05), and after cycle 6 (490 cells/µl basal vs 149 cells/µl after six cycles, p ≤ 0.05). CONCLUSION: Obinutuzumab induces depletion of NK cells in CLL.

Diagnostic screening of paroxysmal nocturnal hemoglobinuria: Prospective multicentric evaluation of the current medical indications.

BACKGROUND: Although consensus guidelines have been proposed in 2010 for the diagnostic screening of paroxysmal nocturnal hemoglobinuria (PNH) by flow cytometry (FCM), so far no study has investigated the efficiency of such medical indications in multicentric vs. reference laboratory settings. METHODS: Here we evaluate the efficiency of consensus medical indications for PNH testing in 3,938 peripheral blood samples submitted to FCM testing in 24 laboratories in Spain and one reference center in Brazil. RESULTS: Overall, diagnostic screening based on consensus medical indications was highly efficient (14% of PNH+ samples) both in the multicenter setting in Spain (10%) and the reference laboratory in Brazil (16%). The highest frequency of PNH+ cases was observed among patients screened because of bone marrow (BM) failure syndrome (33%), particularly among those with aplastic anemia (AA; 45%) and to a less extent also a myelodysplastic syndrome (MDS; 10%). Among the other individuals studied, the most efficient medical indications for PNH screening included: hemolytic anemia (19%), hemoglobinuria (48%) and unexplained cytopenias (9%). In contrast, only a minor fraction of the patients who had been submitted for PNH testing because of unexplained thrombosis in the absence of cytopenia, were positive (0.4%). CONCLUSIONS: In summary, our results demonstrate that the current medical indications for PNH screening by FCM are highly efficient, although improved screening algorithms are needed for patients presenting with thrombosis and normal blood cell counts. © 2016 International Clinical Cytometry Society.

Validation of diagnosis of aplastic anaemia in La Rioja (Spain) by International Classification of Diseases codes for case ascertainment for the Spanish National Rare Diseases Registry.

OBJECTIVE: To analyse the validity of diagnosis of aplastic anaemia (AA) by International Classification of Diseases codes in hospital discharge data (MBDS) and the mortality registry (MR) of La Rioja to detect cases to be included in the Spanish National Rare Diseases Registry. METHODS: International Classification of Diseases (ICD) codes were used to detect AA cases during the period 2007-2012 from two administrative databases: the MBDS and the MR of La Rioja (Spain). Medical records of population selected by merging both databases were used to confirm true AA cases. The annual mean incidence rate of AA was calculated using confirmed incident cases. RESULTS: By merging both databases, 62 hypothetical AA incident patients were detected during the period 2007-2012. The medical records of the 89% of them could be revised, and they confirmed that only the 15% of the patients actually suffered AA. The annual mean AA incidence in La Rioja was 4.17 per million inhabitants (6.23 per million, males; 2.10 per million, females). CONCLUSIONS: The MBDS and the MR are not in themselves sufficient to ascertain AA cases in La Rioja and medical records should be reviewed to confirm true AA cases to be included in the Spanish National Rare Diseases Registry.

Lymphocyte recovery is impaired in patients with chronic lymphocytic leukemia and indolent non-Hodgkin lymphomas treated with bendamustine plus rituximab.

The immune system has the potential to either attenuate tumor growth or to promote tumor progression. The goal of cancer immunotherapy is to shift the balance in favor of tumor immunosurveillance, so that the immune system can recognize the tumor, eliminate it, and prevent its recurrence. Bendamustine plus rituximab is generally considered effective and safe in patients with previously untreated chronic lymphocytic leukemia (CLL) and indolent non-Hodgkin lymphomas. To evaluate the effects of bendamustine-rituximab and rituximab plus cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP) on the recuperation of immune system, we analyze the distribution of CD4+ and CD8+ T cells, B cells, and NK cells in peripheral blood of 18 patients who received 4-6 cycles of rituximab-bendamustine (BR) or six R-CHOP before therapy and 6 months after completing treatment. Our results indicate that lymphocyte recovery is impaired in patients with chronic lymphocytic leukemia and indolent lymphomas treated with bendamustine plus rituximab. Low CD4 T cells (<200 cells/µl) induced by bendamustine (BR) suggest prophylaxis should be applied against opportunistic infections. Asymptomatic EBV and CMV reactivations support a negative effect of BR on the immune system. If cellular immune therapy such as lymphokine-activated killer (LAK) or effector lymphocytes infusion is planned, regimes other than BR should be the first choice.

Intravascular large B cell lymphoma.

Intravascular large B cell lymphoma (IVBCL) is a rare type of extranodal large B cell lymphoma characterized by selective growth of lymphoma cells within the microvasculature. We present an illustrative case of intravascular B cell lymphoma suspected by the presence of a very small monoclonal B cell population identified by immunophenotype and polymerase chain reaction in bone marrow. The diagnosis was confirmed by skin biopsy.