Anticardiolipin-IgG Induction is Associated with Primary Human Herpesvirus-6 Infection

Purpose:Human herpesvirus-6 (HHV-6) is reportedly associated with various chronic neurological diseases; however, no study has analyzed the association between HHV-6 infection and antiphospholipid syndrome (APS). This study aimed to establish a relationship between primary HHV-6 infection and APS. Methods: The prevalence of antiphospholipid antibodies (aPLs), including anticardiolipin-IgG (aCL-IgG), aCL-IgM, and anti-β2 glycoprotein-1 (anti-β2GP1) were investigated according to age in 85 preschool children aged 3–6 months, 7–11 months, and 1, 2, 3, 4, 5, and 6 years, who were immunocompetent and asymptomatic for cerebrovascular and cardiovascular disease. A second study was conducted with 62 infants (7–23 months of age) suspected of primary HHV-6 infection on the basis of symptoms of exanthem subitum. Serum analyses of aPLs and antibodies to HHV-6 were performed within 1 week of symptoms appearance and 2 weeks later to test whether HHV-6 infection induces aPL. Results: All children aged under 6 months tested negative for aPL, whereas those aged between 7 months–3 years tested highly positive for anticardiolipin-IgG (aCL-IgG). Positivity rates of aCL-IgG were significantly higher (p value < 0.05) in the primaryinfected group (59.4%, 19/32) than those in the uninfected group (27.8%, 5/18). Conclusion: This study clearly indicated that the occurrence of aCL-IgG coincided with the period when maternal antibodies decline and infants contract various infectious diseases, and aCL-IgG induction is associated with primary HHV-6 infection.