Efficacy of Chemotherapy in Acute Leukemia Patients Resistant to Previous Standard Treatment According to the Series Measurement of WT1 Gene Expression

Aim. To estimate the efficacy of chemotherapy in acute leukemia patients resistant to previous standard treatment according to the series measurement of WT1 expression. Materials & Methods. The series measurement of WT1 expression formed the basis of the efficacy estimation of induction chemotherapy in 31 patients (15 men and 16 women aged from 3 months to 68 years; the median age was 28 years) with prognostically unfavourable variants of acute myeloid (AML) and lymphoblastic leukemia (ALL) (23 AML and 8 ALL patients). The WT1 gene expression was measured at baseline and 2–3 weeks after the treatment by the quantitative real-time PCR. The threshold level for detection was 250 copies of WT1/104 copies of ABL. The cytogenetic profile of leukemia cells was assessed by standard cytogenetics and FISH. Results. The baseline expression level of WT1 varied from 305 to 58,569 copies/104 copies of ABL. The expected reduction of WT1 expression after the first induction chemotherapy treatment was reported in 22/23 (96 %) AML patients and in 6/8 (75 %) ALL patients. According to our results WT1 expression reached the threshold in 13/31 (42 %) patients, including 9 AML patients and 4 ALL patients. After 11/31 (35 %) patients received the second course of treatment, WT1 expression level became normal in 8 cases (5 ALL and 3 AML patients). Despite high dose chemotherapy, HSCT and such agents as blinatumomab and gemtuzumab, an unfavourable outcome was observed in 18/31 (58 %) patients including 6 patients with complex karyotype (CK+) and 2 patients with monosomal karyotype (MK+). Once the MK+ and CK+ combination was observed, in another case the MK+ was combined with the prognostically unfavourable inv(3)(q21q26) inversion. Conclusion. Our results show that the molecular monitoring should be included as part of treatment of the prognostically unfavourable acute leukemia. The WT1 gene was shown to be the most appropriate marker. WT1 expression was shown to correlate with the common fusion genes allowing to estimate the blast cell count at the molecular level

Results of Allogeneic Hematopoietic Stem Cell Transplantation in Patients with Acute Myeloid Leukemia with t(8;21)(q22;q22)/RUNX1-RUNX1T1 and Additional Cytogenetic Abnormalities

Aim. To evaluate the impact of additional chromosomal aberrations on outcomes of allogeneic hematopoietic stem cell transplantation (allo-HSCT) in patients with acute myeloid leukemia (AML) with t(8;21)(q22;q22)/RUNX1-RUNX1T1 translocation. Methods. Twenty-five AML patients with t(8;21)(q22;q22)/RUNX1-RUNX1T1 translocation (10 women and 15 men, aged from 2 to 58 years; median 20.2) were examined. Analysis of overall (OS) and event-free survival (EFS) predictors after allo-HSCT in patients with different clinical, transplant and cytogenetic characteristics was performed. Results. The additional cytogenetic abnormalities were found in 13 (52 %) patients before the transplantation, at that, complex karyotype with three or more chromosomal abnormalities were registered in 9 (69 %) patients. The univariate analysis showed that OS and EFS after allo-HSCT differed in patients with different characteristics such as age (p = 0.03; p = 0.0006), clinical status at transplantation (p = 0.0002; p = 0,006), donor type (p = 0.0003; p = 0.002), the interval from diagnosis of leukemia to allo-HSCT (p = 0,008, for OS only), additional cytogenetic abnormalities (p = 0.03; p = 0.009) and complex karyotype (p = 0.004; p = 0.0003), respectively. In multivariate analysis, independent predictors of OS were donor type (p = 0.01), the interval from diagnosis of leukemia to allo-HSCT (p = 0.01), and additional cytogenetic abnormalities in karyotype (p = 0.04), as well as donor type (p = 0.04) and patient’s age (p = 0.004) for EFS. Conclusion. AML with t(8;21)(q22;q22)/RUNX1-RUNX1T1 translocation is a heterogeneous disease. The prognosis in patients with the additional cytogenetic abnormalities, especially in those with the complex karyotype, is worse both after the standard chemotherapy (i.e. before allo-HSCT), and after allo-HSCT

