A real-life overview of a hematopoietic cell transplant program throughout a four-year period, including prospective registry, exclusion causes and final donor selection

Traceability of patients who are candidates for Hematopoietic cell transplant (HCT) is crucial to ensure HCT program quality. Continuous knowledge of both a detailed registry from a HCT program and final exclusion causes can contribute to promoting a real-life vision and optimizing patient and donor selection. We analyzed epidemiological data reported in a 4 year-monocentric prospective registry, which included all patients presented as candidates for autologous (Auto) and/or allogeneic (Allo) HCT. A total of 543 patients were considered for HCT: 252 (42.4%) for Allo and 291 (57.6%) for Auto. A total of 98 (38.9%) patients were excluded from AlloHCT due to basal disease progression more commonly (18.2%). Seventy-six (30.2%) patients had an HLA identical sibling, whereas 147 (58.3%) patients had only Haplo. UD research was performed in 106 (42%) cases, significantly more often in myeloid than lymphoid malignancies (57% vs 28.7%, p < 0.001) but 61.3% were finally canceled, due to donor or disease causes in 72.4%. With respect to Auto candidates, a total of 60 (20.6%) patients were finally excluded; progression was the most common cause (12%). Currently, Haplo is the most frequent donor type. The high cancellation rate of UD research should be revised to optimize further donor algorithms.

Application of a digital PCR method for WT1 to myeloid neoplasms in CR and deep ELN WT1 molecular response (< 10 copies)

Bone marrow WT1 mRNA levels assessed by the ELN method are useful to establish prognostic correlations in myeloid malignancies treated with chemotherapy or hematopoietic stem cell transplantation (HCT). Those patients with WT1 levels below ten copies have a good outcome. However, some of these patients relapse. To further characterize this group of cases, we applied a new and sensitive digital (ddPCR) WT1 method. A consecutive series of 49 patients with treated myeloid malignancies and with an ELN WT1 quantitation of < 10 copies were included in the study. All cases (47 AML and 2 MDS) have received intensive chemotherapy or HCT. One to four micrograms of total RNA were retrotranscribed to obtain ≥ 10,000 ABL1 copies using the ELN protocol. Only those cases with a good quality cDNA were used in the ddPCR WT1 test. The ddPCR Gene Expression WT1 Assay of Bio-Rad© was used to perform the PCR amplification, and the microdroplets were quantified in the Bio-Rad's QX200 droplet reader. Eighteen patients showed a negative WT1 ddPCR assay (0 copies/μl), whereas 31 cases were positive (results ranged from 1 to 15.2 copies/μl). Survival analysis showed statistically significant differences in terms of OS between both groups, 83 ± 8% vs. 46 ± 9% (p = 0.024). A statistically significant correlation was also found between ddPCRWT1 results and CD123+ cell number detected by flow cytometry (p = 0.024). Larger series of patients tested with the current ddPCRWT1 method will solve whether it could be used to stratify patients with myeloid malignancies achieving deep WT1 molecular response (< 10 copies).

G-CSF increases the number of peripheral blood dendritic cells CD16+ and modifies the expression of the costimulatory molecule CD86+

Dendritic cells (DC) play a key role in initiating immune reactions after allogeneic stem cell transplantation. The two main peripheral blood DC populations are myeloid (DC1) and lymphoplasmacytoid (DC2). A new subset of myeloid DC, expressing CD16, has been identified. We analyzed the number and CD86 expression of DC subsets in peripheral blood of 18 healthy donors, before and after granulocyte colony-stimulating factor (G-CSF) and in the inoculum of allogeneic peripheral blood transplants (allo-PBT; n=100) and allogeneic bone marrow transplants (allo-BMT; n=22). Granulocyte colony-stimulating factor administration increased the median number of DC1 (P=0.0007), of DC2 (P<0.0001) and of DC CD16+ (P=0.0001). Granulocyte colony-stimulating factor administration was also associated with a significant decrease of CD86 expression on DC1 (P=0.0003) and with a trend for an increase on DC CD16+ (P=0.07). Recipients of allo-PBT received similar quantities of DC1 and higher doses of DC2 and DC CD16+ than recipients of allo-BMT (P=0.5; P=0.0001; P<0.0001, respectively). Granulocyte colony-stimulating factor modifies the number of DC in peripheral blood and the expression of the costimulatory molecule CD86. This resulted in a different composition of DC2 and especially of DC CD16+ in the harvests, which might explain some of the differences observed in allogeneic reactions after allo-PBT with respect to allo-BMT.

Serial quantification of lymphoid and myeloid mixed chimerism using multiplex PCR amplification of short tandem repeat-markers predicts graft rejection and relapse, respectively, after allogeneic transplantation of CD34+ selected cells from peripheral blood

We used multiplex amplification of nine microsatellite sequences (PCR-STR) to analyse chimerism in pure populations of T cells and neutrophils from peripheral blood from 40 patients submitted to an allogeneic transplant, 22 having received a T-cell depleted (TCD) peripheral blood graft by means of CD34(+) selection (allo-PBT/CD34(+)), and 18, an unmodified graft (allo-SCT; 13 allogeneic bone marrow transplants and five allo-PBT). T-cell mixed chimerism (TcMC) was observed in 16 of the 22 (72.3%) patients receiving an allo-PBT/CD34(+), but in only one of the 18 (5.5%) patients receiving an allo-SCT (P=0.0001). TcMC was transient (n=6), stable (n=7), and associated with poor haematopoietic engraftment (n=4). All patients with TcMC who developed graft failure had more than 30% of host T cells. Myeloid MC (MyMC) was observed in four (19%) allo-PBT/CD34(+) patients and in three (17%) allo-SCT patients (P=NS). Five out of seven (71%) patients with MyMC relapsed, all of them diagnosed with myeloid malignancies, as compared with two of the 20 (10%) patients with complete donor chimerism (P&<0.0001). In conclusion, TcMC appears in a significant number of allo-PBT/CD34(+) patients and may be associated with poor engraftment when the percentage of host T cells is >30%; likewise, MyMC appears in a small percentage of recipients of both allo-PBT/CD34(+) and allo-SCT patients, and is associated with leukaemia relapse in myeloid malignancies.

Hypercalcemia as the presenting feature of t-cell lymphoid blast crisis of ph-positive chronic myeloid leukemia

Hypercalcemia is a rare complication of chronic myeloid leukemia (CML), usually seen in the accelerated or blastic phases of the disease and associated with a poor prognosis. T-cell lymphoid phenotype is also an infrequent finding in the blast crisis (BC) of CML. A CML patient who had hypercalcemia as the presenting feature of a T-cell BC is reported. She was a 78 year-old woman who, at four months of CML diagnosis, developed weakness, bone pain, and mental confusion, with hypercalcemia being subsequently found. Although the peripheral blood and bone marrow were consistent with the chronic phase of CML, mediastinal enlargement, a soft tissue mass adjacent to the iliac bone, and multiple osteolytic lesions were seen. Serum levels of parathyroid hormone (PTH) and PTH-related peptide were normal, whereas the search for a second neoplasm was negative. The hypercalcemia initially responded to conventional treatment, but it reappeared two weeks later. Coincidentally, a high proportion of blast cells of T-cell origin at the cortical thymocyte stage were observed in the patient's peripheral blood and bone marrow, and she died shortly afterwards.