Myriad Mapping of nanoscale minerals reveals calcium carbonate hemihydrate in forming nacre and coral biominerals

Calcium carbonate (CaCO3) is abundant on Earth, is a major component of marine biominerals and thus of sedimentary and metamorphic rocks and it plays a major role in the global carbon cycle by storing atmospheric CO2 into solid biominerals. Six crystalline polymorphs of CaCO3 are known-3 anhydrous: calcite, aragonite, vaterite, and 3 hydrated: ikaite (CaCO3·6H2O), monohydrocalcite (CaCO3·1H2O, MHC), and calcium carbonate hemihydrate (CaCO3·½H2O, CCHH). CCHH was recently discovered and characterized, but exclusively as a synthetic material, not as a naturally occurring mineral. Here, analyzing 200 million spectra with Myriad Mapping (MM) of nanoscale mineral phases, we find CCHH and MHC, along with amorphous precursors, on freshly deposited coral skeleton and nacre surfaces, but not on sea urchin spines. Thus, biomineralization pathways are more complex and diverse than previously understood, opening new questions on isotopes and climate. Crystalline precursors are more accessible than amorphous ones to other spectroscopies and diffraction, in natural and bio-inspired materials.

A Molecular-Scale Understanding of Misorientation Toughening in Corals and Seashells

Biominerals are organic-mineral composites formed by living organisms. They are the hardest and toughest tissues in those organisms, are often polycrystalline, and their mesostructure (which includes nano- and microscale crystallite size, shape, arrangement, and orientation) can vary dramatically. Marine biominerals may be aragonite, vaterite, or calcite, all calcium carbonate (CaCO₃ ) polymorphs, differing in crystal structure. Unexpectedly, diverse CaCO₃ biominerals such as coral skeletons and nacre share a similar characteristic: Adjacent crystals are slightly misoriented. This observation is documented quantitatively at the micro- and nanoscales, using polarization-dependent imaging contrast mapping (PIC mapping), and the slight misorientations is consistently between 1° and 40°. Nanoindentation shows that both polycrystalline biominerals and abiotic synthetic spherulites are tougher than single-crystalline geologic aragonite, and molecular dynamics (MD) simulations of bicrystals at the molecular scale reveals that aragonite, vaterite, and calcite exhibit toughness maxima when the bicrystals are misoriented by 10°, 20°, and 30°, respectively, demonstrating that slight misorientation alone can increase fracture toughness. Slight-misorientation-toughening can be harnessed for synthesis of bioinspired materials that only require one material, are not limited to specific top-down architecture, and are easily achieved by self-assembly of organic molecules (e.g., aspirin, chocolate), polymers, metals, and ceramics well beyond biominerals.

Orientation-controlled crystallization of γ-glycine films with enhanced piezoelectricity

Glycine, the simplest amino acid, is considered a promising functional biomaterial owing to its excellent biocompatibility and strong out-of-plane piezoelectricity. Practical applications require glycine films to be manufactured with their strong piezoelectric polar 〈001〉 direction aligned with the film thickness. Based on the recently-developed solidification approach of a polyvinyl alcohol (PVA) and glycine aqueous solution, in this work, we demonstrate that the crystal orientation of the as-synthesized film is determined by the orientation of glycine crystal nuclei. By controlling the local nucleation kinetics via surface curvature tuning, we shifted the nucleation site from the edge to the middle of the liquid film, and thereby aligned the 〈001〉 direction vertically. As a result, the PVA-glycine-PVA sandwich film exhibits the highest aver-age piezoelectric coefficient d₃₃ of 6.13 ± 1.13 pC N^-1. This work demonstrates a promising kinetic approach to achieve crystallization and property control in a scalable biocrystal manufacturing process.

Faster Crystallization during Coral Skeleton Formation Correlates with Resilience to Ocean Acidification

The mature skeletons of hard corals, termed stony or scleractinian corals, are made of aragonite (CaCO₃). During their formation, particles attaching to the skeleton’s growing surface are calcium carbonate, transiently amorphous. Here we show that amorphous particles are observed frequently and reproducibly just outside the skeleton, where a calicoblastic cell layer envelops and deposits the forming skeleton. The observation of particles in these locations, therefore, is consistent with nucleation and growth of particles in intracellular vesicles. The observed extraskeletal particles range in size between 0.2 and 1.0 μm and contain more of the amorphous precursor phases than the skeleton surface or bulk, where they gradually crystallize to aragonite. This observation was repeated in three diverse genera of corals, Acropora sp., Stylophora pistillata—differently sensitive to ocean acidification (OA)—and Turbinaria peltata, demonstrating that intracellular particles are a major source of material during the additive manufacturing of coral skeletons. Thus, particles are formed away from seawater, in a presumed intracellular calcifying fluid (ICF) in closed vesicles and not, as previously assumed, in the extracellular calcifying fluid (ECF), which, unlike ICF, is partly open to seawater. After particle attachment, the growing skeleton surface remains exposed to ECF, and, remarkably, its crystallization rate varies significantly across genera. The skeleton surface layers containing amorphous pixels vary in thickness across genera: ∼2.1 μm in Acropora, 1.1 μm in Stylophora, and 0.9 μm in Turbinaria. Thus, the slow-crystallizing Acropora skeleton surface remains amorphous and soluble longer, including overnight, when the pH in the ECF drops. Increased skeleton surface solubility is consistent with Acropora’s vulnerability to OA, whereas the Stylophora skeleton surface layer crystallizes faster, consistent with Stylophora’s resilience to OA. Turbinaria, whose response to OA has not yet been tested, is expected to be even more resilient than Stylophora, based on the present data.

From particle attachment to space-filling coral skeletons

Reef-building corals and their aragonite (CaCO3) skeletons support entire reef ecosystems, yet their formation mechanism is poorly understood. Here we used synchrotron spectromicroscopy to observe the nanoscale mineralogy of fresh, forming skeletons from six species spanning all reef-forming coral morphologies: Branching, encrusting, massive, and table. In all species, hydrated and anhydrous amorphous calcium carbonate nanoparticles were precursors for skeletal growth, as previously observed in a single species. The amorphous precursors here were observed in tissue, between tissue and skeleton, and at growth fronts of the skeleton, within a low-density nano- or microporous layer varying in thickness from 7 to 20 µm. Brunauer-Emmett-Teller measurements, however, indicated that the mature skeletons at the microscale were space-filling, comparable to single crystals of geologic aragonite. Nanoparticles alone can never fill space completely, thus ion-by-ion filling must be invoked to fill interstitial pores. Such ion-by-ion diffusion and attachment may occur from the supersaturated calcifying fluid known to exist in corals, or from a dense liquid precursor, observed in synthetic systems but never in biogenic ones. Concomitant particle attachment and ion-by-ion filling was previously observed in synthetic calcite rhombohedra, but never in aragonite pseudohexagonal prisms, synthetic or biogenic, as observed here. Models for biomineral growth, isotope incorporation, and coral skeletons' resilience to ocean warming and acidification must take into account the dual formation mechanism, including particle attachment and ion-by-ion space filling.