Allogeneic Hematopoietic Stem Cell Transplantation in Acute Myeloid Leukemias: Prognostic Significance of Complex Karyotype Including del(5q), –7, del(7q) Abnormalities

Aim. To evaluate the prognostic significance of the complex karyotype including del(5q), –7, del(7q) abnormalities in acute myeloid leukemia (AML) after allogeneic hematopoietic stem cell transplantation (allo-HSCT). Materials & Methods. Forty-four AML patients with chromosome 5 and/or 7 abnormalities (22 women and 22 men, aged from 1.2 to 67 years, median 31.2 years) were examined. Analysis of overall (OS) and event-free survival (EFS) predictors after allo-HSCT in patients with different clinical, transplant and cytogenetic characteristics was performed. Results. Prior to allo-HSCT, the complex karyotype (with three or more chromosomal abnormalities) was observed in 19 (43 %) patients, the monosomal karyotype was in 8 (18 %) patients. Univariate analysis demonstrated that OS and EFS differed in patients from different age groups (³ 18 vs. < 18 years; p = 0.01 and p = 0.05, respectively), with different disease status at transplantation (1 remission vs. other clinical status; p = 0.1 and p = 0.008, respectively), with and without complex karyotype (СK– vs. CK+; p = 0.05 and p = 0.002, respectively), with and without monosomal karyotype (МK– vs. MK+; p = 0.009, only for EFS), and with different stem cells source (bone marrow vs. other source; p = 0.03 only for OS). Multivariate analysis confirmed that age of 18 years and more (p = 0.02 and p = 0.01, respectively), active disease at allo-HSCT (p = 0.04 and p = 0.005, respectively), complex karyotype (p = 0.04 и p = 0.0008, respectively) and stem cell source other than bone marrow (p = 0.02 only for OS) were independent predictors of OS and EFS deterioration. Conclusion. The study demonstrates that chromosome 5 and/or 7 abnormalities as a part of the complex karyotype is high-risk factor in AML patients undergoing allo-HSCT (unlike the monosomal karyotype), that requires the special therapeutic approach

Immunological Cross-Reactivity between Malaria Vaccine Target Antigen P48/45 in <i>Plasmodium vivax</i> and <i>P</i>. <i>falciparum</i> and Cross–Boosting of Immune Responses

<div><p>In general, malaria immunity has been suggested to be species specific with very little, if any, known cross-reactivity between <i>Plasmodium vivax</i> and <i>P</i>. <i>falciparum</i>, both of which are responsible for >90% of human malaria, and co-endemic in many countries. It is therefore believed that species-specific immunity may be needed to target different species of <i>Plasmodium</i>. Pfs48/45 and Pvs48/45 are well established targets in the sexual stages of the malaria parasites, and are being pursued for the development of transmission blocking vaccines. Comparison of their sequences reveals 61% and 55% identity at the DNA and protein level, respectively raising the possibility that these two target antigens might share cross-reacting epitopes. Having succeeded in expressing recombinant Pfs48/45 and Pvs48/45 proteins, we hypothesized that these proteins will not only exhibit immunological cross–reactivity but also cross-boost immune responses. Mice were immunized with purified recombinant proteins using CFA, Montanide ISA-51 and alum as adjuvants, and the sera were analyzed by ELISA, Western blotting and indirect fixed and live IFA to address the hypothesis. Our studies revealed that Pvs48/45-immune sera showed strong cross-reactivity to full length Pfs48/45 protein, and the majority of this cross reactivity was in the amino-terminal and carboxyl-terminal sub-fragments of Pfs48/45. In cross-boosting experiments Pfs48/45 and Pvs48/45 antigens were able to cross-boost each other in mouse immunization studies. Additionally we also noticed an effect of adjuvants in the overall magnitude of observed cross-reactivity. These studies may have significant implications for immunity targeting transmission of both the species of malaria parasites.</p></div