OBJECTIVETo investigate the expression of vasoactive intestinal peptide (VIP) in peripheral blood of children with hand, foot and mouth disease and its significance.

METHODSAccording to the condition of the disease, 86 children with hand, foot and mouth disease were classified into phase 1 group (19 children) and phase 2 group (67 children). ELISA was used to measure the concentrations of plasma VIP, interferon-γ (IFN-γ), and interleukin-4 (IL-4) in peripheral blood. Flow cytometry was used to measure CD3, CD4, and CD8T lymphocyte subsets. RT-PCR was used for qualitative detection of enterovirus 71 (EV71) RNA in stool.

RESULTSCompared with the phase 1 group, the phase 2 group had a significantly higher positive rate of EV71-RNA (P<0.05) and significantly higher serum levels of IgG, IgA, IgM, and C3 (P<0.05). The phase 2 group had significantly lower proportions of peripheral CD3, CD4, and CD8T lymphocyte subsets than the phase 1 group (P<0.05), as well as significantly lower proportion of peripheral B cells and CD4/CD8ratio than the phase 1 group (P<0.05). The phase 2 group also had a significantly lower concentration of VIP in peripheral blood than the phase 1 group (P<0.05). In the 86 children with hand, foot and mouth disease, the concentration of VIP in peripheral blood was positively correlated with the proportion of CD4T lymphocyte subset and CD4/CD8ratio (r=0.533 and 0.532 respectively; P<0.05).

CONCLUSIONSVIP may be an important marker of the severity of hand, foot and mouth disease.