COGENT (COlorectal cancer GENeTics): an international consortium to study the role of polymorphic variation on the risk of colorectal cancer

It is now recognised that a part of the inherited risk of colorectal cancer (CRC) can be explained by the co-inheritance of low-penetrance genetic variants. The accumulated experience to date in identifying these variants has served to highlight difficulties in conducting statistically and methodologically rigorous studies and follow-up analyses. The COGENT (COlorectal cancer GENeTics) consortium includes 20 research groups in Europe, Australia, the Americas, China and Japan. The overarching goal of COGENT is to identify and characterise low-penetrance susceptibility variants for CRC through association-based analyses. In this study, we review the rationale for identifying low-penetrance variants for CRC and our proposed strategy for establishing COGENT.

Inhibition of BCL11B expression leads to apoptosis of malignant but not normal mature T cells

The B-cell chronic lymphocytic leukemia (CLL)/lymphoma 11B gene (BCL11B) encodes a Krüppel-like zinc-finger protein, which plays a crucial role in thymopoiesis and has been associated with hematopoietic malignancies. It was hypothesized that BCL11B may act as a tumor-suppressor gene, but its precise function has not yet been elucidated. Here, we demonstrate that the survival of human T-cell leukemia and lymphoma cell lines is critically dependent on Bcl11b. Suppression of Bcl11b by RNA interference selectively induced apoptosis in transformed T cells whereas normal mature T cells remained unaffected. The apoptosis was effected by simultaneous activation of death receptor-mediated and intrinsic apoptotic pathways, most likely as a result of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) upregulation and suppression of the Bcl-xL antiapoptotic protein. Our data indicate an antiapoptotic function of Bcl11b. The resistance of normal mature T lymphocytes to Bcl11b suppression-induced apoptosis and restricted expression pattern make it an attractive therapeutic target in T-cell malignancies.

Disruption of the BCL11B gene through inv(14)(q11.2q32.31) results in the expression of BCL11B-TRDC fusion transcripts and is associated with the absence of wild-type BCL11B transcripts in T-ALL

T-cell acute lymphoblastic leukemia (T-ALL) is associated with chromosomal aberrations characterized by juxtaposition of proto-oncogenes to T-cell receptor gene loci (TCR), resulting in the deregulated transcription of these proto-oncogenes. Here, we describe the molecular characterization of a novel chromosomal aberration, inv(14)(q11.2q32.31), in a T-ALL sample, involving the recently described BCL11B gene and the TCRD locus. The inversion joined the 5' part of BCL11B, including exons 1-3, to the TRDD3 gene segment of the TCRD locus, whereas the reciprocal breakpoint fused the TRDV1 gene segment to the fourth exon of BCL11B. The TRDV1-BCL11B joining region was 1344 bp long and contained fragments derived from 20q11.22, 3p21.33 and from 11p12, indicating the complex character of this aberration. A strong expression of in-frame transcripts with truncated BCL11B and TCRD constant region (TRDC) were observed, but in contrast to normal T cells and other T-ALL samples, no wild-type BCL11B transcripts were detected in the T-ALL sample. Screening of 37 other T-ALLs revealed one additional case with expression of the BCL11B-TRDC fusion transcript. As BCL11B appears to play a key role in T-cell differentiation, BCL11B disruption and disturbed expression may contribute to the development of T-cell malignancies in man.

[Lung metastases of colorectal tumors: clinical background and development of care supply]

The incidence of most cancers increases with age, including colorectal-, lung- and breast carcinomas. Each year, approximately 50,000 new cases of colorectal carcinoma (CRC) are diagnosed in Germany with a peak incidence around the age of 65. At diagnosis, 50% of CRC-cases show already metastases. Cure of metastatic disease with chemotherapy, radiology or surgery alone or in combination can be rarely achieved in this situation. However, palliative therapy regimens can significantly prolong life in most cases. Besides systemic therapy, minimal invasive techniques for tumor reduction are an interesting option in the palliative situation, especially in elderly patients. Yet the clinical impact of these new techniques has to be determined in future studies.

Biological evaluation of recombinant human erythropoietin in pharmaceutical products

The potencies of mammalian cell-derived recombinant human erythropoietin pharmaceutical preparations, from a total of five manufacturers, were assessed by in vivo bioassay using standardized protocols. Eight-week-old normocythemic mice received a single subcutaneous injection followed by blood sampling 96 h later or multiple daily injections with blood sampling 24 h after the last injection. Reticulocyte counting by microscopic examination was employed as the end-point using the brilliant cresyl blue or selective hemolysis methods, together with automated flow cytometry. Different injection schedules were investigated and dose-response curves for the European Pharmacopoeia Biological Reference Preparation of erythropoietin were compared. Manual and automated methods of reticulocyte counting were correlated with respect to assay validity and precision. Using 8 mice per treatment group, intra-assay precision determined for all of the assays in the study showed coefficients of variation of 12.1-28.4% for the brilliant cresyl blue method, 14.1-30.8% for the selective hemolysis method and 8.5-19.7% for the flow cytometry method. Applying the single injection protocol, a combination of at least two independent assays was required to achieve the precision potency and confidence limits indicated by the manufacturers, while the multiple daily injection protocol yielded the same acceptable results within a single assay. Although the latter protocol using flow cytometry for reticulocyte counting gave more precise and reproducible results (intra-assay coefficients of variation: 5.9-14.2%), the well-characterized manual methods provide equally valid alternatives for the quality control of recombinant human erythropoietin therapeutic products.

