To detect the expression levels of mitochondrial antiviral signaling protein (MAVS) and mitochondrial fusion protein 1 (MFN1) in children with hand, foot and mouth disease (HFMD), and to explore the clinical significances of HFMD.

Total of 82 children with HFMD were selected, including 18 cases with severe enterovirus 71 (EV71)-HFMD, 22 cases with mild EV71-HFMD, 16 cases with severe Coxsackievirus A16 (CA16)-HFMD and 26 cases with mild CA16-HFMD, while 42 healthy children of the same age range were selected as controls. Peripheral blood of these groups of children were obtained to detect and compare the mRNA expression levels of MAVS and MFN1 in mononuclear cells. MAVS and MFN1 expressions among different groups were analyzed by univariate variance analysis and t-test and the correlation between mRNA expression of the two indexes and clinical characteristics were analyzed by Spearman correlation analysis.

The relative expression levels of MAVS of cases with EV71-HFMD and CA16-HFMD were [(8.42 ± 2.27)%] and [(7.40 ± 2.34)%], respectively, which were significantly lower than that of control group [(11.78 ± 3.42)], with significant differences (t = 3.450, P = 0.0016; t = 4.512, P < 0.001). However, there was no significant difference of MAVS expression levels of cases with severe HFMD and mild HFMD, either of cases with CA16 HFMD [severe vs. mild: (7.58 ± 2.52)% vs. (7.29 ± 2.32)%; t = 0.270, P = 0.790] or cases with EV71 HFMD [severe vs. mild: (8.07 ± 2.26)% vs. (8.71 ± 2.35)%; t = 0.611, P = 0.549]. The relative expression of MFN1 of cases with EV71-HFMD [(2.87 ± 1.20)%] and CA16-HFMD [(2.56 ± 1.22)%] were significantly lower than that of control group [(4.38 ± 1.28)%], with significant differences (t = 3.510, P < 0.001; t = 4.232, P < 0.001). The relative expression levels of MFN1 between cases with severe and mild EV71-HFMD were (2.44 ± 1.20)% and (3.22 ± 1.14)%, with significant difference (t = 1.492, P = 0.153). However, the relative expression of MFN1 in CA16-HFMD showed statistically significant difference between cases in severe group and mild group [(3.23 ± 1.37)% vs. (2.15 ± 0.95)%], with significant difference (t = 2.150, P = 0.045). MAVS relative expression level was correlated with age (r = 0.339, P = 0.030); MFN1 relative expression level was correlated with blood glucose level (r = 0.442, P = 0.004).

The expression levels of MAVS and MFN1 decreased in HFMD patients, and the high expression of MFN1 may be related to the severity of CA16-HFMD.