Alterations in adhesion molecule (CD11b/CD18 and CD62L) expression on granulocytes after chemotherapy

Optimal use of recombinant granulocyte colony-stimulating factor with chemotherapy for solid tumors

Neutropenia is a frequent complication of anticancer chemotherapy (CT) often associated with life-threatening infections, hospitalization, dose reduction and/or delay in the administration of CT. Administration of recombinant granulocyte colony-stimulating factor (rG-CSF) reduces the duration and the degree of CT-neutropenia. rG-CSF that stimulates both neutropoiesis and neutrophil function, has become an integral part of supportive care during cytotoxic CT, to prevent febrile neutropenia (FN), particularly in patients with a risk of FN ≥ 20%. International guidelines have standardized conditions for rG-CSF administration, however, some 'gray zones' still exist around optimal timing and tailoring of this therapy. We report here the results of a research project aimed to extend the consensus on the optimal use of rG-CSF in association with CT in patient with solid tumours. We also propose a recently developed pharmacodynamic model, based on the biological effects of CT and rG -CSF on bone marrow compartments that clearly indicates within the prophylactic rather than therapeutic setting the better way of rG-CSF administration.

Pharmacologic rationale for early G-CSF prophylaxis in cancer patients and role of pharmacogenetics in treatment optimization

The use of recombinant human granulocyte colony stimulating factors (G-CSF) has become an integral part of supportive care during cytotoxic chemotherapy. Current guidelines recommend the use of G-CSF in patients with substantial risk of febrile neutropenia. However, little consensus exists about optimal timing and tailoring of this therapy. Based on the known effects of chemotherapy and G-CSF on bone marrow compartments, we propose a model that supports the prophylactic rather than therapeutic use of G-CSF therapy. In addition, several genetic alterations in G-CSF signalling pathway have been described. These genetic variants may predict the risk of febrile neutropenia and response to G-CSF. Thus, future pharmacogenetic/omics studies in this field are warranted. Through the identification of patients at risk and the knowledge of biological basis for optimal timing, hopefully we should soon be able to improve the application of the existing guidelines for G-CSF therapy and patient's prognosis.

Fluorouracil induces apoptosis and surface molecule modulation of peripheral blood leukocytes

Little is known about the direct effect of chemotherapy on normal peripheral blood leukocytes (PBL) or its contribution to leukopenia. We examined 5'-fluorouracil's (5FU) effect on PBL apoptosis and adhesion molecules' expression in a single-drug solid-tumor model. Possible apoptosis mediators were examined. The study included 32 colorectal cancer patients; apoptosis was determined by annexin-V binding and light-scatter morphology before and after drug infusion. CD18, CD11a, CD11b, and CD63 membranal levels were assayed by flow cytometry. Apoptosis was increased post-5FU administration in neutrophils (PMN), monocytes and lymphocytes (P < 0.05). Levels of Fas receptor and activated caspase 3 did not vary indicating that the process was not mediated by caspase 3 in the timeframe studied. Reduced CD63 on monocytes and decreased CD18 expression on PMN and non-apoptotic monocytes were observed (P < or = 0.05). CD11a,b expression did not vary. Decreased CD18 and CD63 levels were demonstrated in apoptotic and non-apoptotic PBL implying a more direct association with the drug itself.

The effects of doxorubicin on apoptosis and adhesion molecules of normal peripheral blood leukocytes-an ex vivo study

This ex vivo study was designed to evaluate the effect of doxorubicin (Dox) on normal peripheral blood leukocytes (PBL) in terms of apoptosis and membranal expression levels of adhesion molecules. Blood was drawn immediately prior to and after Dox administration from 21 breast cancer patients, and incubated at room temperature for 24 h. Flow cytometry was employed in analysis of apoptosis with Annexin-V and protein membranal expression levels with monoclonal antibodies to CD49d, CD18, CD11a-c and CD63. Dox induced statistically significant apoptosis in all three major PBL subpopulations (p<0.01). Between 70 and 90% of samples underwent apoptosis in all PBL subgroups. No significant change was observed in the membranal level of CD63, CD49d and CD11a-c after chemotherapy in any PBL subpopulation. However, a significant reduction in the membranal level of CD18 was demonstrated in polymorphonuclear cells after Dox (p<0.005) both in apoptotic and non-apoptotic cells (p<0.05), suggesting a direct effect of Dox rather than an apoptosis-associated phenomenon. We observed the expected leukopenia 10 days after Dox administration with no correlation to apoptosis, suggesting that leukopenia by Dox is largely attributed to toxicity of blood progenitors.

Granulocyte function in elderly patients receiving chemotherapy for aggressive non-Hodgkin's lymphoma. Effect of granulocyte colony-stimulating factor

BACKGROUND: Treatment with granulocyte colony-stimulating factor (G-CSF) is given in order to mitigate chemotherapy-induced granulocytopenia and the risk of infectious complications, which constitute a major threat to elderly patients, in particular, with malignant disorders. The aim of this study was to evaluate whether G-CSF therapy would improve granulocyte defence mechanisms against infectious agents in this elderly, high-risk patient population. METHODS: Fourteen elderly (>60 years) patients with aggressive non-Hodgkin's lymphoma were enrolled in the study. Using flow cytometry we studied the expression of CD11b, before and after stimulation with fMLP, and CD16, as well as granulocyte metabolic activation measured as intracellular accumulation of dichlorofluorescein during induction chemotherapy. Eight patients were randomised to receive G-CSF treatment (5 &mgr;g/kg) on days 2-15. Granulocyte studies were done regularly during one 3-week cycle of chemotherapy consisting of cyclophosphamide, doxorubicin, vincristine and prednisolone (CHOP) or CNOP (doxorubicin substituted by mitoxantrone). RESULTS: Patients receiving G-CSF showed a faster restitution of granulocyte counts. Granulocyte CD11b expression following fMLP stimulation in vitro decreased during G-CSF therapy (P<0.005). A less pronounced (but not significant) reduction in CD16 expression was noted in the G-CSF-treated group. In contrast, fMLP-stimulated metabolic activation did not show consistent changes during the treatment cycle. Two episodes of infections during granulocytopenia that required hospitalisation were observed in each group. CONCLUSIONS: G-CSF treatment efficiently accelerated granulocyte recovery following chemotherapy. This probably compensates for the transient functional aberrations in circulating granulocytes observed in this patient group.

Activation of granulocytes in patients treated with chemotherapy

It is well known that patients with granulocytopenia due to chemotherapy are susceptible to life-threatening infections. To determine whether or not granulocyte function is also impaired by chemotherapy, respiratory burst, CD11b and CD18 expression were analysed by flow cytometry in granulocytes from 10 patients with haematological malignancies: before and after the commencement of high-dose chemotherapy and in the recovery phase. As a comparison, the same granulocytic functions were analysed in patients treated with low-dose hydroxyurea and in healthy volunteers. The granulocytes were activated by Staphylococcus aureus and Staphylococcus epidermidis. A decreased ability to mobilize CD18 in the recovery phase was seen, but the significance of this finding must be evaluated carefully owing to the small patient number.