Comparative evaluation of the human whole blood and human peripheral blood monocyte tests for pyrogens

Two different in vitro tests for pyrogens, using human peripheral blood monocytes (PBMNC) and diluted whole blood (WBC), respectively, were applied to different classes of parenteral medicinal products. Many of these products did not have a specified endotoxin limit concentration that was established as the maximum valid dilution to comply with the test. The results of the in vitro tests for pyrogens were compared with the results from the Limulus amoebocyte lysate (LAL) and rabbit pyrogen tests. The Second International Standard for endotoxin was used to calibrate all of the assays and the International Standard for IL-6 was used to calibrate the IL-6 ELISA which provided the readout for the in vitro tests for pyrogens. Preparatory tests were conducted to ensure that the "criteria for validity and precision of the standard curve" were satisfied and that the drugs being tested did not interfere in the tests. The PBMNC/IL-6 test had a detection limit of 0.06 EU/ml and spike recoveries were 62-165%. The whole blood/IL-6 test also had a detection limit of 0.06 EU/ml and spike recoveries were 58-132%. The application to the detection of non-endotoxin pyrogens needs to be evaluated in more detail, but the two in vitro tests for pyrogens showed good agreement overall, both with each other and with the LAL test and the rabbit pyrogen test for the detection of endotoxins.

Quantitative analysis of beta-actin, beta-2-microglobulin and porphobilinogen deaminase mRNA and their comparison as control transcripts for RT-PCR

Quantitation of target mRNAs using the reverse-transcription polymerase chain reaction found a widespread field of application in diverse biomedical diagnostic assays. However, the problem of varying sample quality has to be solved by correcting target molecule amounts through detection of an endogenous control template. The choice of an appropriate reference gene is still object of debate as pseudogene co-amplification and expression level variations may limit the usefulness of some currently used reference reactions. We compared quantitative expression levels of the commonly used endogenous reference genes beta-actin (beta-actin), beta-2-microglobulin (beta2-MG) and porphobilinogen deaminase (PBDG) using the TaqMan chemistry. With these assays we investigated the respective expression patterns in K562 cells and leucocytes of normal individuals as well as of malignoma patients. In K562 cells 1544+246 beta-actin, 65+30 beta2-MG and 22+/-8 PBDG copies/cell were detected. In normal leucocytes 491+/-97 beta-actin, 40+/-17 beta2-MG and <1 PBDG copies/cell were quantified. Leucocytes of various malignancies exhibited 84+/-51 beta-actin, 106+/-8 beta2-MG and <1 PBDG copies/cell. We conclude that beta2-MG is the most suitable reference gene tested as its variation between different sample origins and within distinct cell types was acceptable low.

Novel T-cell receptor delta gene rearrangement involving a recombining element located 2.6 kb 3' from the Vdelta2 gene segment

In this study, we describe a novel T-cell receptor delta (TCRdelta) gene rearrangement observed in acute myeloid leukemia with coexpression of T-lymphoid antigens (Ly+AML) and in peripheral blood leukocytes (PBL) from one out of ten healthy donors. The rearrangement was identified by Southern blot analysis using a joining region (Jdelta1) specific probe and amplified by polymerase chain reaction (PCR) with a variable region (Vdelta2) and Jdelta1 specific primers. The nucleotide sequence analysis of an atypical 3000 bp PCR product allowed localization of the breakpoint within the TCRdelta gene locus, 2.6 kb 3' from the Vdelta2 gene segment. A regular Ddelta2-Ddelta3-Jdelta1 joining was found at the 3' end of the breakpoint, indicating that the rearrangement was mediated by the VDJ recombinase, but no TCRdelta gene segment was detected at the 5' end. Analysis of the germline sequence 3' from the breakpoint revealed an isolated recombination signal sequence (RSS) capable of initiating a rearrangement. The RSS motif described by us is the second TCRdelta recombining element (deltaRec2). The deltaRec2(Ddelta)Jdelta1 recombination is a rather rare event and can be found in acute leukemia and in PBL from healthy individuals. Most likely, the nonfunctional deltaRec2(Ddelta)Jdelta1 rearrangement is a transient step during the VDJ recombination. It may potentially lead to deletion of the deltaRec2(Ddelta)Jdelta1 complex and either to direct joining of a Vdelta region to one of the downstream Jdelta regions or to a rearrangement of the TCRalpha gene.

Selection of B-cell chronic lymphocytic leukemia cell variants by therapy with anti-CD20 monoclonal antibody rituximab

OBJECTIVE

Anti-CD20 chimeric monoclonal antibody rituximab (Mabthera; IDEC-C2B8) is currently tested in several clinical trials for the treatment of B-cell chronic lymphocytic leukemia (B-CLL). In the present study, we investigated whether rituximab therapy may select for CD20(-) subclones.

MATERIALS AND METHODS

Leukemic B-CLL cells were isolated from patients with B-CLL and sensitivity to rituximab-induced cell death was examined. Levels of CD20 protein and mRNA were determined using flow cytometry and real-time PCR, respectively. Clonality analyses of leukemic cells throughout rituximab therapy were performed by GeneScan analysis of patient clone specific rearrangements of the complementarity determining region III of the heavy chain immunoglobulin.

RESULTS

Cytotoxicity of rituximab in vitro did not depend on the protein levels of CD20. During therapy with rituximab CD20(+) B-CLL cells were depleted and CD20(-) leukemic cells emerged. After treatment, the initial CD20(+) B-CLL cell clone reexpanded. CD20(-) B-CLL cells retained their capacity to synthesize the CD20 molecule.

CONCLUSIONS

These data support the concept that in B-CLL rituximab treatment may not lead to the emergence of CD20(-) leukemic variants. Our findings support clinical studies investigating the benefit of prolonged period of rituximab therapy in B-CLL disease.

Prospective randomized trial to assess the value of preemptive oral therapy for CMV infection following liver transplantation

BACKGROUND

With the development of sensitive tests to detect cytomegalovirus (CMV) viremia, preemptive approaches become a reasonable alternative to general CMV prophylaxis. We performed a randomized trial comparing pp65-antigenemia guided preemptive therapy using oral ganciclovir with symptom-triggered intravenous ganciclovir treatment.

METHODS

Eighty-eight of 372 liver transplant recipients developed antigenemia early after orthotopic liver transplantation. Twenty-eight symptomatic patients with antigenemia were excluded from randomization and treated with intravenous ganciclovir. Sixty pp65-antigen-positive asymptomatic patients were randomized to receive either oral ganciclovir 3x1 g/day for 14 days (group 1) or no preemptive treatment (group 2). Patients that developed CMV disease were treated with intravenous ganciclovir 2x5 mg/kg body weight for 14 days. The high-risk (Donor+/Recipient-) patients were equally distributed in the two study groups.

RESULTS

Three of 30 (10%) patients on oral ganciclovir developed mild to moderate CMV disease compared with 6/30 (20%) patients in the control group. In the Donor+/Recipient- patients, the incidence of CMV disease was 1/6 and 3/7. All disease episodes resolved after intravenous treatment. The 1- and 3-year patient and organ survival was the same in the study groups and in the patients with or without CMV infection. No deaths related to CMV occurred.

