新生儿感染性肺炎时IL-18、IFN-γ与免疫球蛋白关系探讨

Relationship between interleukin-18, interferon-gama and immunoglobins in newborn infants with infectious pneumonia

目的探讨新生儿感染性肺炎白细胞介素_18(IL_18)和γ_干扰素 (IFN_γ)与免疫球蛋白 (IgG、IgA和IgM )的关系。方法采用免疫酶法 (ELISA)和速率散射比浊法检测111例感染性肺炎患儿血清IL_18、IFN_γ、IgG、IgA和IgM含量。以CRP≥20mg/L作为诊断细菌感染的界限值 ,结合其他临床资料 ,将肺炎患儿分为4组进行分析。结果①肺炎组111份血清中 ,8型常见病毒及支原体特异性IgM阳性40份 (36.0 % ) ,对照组30份血清均阴性 ;病毒及支原体感染23例 (20.7% ) ,细菌感染45例 (40.6 % ) ,病毒及支原体与细菌混合感染17例 (15.3% ) ,其他不明病原感染26例 (23.4% )。②肺炎组IgA、IgM含量>对照组 (P<0.05)。其中 ,病毒及支原体感染组IgA含量>其他不明病原感染组和对照组 (P<0.05) ;细菌感染组IgM含量>对照组 (P<0.05)。肺炎各组IgG、IL_18和IFN_γ含量与对照组比较 ,差异无统计学意义 (P>0.05)。③对照组IgM与IFN_γ呈正相关 (P<0.01)。病毒及支原体感染组IgA和IgM分别与IFN_γ呈正相关 (P<0.01) ;IgA和IgM分别与IL_18呈正相关 (P<0.05) ;IFN_γ与IL_18呈正相关 (P<0.05)。细菌感染组IgA与IL_18呈正相关 (P<0.01)。结论新生儿发生病毒或细菌感染时 ,体内抗感染免疫和免疫调节的机制不同 。

Objective To explore relations between interleukin_18(IL_18),interferon_gama(IFN_γ)and immunoglobulins(IgG, IgA, IgM) in newborn infants with infectious pneumonia caused by different pathogens. Methods Serum IL_18,IFN_γ,IgG,IgA,IgM were detected by ELISA and rate scattered nephe_lometry in infants with infectious pneumonia and in control infants.A serum CRP concentration of higher than 20 mg/L was defined as the indication of bacterial infection. Other clinical data were also included for the analysis. All infants with pneumonia were divided into four groups.Results (1)In 111 infants with pneumonia, there were 40 cases(36.0%)who were positive with specific serum IgM antibodies either for any of 8 common viruses or for mycoplasmas,negative results were obtained in all 30 controls.23(20.7%)cases were probably infected with viruses and mycoplasmas;45(40.5%)cases were bacterial infections;17(15.3%)were mixed infections with virus and/or mycoplasmas or complicated with bacteria; 26(23.4%)cases were caused by unknown pathogens.(2)Serum IgA and IgM concentrations of infants with pneumonias were higher than those of the controls.Among them, serum IgA concentration of infants with viral and mycoplasmal infections were higher than those with unknown infection and the control group;serum IgM concentration of infants with bacterial infection was higher than those of the controls. There was no significant difference of serum IgG,IL_18,IFN_γ concentrations between pneumonia group and the control group, as well as between various types of infectious groups and the control group.(3)A positive correlation was noted between serum IgM and IFN_γ in the control group.There was also a positive correlation between serum IgA,IgM and IFN_γ ininfants with viral and mycoplasma infections;positive correlations between serum IgA,IgM and IL_18,between serum IFN_γ and IL_18 in the same group of infants was also observed.There was a positive correlation between serum IgA and IL_18 in infants with bacterial infection.Conclusions Viral or bacterial infection in newborn infants causes different anti_infectious immunity and immuno_regulatory response mecha_nisms that are reflected by different serum concentrations of immnoglobulins and cytokines.