The increasing trend of incidence rate in children with allergic diseases has drawn increasingly attention,especially in children with bronchial asthma,which may affect children's life quality.The hygiene hypothesis indicates that early microbial contact and stimulation can affect the development of body immune system,lack of early microbial stimulation results in aberrant immune responses to innocuous antigens later in life.The distribution of intestinal flora in the body between children with allergic diseases and healthy children are different,indicating that the occurrence of allergic diseases is associated with intestinal flora.The abnormal number or function of regulatory T cell may be the key mechanism of allergic diseases.Although the exact mechanism is not yet fully understood,more and more researches are underway.Meanwhile,the positive effect of probiotics has been showed in the prevention and treatment of asthma and other allergic diseases cannot be ignored.Studies on allergic diseases and intestinal flora may provide a new way for their prevention and control.

Acute lung injury (ALI) is a kind of clinical syndrome which is characterized by the rising on capillary permeability.Acute respiratory distress syndrome(ARDS) is a serious kind of manifestation of ALI and also a usual kind of critical illness in children.Alveolar macrophage is the first defense line against pathogenic microorganisms and lung injury.More and more evidences show that it plays an important role during the period of occurrence, development and prognosis in ALI.In the last few years, there is an extensive focus on the effect of alveolar macrophage in ALI.This summarization makes a general review on the recent research progress of the effect of alveolar macrophages in ALI.

Objective To discuss the efficacy of ulinastatin in treatment of children with severe pneumonia.Methods One hundred children with severe pneumonia were analyzed retrospectively.They were divided into two groups.One was treatment group with 48 cases of patients and another was control group with 52 cases of patients.The two groups both accepted routine treatments,while the treatment group was given ulinastatin[(20 kU/(kg·d),5 d in total] additionally.The clinical improvement of both groups was observed.Changes of clinical syndromes including temperature and lung rale were observed.The effect of treatment in following aspects were evaluated:time of oxygen therapy,the length of stay in PICU and total hospitalization day.Recovery times of infectious indicators were monitored including peripheral WBC count,C-reactive protein (CRP) and procalcitonin (PCT).Meanwhile,the clinical adverse effect of the drug was observed.Results After treatment,recovery time of temperature in treatment group was (5.81±1.26) d,while in control group was(8.04±1.38) d.There was an obvious difference between two groups(t=-8.42,P＜0.01).Compared to control group,the recovery times of infectious indicators including WBC count,CRP,and PCT were shorter[(5.35±1.39) d vs.(6.65±1.79) d,t=-4.03,P＜0.01;(6.98±1.66) d vs.(8.17±1.64) d,t=-3.60,P＜0.01;(6.13±1.72)d vs.(7.52±1.78)d,t=-3.96,P＜0.01].In the treatment group,the length of stay in PICU was (8.44±2.47) d,which was shorter than that in control group [(10.62±3.13)d,t=-3.84,P＜0.05].But there was no significant difference in both groups of time of lung rale disappearing,oxygen therapy and the total hospitalization days.No side effect was found in treatment group.Conclusion For the children with severe pneumonia,besides the treatments of anti-infection,breathing and nutrition support,the use of ulinastatin can improve the condition of patients and the index of inflammatory reaction.It also can shorten the length of stay in PICU.Since the curative effect of ulinastatin is specific and it has less adverse reactions,ulinastatin can be used as one of the effective measure in treatment of severe pneumonia in children.