Ten-year experience with cryopreserved vascular allografts in the Croatian Cardiovascular Tissue Bank.

The Croatian Cardiovascular Tissue Bank (CTB) was established in June 2011. Activities managed by CTB are processing of heart valves and blood vessels, as well as quality control, storage, medical release and distribution of allografts. The aim of this report is to present CTB's vascular tissue activities and retrospectively evaluate the outcomes of their use in the University Hospital Centre Zagreb. Between June 2011 and July 2021, 90 vascular allografts (VAs) from 55 donors after brain death were referred to CTB. Only 54% of VAs met the tissue quality requirements while 46% of tissues were discarded. The most frequent reasons for discard were unacceptable morphology and initial microbiological contamination. Altogether 42 VAs were released for transplantation and 37 of them were used in 27 surgical procedures. The most common indication for surgery was prosthetic graft or stent infection. According to the anatomic position of vascular reconstruction, patients were divided in the aortic and peripheral reconstruction group. A total of 23 patients were treated. In the aortic reconstruction group 58% of patients did not experience any graft-related complications. In the group of patients who underwent peripheral reconstruction significant incidence of reinfection was observed highlighting it as a major graft-related complication. Despite the small patient groups and limited duration of follow-up, presented clinical outcomes provide valuable information on the efficacy of vascular allografts. Additional clinical results collected on a larger patient groups and comparison to other reconstructive treatment options are necessary.

IgH and TCRgamma gene rearrangements, cyclin A1 and HOXA9 gene expression in biphenotypic acute leukemias.

In this study we investigated IgH and TCRgamma gene rearrangements, cyclin A1 and HOXA9 gene expression as well as the in vitro growth of biphenotypic acute leukemia (BAL) blasts in relation to acute lymphoblastic leukemia (ALL) and acute myeloid leukemia (AML). The aim of the study was to correlate BAL morphology and its biological parameters in order to get information that might be used for additional stratification of BAL. This rare form of AL was identified in a total of 10 patients, comprising 4.3% of adult and 3.0% of pediatric patients with de novo AL referred to our institution during the 1999-2003 period. Our results indicate that IgH and TCRgamma gene rearrangements correlated well with lymphoid BAL morphology, whereas the expression of cyclin A1 correlated with myeloid and undifferentiated BAL morphology. Surprisingly, HOXA9 expression, a marker associated with myeloid cell lineage, showed no strong correlation with BAL morphology. Finally, in vitro growth of blasts during a 7-day culture showed autonomous cell growth in 3/10 AML and 3/8 myeloid BAL samples tested, but not in any of the AL with lymphoid features. Further studies are needed to confirm these findings and to extend research to a broader spectrum of cell markers.

Double immunoenzymatic APAAP staining for the detection of leukemia-associated immunophenotypes.

Detection of unusual or aberrant cell immunophenotype with flow cytometry is the basis for the immunologic recognition of minimal residual disease (MRD) in patients with acute leukemia (AL). In this study, we have shown that the double immunocytochemical alkaline phosphatase antialkaline phosphatase (APAAP) staining technique also makes possible the detection of leukemic cells with unusual (leukemic) combinations of antigens (ULCA) both at diagnosis and during follow-up of patients with ULCA+ AL. The applicability of double APAAP was analyzed on bone marrow (BM) samples obtained from 12 patients (8 with AML, 3 with ALL, and 1 with undifferentiated acute leukemia [AUL]) randomly chosen from a larger group of 22 ULCA+ patients treated at our center in a 3-year period (22% observed ULCA+ AL frequency). The percentages of ULCA+ BM cells before chemotherapy were in the range of 5%-60%, which dropped to 0%-7% in 10 patients who achieved remission (range 0%-7%, p < 0.01). However, these cells could also be found 60 days after the initiation of therapy, ranging from 0%-2% of all nucleated cells. In 2 of 10 patients who achieved remission, 2% ULCA+ BM cells were found on days 35 and 60 after initiation of chemotherapy, and this finding was followed by relapse on days 110 and 270. However, the other 8 patients remained in remission despite positive finding of ULCA+ BM cells ranging from 0.2%-2% on at least one occasion. In 2 patients with AML FAB-M3 and cytomorphologic remission, the finding of ULCA+ cells by double APAAP correlated with the molecular finding of PML/RARalpha junction. These results indicate that double APAAP staining can identify leukemic cells in samples with a cytomorphologic pattern consistent with remission, but its applicability in detection of MRD awaits additional studies on a larger number of patients with ULCA+ AL.