Comprehensive analysis of serum cytokines/chemokines in febrile children with primary human herpes virus-6B infection

Cytokines and chemokines induced by primary human herpes virus (HHV)-6B infection may play a critical role in the clinical manifestations of infection. In this study, we analyzed 40 cytokines/chemokines in febrile children with primary HHV-6B infection. Blood samples from 233 febrile and 36 afebrile patients 0–3 years of age were used for this study. In febrile patients, primary HHV-6B infection was determined by detection of HHV-6B DNA without anti-HHV-6 immunoglobulin G in the blood (HHV-6B group). Infection by other pathogens was assumed when HHV-6B DNA was not detected in the blood (non-HHV-6B group). Of the 233 febrile patients, 30 patients (13%) were diagnosed with primary HHV-6B infection. To analyze serum cytokines/chemokines, patients were randomly chosen from the HHV-6B (n = 25) and non-HHV-6B groups (n = 8). Sera from 25 afebrile patients were used as a control. When comparing the levels of 40 cytokines/chemokines between the HHV-6B and control groups, we found that four chemokines (chemokine [C-X-C motif] ligand [CXCL] 11, CXCL10, CXCL16, and chemokine [C-C motif] ligand [CCL] 2) were significantly upregulated in the HHV-6B group compared with those in the control. Of these, only CXCL11 levels were significantly higher in the HHV-6B group than in the non-HHV-6B group. Because the induction of CCL2 was already reported in an early study, we found, for the first time, the induction of three new chemokines, i.e., CXCL11, CXCL10, and CXCL16 in patients with primary HHV-6B infection. Importantly, we demonstrated that serum CXCL11 levels increased specifically in patients with HHV-6B infection.