Clonal hemopoiesis and risk of thrombosis in young female patients with essential thrombocythemia.

OBJECTIVE: Several studies demonstrated a high prevalence of nonrandom X-chromosome inactivation pattern (X-CIP) in essential thrombocythemia (ET). This study explored the incidence of clonal hemopoiesis in myeloid precursors and endogenous erythroid colonies (EECs) in ET patients and its correlation with thrombotic manifestations. MATERIALS AND METHODS: Clonal analysis of hemopoiesis using X-CIP was performed in 40 female patients with ET. Median age was 40.5 years (range 20-64), and median platelet count at testing time was 700 x 10(9)/L (range 220-1300 x 10(9)/L). Patients older than 65 years were excluded to reduce age-related skewing. Clonality was assessed on neutrophils, platelets, EECs, and bone marrow CD34(+) cells. RESULTS: Eight (20%) of 40 patients developed thrombosis mainly at diagnosis. Clonal hemopoiesis was found in 17 (42.5%) patients, 15 (37.5%) had polyclonal hemopoiesis, and 8 (20%) were considered uninterpretable due to constitutive skewing. Clonality was confirmed on purified CD34(+) subpopulations from bone marrow, documenting that clonality does not appear lineage-restricted. There were no statistical differences in age at diagnosis, median platelet count at testing time, and length of follow-up. Thrombotic episodes were significantly more frequent in the monoclonal group (p = 0.04, Fisher exact test). CONCLUSIONS: Young female patients with ET exhibiting a clonal pattern of hemopoiesis by X-CIP analysis are at higher risk for thrombosis. X-CIP analysis may contribute to defining the individual risk leading to appropriate treatment. X-CIP will allow a correct diagnosis in patients with latent myeloproliferative disorders and thrombosis in unusual sites. Clonal hemopoiesis is easily recognized by X-CIP, but its applicability is limited to the female sex and is hampered by the presence of age-related or constitutive skewing.

Molecular and clinical follow-up after stem cell transplantation for multiple myeloma.

Molecular follow-up has been carried out using immunoglobulin heavy-chain (IgH) gene finger-printing, a polymerase chain reaction (PCR)-based technique with a sensitivity of 0.1-0.01% (10(-3)-10(-4)), in 22 patients affected by multiple myeloma and submitted to stem cell transplantation (SCT). Twelve patients were submitted to either single or double autologous unselected peripheral blood progenitor cell transplantation, eight patients were submitted to autologous CD34+ immunoselected transplantation and two patients were submitted to allogeneic bone marrow (one patient) or peripheral blood CD34+ stem cell (one patient) transplantation. At diagnosis, all patients showed clonal CDIII rearrangement. The molecular analysis performed on leukapheresis products and CD34+ purified fractions proved to be contaminated by myeloma cells. During follow-up after autografting, all but one patient retained clonal rearrangement despite clinical complete remission (CR) in ten of them. These ten patients either relapsed (Rel) or showed progressive disease (PD) after transplantation; four of them died. Only one patient did not retain clonal rearrangement after autologous transplantation; she is currently alive in CR after a follow-up of 100 months. One patient submitted to allogeneic transplantation is currently alive with no evidence of the disease, but still retains clonal rearrangement after a follow-up of 47 months. Another patient died 4 months after transplantation after succumbing to fatal pneumonia showing myeloma progression.

MiCMA: an alternative treatment for refractory or recurrent Hodgkin's disease.