CONCLUSIONS

The positive predictive value of pp65-antigenemia for the development of CMV disease was very low, and, in 28/88 patients (32%), antigenemia did not precede symptoms. Therefore, pp65-antigenemia is of limited value in deciding on the timing and need for ganciclovir therapy after liver transplantation.

Fluorescent 5'-exonuclease assay for the absolute quantification of Wilms' tumour gene (WT1) mRNA: implications for monitoring human leukaemias

The Wilms' tumour gene (WT1) has been suggested as a powerful parameter for molecular monitoring of minimal residual disease (MRD) in leukaemias. However, molecular monitoring via WT1 RNA levels is far from being routinely performed, which is possibly owing to the complex and inaccurate quantitative reverse transcription polymerase chain reaction (RT-PCR) procedures. Using a newly-developed quantitative real time RT-PCR, we measured WT1 transcripts in peripheral blood leucocytes of patients with acute myeloid (AML), acute lymphoid (ALL) and chronic myeloid leukaemia (CML). While healthy blood donors did not show measurable amounts of WT1 transcripts, WT1 RNA levels were detectable in all types of leukaemia. Furthermore, intraindividual WT1 transcript kinetics were exclusively dependent on disease progression, treatment and subsequent disease outcome. Using this approach, we could distinguish between treatment response and failure within the first days of therapeutic intervention. Moreover, gradually rising WT1 levels over a period of weeks and months paralleled long-term disease progression and appeared to be a prognostic indicator for subsequent clinical relapse. A linear correlation between quantities of WT1 and bcr/abl fusion transcripts could be seen in CML. We conclude that quantitative assessment of WT1 transcripts using real-time PCR is an appropriate method for molecular monitoring of AML, ALL and CML, and can be used independently for both short- and long-term monitoring of leukaemia patients.

Elevated p21 mRNA level in skeletal muscle of DMD patients and mdx mice indicates either an exhausted satellite cell pool or a higher p21 expression in dystrophin-deficient cells per se

Abnormalities in proliferation and differentiation of the dystrophin-deficient muscle are a controversial aspect of the pathogenesis of Duchenne muscular dystrophy (DMD). Analyses of molecules involved in cell cycle modulation do not exist in this context. Cells withdrawn from the cell cycle permanently express p21. The fact that p2 1, in contrast to other cell cycle proteins, is not diminished when myotubes are reexposed to growth media, allocates this cyclin-dependent kinase inhibitor a special function. Here we report for the first time statistically increased p21 mRNA levels in dystrophin-deficient muscle tissue. Only 42% of conventional RT-PCRs from six muscle samples of human controls yielded positive results but almost all skeletal muscle biopsy samples (87%) from DMD patients (n=5). For p21 mRNA quantification in murine muscle samples we were able to use the exact real-time TaqMan PCR method due to generally higher p21 mRNA levels than in human muscles. In addition, contamination with fibroblasts can be excluded for the murine samples because they do not demonstrate fibrosis at the age of 350 days but start to lose their regenerative capacity. In accord with the results in humans, we observed p21 mRNA levels in mdx mice that were approx. four times as high as those in control mice. Elevated p21 mRNA level may indicate a shift in cell composition towards differentiated p21 expressing cells as a result of an exhausted pool of undifferentiated, non-p21-expressing satellite cells due to previous cycles of de- and regeneration. Alternatively, dystrophin-deficient cells per se may express higher p21 levels for unknown reasons. Although we cannot distinguish between these possibilities, the eventual transfec tion of a patient's own satellite cells with p21 antisense oligonucleotides may enable the dystrophic process to be influenced.

Regulation of the nuclear proteasome activity in myelomonocytic human leukemia cells after adriamycin treatment

Treatment of different human leukemia cell variants with the anthracycline adriamycin was associated with a rapid activation of the proteasome. Thus, proliferating U937, TUR, and retrodifferentiated U937 cells exhibited a 4.3-fold, 5.8-fold, and 4.3-fold proteasome activation within 15 minutes after adriamycin treatment, respectively. In contrast, little if any proteasome activation was detectable in a growth-arrested differentiated U937 population following adriamycin treatment. Further analysis of this mechanism revealed a significant reduction of adriamycin-induced proteasome activity after inhibition of poly(ADP-ribose) polymerase (PARP) by 3-aminobenzamide (3-ABA) in the proliferating leukemic cell types. These findings suggested that PARP is involved in the regulation of drug-induced proteasome activation. Indeed, anti-PARP immunoprecipitation experiments of adriamycin-treated cells revealed increasing levels of coprecipitated, enzymatically active proteasome particularly in the proliferating cell variants in contrast to the differentiated U937 cells, with a maximum after 15 minutes, and sensitivity to PARP inhibition by 3-ABA. The specific role of the PARP was investigated in U937 and TUR cell clones stably transfected with a constitutively active antisense PARP (asPARP) vector. Thus, asPARP-TUR cells developed a 25-fold increased sensitivity to adriamycin treatment. Furthermore, we investigated leukemic blasts isolated from acute myelogenous leukemia patients and obtained a similarly enhanced proteasome activity after adriamycin treatment, which was dependent on the PARP and thus could be coprecipitated with anti-PARP antibodies. Transient transfection of leukemic blasts with the asPARP vector significantly reduced the adriamycin-induced proteasome activation. These data suggest that the PARP-associated nuclear proteasome activation represents a potential target within chemotherapeutic defense mechanisms developed by leukemia cells.

Epstein-Barr virus DNA quantitation assessed by a real-time polymerase chain reaction in a case of Burkitt's lymphoma

A real-time PCR technique was used to quantify EBV DNA load in plasma, leukocytes, peritoneal cells, ascites and cerebrospinal fluid (CSF) at diagnosis and during the follow-up of a 21-year-old patient suffering from an abdominal form of EBV-associated Burkitt's lymphoma. The EBV DNA load correlated well with the clinical and biological remission status of the patient after chemotherapy confirming that EBV DNA quantitation in plasma and leukocytes from peripheral blood can be considered as a marker of the tumor load and can be analyzed in parallel for monitoring of EBV-related malignancies.

