Dynamic changes of immune function and inflammatory factors in infants at different stages of Mycoplasma pneumonia infection

Objective To investigate the dynamic changes of immune function and inflammatory factors in infants with mycoplasma pneumonia infection. Methods From April 2016 to April 2018, a total of 80 infants with mycoplasma pneumonia infection were selected as observation subjects, including 40 cases in acute stage group and 40 cases in convalescence stage group, while 40 healthy children were selected as control group. Results There were significant differences in levels of immunoglobulin (IgG, IgM and IgA) and complement (C3 and C4) among the groups (F = 5.902, 2.936, 3.187, 2.059, 3.786; P = 0.000, 0.011, 0.008, 0.021, 0.004). The level of IgG in convalescent group was (10.30 ± 2.27) g/L, which was significantly higher than that of acute phase group and control group (t = 3.203, 3.044; both P < 0.001). Levels of IgM, C3 and C4 were significantly higher than those of control group and convalescence group (all P < 0.05). IgA level in acute phase group and convalescence group were significantly lower than that of control group (t = 2.565, P = 0.021; t = 2.752, P = 0.018). The difference of T lymphocyte subsets (CD3, CD4, CD8, CD4/CD8) and NK cells were statistically significant in each group (F = 8.602, 9.031, 8.917, 4.281, 4.335; all P < 0.001), the levels of CD3, CD4, CD4/CD8 and NK cells of acute phase group and convalescence group were significantly lower than those of control group (all P < 0.05). Levels of CD8+ T of acute phase group and convalescence group were (35.53 ± 5.33)% and (30.47 ± 4.17)%, respectively, which were significantly higher than those of control group [ (27.81 ± 4.51)%] (t = 3.742, P < 0.001; t = 2.184, P = 0.028), and the difference of CD8, CD4/CD8, NK cells in acute phase group and convalescent group were significantly different (t = 2.770, 2.337, 2.182; P = 0.020, 0.023, 0.024). The levels of cytokines (hBD-1, hBD-2, TNF-α, IL-8, IL-10 and IL-13) were significantly different in each group (all P < 0.001), the levels of TNF-α, IL-8, IL-10 and IL-13 in acute phase group and convalescence group were significantly higher than those of control group (all P < 0.001), but level of HBD-1 was significantly lower than that of the control group (t = 3.583, P < 0.001; t = 3.192, P = 0.001); the levels of TNF-α, IL-8, IL-10 and IL-13 in acute phase group were significantly higher than those of convalescence group (all P < 0.05). Conclusions The children with mycoplasma pneumonia infection have the deficiency of immune function and abnormal level of inflammatory factors, which should be paid more attention in clinical diagnosis and treatment. Key words: Pneumonia; Infection by mycoplasma; Immune function; Inflammatory factor