Paediatric Hodgkin's disease in Spain: association with Epstein-Barr virus strains carrying latent membrane protein-1 oncogene deletions and high frequency of dual infections.

The present report analyses the distribution of 30-base pair (bp) latent membrane protein-1 (LMP-1) oncogene deletions in 24 cases of Epstein-Barr virus (EBV)-positive paediatric Hodgkin's disease (HD) and 39 normal controls. The 30 bp deletion was identified in 19/24 paediatric HD cases (79.2%), of which seven (29.2%) showed the deleted fragment alone, whereas in the remaining 12 (50%) it was accompanied by the nondeleted fragment. Conversely, the deletion was found in 8/22 (36.4%) EBV-positive healthy children, in two (9.1%) of whom the deleted fragment was alone, and was coinfecting with the nondeleted fragment in the other six (27.3%). The LMP-1 deletion was significantly associated with paediatric HD, both including dual infections (P=0.006) or excluding them (P=0.01). Type 2 EBV was carried by 25% of HD children, whereas all controls harboured type 1 EBV. The 30 bp deletion was present in all the paediatric HD specimens that contained type 2 EBV, suggesting that a deleted type 2 EBV strain may be more tumourigenic than a nondeleted type 2 EBV strain. These findings indicate that EBV strains carrying a 30 bp deletion in the third exon of the LMP-1 oncogene may have a more important role in the pathogenesis of paediatric HD than full-length EBV strains. Dual infection by LMP-1 deleted and nondeleted EBV strains is a frequent event both in healthy children and in the paediatric HD population.

Molecular analysis of the IgH gene in 212 cases of Hodgkin's disease: correlation of IgH clonality with the histologic and the immunocytochemical features.

The aims of this study are to evaluate the frequency of clonal immunoglobulin heavy chain gene rearrangements in paraffin-embedded samples of Hodgkin's disease (HD) with use of the polymerase chain reaction method and to correlate the molecular findings with the histologic and immunocytochemical features. DNA extracts from paraffin-embedded sections from 212 HD samples were used for amplification of the IgH gene by use of framework 2 and framework 3 region primers. Immunohistochemical studies were performed on paraffin sections by use of monoclonal antibodies for CD20 and latent membrane protein-1 and polyclonal antibody for CD3. With use of both primer combinations, monoclonality was detected in 18.7% of lymphocyte-predominant HD cases and in 32.2% of classical HD cases. These results suggest that immunoglobulin heavy chain gene clonal rearrangements are relatively frequent in classical HD. In addition, the statistical analyses of the genotypic and immunocytochemical data revealed that the detection of B-cell populations is significantly associated with the expression of CD20 on HRS cells. There was, however, no correlation between the histologic subtype, the percentage of HRS cells, the presence of latent membrane protein-1 expression, and the molecular analysis results.

Deletions in the Epstein-Barr virus latent membrane protein-1 oncogene in Hodgkin's disease.

Aims-To analyse the latent membrane protein-1 (LMP-1) gene in a series of patients with Epstein-Barr virus (EBV) positive LMP expressing ordinary and HIV associated Hodgkin's disease to detect possible genetic alterations and particularly the existence of deletions near the 3' end of the gene.Methods-Expression of the EBV LMP-1 was assessed using immunohistochemistry in 186 cases of Hodgkin's disease and 31 cases of HIV associated Hodgkin's disease. Genomic DNA was extracted from frozen lymph node biopsy specimens from 25 cases of Hodgkin's disease and 11 of HIV associated Hodgkin's disease, all of whom expressed the LMP-1 protein within diagnostic Hodgkin and Reed-Sternberg (HRS) cells, and amplified by polymerase chain reaction (PCR) using primers specific for the different LMP-1 regions.Results-LMP-1 expression was observed in 106 of 186 Hodgkin's disease cases and in all 31 HIV associated Hodgkin's disease cases. Molecular analysis of the LMP-1 gene showed a high degree of genetic heterogeneity in the carboxy-terminal domain compared with the prototype B95-8 EBV strain, specially in the patients with HIV associated Hodgkin's disease. Variation in the size of the repeated region was found in 17 of 25 Hodgkin's disease and nine of 11 HIV associated Hodgkin's disease cases. Deletions of 30 base pairs near the 3' end of the gene were detected in all cases of HIV associated Hodgkin's disease and in six Hodgkin's disease. In one case of Hodgkin's disease a larger deletion was observed. In all patients with LMP-1 deletion mutants, 50-90% of the diagnostic HRS cells expressed the LMP-1 protein.Conclusions-The presence of the 30 base pair deletion in all cases of HIV associated Hodgkin's disease supports previous studies that reported aggressive histological and clinical behaviour in tumours harbouring this deletion. This deletion may prolong the half-life of the protein which would explain the high levels of LMP-1 expressing HRS cells in those cases carrying LMP-1 deletions. That the 30 base pair deletion was present in all of the HIV associated Hodgkin's disease specimens suggests that impairment of immune function is a stringent requirement for the expansion of malignant cells infected by EBV strains containing the deleted LMP-1 gene.