BACKGROUND: We determined the response rate to MiCMA (mitoxantrone, carboplatinum, methylprednisolone and aracytin) in a group of 29 patients with Hodgkin's disease (HD) and poor prognostic factors either resistant to first line or relapsing after conventional chemotherapy and subsequently evaluated the role of autologous stem-cell transplantation (ASCT) in these patients after MiCMA. PATIENTS AND METHODS: The treatment was intended as a brief tumor debulking program before ASCT. Twenty-nine patients with primary refractory HD or relapsed HD were submitted to two courses of MiCMA (mitoxantrone 10 mg/m2 day 1; carboplatinum 100 mg/m2 days 1-4; aracytin 2 g/m2 day 5; methylprednisolone 500 mg/m2 days 1-5) and subsequently evaluated for response. Those with responding or stable disease, received one or two other courses of MiCMA followed by ASCT. RESULTS: There were 10 complete responses (34% CR), 15 partial responses (52% PR) and 4 treatment failures with disease progression (14% PD). In total there were 25 evaluable responses out of 29 patients (86% CR + PR). Myelosuppression was the main toxicity of this treatment. At this time 20 patients (69%) are alive with a median follow-up of 26.5 months (7-100), 13 patients in CR (45%), 8 patients died, 7 of them from disease progression and one due to multi-organ failure, one patient is lost to follow-up. All but one of the patients who achieved CR after MiCMA are alive. Only the number of extranodal sites was found to predict a poor response to MiCMA. CONCLUSIONS: A short pre-transplantation treatment with MiCMA is an effective tumor debulking approach in patients with refractory or relapsed HD.

Autologous graft-versus-host disease after CD34+-purified autologous peripheral blood progenitor cell transplantation.

Autologous graft-versus-host disease (GVHD) has been frequently reported after cyclosporine A (CsA) administration in the autologous setting. This complication is related to the disruption of self-tolerance mechanisms induced by CsA and may exert an antitumor effect. We report the spontaneous occurrence of autologous GVHD after CD34+-purified peripheral blood progenitor cell transplantation (PBPCT) in 5 out of 24 consecutive patients (20.8%). The syndrome was characterized by skin rash (5/5), pruritus (5/5), eosinophilia (5/5), and fever (2/5) occurring at a median of 37 days (range 22-60) after transplantation. Diagnosis was confirmed by skin biopsy in all patients. The syndrome was self-limiting, lasted a median of 25 days, and did not require treatment. The rate of autologous GVHD was high after CD34+-purified autologous PBPCT. In fact, no autologous GVHD was documented in an historical control of 100 consecutive patients submitted to unmanipulated PBPCT at the same institution. The manipulation of the graft by the purging procedure causes a profound T lymphocyte depletion, thus possibly perturbing the equilibrium between autoregulatory cells and autocytotoxic T cells. These observations add new interest to the antitumor efficacy of autologous GVHD and suggest new questions regarding the role of transplantation for autoimmune diseases.

Long-term immune recovery after CD34+ immunoselected and unselected peripheral blood progenitor cell transplantation: a case-control study.

BACKGROUND AND OBJECTIVE: CD34+ stem cell selection induces extensive T-cell depletion as a consequence of ex vivo manipulation. The impact of T-cell depletion on long-term immunologic recovery after autologous CD34+ peripheral blood progenitor cell transplantation (CD34+ PBPCT) is not well characterized. We compared the long term immunologic recovery in two groups of patients submitted to CD34+ PBPCT or unselected autologous peripheral blood progenitor cell transplantation (uPBPCT). DESIGN AND METHODS: Eight patients in both groups were closely matched for diagnosis, age, disease status at transplantation and conditioning regimen and lymphocyte phenotype was prospectively evaluated during long-term post-transplantation follow-up. RESULTS: At a median of 18 months after transplantation, CD3+ lymphocyte subset remained below the normal range in both groups. CD19+ B lymphocytes subset after CD34+ PBPCT was within the normal range in both groups. CD4+ lymphocytes were depressed while the CD8+ lymphocyte subset was increased in group A and in the normal range in group B. As a result, inversion of CD4/CD8 ratio was documented in both groups. T-activated lymphocytes (CD3DR+) and natural killer (CD16/56+) cells were increased in both groups. INTERPRETATION AND CONCLUSIONS: Long-term immune recovery appears to be unaffected by extensive ex vivo manipulation in this adult population when compared to recovery after unmanipulated PBPCT. CD34+ selection, although causes an extensive depletion of T lymphocytes in the graft does not represent a risk factor for delayed CD4+ recovery late after transplantation. Elevated numbers of NK cells and activated T-cells, which have antineoplastic activity, are maintained late after autologous CD34+ transplantation.

