Epstein-Barr virus (EBV) is believed to have a pathogenic role in lymphomas of the upper-aerodigestive tract. This study aims to elucidate the virus association pattern in nasal and nasal-type NK/T-cell lymphomas, and in sequential biopsies of these tumours. A total of 31 cases of previously diagnosed as lethal midline granuloma. Stewart's granuloma, nasal T-cell non-Hodgkin's lymphoma (T-NHL) and NK/T-cell lymphomas from all anatomical sites were retrieved from the files for the study. Reviews of these cases confirm 8 nasal T-NHL, 19 nasal and 4 extranasal lymphomas of NK/T-cell phenotype from 10 Malays, 18 Chinese, 2 Indian and 1 Kadazan. The male: female ratio was 2.4: 1. All T- and NK/T-cell lymphomas strongly expressed TIA-1 and 63% expressed CD2. The majority of NK/T-cell lymphoma occurred in Chinese (13/23), of which 12/13 (92%) of these cases were associated with EBV. Of the 15 nasal and 9 tonsillar B-cell lymphomas included for a comparison study, only 3 (20%) of the nasal cases were associated with EBV (1 male Chinese, 1 female Chinese and 1 male of other ethnic group). Eight cases of NK/T-cell tumours with sequential biopsies show persistence of EBV, irrespective of the interval and sites of subsequent presentations. This study confirms the cytotoxic nature of NK/T-cell tumour and that EBV is strongly associated with the disease regardless of the anatomical site of presentation and ethnicity. However, nasal and paranasal lymphomas of all phenotypes appear to show higher predilection of EBV association in the ethnic Chinese when compared to non-Chinese.
Rearrangement of the immunoglobulin heavy chain (IgH) gene has been used as a marker of lineage and clonality in the diagnosis of B lymphoproliferative disorders. A number of PCR-based techniques have been developed to overcome the disadvantages of Southern blotting, the standard technique in detecting IgH gene rearrangement. Using an established seminested PCR technique with consensus primers to the V and J regions of the IgH gene, we analysed DNA prepared from peripheral blood and/or bone marrow specimens from 30 cases of known B cell malignancies (16 chronic lymphocytic leukemia, 11 acute lymphoblastic leukemia and 3 Non-Hodgkin Lymphoma), 3 cases of T lymphoproliferative disease and 3 cases of reactive lymphocytosis diagnosed in Hospital UKM to detect rearranged IgH gene. We found that monoclonality as represented by the presence of rearranged IgH gene were demonstrated in all the 30 cases. The PCR findings showed 100% concordance with the Southern blot analysis results which also showed rearranged IgH bands in all the 30 cases. We also found that none of the cases of T lymphoproliferative diseases and reactive lymphocytosis showed presence of rearranged IgH band, suggesting that the amplification using the IgH primers is lineage-specific. In conclusion, we find the PCR a useful method to detect IgH gene rearrangement in peripheral blood and bone marrow specimen. Since the PCR results are comparable to that of the Southern blotting in demonstrating B cell monoclonality and owing to its many advantages we feel that it can replace the Southern blot technique for the diagnosis of B cell malignancies.