Antibodies to herpes‐type virus in nasopharyngeal carcinoma and control groups

Sera collected from patients with nasopharyngeal carcinoma (NPC), in Taiwan, were titrated for antibodies to herpes‐type virus (HTV) in a Burkitt's lymphoma cell line (P3HR‐1) by the indirect immunofluorescence antibody technique. The results were compared with those of neighborhood controls matched by age and sex, with patient families and with neighborhood control families. Antibody liters were higher in the NPC cases than in any of the 3 control groups. Dissociations in the frequency distributions of antibody titers in the NPC and healthy control groups were found to be maximum when the limiting value was set at 1:640. There were no significant differences in the frequency distribution among the 3 control groups. Of 117 NPC patients, 40% had anti‐HTV titers equal to or greater than 1:640, while such values occurred in only 5, 5, and 6%, respectively, of the neighborhood controls, patient families, and control families. Though not statistically significant, there was difference in the percentages of “sero‐positive” cases for the NPC patients by sex—42% for males and 35% for females. There was no sex difference, or it was a little higher in females, in the 3 control groups. The geometric mean titers were 1:242, 1:65, 1:69, and 1:61, respectively, for the NPC patients, neighborhood controls, patient families, and neighborhood control families. There was a difference in the geometric means by sex in the patients, i.e., 1:253 and 1:210, respectively, for males and females, while no differences by sex were noted in the 3 control groups. Ridit analysis and chi square test showed definitely different results between the NPC patients and the 3 control groups. The relative risks indicated that persons with antibody titer of 1:2560 had more than 200 times the NPC risk of those with antibody titer of less than 1:40. There were no indications of household aggregation of high anti‐HTV titer (≥ 1:640) in the patients and control families. The significance and implications of these findings are discussed.