Objective   To observe the differences in the dynamic change of the EB virus antibody between general population and first-degree relatives (FDR) of nasopharyngeal carcinoma patients during follow-up study one year after initial screening and discuss the difference among the nasopharyngeal carcinoma detections.

  Methods   Serologic data of all subjects that participated in the follow-up study were collected. Changes in EB virus antibodies were investigated and correlation of these changes with gender and age level was analyzed. Differences in the nasopharyngeal cancer detection rate of different populations were also compared.

  Results   NA1/ IgA negative conversion rate was higher in the family group than in the control group (χ²=20.28, P < 0.001). This rate was also higher in both male and female family groups than in the male and female control groups (χ ²=22.59, P < 0.001; χ ²= 4.03, P < 0.05, respectively). NA1/IgA positive conversion rate was lower in the family group than in the control group (χ ²=7.79, P < 0.05). Likewise, this rate was lower in both male and female family groups than in the male and female control groups (χ²⁼9.46, P < 0.05; χ²=0.74, P=0.39, respectively). VCA/IgA negative conversion rate was higher in the family group than in the control group (χ²=1.90, P < 0.001). This rate was also higher in the male and female family groups than in the male and female control groups (χ² =7.50, P < 0.05; χ²=no expression, P=0.108, determined by Fish exact test, respectively). VCA/IgA positive conversion rate was higher in the family group than in the control group (χ²=0.10, P=0.70). This rate was again higher in both male and female family groups than in the male and female control groups (χ²= 0.02, P=0.90, χ²=0.51, P=0.48, respectively). Ten cases from the control group manifested nasopharyngeal carcinoma; the same disease was not observed in the family group. Nasopharyngeal carcinoma detection rate was significantly higher in the control group than in the family group, but the difference was not statistically significant (χ ²=1.05, P=0.31).

  Conclusion   a. Reactivation of the EB virus is not closely linked with genetic factors. b. The detection rate of NPC in FDR was lower compared with the general population after initial screening; thus, the rule of selective follow-up is not applicable for FDR.