In vivo cytoreduction studies and cell sorting--enhanced tumor-cell detection in high-risk neuroblastoma patients: implications for leukapheresis strategies.

PURPOSE: To improve autologous leukapheresis strategies in high-risk neuroblastoma (NB) patients with extensive bone marrow involvement at diagnosis. PATIENTS AND METHODS: Anti-G(D2) immunocytochemistry (sensitivity, 1 in 10(5) to 10(6) leukocytes) was used to evaluate blood and bone marrow disease at diagnosis and during the recovery phase of the first six chemotherapy cycles in 57 patients with stage 4 NB and bone marrow disease at diagnosis. A total of 42 leukapheresis samples from the same patients were evaluated with immunocytology, and in 24 of these patients, an anti-G(D2) immunomagnetic enrichment step was used to enhance tumor-cell detection. RESULTS: Tumor cytoreduction was much faster in blood compared with bone marrow (3.2 logs after the first cycle and 2.1 logs after the first two cycles, respectively). Bone marrow disease was often detectable throughout induction, with a trend to plateau after the fourth cycle. By direct anti-G(D2) immunocytology, a positive leukapheresis sample was obtained in 7% of patients after either the fifth or sixth cycle; when NB cell immunomagnetic enrichment was applied, 25% of patients had a positive leukapheresis sample (sensitivity, 1 in 10(7) to 10(8) leukocytes). CONCLUSION: Standard chemotherapy seems to deliver most of its in vivo purging effect within the first four cycles. In patients with overt marrow disease at diagnosis, postponing hematopoietic stem-cell collection beyond this point may not be justified. Tumor-cell clearance in blood seems to be quite rapid, and earlier collections via peripheral-blood leukapheresis might be feasible. Immunomagnetically enhanced NB cell detection can be highly sensitive and can indicate whether ex vivo purging should be considered.

[The identification of minimal residual disease in the bone marrow and peripheral blood in neuroblastoma. The prognostic and therapeutic implications]. / Identificazione della malattia residua minima nel midollo e nel sangue periferico nel neuroblastoma. Implicazioni prognostiche e terapeutiche.

A highly sensitive and specific methodology to detect neuroblastoma cells in the bone marrow and peripheral blood of children with neuroblastoma is of critical importance for proper staging and treatment of these patients. In addition, patients with bone marrow infiltration at diagnosis need to undergo regular investigation to measure the effectiveness of chemotherapy (so called "in vivo" purging). Finally, the evaluation of autologous stem cells taken from bone marrow or peripheral blood is necessary to rule out or minimise the possibility of reinfusing tumor cells to the patient following myeloablative therapy. The authors provide a "state of the art" data on this complicated issue and give their preliminary results of their own experience, mainly concerning the immunocytological methods.

High-sensitivity immunocytologic analysis of neuroblastoma cells in paired blood and marrow samples.

High-sensitivity immunocytochemistry was used to evaluate the relative frequency of neuroblastoma cells in bone marrow and peripheral blood in patients with neuroblastoma (NB). A total of 51 concomitant paired blood and marrow samples (102 total) from 35 patients with NB (age 4 months-31 years; stage 29 stage IV, 4 stage III, 2 stage IVS; 14 at diagnosis, 18 in relapse, 12 during treatment, and 7 off-therapy) were analyzed. Cytospins containing up to 10(6) cells each were prepared using the mononuclear cell (MNC) fraction. For immunocytologic staining, a primary mouse monoclonal anti-GD2 antibody (3F8), a secondary antimouse biotinylated antibody, and a streptavidin-alkaline phosphatase complex were used. A minimum of two cytospins containing a mean of 1.4 x 10(6) total MNCs was analyzed in addition to a negative and a positive control. No circulating tumor cells were detected when the concomitant marrow samples were negative or had <10 positive cells per 106 MNC (23 of 51 samples). Of the 18 marrow samples positive at 10-10,000 cells per 106 MNC, 6 had detectable NB cells in the corresponding blood sample, whereas for marrow samples with >10,000 NB cells per 10(6) MNC (1%), the concomitant blood sample was positive for 9 of the 10. When both marrow and blood samples were positive (15 BM-PB pairs), NB cell frequency was significantly lower in blood, with a mean difference of 2.14 logs (median 2.22, range -0.16-4.8, standard error 0.38). In patients with NB, circulating tumor cell frequencies seem to be substantially lower than in concomitant marrow samples, with a mean difference of >2 logs.

