Thalidomide in multiple myeloma, myelodysplastic syndromes and histiocytosis. Analysis of clinical results and of surrogate angiogenesis markers.

BACKGROUND: Thalidomide, as a single agent, has been recently found to induce a clinical response in one third of refractory or relapsed myeloma patients. Although it has been reported that thalidomide significantly inhibits angiogenesis. it is still unclear whether its clinical effect is mediated, at least in part, by its anti-angiogenic properties. PATIENTS AND METHODS: We evaluated thalidomide as a single agent in myeloma, myelodysplastic syndromes (MDS) and histiocytosis, i.e. hematological diseases characterized by increased angiogenesis, and measured prospectively a number of surrogate angiogenesis markers. RESULTS: Clinical responses were observed in 7 of 17 myeloma and 2 of 5 MDS patients. The histiocytosis patient had a partial response. At the time of the best clinical response, plasma levels of angiogenic growth factors, vascular endothelial growth factor (VEGF) and basic-fibroblast growth factor (b-FGF), were significantly decreased, and flow cytometry indicated a decrease of activated endothelial cells in the bone marrow of responding MDS patients. CONCLUSIONS: These observations confirm thalidomide efficacy in myeloma, suggest a possible use in MDS and histiocytosis and may contribute to the prediction of clinical response and to understanding the mechanism of thalidomide's action.

Kinetics and viability of circulating endothelial cells as surrogate angiogenesis marker in an animal model of human lymphoma.

Circulating endothelial cells (CECs) were evaluated by flow cytometry in immunodeficient mice bearing human lymphoma. A trend toward higher CEC values was observed on days 7 and 14 after transplant, and differences versus controls were highly significant on day 21 (P = 0.0061). A strong correlation was found between CEC and tumor volume (r, 0.942; P = 0.004) and between CEC and tumor-generated VEGF (r, 0.669; P = 0.02). In mice given cyclophosphamide, most of the circulating apoptotic cells were hematopoietic and not endothelial. Conversely, in mice given endostatin, all of the increase in apoptotic cells was in the endothelial cell compartment. CEC evaluation is promising as a noninvasive, surrogate angiogenesis marker.

Resting and activated endothelial cells are increased in the peripheral blood of cancer patients.

Circulating endothelial cells (CECs) were enumerated in 20 healthy controls and 76 newly diagnosed cancer patients by means of 4-color flow cytometry. In breast cancer (n = 46) and lymphoma (n = 30) patients, both resting and activated CECs were increased by 5-fold (P <.0008 vs control). CECs significantly correlated with plasma levels of vascular cell adhesion molecule-1 and vascular endothelial growth factor. Resting and activated CECs were similar to healthy controls in 7 lymphoma patients achieving complete remission after chemotherapy, and activated CECs were found to decrease in 13 breast cancer patients evaluated before and 24 hours after quadrantectomy. (Blood. 2001;97:3658-3661)

Use of IgM monoclonal reagents licensed for tube tests in column agglutination technology.

BACKGROUND: Red cell (RBC) phenotyping using column agglutination technology (CAT) is currently limited by the reagents formulated in the system. To overcome this limitation, it was investigated whether monoclonal IgM reagents licensed for use with tube tests produced valid results with CAT. STUDY DESIGN AND METHODS: Commercial CAT, does not contain antisera, was used to evaluate Procedures A (40 microL of reagent and 10 microL of 4% RBCs) and B (50 microL of reagent and 50 microL of 0.8% RBCs) with or without incubation at room temperature. In Study 1, reagents were tested to determine whether potentiators inhibit the passage of antigen-negative RBCs through the column. In Study 2, CAT sensitivity was measured by the use of potency titrations to define a procedure for each reagent that matched or exceeded that of the tube method. In Study 3, the specificity of each reagent was determined in parallel with the CAT and tube tests. Typing of 1644 samples was performed. RESULTS: Study 1: Free passage was obtained with all reagents. Study 2: Immediate-spin methods using CAT produced the same results as the tube method. Study 3: With 8048 comparisons made, discrepant results were found in 32 transfused patients and in 6 cord blood samples, mainly with Lewis reagents. With comparison of CAT and the standard tube method, complete agreement was obtained with Kell reagents, 99.9-percent agreement with Kidd reagents, and 98.9-percent and 99.4-percent agreement with Lewis reagents. CONCLUSION: Most examined reagents seem suitable for use with CAT.