The application of two different blood cell separators to harvest CD34+ cells in patients suffering from non Hodgkin's lymphoma.

From January 1996 until now, thirty-eight PBSC procedures were carried out on 20 patients suffering from NHL, mobilized by polichemotherapy regimens plus recombinant human Granulocyte-Growth Factor (rhG-CSF). Patients were enrolled in PBSC procedures using Dideco Excel (group A) and Cobe Spectra v.4.7 (group B) blood cell separators. Twelve patients were enrolled in group A (6 males and 6 females, median age 33) and 9 patients in group B (5 males and 4 females, median age 55). The mean White Blood Cell (WBC) and Mononuclear Cells Fraction (MNC) peripheral blood counts were not statistically different in either group and neither were blood CD34+ cell peripheral counts. CD34+ cell peripheral value was predictive of the CD34+ yield while mean values of harvested CD34+ cells were not significantly different. CD34+ cell efficiencies were statistically the same. The CD34+ cell purity of the apheresis harvest was statistically different between the two groups (group A = 3.0+/-2.2%; group B = 1+/-0.9%) p = 0.001. High CD34+ cell yields were observed in both groups which confirms that both blood cell separators are able to harvest hematopoietic progenitor cells from peripheral blood.

Inappropriate antidiuretic hormone secretion after high-dose thiotepa.

High-dose thiotepa has been successfully included in a variety of conditioning regimens for stem cell transplantation in hematological and solid neoplasms. Toxicity of high-dose thiotepa mainly manifests as profound myeloablation and some degree of liver damage. We report a case of inappropriate secretion of antidiuretic hormone (SIADH) in a patient with primary CNS lymphoma who underwent therapy with high-dose thiotepa.

Optimal timing of G-CSF administration after CD34+ immunoselected peripheral blood progenitor cell transplantation.

G-CSF accelerates neutrophil recovery after autologous peripheral blood progenitor cell transplantation (aPBPCT), although the optimal timing for its administration is currently unknown. In order to establish the role and the optimal timing of administration of G-CSF after immunoselected CD34+ aPBPCT, we analyzed the data from 21 consecutive patients affected by haematological malignancies. Patients were randomized into three groups according to G-CSF administration after transplantation: day +1 (group B); day +7 (group C) or no G-CSF (group A). Serum G-CSF level was evaluated until engraftment. The CD34+ cell dose reinfused was similar (P = 0.48). G-CSF significantly reduced time to recovery of PMN >0.5 x 10(9)/l (11 vs 14 vs 20.5 days) (P= 0.00046); >1.0 x 10(9)/l (12 vs 15 vs 22) (P = 0.001). No difference was observed in the number of days with PMN <0.1 x 10(9)/l (5.5 vs 7 vs 8 days). Platelet count >50 x 10(9)/l and >100 x 10(9)/l, reticulocytes >1%, length of hospitalization, non-prophylactic antibiotic therapy, fever, incidence of sepsis and transfusion support did not differ. Early or delayed G-CSF after immunoselected CD34+ aPBPCT significantly accelerated PMN recovery but did not reduce the amount of supportive treatment or the duration of hospitalization. Delaying the initiation of G-CSF did not reduce the length of treatment (11.5 vs 12 days). Early or delayed G-CSF administration resulted in G-CSF peak serum levels 7 (early)-12 (delayed)-fold greater than an endogenous response to neutropenia.

Long-lasting complete remission in plasma cell leukemia after aggressive chemotherapy and CD34-selected autologous peripheral blood progenitor cell transplant: molecular follow-up of minimal residual disease.