G-CSF serum pharmacokinetics during peripheral blood progenitor cell mobilization: neutrophil count-adjusted dosage might potentially improve mobilization and be more cost-effective.

The optimal dosing schedule of G-CSF for peripheral blood progenitor cell (PBPC) mobilization is still under investigation although many centers use 10 microg/kg/day in a single subcutaneous dose. However, G-CSF clearance increases with increasing absolute neutrophil count (ANC). Hence a G-CSF dosage adjusted to ANC might be a reasonable approach. We measured G-CSF trough serum levels by sandwich ELISA assay at different ANCs in eight patients undergoing treatment with filgrastim at 10 microg/kg/day in a single subcutaneous dose. A total of 26 samples were analyzed, and a strong correlation between increasing ANC and decreasing G-CSF levels was found by linear regression analysis (P < 0.0003, r2 = 0.4199). For ANC values above 5000/microl the trough serum levels, ie 24 h after administration, were consistently below the level that provides maximal clonogenic precursor stimulation in vitro (10 ng/ml). Serial serum G-CSF measurements performed in three patients at 0, 3, 6, 9 and 24 h after G-CSF administration, showed a reduction of the area under the curve (AUC) with increasing ANC. For an ANC of 20000/microl or greater, the G-CSF serum level fell under the maximal in vitro stimulation threshold of 10 ng/ml within 12 h. This preliminary pharmacokinetic data seems to suggest that an ANC-adjusted G-CSF dosing schedule might improve the design of PBPC mobilization regimens.

Pediatric peripheral blood progenitor cell collection: haemonetics MCS 3P versus COBE Spectra versus Fresenius AS104.

BACKGROUND: An increasing number of apheresis machines are becoming available for peripheral blood progenitor cell (PBPC) collection in children. STUDY DESIGN AND METHODS: At the Children's Hospital of Florence (Italy), three apheresis machines were evaluated: MCS 3P (Haemonetics) (10 procedures in 4 patients, aged 10-12 years, weight 23.5-64 kg), Spectra, (COBE) (8 procedures in 3 patients, aged 4-17 years, weight 19-59 kg), and AS104 (Fresenius) (24 procedures in 9 patients, aged 2-16 years, weight 13.6-60 kg). For PBPC quantitative analysis, CD34 cytofluorimetry was employed. Relevant variables analyzed included efficiency of CD34+ cell extraction and enrichment, mononuclear cell purity and red cell contamination of the apheresis components, and platelet count decreases after leukapheresis. RESULTS: No significant differences in CD34+ cell-extraction abilities were found. However, the AS104 provided consistently purer leukapheresis components in terms of mononuclear cell and CD34+ cell enrichment (441 +/- 59%, vs. 240 +/- 35% and 290 +/- 42% for MCS 3P and Spectra, respectively). Postapheresis platelet counts dropped the least with the AS104. The smallest patient who underwent apheresis with MCS 3P (the only machine working on discontinuous flow and hence with greater volume shifts) weighed 23.5 kg and tolerated the procedure well, with no signs of hemodynamic instability. No significant complications were observed. CONCLUSION: All machines seem to have comparable PBPC extraction efficiency, but the AS104 seems to give the component with the greatest PBPC enrichment. This feature might be relevant for further ex vivo cell processing (CD34+ cell selection, expansion, and so on).

[Adrenal cortex neoplasms in children: diagnostic and therapeutic difficulties]. / Neoplasie corticosurrenali dell'infanzia: difficoltà diagnostiche e terapeutiche.

Two cases of adrenal cortical carcinoma in the pediatric age group are reported: the first case regards a fourteen month old female patient which presented with virilization and Cushing's syndrome: the second case regards a twelve year old boy with severe hypertension. Histopathologic distinction between benign and malignant adrenal cortical neoplasms is difficult: the usual cytologic criteria of benignity and malignancy in relation to prognosis are not very helpful while tumor size and tumor invasion appear to be the more important prognostic factors. Therefore early diagnosis, which is easier in the pediatric age because of the more frequent presentation of these neoplasms with hormonal effects, is essential.