Clinical significance of the ABCB1 and ABCG2 gene expression levels in acute lymphoblastic leukemia.

OBJECTIVES: Acute lymphoblastic leukemia (ALL) is a clonal disease that accounts for 20% of acute leukemias in adults. A high percentage of adult patients (ranging from 70 to 80%) reach complete remission; however, the 5-year survival rate is only 20-40%. One of the main obstacles to treatment success is the drug resistance of leukemic cells. Therefore, our research group analyzed the ABCB1 and ABCG2 gene expression levels in 61 patients diagnosed with ALL and assessed whether the levels affected the clinical parameters and 40-month survival rate. METHODS: The ABCB1 and ABCG2 gene expression levels were analyzed using real-time polymerase chain reaction in 61 patients diagnosed with ALL and 99 healthy donors as controls. The association between ABCB1 and ABCG2 gene expression levels and clinical variables was determined using the Chi-square test and Fisher's exact test. Overall survival (OS) was determined using the Kaplan-Meier method. RESULTS: The results showed high ABCB1 and ABCG2 gene levels, which were 4.5 and 2.3 times the levels of healthy donors, respectively. A total of 52% of the study patients expressed high ABCB1 levels and were significantly associated with the high-risk patient group and a decreased 40-month survival rate of 78%. Only 49% of the patients expressed high ABCG2 gene levels. No association was found between the clinical parameters and the ABCG2 gene expression levels. CONCLUSIONS: Early detection of ABCB1 gene expression levels could be important for the diagnosis and monitoring of ALL patients.

Treatment of patients with hemophilia A and inhibitors to factor FVIII with cimetidine.

In this study, cimetidine was used to treat patients with hemophilia A and inhibitors to factor VIII who presented with acute hemorrhages (Group A) and those without hemorrhages (Group B). The dose of cimetidine was 15 mg/kg/day. Group A consisted of five patients with inhibitors between 156 and > 10,000 Bethesda Units (BU), all with serious hemorrhagic problems. The control of hemorrhaging was effective in 100% of these patients, although inhibitor levels remained high (25-380 BU). Group B consisted of seven patients who did not have hemorrhages, whose inhibitor levels were 41-358 BU. Five of these patients no longer had anamnestic responses to Factor VIII after several months of treatment with cimetidine. No difference in the response to cimetidine was seen between HIV positive and HIV negative patients. The results suggest that cimetidine is useful to suppress inhibitors to Factor VIII in patients with hemophilia A.

[Report of 2 cases with acquired von Willebrand disease and one with acquired hemophilia A]. / Informe de dos casos con enfermedad de von Willebrand adquirida y uno con hemofilia A adquirida.

We report three patients with acquired inhibitors against F VIII:C/F vW:Ag complex. Two patients had acquired hemophilia A. The three patients presented with bleeding diathesis. Case 1 was a 19 years old woman with Graves-Basedow disease; case 2 was a 40 years old woman with systemic lupus erythematosus of four years; and case 3 a 38 years old woman who had had rheumatoid arthritis for five years and was in her 3d month postpartum. The F VIII:C level was below 8 U/dL in all cases. The F vW:Ag, ristocetin cofactor and platelet aggregation with ristocetin were diminished in the two cases with von Willebrand. Inhibitor to F VIII:C was 50, 38 and 20 Bethesda units, respectively, for cases 1, 2 and 3. The three patients showed clinical response to DDAVP and cryoprecipitates with partial response in laboratory tests. All patients responded to corticosteroid treatment, but immunosuppressive treatment was necessary in case 3.

Estimulación de la proliferación de las células de leucemia aguda linfoblástica en cultivo / Stimulation of acute lymphoblastic leukemia cell proliferation in cell cultures

Para conocer los estimulantes mitógenos más adecuados para la iniciación de la actividad mitótica de los blastos se utilizaronultivos de 20 muestras de células de leucemia aguda linfoblástica (LAL). Se analizaron diferentes concentraciones de fitohemaglutinina (PHA), lectina (Phitolacca americana) (FL) y 2-mercaptoetanol (2-ME) mediante la estimulación de cultivos celulares de 20 muestras. La mucoproteina extraída de las plantas (PHA) resultó ser el mejor activador de la mitosis y de la proliferación. A una concentración de 2.5 mg/ml, ocurrió la división celular; en su ausencia, no se observó proliferación celular. Por otra parte, la FL tuvo un efecto menor de la activación de la mitosis en los cultivos; y el 2-ME no presentó efecto alguno sobre la proliferación de estas células. Además, se observó que la acción mitogénica de la PHA implica la activación de la replicación del ADN celular, tal y como lo demostró la incorporación de [3H]-timidina

[Agreement among observers in the classification of acute leukemias]. / Concordancia de observadores en la clasificación de las leucemias agudas.

This study was carried out to establish the level of concordance between two observers from two different health institutions in Mexico City, in the diagnosis of acute leukemias and their different varieties. We studied 73 consecutive cases of adults with these diseases. Each one of the two observers established their diagnosis on two occasions at least 15 days apart. They first made their diagnosis taking as a base the neoplastic cells morphology in bone marrow smears, and after that, with morphology plus specific cytochemistry. The outcomes of the two observers were also compared with the official diagnosis. Kappa test was performed to know interobserver and intraobserver concordance. The kappa values for the diagnosis myeloid/lymphoid were found among the highest (51 to 91). Weighted kappa was also applied to know the level of concordance in the diagnosis of the different varieties of acute leukemia, myeloid and lymphoid. In these cases the weighted kappa values were lower compared with the previous values (lymphoid, from 47 to 82; myeloid, from 30 to 66). Cytochemistry paradoxically was a confusing factor when it was used: in these cases the kappa values were lower (32 to 84) than morphology alone (39 to 91). The outcomes showed the subjective level in the diagnosis of the myeloid subtypes was more important in them than in the lymphoid subtypes.

[MYC protein and proteins antigenically related with MYC in acute lymphoblastic leukemia]. / Estudio de la proteína MYC y de proteínas antigénicamente relacionadas a MYC en leucemia aguda linfoblástica (LAL).

The gross structure and the expression of the c-myc oncogene were analyzed in primary cells from 15 acute lymphoblastic leukemia patients. Southern blot analysis was used to detect possible alterations in the structure of this gene. Alterations (rearrangement and/or amplification) were observed in seven of the 15 samples studied. When the expression of MYC protein was evaluated by Western blot analysis, we found no correlation between c-myc gene alterations and p67 c-myc, which was expressed in the 15 samples studied. The analysis of expression also revealed various MYC-related proteins (115, 110 and 60 kD). These proteins were expressed at variable levels in all leukemic cells, other transformed cells, and in normal peripheral blood lymphocytes (PBL) induced to proliferate with interleukin 2. We detected the 110 kD and 40 kD MYC-related proteins in fresh normal PBL and in samples from patients in complete remission. These studies indicate that the c-myc alterations and protein expression are unrelated to percentage of leukemic blasts, cell morphology or immunophenotype. Our work shows that the expression of MYC-related proteins from 115, 60 and 40 kD is associated with mechanisms of cell activation, and perhaps these proteins may play a role in cellular proliferation-transformation.