Plasma cell leukemia is a rare disease associated with very poor survival with standard treatment. We report a patient affected by plasma cell leukemia treated with aggressive chemotherapy and autologous CD34-selected PBPC who achieved a complete remission now lasting more than 2 years. Molecular studies confirmed the presence of minimal residual disease (MRD) despite the absence of disease activity. High-dose chemotherapy with stem cell rescue may be applied to selected patients considering the impact of the treatment on survival. The meaning of molecular MRD in this setting is unclear.

Expression of p15INK4B in normal hematopoiesis.

The cyclin-dependent kinase inhibitor (CDKI) p15INK4B (p15) induces cell cycle arrest in G0/G1 phase. Several studies report deletion or transcriptional loss of the p15 gene in myeloid and lymphoid hematological malignancies, and a possible role as a tumor suppressor gene has been proposed for this CDKI. In this study we evaluated the expression of p15 by cytofluorometric, immunohistochemical, and reverse transcriptase-polymerase chain reaction (RT-PCR) methods in CD34+ progenitors (both during steady state and after chemotherapy and/or granulocyte-colony stimulating factor [G-CSF] administration) and in cells belonging to different hematopoietic differentiative lineages. We found that p15 is not expressed in normal G0/G1-arrested peripheral blood (PB)- or bone marrow (BM)-CD34+ cells. Moreover, p15 is expressed in G0/G1-blocked CD34+ cells mobilized by chemotherapy and G-CSF but not in CD34+ cells mobilized by G-CSF alone. To clarify the role of p15 in normal hematopoiesis, we used flow cytometry to investigate its expression in normal differentiating BM and PB cells. We found that p15 was expressed in cells belonging to the granulocyte-monocyte lineage and in B and T lymphocytes, whereas erythroid and megakaryocytic cells were p15 negative. These findings, which were confirmed both by immunohistochemical and RT-PCR analysis, definitely establish a linkage between p15 expression and granulocyte-monocyte differentiation.

Highly fluorescent reticulocytes after CD34+ peripheral blood progenitor cell transplantation.

Highly fluorescent reticulocyte (HFR) counts were evaluated in 13 consecutive patients affected by hematological malignancies and submitted to autologous selected CD34+ peripheral blood progenitor cell (PBPC) transplantation. Results were compared with a historical group of patients comparable for age, disease and conditioning regimen submitted to unfractionated PBPC transplantation. HFR counts of the CD34+ group declined to an undetectable level from day +4 to day +10 when they became detectable and reached 5% of total reticulocyte count by day +12. In the historical group, the nadir was identical but the recovery was faster (day +9). Total reticulocyte count > 1% was achieved at days +17 and +11, respectively. The absolute neutrophil count (ANC) recovery was identical in both groups, achieving a value > 0.5 x 10(9)/l at day +13 after reinfusion. Hence, in the historical group, HFR count gave advance notice of complete and stable hemopoietic engraftment while in the CD34+ group HFR and ANC count showed almost simultaneous recovery.

Differential sensitivity of leukemic and normal hematopoietic progenitors to the killing effect of hyperthermia and quercetin used in combination: role of heat-shock protein-70.

Autologous bone-marrow transplantation (ABMT) is widely used in the treatment of acute leukemias where a matched sibling donor is not available for allogeneic transplantation. However, a major problem in ABMT is relapse, and ex vivo purging may be very important in preventing it. We show here that quercetin enhances the growth-inhibitory effect of hyperthermia (HT) in AML (19 cases) and ALL (6 cases) leukemic blasts. Furthermore, the inhibitory effect of this combined treatment resulted in leukemic-cell apoptosis. On the contrary, normal hematopoietic progenitors were neither growth-inhibited nor induced to apoptosis by HT-plus-quercetin treatment. To explain this difference in sensitivity of leukemic and normal hematopoietic progenitors, we analyzed the effect of quercetin on heat-induced expression of heat-shock protein-70 (HSP-70), which has been shown to be important in regulating thermosensitivity. We found that quercetin inhibits heat-induced HSP-70 expression both at protein and at mRNA levels in AML and ALL blasts. In normal CD34+ progenitors, the combined treatment with HT and quercetin did not reduce HSP-70 expression and did not induce cell apoptosis. Considering the difference in heat sensitivity of normal CD34+ and leukemic progenitors in the presence of quercetin, the combined use of HT and quercetin could constitute a purging protocol for ABMT.

