Fluorescent in situ hybridization (FISH) was used to investigate the chromosomal integration sites of human herpesvirus 6 (HHV-6) in phytohemagglutinin-stimulated leukocytes and B lymphocytes from Epstein-Barr virus transformed lymphoblastoid cell lines (LCLs). Five different chromosomal integration sites were found in nine individuals. Only one site was identified in each individual, each site was in the vicinity of the telomeric region and was on either the p or q arm of only one of the two chromosome homologues. The sites were 9q34.3, 10q26.3, 11p15.5, 17p13.3, and 19q 13.4, of which three have not been previously identified. For 9q34.3 the site of integration was further mapped using a locus-specific probe for 9q34.3 together with a pan-telomeric probe and both co-localized with the HHV-6 signal. Similarly an arm-specific telomeric probe for 19q co-localized with the HHV-6 signal. It was therefore concluded that the site of integration is actually within the telomere. The number of viral DNA copies/cell was calculated in blood, LCL cells and hair follicles and was one or more in every case for each of the nine individuals. This result was confirmed by FISH where 100% of cells gave an HHV-6 signal. These findings add to previous reports suggesting that integrated HHV-6 DNA is found in every cell in the body and transmitted vertically. Finally, including our data, worldwide seven different chromosomal sites of HHV-6 integration have now been identified. Large epidemiological studies of chromosomal integration are required to identify further telomeric sites, geographical or racial variation and possible clinical consequences.

BackgroundChronic myelogenous leukemia (CML) results from the neoplastic transformation of a haematopoietic stem cell. The hallmark genetic abnormality of CML is a chimeric BCR/ABL1 fusion gene resulting from the Philadelphia chromosome rearrangement t(9;22)(q34;q11). Clinical and laboratory studies indicate that the BCR/ABL1 fusion protein is essential for initiation, maintenance and progression of CML, yet the event(s) driving the transformation from chronic phase to blast phase are poorly understood.ResultsHere we report multiple genome aberrations in a collection of 78 CML and 14 control samples by oligonucleotide array comparative genomic hybridization. We found a unique signature of genome deletions within the immunoglobulin heavy chain (IGH) and T cell receptor regions (TCR), frequently accompanied by concomitant loss of sequences within the short arm regions of chromosomes 7 and 9, including IKZF1, HOXA7, CDKN2A/2B, MLLT3, IFNA/B, RNF38, PAX5, JMJD2C and PDCD1LG2 genes.ConclusionsNone of these genome losses were detected in any of the CML samples with myeloid transformation, chronic phase or controls, indicating that their presence is obligatory for the development of a malignant clone with a lymphoid phenotype. Notably, the coincidental deletions at IGH and TCR regions appear to precede the loss of IKZF1 and/or p16 genes in CML indicating a possible involvement of RAG in these deletions.

Summary Two patients with the characteristic high human herpesvirus 6 (HHV‐6) DNA loads in peripheral blood caused by chromosomally integrated (CI) virus received a haematopoietic stem cell transplant (HSCT) from a donor without CI HHV‐6. Both patients died in consequence of cytomegalovirus (CMV) pneumonitis. At autopsy, high amounts of CMV DNA were detected in lungs but at much lower levels in other organs. In contrast HHV‐6 DNA was detected at high levels throughout the organs with the exception of donor‐derived haematopoietic tissue. In individuals with chromosomal integration, HHV‐6 DNA is found in every tissue of recipient origin indicating inheritance through the germ line.

BackgroundPatients harbouring the UGT1A1*28/*28 genotype are at risk of severe toxicity with the standard irinotecan dose. However, this dose is considerably lower than the dose that can be tolerated by UGT1A1*1/*1 and *1/*28 patients. This randomised phase II trial evaluated the efficacy and safety of the FOLFIRI regimen with high-dose irinotecan (HD-FOLFIRI) in metastatic colorectal cancer patients.MethodsEighty-two patients with the UGT1A1*1/*1 or the *1/*28 genotype were randomised to receive HD-FOLFIRI versus FOLFIRI. Patients with the UGT1A1*28/*28 genotype were excluded. In the experimental group, the irinotecan dose was 300 mg/m2 for UGT1A1*1/*1 and 260 mg/m2 for *1/*28 patients. In the control group, the dose was 180 mg/m2. We analysed the overall response rate (ORR), toxicity, and survival.ResultsThe ORR was significantly higher in the HD-FOLFIRI group (67.5 versus 43.6%; p = 0.001 OR: 1.73 [95% CI:1.03–2.93]). Neutropenia (17.7%), diarrhoea (5.1%), and asthenia (5.1%) were the most common grade 3–4 toxicity. No differences were observed in severe toxicity (22.5% versus 20.5%), dose reduction (22.5% versus 28.2%), or prophylactic G-CSF (17.5% versus 12.8%). No difference in survival was found.ConclusionsPatients with the UGT1A1*1/*1 and *1/*28 genotypes can receive high doses of irinotecan to achieve a more favourable ORR without significant adverse events.