Molecular quantification of response to therapy and remission status in TEL-AML1-positive childhood ALL by real-time reverse transcription polymerase chain reaction

Although TEL-AML1 positivity [translocation t(12;21)(p13;q22)], detected in 20-25% of initial childhood acute lymphoblastic leukemia (ALL), has been associated with an excellent prognosis, its positive predictive value is insufficient for appropriate treatment stratification considering reported prevalence in relapsed ALL (3-28%). Molecular quantification of response to therapy by PCR-based methods has been shown to improve risk assessment. Here, we report on the sensitive quantification of leukemia-specific TEL-AML1 fusion transcript levels normalized to beta-actin expression (sensitivity threshholds, 10(-5)) by a novel real-time reverse transcription-PCR (RQ-RT-PCR) based on fluorescent TaqMan technique providing early and rapid evidence on the treatment efficacy of children with initial or relapsed TEL-AML1+ ALL enrolled in frontline or relapse trials of the Berlin-Frankfurt-Münster (BFM)-Study Group. In initial ALL, TEL-AML1/beta-actin decrease was > or =10(5)-fold in 50% of patients after induction therapy (day 33) and stayed TEL-AML1-negative throughout therapy, which suggested high sensitivity of leukemic cells to antineoplastic therapy. The remaining patients were still TEL-AML1+ before reintensification (ratios, 0.7 x 10(-2):10(-4)). In relapsed ALL, TEL-AML1/beta-actin decrease was generally less pronounced at corresponding time points, and conversion to TEL-AML1 negativity was observed in 40% of patients. Most notably, subsequent relapses occurred only among molecular poor responders, whereas all early responders remain in their second complete remission. In conclusion, real-time quantification of TEL-AML1/beta-actin kinetics distinguishes distinct molecular response groups, and provides indications capable of directing therapeutic interventions for patients with TEL-AML1+ ALL. Before considering modification of therapy, results should be interpreted cautiously taking into account the long duration of remission associated with TEL-AML1+ ALL.

Simultaneous absolute quantification of target and control templates by real-time fluorescence reverse transcription-PCR using 4-(4'-dimethylaminophenylazo)benzoic acid as a dark quencher dye

BACKGROUND

Despite the many advantages of real-time fluorescence reverse transcription-PCR (RT-PCR) as a quantitative analytical tool, simultaneous quantification of target and reference templates within one reaction has not been reported. We developed such an assay with an internal reference template.

METHODS

For quantification of target and reference sequences, we used two fluorescent probes in one reaction vessel on an ABI PRISM 7700 SDS instrument. Fluorescent probes were labeled with either 6-carboxy-fluorescein or hexachloro-6-carboxy-fluorescein as reporter dye and 4-(4'-dimethylaminophenylazo)benzoic acid (DABCYL) as a dark quencher fluorophore. To test the sensitivity and specificity of this assay, serial dilutions of reference and target templates were analyzed in one PCR reaction. In the presence of 10 beta-actin molecules as control templates, 10(5) bcr/abl molecules were amplified, and 10(5) beta-actin molecules were amplified in the presence of 10 bcr/abl copies. We also performed single and duplex measurements on samples from five patients with documented Philadelphia chromosome-positive chronic myelogenous leukemia disease courses (72 samples) and three with minor bcr/abl+ acute myelogenous leukemias (26 samples).

RESULTS

For M-bcr/abl duplex RT-PCR, the correlation coefficient (r) for starting template amounts and threshold cycle values was 0.99; for m-bcr/abl, r = 0.96, indicating a precise log-linear relation for 10-10(5) copies/100 ng of cDNA. In the same PCR reactions, r = 0.99 for beta-actin (coamplified with M-bcr/abl or m-bcr/abl) for 10(3)-10(7) copies/100 ng cDNA. The linear correlation coefficient for single and duplex measurements was 0.98 for M- and m-bcr/abl in patient samples.

CONCLUSIONS

DABCYL can be used as dark quencher fluorophore in real-time fluorescence PCR. The duplex fluorescence RT-PCR assay for bcr/abl and beta-actin transcripts allows monitoring of bcr/abl+ leukemias.

What can we learn from leukemia as for the process of lineage commitment in hematopoiesis?

Most contemporary models of hematopoiesis assume lineage fidelity of early progenitor cells. Along with this concept normal hematopoietic cells and the majority of leukemias express exclusively myeloid or lymphoid specific antigens. On the other hand, growing evidence exists challenging the lineage fidelity model. Chronic myeloid leukemia (CML) in the blast crisis may switch to acute lymphoblastic leukemia (ALL) and as a result of the chemotherapy ALL may converse to acute myeloid leukemia (AML). Furthermore, a substantial portion of leukemia cases, named acute mixed-lineage leukemia (AMLL), show simultaneous expression of both myeloid and lymphoid antigens. Immunoglobulin (Ig) and T-cell receptor (TCR) gene rearrangements, correlating with myeloid-lymphoid immunophenotype in AMLL, support the hypothesis of lineage infidelity of early progenitor cells, rather than the aberrant antigen expression. Based on a detailed characterization of AMLL we present a modified model of a "common myeloid/lymphoid progenitor cell". This hypothetical very early hematopoietic progenitor cell shows a transient expression of myeloid and B- or T-lymphoid antigen and may also have rearranged its Ig and/or TCR genes. Subsequently, myeloid or lymphoid markers are downregulated and the hematopoietic cell enters either myeloid, T-lymphoid or B-lymphoid differentiation pathway.

Cardiopulmonary bypass in patients with heparin-induced thrombocytopenia and thrombosis

Heparin-induced thrombocytopenia and thrombosis (HITT) is an immunomediated disorder induced by the administration of heparin for therapeutic purposes. The presence of this condition in patients requiring full heparinization for cardiopulmonary bypass constitutes a formidable challenge for the cardiac surgeon. In this review, the clinical and experimental experience described in the literature are discussed in the perspective of the normal coagulation and the pathophysiology of HITT and in the light of a variety of old and new alternative anticoagulants.

Enhanced p73 expression during differentiation and complex p73 isoforms in myeloid leukemia

The p53 homologue p73 is expressed in at least six different isoforms (alpha, beta, gamma, delta, epsilon, and zeta), but unlike p53 it has rarely been found mutated in human cancers. However, altered expression of this gene has been reported in cancer cells. In order to understand if p73 is involved in normal and malignant development of myeloid cells, we investigated the expression pattern of the different p73 isoforms in progenitor and mature normal myeloid cells as well as in cells derived from acute and chronic myeloid leukemias. The results show that expression of p73 is markedly enhanced during differentiation of myeloid leukemic cells and that leukemic blasts from patients show an increased expression of the shorter p73 isoforms (gamma, delta, epsilon, zeta). In particular the epsilon isoform is only expressed in leukemic cells and completely absent in mature myeloid cells. Altogether our data suggest that p73 is involved in myeloid differentiation and its altered expression is involved in leukemic degeneration.

