Strong Correlations of Anti-Viral Capsid Antigen Antibody Levels in First-Degree Relatives from Families with Epstein-Barr Virus-Related Lymphomas

Background. Markers of Epstein-Barr virus (EBV) infection include anti-viral capsid antigen (VCA) immunoglobulin (Ig) G. High anti-VCA titers are associated with EBV-related lymphoproliferation, such as Burkitt lymphoma (BL) and Hodgkin lymphoma (HL). Methods. Intrafamilial correlations of anti-VCA IgG levels were studied in 3 settings: 127 families recruited through patients with HL in France (population A), 31 families recruited through patients with BL in Uganda (population B), and 74 large families from a general population in Cameroon (population C). Titers were determined by enzyme-linked immunosorbent assay (populations A and C) or by immunofluorescence analysis (population B). Results. In populations A and B, the anti-VCA IgG titers of the relatives of patients with HL or BL increased significantly (P = .01 and P < .001, respectively) with those of the index case patient. In all 3 populations, anti-VCA IgG titers were significantly correlated (P < .001 for A, P < .002 for B, and P < .001 for C) between genetically related individuals (father-offspring, mother-offspring, and sibling-sibling) but not between spouses. Similar results were obtained for population A after adjustment for total IgG levels. In all cases, the pattern of correlations was consistent with a polygenic model, with heritability ranging from 0.32 to 0.48. Conclusion. These results provide evidence for the genetic control of anti-VCA IgG titers and pave the way for identification of the loci involved.