The incidence of follicular lymphoma differs significantly between white and Japanese individuals. Translocation between the BCL-2 and immunoglobulin heavy chain genes is detected in 85% to 90% of all follicular lymphomas in whites. Recently, BCL-2/J H translocation was detected in peripheral blood lymphocytes from more than 50% of healthy white individuals. To clarify the reason for the difference in incidence of follicular lymphoma between whites and Japanese, the frequency of BCL-2/J H translocation in peripheral blood lymphocytes of healthy Japanese individuals was compared with that of German individuals. The prevalence of BCL-2/J H translocation in Japanese adults appeared to be significantly lower than that in German adults. The present data suggest that the low frequency of BCL-2/J H translocation in the Japanese general population may be one of the major reasons for the difference in incidence of follicular lymphoma between whites and Japanese. IntroductionThe incidence of follicular lymphoma differs between white and Japanese individuals, accounting for about 40% of all non-Hodgkin lymphomas in whites, compared with less than 10% in Japanese. [1][2][3][4][5] The age-adjusted incidence of follicular lymphoma (per 100 000) is reported to be 3.8 in the United States and 0.5 in Japan. 2 The reason for this difference between the 2 populations is unknown.The translocation t(14;18)(q32;q21) between the BCL-2 protooncogene and the J H immunoglobulin gene region is detected in 85% to 90% and approximately 50% of all follicular lymphomas in whites and Japanese, respectively. [5][6][7][8][9][10] This leads to overexpression of BCL-2, conferring a growth advantage on the neoplastic cells. 11 Recently, it has been reported that BCL-2/J H translocation is frequently detected in peripheral blood lymphocytes of healthy white individuals. [12][13][14][15][16][17] In the multihit theory of tumorigenesis, translocation of the BCL-2 gene is considered to be the first somatic mutation, and additional mutations are needed for development of follicular lymphoma. From this viewpoint, the low incidence of follicular lymphoma in Japanese individuals may be due to the low frequency of BCL-2/J H translocation in the general population or other factors affecting lymphomagenesis. Accordingly, we compared the frequency of BCL-2/J H translocation in peripheral blood lymphocytes of Japanese individuals with that of German individuals. The results showed that the incidence of BCL-2/J H translocation in healthy Japanese individuals is significantly lower than that in German individuals. Study designPeripheral blood mononuclear cells were obtained with informed consent from Japanese and German (white) individuals who had no serious diseases, and the DNA was extracted using standard procedures. The DNA samples from German individuals were sent to Japan and used for experiments. The presence of the BCL-2/J H translocation in the major breakpoint region (MBR) of the BCL-2 gene was examined using a nested polymerase chain reaction (PCR), a...

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In order to define the major sites of persistence of human herpesvirus 6 (HHV-6) and HHV-7, PCR with DNAs from more than 100 specimens of 3 different salivary glands was performed. HHV-6 DNA was detected in 52 (88.1%) of 59 submandibular gland, 17 (63.0%) of 27 parotid gland, and 9 (52.9%) of 17 lip salivary gland specimens. On the other hand, HHV-7 DNA was detected in 59 (100%) of 59 submandibular gland, 23 (85.2%) of 27 parotid gland, and 10 (58.8%) of 17 lip salivary gland specimens. These findings demonstrate that salivary glands are a site of persistent infection of both HHV-6 and HHV-7 and that among the three types of salivary gland examined, the submandibular gland is the primary one in which these herpesviruses, especially HHV-7, persist.

Monoclonal antibodies against etiological agents of Weil's disease were produced by cell fusion technology. Twenty hybridomas were produced through the fusion of P3×63Ag8.653 cells with spleen cells from BALB/c mice immunized against Leptospira interrogans serovar icterohaemorrhagiae RGA strain and serovar copenhageni Shiromizu and M20 strains. Reactivities of the antibodies produced by the hybridomas were determined by the microscopic agglutination test. Among the five hybridoma antibodies to the RGA strain, two reacted specifically to serovar icterohaemorrhagiae, two reacted to serovar icterohaemorrhagiae at a high titer and serovar copenhageni at a low titer, and one reacted to serovars icterohaemorrhagiae, copenhageni, pyrogenes, and canicola. Of the ten hybridoma antibodies to the Shiromizu strain, one reacted specifically to serovar copenhageni, seven reacted to both serovars copenhageni and icterohaemorrhagiae at almost the same titer, and two exhibited intermediate properties. Of the five hybridoma antibodies to the M20 strain, three reacted to both serovars copenhageni and icterohaemorrhagiae at almost the same titer, one reacted to serovar copenhageni at a low titer and serovar icterohaemorrhagiae at a high titer, and one reacted to serovars copenhageni, icterohaemorrhagiae, and pyrogenes. The results revealed that each serovar has its own antigen(s) and their common antigens. In addition, 20 strains of leptospires were recently isolated and tested with three monoclonal antibodies characterized by different reactivities. Twenty strains were clearly identified by their antibodies, i.e., 16 strains were identified as serovar icterohaemorrhagiae and three strains were identified as serovar copenhageni. The remaining strain, which was not agglutinated by three antibodies, was identified as serovar autumnalis by an agglutination test with immune rabbit sera.