Presence of human beta- and gamma-herpes virus DNA in Hodgkin's disease

Herpes viruses have been implicated in the etiology of Hodgkin's disease (HD). We studied the prevalence of human cytomegalovirus (CMV), human herpes viruses type-6 (HHV-6), type-7 (HHV-7) and type 8 (HHV-8) DNA in up to 88 Hodgkin's disease biopsies in comparison to Epstein-Barr virus (EBV) DNA by polymerase chain reaction (PCR). Non-Hodgkin lymphomas (NHL) and reactive lesions served as controls. CMV and HHV-6 were found in 8/86 (9%) and 11/88 (13%) HD cases, respectively, by nested primer PCR. Except for three cases harbouring HHV-6 type-B, only HHV-6 type-A was detected in HD. HHV-7 was observed by nested PCR in 33/88 (38%) HD cases and was already detectable in 15/88 (17%) HD cases by a single-round PCR indicating elevated virus copy numbers. Seven of these cases showed co-infection with HHV-6, and 11 cases were found to contain EBV DNA. 7/8 CMV-positive HD cases also harboured EBV DNA. HHV-8 DNA was not detected by single round or nested PCR in any HD case investigated. Thus, CMV, HHV-6, and HHV-7 were present in small proportions of HD cases, with frequent co-infection of HHV-6 and HHV-7, and frequent association with EBV. In contrast to EBV, beta-herpes viruses are therefore unlikely to have a role in the aetiology of HD. Rather, the presence of these viruses seems to reflect impaired immunological surveillance.

Quality assurance in RT-PCR-based BCR/ABL diagnostics--results of an interlaboratory test and a standardization approach

Here we describe the results of an interlaboratory test for RT-PCR-based BCR/ABL analysis. The test was organized in two parts. The number of participating laboratories in the first and second part was 27 and 20, respectively. In the first part samples containing various concentrations of plasmids with the ela2, b2a2 or b3a2 BCR/ABL transcripts were analyzed by PCR. In the second part of the test, cell samples containing various concentrations of BCR/ABL-positive cells were analyzed by RT-PCR. Overall PCR sensitivity was sufficient in approximately 90% of the tests, but a significant number of false positive results were obtained. There were significant differences in sensitivity in the cell-based analysis between the various participants. The results are discussed, and proposals are made regarding the choice of primers, controls, conditions for RNA extraction and reverse transcription.

Preemptive therapy in CMV-antigen positive patients after liver transplantation--a prospective trial

OBJECTIVE

Preemptive therapy with intravenous ganciclovir and CMV-hyperimmunoglobulin in asymptomatic CMV pp65-antigen positive patients was compared with treatment of only symptomatic CMV-disease after liver transplantation in an open prospective study.

PATIENTS AND METHODS

48 out of 200 liver transplant recipients became positive during six weeks follow-up after transplantation. 17 out of these 48 patients who were already symptomatic at the time of positive antigen testing were successfully treated with ganciclovir and CMV-hyperimmunoglobulin. 31 asymptomatic antigen-positive patients were randomised to receive preemptive therapy or to receive therapy only at onset of clinical symptoms.

RESULTS

Only two out of 15 patients in this latter group without preemptive therapy developed CMV-syndrome and were successfully treated with intravenous ganciclovir. 13 patients did not experience any clinical symptoms or disease and were therefore spared unneccessary toxicity and costs. The overall incidence of CMV-infection and -disease in the whole study population of 200 liver transplant recipients was 25% and 10%. As expected, CMV-negative patients who received an organ from a seropositive donor were at a higher risk of CMV-infection and -disease, but did not show more severe infections clinically. Patients with IL-2 receptor antibody induction therapy seemed to have a higher risk for CMV-infection and -disease.

Detection of human cytomegalovirus DNA by real-time quantitative PCR

A real-time PCR assay was developed to quantify human cytomegalovirus (CMV) DNA. This assay was used to demonstrate a higher CMV DNA load in plasma of bone marrow transplant patients than in that of blood donors. The CMV load was higher in CMV antigen-positive patients than in antigen-negative patients.

Applicability of an absolute quantitative procedure to monitor intra-individual bcr/abl transcript kinetics in clinical samples from chronic myelogenous leukemia patients

Chimeric bcr/abl fusion proteins are thought to be the molecular 'pathogen' of chronic myelogenous leukaemia (CML). Expression levels of the respective fusion RNAs reflect disease progression as well as remission upon therapeutic intervention in CML patients. However, there is no quick and reliable method that would allow the quantitative routine monitoring of bcr/abl hybrid transcripts. A fluorescent probe-based PCR assay (TaqMan) has been described to quantitfy the exact amount of target sequences. We have established TaqMan real-time RT-PCRs for M-bcr/abl (b2a2, b2a3, b3a2, b3a3) and m-bcr/abl (e1a2) fusion transcripts as well as for beta-actin. All PCRs quantified as little as 10 copies/100 ng total cDNA. In order to investigate whether this procedure is appropriate for routine diagnostic monitoring, we performed retrospective measurements on 9 documented CML disease courses. Our data show that ongoing or relapsing CML is paralleled by increasing peripheral levels of bcr/abl fusion RNAs. Furthermore, sucessful anti-leukemic treatment is reflected by decreasing absolute bcr/abl transcript numbers. In contrast with conventional bcr/abl PCR techniques we could distinguish single positive values and gradually increasing copy numbers.

Influence of DNA polymerases on quantitative PCR results using TaqMan probe format in the LightCycler instrument

Real-time fluorescence polymerase chain reaction (PCR) techniques are increasingly used to quantitate target sequences for diagnostic and research purposes. Currently, the so called TaqMan probe chemistry is mostly used as fluorogenic system. This probe format is strictly dependent on the 5'-exonuclease activity of DNA polymerase as fragmentation of the probe during the reaction is essential for this assay. Based on our experience that dramatic differences in quantitative PCR results may be due to different DNA polymerases we performed a detailed comparison of 15 enzymes. We found that clear differences exist between polymerases of different manufacturers. Thus, three out of seven polymerases which were declared to possess 5'-exonuclease activity appeared to be completely unsuitable for this method while the remaining had significantly different reaction efficiencies. We conclude that different DNA polymerases may determine the entire analytical performance of TaqMan assays suggesting that DNA polymerase testing is of special importance when this probe format is used.

