L Risch¹ , U Luethi² , A.R. Huber²

¹Department of Internal Medicine, Academic Teaching Hospital, Feldkirch, Austria, ²Department of Laboratory Medicine, Kantonsspital, Aarau, Switzerland

Background: Low molecular weight proteins like cystatin C or beta-2-microglobulin have been described as markers of renal function with better diagnostic characteristics than serum creatinine. Beta-trace protein (prostaglandin D synthase), another low molecular weight protein, has been proposed as a further suitable marker.
Aim: To describe the diagnostic usefulness of serum-beta-trace Protein (sBtp) in detecting impaired renal function in daily clinical routine.
Methods: First, assessment of creatinine clearance (according to the method of Jelliffe) was done in 73 patients (median age 52 years, interquartile range 39-71) from a tertiary hospital covering the whole range of renal function. After determination of serum creatinine (sCr, modified Jaffé method, Dade Behring, US) and sBtp (nephelometric assay, Dade Behring US), correlations were calculated. Further, Passing-Bablok regression analysis and ROC-analysis were done.
Results: Creatinine clearance correlated significantly with sCr (0.92;p < 0.001) and sBtp (0.81; p < 0.001). The equations obtained from Passing Bablok regression analysis were: creatinine clearance = -15.1 + 92.64 x 1/sCr and creatinine clearance= -3.6 + 45.79 x 1/sBtp. According to ROC-analysis, the area under the curve (AUC) of sCr and sBtp in detecting a creatinine clearance < 60 ml/min was 0.98, and, 0.97, respectively (n.s.). In detecting a creatinine clearance < 100 ml/min, the AUC was 0.94 for sCr, and 0.90 for sBtp (n.s).
Conclusions: Reciprocal values of serum beta trace protein concentrations exhibit a significant correlation with creatinine clearance. Serum beta-trace exhibits clinically useful diagnostic characteristics in detecting a creatinine clearance < 60ml/min. However, we were not able to demonstrate superiority to the diagnostic characteristics of the widely used method of serum creatinine determination.

B Röthlisberger¹ , E Benedek¹ , M Bargetzi² , M Hergersberg¹ , A Huber¹

¹Zentrum für Labormedizin, Kantonsspital Aarau, ²Zentrum für Onkologie/Hämatologie und Transfusionsmedizin, Kantonsspital Aarau

Recently we published a proposal of a simpler, more practical approach for BCR-ABL fusion transcript quantification in a routine setting. We concluded that the major advantages are better standardization with the PAXgene Blood RNA System, use of only 2.5 ml peripheral blood (instead of 10-40 ml), no need to create a standard curve with each run and running samples as single measurements, i.e. non-repeated and estimating the inaccuracy of the method especially for low transcript rates. Using this proposed procedure should allow considerable savings in time and money, while preserving the level of accuracy. However, a major drawback is the reduced sensitivity of our approach.
Since our first proposal the results of more than 100 patient samples now clearly show the feasibility of our approach. Even with the reduced sensitivity of our approach we were able to amplify the BCR-ABL b3a2 MBCR transcript in all samples from CML patients treated with Imatinib mesylate. We conclude therefore, that our proposed RQ-PCR approach is a practical one for quantitative fusion transcript analysis not only in a research but also in a routine laboratory. It can be performed on peripheral blood samples and it is sensitive enough.

B Röthlisberger¹ , M Fischer¹ , R Huber² , A Capone² , M Hergersberg¹ , AR Huber¹

¹Kantonsspital Aarau, Zentrum für Labormedizin, Aarau, Switzerland, ²Kantonsspital Aarau, Kinderklinik, Aarau, Switzerland

We report a case of a 29 months old boy with growth retardation, microcephaly, minor facial anomalies, mental retardation, cerebral atrophy, cerebral ventricular dilatation, hypotonia and pes equinovarus. Conventional cytogenetics showed the presence of additional material on the long arm of chromosome 4. Since at the time of diagnosis blood of the parents could not be obtained, 24-colour-FISH (fluorescence in situ hybridization) was performed and it could be demonstrated, that the additional chromosomal material originates from chromosome 12. After revealing this result to the parents their blood could be collected, and, by conventional cytogenetics a balanced chromosome translocation between the long arm of chromosome 4 and the long arm of chromosome 12 was found in the father. Therefore the karyotype in the patient can be described as following: 46,XY,der(4)t(4;12)(q35;q24.2)pat.
We compare the phenotype of our patient with previous reports of patients with partial duplication of the long arm of chromosome 12 and with subtelomeric deletions of the long arm of chromosome 4. Our investigation provides further information for a better clinical delineation of these two chromosomal aberrations.

P Fernandez¹ , B Röthlisberger² , I Heijnen² , M Jotterand³ , D Mühlematter³ , A Huber² , M Bargetzi¹

¹Blutspendedienst, Kantonsspital Aarau, ²Zentrum für Labormedizin, Kantonsspital Aarau, ³Unité de Cytogénétique du Cancer, Service de génétique médicale, CHUV, Lausanne, ⁴Zentrum für Onkologie/Hämatologie, Kantonsspital Aarau

Structural rearrangements implicating the region 3q26 have been described in 2% of the patients with acute myeloid leukemia (AML), myelodysplastic syndrome (MDS) or chronic myeloid leukemia in blast crisis. These rearrangements are frequently associated with trilineage myelodysplasia, especially dysmegakaryocytosis, and with a particularly poor prognosis. On the molecular level it was shown that inv(3)(q21q26)and t(3;3)(q21;q26), the most frequent alterations with breakpoints in 3q26 (3q21q26 syndrome) involve the oncogene EVI1 which is inappropriately overexpressed.

So far, the translocation t(3;8)(q26;q24) has been reported in 3 patients with MDS (1case) or acute myeloid leukemia AML (2 cases) without further molecular analysis. No other recurrent chromosome aberration with breakpoint in 8q24 has been shown in AML.

We report a case of a 58 year old male patient with a multilineage AML showing a t(3;8)(q26;q24) occurring as a single defect in 80% of bone marrow cells investigated by conventional cytogenetics. The bone marrow aspirate was normocellular, with 25-50% atypical blasts, dyserythropoiesis, dysplastic myelopoiesis and hyperactivated megakaryopoiesis with many micromegakaryocytes. FACS-analysis of the blast showed two cell populations, one with a immunophenotype of CD45+(dim), CD13+, CD14-, CD15-, CD33+, CD34+, CD117+ and MPO- , the other with CD13+, CD14+, CD33+, CD64+, CD34+(dim) and CD117+. After two cycles of chemotherapy pancytopenia persisted and 4 month later relapse was evident. By real time quantitative RT-PCR (RQ-PCR) we showed that EVI1 is highly overexpressed (>100:1) in this patients bone marrow cells as compared with an AML patient without 3q26 involvement. We intend to perform additional investigations to further characterize the breakpoints in 8q24 and 3q26 by Fluoresence-in-situ Hybridization (FISH) and by molecular methods.

The chromosomal translocation t(3;8)(q26;q24) leads to overexpression of EVI1 and, as in other aberrations involving 3q, shows a poor prognosis in AML.