Persistent high plasma levels of interleukins 18 and 4 in children with recurrent infections of the upper respiratory tract

Intestinal microbiota dysbiosis in children with recurrent respiratory tract infections

BACKGROUND

The impact of the gut microbiota on recurrent respiratory tract infection (RRTI) remains to be fully elucidated.

METHODS

To characterize the gut microbiota in patients with RRTI, fecal samples from 26 patients with RRTI and 23 healthy volunteers were profiled using the Illumina MiSeq platform. Beta diversity (Principal Component Analysis (PCA), Principal Co-ordinates Analysis (PCoA), Non-metric multidimensional scaling (NMDS)) analysis showed that the bacterial community structure segregated differently between the RRTI and control groups.

RESULTS

Results from alpha diversity analysis revealed lower microbiota diversity in samples from RRTI patients than in normal controls. Taxonomic analysis illustrated that the abundance of six phyla (Firmicutes, Proteobacteria, Bacteroidetes, Actinobacteria, Verrucomicrobia, Tenericutes) and four genera (Enterococcus, Faecalibacterium, Bifidobacterium, Eubacterium were significantly different between these two groups. In addition, Enterococcus (P < 0.001) was more enriched in the RRTI group, whereas the abundances of Eubacterium (P < 0.001), Faecalibacterium (0.01 < P < 0.05) and Bifidobacterium (0.01 < P < 0.05) were reduced in the RRTI group compared to those in the normal control group. The performance of the model was assessed using ROC analysis, and Enterococcus, Eubacterium and Bifidobacterium achieved AUC values of 0.860, 0.820, and 0.689, respectively.

CONCLUSIONS

These results provide fundamental evidence in support of intestinal microbiota dysbiosis in children with RRTI.

Efficacy and safety of pidotimod in the prevention of recurrent respiratory infections in children: a multicentre study

Acute respiratory infections (ARI) still represent a big challenge for paediatricians, especially in those children defined as "ailed" as they are more susceptible to such kinds of disease. In this paediatric population, the immune system is still under-developed with an evident alteration in cytokine levels. A clinical study was carried out in 5 sites in Russia with the intention to enroll children particularly susceptible to contract respiratory infections (defined as "ailing"), assigning them to a treatment group with pidotimod in comparison with a control group, treating them for 30 days and observing the reduction in the number of ARI episodes throughout the follow-up period (6 months). Moreover, changes in serum immunological markers were evaluated at baseline and 30 days after treatment discontinuation. One hundred and fifty-seven ailing children were enrolled and assigned to two arms: a main pidotimod treatment group or a control group. The percentage of incidence of ARIs in the observation period at three different time points was statistically significant (p < 0.05). At the end of the follow-up period (after 6 months), ARIs had developed in 72 children (92.3%) in the main group and in 79 patients (100%) in the control group. Concerning changes of the immunological markers, the treatment group showed a better profile of normalization compared to the control group. The 30-day pidotimod therapy course led to improvement/reduction in the rate of acute respiratory infection recurrence in ailing children within a 3-month period, with a quick elimination of symptoms and signs of infection and, as a result, a faster recovery. The normalisation of the content of the pro-inflammatory cytokine interleukin-8 confirmed the immune-modulatory effect of the investigational drug, underlying its prophylactic effect.

The child with recurrent respiratory infections: normal or not?

Respiratory infections (RI) are one of the major complaints in children and adolescents, and represent a demanding challenge for the pediatrician. It has been estimated that at least 6% of Italian children younger than 6 yr of age present recurrent respiratory infections (RRI). Children with RRI are not affected by severe alterations of the immune system. RRI represent essentially the consequence of an increased exposure to infectious agents during the first years of life, when immune functions are still largely immature. Several social and environmental factors, such as day-care attendance, family size, air pollution, parental smoking, and home dampness, represent important risk factors for airway diseases and may contribute in various degrees to determine the incidence of RRI. The main problem for the pediatrician is to discriminate normal children with high RI frequency related to an augmented exposure to environmental risk factors from children affected by other underlying pathological conditions (immunological or not), predisposing to infectious diseases. When RRI diagnosis has been formulated, removal of environmental risk factors (i.e. precocious day-care attendance, smoking in the household) must first be suggested.