Different real-time PCR formats compared for the quantitative detection of human cytomegalovirus DNA

BACKGROUND

The aim of this study was to compare the ABI PRISM 7700 Sequence Detection System and the LightCycler to develop a quantitative real-time PCR assay for the detection of human cytomegalovirus (HCMV) DNA suitable for routine hospital application.

METHODS

We used one exonuclease probe and five different hybridization probe sets as sequence-specific fluorescence detection formats. For the exonuclease assay and two hybridization probe sets, reproducibility and the detection limit were determined. To keep the total assay time to a minimum, we gradually shortened individual reaction steps on both instruments.

RESULTS

The exonuclease assay can be interchangeably performed on the 7700 and the LightCycler. No change of reaction conditions is required, except for the addition of bovine serum albumin to the LightCycler reaction. The shortest possible total assay time is 80 min for the ABI PRISM 7700 Sequence Detection System and 20 min for the LightCycler. When the LightCycler is used, the exonuclease probe can be replaced by a set of hybridization probes. All assays presented here detected HCMV DNA in a linear range from 10(1) to 10(7) HCMV genome equivalents/assay (r >0.995) with low intraassay (<5%) and interassay (<10%) variation.

CONCLUSIONS

The ABI PRISM 7700 Sequence Detection System as well as the LightCycler are useful instruments for rapid and precise online PCR detection. Moreover, the two principles of fluorescence signal production allow HCMV quantification with the same accuracy.

Hepatocytes are permissive for human cytomegalovirus infection in human liver cell culture and In vivo

The cytopathic potential of human cytomegalovirus (HCMV) in human liver cells was analyzed in cell culture and in tissue sections from patients with HCMV hepatitis. Liver cell cultures, consisting of hepatocytes, bile duct epithelial cells, and stromal cells were infected by various HCMV strains. Cytopathic effects, viral gene expression, and virus production were detected. Infected cell types were identified by immunocytochemical double labeling. Hepatocytes were the predominant target cells of HCMV infection in liver tissues and in cell culture. Late-stage infected cultured hepatocytes produced infectious progeny virus, and infectious virus was propagated from liver tissue specimens. HCMV infection in cultured liver cells closely resembled in vivo infection of the liver with regard to the target cell spectrum and the permissive course of infection. It is concluded that HCMV can cause direct liver parenchyma damage by efficient cytolytic infection of hepatocytes.

Phase I trial of gemcitabine (Gemzar), 24 h infusion 5-fluorouracil and folinic acid in patients with inoperable pancreatic cancer

Gemcitabine (Gemzar) has a significant impact upon survival and quality of life for patients with pancreatic cancer, compared with 5-fluorouracil (5-FU). This phase I study was initiated to define the recommended dose of 5-FU delivered as a 24 h infusion in combination with gemcitabine (1000 mg/m2) and folinic acid (200 mg/m2) in patients with inoperable pancreatic cancer, treated on an outpatient basis. Drugs were administered weekly for 4 weeks out of 6 weeks. Sixteen chemonaive patients (median age 59 years, range 51-66) were enrolled, 15 had stage IV and one stage III disease. The median Karnofsky performance score (KPS) was 70 (range 60-80). Six patients received 5-FU 750 mg/m2, eight received 5-FU 1000 mg/m2 and two received 5-FU 1250 mg/m2. The maximum tolerated dose of 5-FU was 1000 mg/m2. Hepatotoxicity was dose limiting. One patient who received 5-FU 1250 mg/m2 died as a result of hepatorenal failure. There was one partial response, nine patients had stable disease for more than 3 months and 13 patients had improved KPS. The median time to progressive disease was 31 weeks (range 5-50 weeks). A phase 11 trial is underway to further assess the activity of this combination at the recommended dose of 750 mg/m2 5-FU.

Distinct expression patterns of the p53-homologue p73 in malignant and normal hematopoiesis assessed by a novel real-time reverse transcription-polymerase chain reaction assay and protein analysis

The role of the recently identified first p53-homologue, p73, in neoplastic transformation is unknown. To elucidate p73 gene expression in hematopoiesis, we investigated samples from chronic myeloid leukemia (CML) and acute myeloid leukemia patients, leukemia cell lines, as well as mature and immature normal hematopoietic cells by real-time quantitative RT-PCR and Western blot analysis. We found a distinct p73 expression profile with highest p73 mRNA transcript levels in hematopoietic malignancies such as CML blast crisis and acute myelogenous leukemia versus CML chronic phase and normal controls. Mono- and biallelic p73 expression was found in both normal and malignant hematopoiesis. p73 protein was expressed at various levels in leukemia samples and cell lines but could not be detected in any normal controls tested. Our results point to a distinct yet undefined role of p73 in the pathogenesis of myeloid neoplasms.

LightCycler technology for the quantitation of bcr/abl fusion transcripts

Quantifying bcr/abl fusion transcripts in chronic myelogenous leukemia is thought to serve as a powerful parameter for monitoring the kinetic nature of this clonal disease in vivo and in vitro. Recently, we demonstrated the technical advantages as well as the clinical relevance of quantitating bcr/abl fusion mRNA using the 5-nuclease assay and a real-time fluorescence reverse transcriptase-PCR (RT-PCR) detection system (ABI PRISM 7700 SDS). Meanwhile, another technique was introduced (LightCycler technology) that may be used for the same purpose. To investigate whether this method may be an appropriate alternative to the described procedure, we have established bcr/abl LightCycler RT-PCR for major and minor bcr/abl fusion transcripts. We found that, with only minor modifications, TaqMan RT-PCR and fluorescent probe design can be used to obtain comparable results in the LightCycler system. The developed method could quantitate as little as 10 bcr/abl copies per 100 ng cDNA and was as safe and reproducible as the previously described technique. Because reaction efficiency was identical within different bcr/abl major fusions, one single RT-PCR could be established that simultaneously detects b2a3, b2a2, b3a2, and b3a3 fusion RNA with equal specificity and sensitivity. Compared to results generated by the ABI PRISM 7700 SDS, absolute amounts of bcr/abl did not differ significantly, and there was a linear correlation between the respective values. We conclude that TaqMan chemistry can be used in the LightCycler and that both real-time fluorescence PCR detection systems equally fulfill the criteria for the safe and reliable quantitation of bcr/abl fusion RNA in clinical samples. This may be of help for further standardization of quantitative bcr/abl RT-PCR, which, again, is necessary for the comparison of results generated by different investigators.