Bacteremia in patients with hematological malignancies. Analysis of risk factors, etiological agents and prognostic indicators.

BACKGROUND AND OBJECTIVE: Patients with hematological malignancies are at increased risk for developing bacteremia. No previous study has investigated the risk and prognostic indicators of bacteremia in such patients using a statistical approach. METHODS: A case-control study was performed in 106 patients with hematological malignancies (group A). Two hundred and twelve patients were included as controls and divided into two groups: 106 patients with hematological malignancy without bacteremia (group B) and 106 HIV-infected patients with bacteremia (group C). RESULTS: At univariate analysis, bacteremia risk factors in group A were: neutropenia for more than six days (p = 0.03 vs. group B), central venous catheter usage (p = 0.04) and absence of antibiotic prophylaxis (p = 0.03). At multivariate analysis, the use of CVC and neutropenia were independent bacteremia risk factors. The most frequent etiological agents were: Staphylococcus epidermidis and Pseudomonas aeruginosa. Comparing groups A and C, the distribution of Staphylococcus spp. was different, with S. epidermidis being prevalent in hematological patients only. As regards gram-negative organisms, it is of note that no episode of NT-Salmonella bacteremia was observed in group A, unlike group C, where they represent the second leading etiological agents. In group A, 14% of the patients died. Persistent neutropenia (p = 0.01) and the presence of relapsed neoplasm (p = 0.04) were prognostic indicators of bacteremia. INTERPRETATION AND CONCLUSIONS: Our findings suggest that bacteremia in patients with hematological malignancies strictly correlates with the intensity and length of neutropenia and CVC usage. Although we observed a low mortality rate, we stress that this clinical condition requires special attention from the physician, who must recognize and treat it promptly.

Telomerase activity in human hematopoietic progenitor cells.

BACKGROUND AND OBJECTIVE: Telomerase is the enzyme that stabilizes and elongates the telomeric ends of chromosomes. It is expressed in germline and malignant cells and absent in most human somatic cells. The selective expression of telomerase has thus been proposed to be a basis for the immortality of germline and malignant cells. Recently, telomerase activity has been observed in human bone marrow (BM) and peripheral blood (PB) samples. The objective of our study was to further characterize the telomerase-expressing population in BM and PB. METHODS: CD34+ cells were isolated from BM and PB, cultured in vitro, and telomerase activity was assessed by the PCR-based TRAP assay. RESULTS: Telomerase activity in human BM and PB could be almost exclusively assigned to the hematopoietic progenitor cell fraction expressing the CD34 antigen. We observed telomerase activity in CD34+ cells from BM and cytokine-mobilized PB. CD34+ cells lacking co-expression of CD33 demonstrated higher levels of telomerase than myeloid committed CD34+/CD33+ cells. In vitro culture of CD34+ cells in the presence of a cocktail of growth factors inducing differentiation resulted in a decrease of telomerase activity. Telomerase activity increased in peripheral blood during cytokine-induced mobilization of hematopoietic progenitor cells. INTERPRETATION AND CONCLUSIONS: Our data demonstrate that at least a portion of the hematopoietic stem/progenitor cell fraction expresses telomerase and downregulates its expression through differentiation.

Granulocyte colony-stimulating factor-primed leukocyte transfusions in candida tropicalis fungemia in neutropenic patients.

Optimal management of fungemia in neutropenic patients is still controversial. Several reports have already stressed the poor prognosis in invasive candidiasis (80% mortality in several reports). Therefore granulocyte transfusions would appear to be useful in the management of these infections. We report the use of rhG-CSF-primed granulocyte transfusions plus amphotericin B in two neutropenic patients who developed life-threatening systemic fungal infections. This approach was successful and both patients fully recovered from the infection.