Identification of human cytomegalovirus variants by analysis of single strand conformation polymorphism and DNA sequencing of the envelope glycoprotein B gene region-distribution frequency in liver transplant recipients

Single strand conformation polymorphism analysis (SSCP) of PCR-amplified DNA and subsequent DNA sequencing of human cytomegalovirus (HCMV) glycoprotein B (gB) gene were applied to identify known HCMV strains and to detect new virus variants. 61 HCMV PCR positive patients were studied out of a cohort of 410 patients after liver transplantation (LTX). SSCP was able to distinguish between strains Davis, AD169, and Towne, and in addition could identify five new virus variants (Berlin B, C, E, F, and H). Their frequency, gB and gH types were determined. Simultaneous infections with two or three strains or variants, as well as a switch from one virus to another virus were observed during long-term follow-up. No correlation between the occurrence of certain virus strains or gB types and defined clinical manifestations of HCMV infection after LTX was drawn.

Acute myeloid and T-cell acute lymphoblastic leukaemia with aberrant antigen expression exhibit similar TCRdelta gene rearrangements

TCR delta gene recombination patterns were analysed by Southern blot, polymerase chain reaction and nucleotide sequencing in acute myeloid leukaemias, with coexpression of lymphoid antigens (Ly+ AML, n=10) as well as in early T-cell acute lymphoblastic leukaemias with (My+ T-ALL, n=10) and without coexpression of myeloid antigens (My(-) T-ALL, n=9). These 29 acute leukaemias exhibiting TCR delta gene rearrangements were selected from 66 Ly+ AML, 14 My+ T-ALL and 12 My(-) T-ALL cases. Similar recombination patterns, namely D delta 2J delta1 and V delta 1J delta1 gene rearrangements, were observed in Ly+ AML and My+T-ALL. In contrast to V delta2 D delta3 rearrangements in B-cell precursor ALL, these rearrangements require activation of a T-cell-specific TCR delta enhancer. Comparison of My+ T-ALL and Ly+ AML with My(-) T-ALL exhibited a higher incidence of incomplete D delta 2J delta1 rearrangements in My+ T-ALL and Ly+ AML. Since a D delta 2J delta1 rearrangement is an early event in TCR delta recombination, these leukaemias seem to be arrested at an earlier stage of differentiation. Similar patterns of TCR delta rearrangements in My+ T-ALL and Ly+ AML suggest existence of a common myeloid/T-lymphoid progenitor cell. Although weak or missing expression of terminal deoxynucleotidyl transferase (T delta T) was found in 7/10 Ly+ AML cases, no difference was observed in numbers of N-nucleotides inserted in junctional regions when comparing with 3/10 cases exhibiting TdT expression. Since TdT activity is necessary for N-nucleotide addition, this finding suggests down-regulation of T delta T expression after rearrangement took place in these Ly+ AML cases.

A prospective study of human herpesvirus type 6 detected by polymerase chain reaction after liver transplantation

Human herpesvirus type 6 (HHV-6) causes roseola infantum (exanthema subitum) upon primary infection in young children. Thereafter it persists lifelong in the organism. Like other herpesviruses, HHV-6 can be reactivated in periods of immunosuppression - e.g., after organ transplantation. In order to study the incidence and the time to reactivation after orthotopic liver transplantation (OLT) we tested buffy coat lysates before and up to 10 weeks after transplantation for the presence of HHV-6 DNA by polymerase chain reaction (PCR). Forty-six patients (male n=27, female n=19) with a median age of 48 years (range 20-66) were studied. Altogether, 30 of 287 (10.5%) buffy coat samples were PCR-positive. Before OLT 2 of 21 (9.5%) patients were positive. This ratio is not different from healthy blood donor controls. After OLT 13 of 46 (23.8%) patients were positive on one or more occasions. However, there was no statistically significant difference before and after OLT. Ten patients were analyzed for HHV-6 variants by restriction enzyme digestion of PCR products. One patient carried variant A and 9 variant B. In conclusion, HHV-6 can be detected in buffy coat cells after OLT. Our observations do not argue in favor of a reactivation.

TCR delta gene rearrangements in acute myeloid leukemia with T-lymphoid antigen expression

In this review we present our data concerning T-cell receptor (TCR) delta gene rearrangements in acute myeloid leukemia with coexpression of T-lymphoid features (CD2/CD4/CD7; Ly+ AML). We found a correlation between TCR delta gene rearrangements and coexpression of these T-lymphoid features. Ten of 66 Ly+ AML and only one of 44 AML cases without this coexpression exhibited TCR delta gene rearrangements (p = .028). In contrast, no correlation was observed between terminal deoxynucleotidyl transferase (TdT) expression and the occurrence of TCR delta gene rearrangements in AML. Rearrangements were found in two of 25 AML with and seven of 71 AML cases without TdT expression. Interestingly, nucleotide sequencing of junctional sites revealed up to 36 N-nucleotides in cases without or with only weak TdT expression indicating downregulation of TdT expression after the TCR rearrangement took place. Complete V delta 1J delta 1 and incomplete D delta 2J delta 1 gene rearrangements were observed most frequently in Ly+ AML. These recombination patterns were similar to patterns observed in acute T-lymphoblastic leukemia with coexpression of myeloid features (My+ T-ALL) suggesting transformation of a common myeloid/T-lymphoid progenitor cell in these cases.

Human herpesvirus type 7 in blood donors: detection by the polymerase chain reaction

In order to evaluate the prevalence of human herpesvirus type 7 (HHV-7) in adult blood donors oral lavage fluid, buffy coat, and urine samples from 112 persons were examined by the polymerase chain reaction (PCR) at one time point. In addition, 11 donors were studied longitudinally over 11 weeks. When the results of the initial and the longitudinal study were combined HHV-7 DNA was found in samples from 109 of 112 (97.3%) adult blood donors. On the basis of different sensitivity levels of the first and the nested PCR differences were detected in the viral DNA load in the samples. It was found that lavage fluid regularly carried significantly higher DNA concentrations than buffy coat. Out of 112 donors, 102 (91.1%) and 8 (7.1%) were positive in the first, less sensitive PCR in lavage fluid and buffy coat, respectively (P < .0001). After nested PCR, 107 (95.5%) and 74 (66.1%) were positive in lavage fluid and buffy coat, respectively (P < .0001). Urine samples were found positive only sporadically. The longitudinal study showed that the oral lavage fluid of most of the donors consistently carried HHV-7 over up to 53 weeks, whereas buffy coat samples were positive less often. In conclusion, HHV-7 is found frequently in adult blood donors in the oral lavage fluid and buffy coat, which are, therefore, potential sources of HHV-7 transmission.