CD39/CD73 and the imbalance of Th17 cells and regulatory T cells in allergic asthma.

In the immune system, CD4+CD25+Foxp3+ regulatory T cells (Tregs) maintain self­tolerance and Th17 cells mediate inflammatory responses. CD39 is expressed on the surface of a subset of naturally occurring human Tregs that are important in constraining pathogenic Th17 cells. Additional studies have shown that Tregs differentiate into interleukin­17 (IL­17)+Foxp3+ T cells. Our previous study indicated an imbalance of Th17 and Tregs in allergic asthma; however, the underlying mechanisms remain poorly understood. Using quantitative PCR (qPCR), CD39 and CD73 mRNA levels in CD4+ T cells were investigated. Flow cytometry was used to analyze the proportion of IL­17+Foxp3+ T cells, and CD39 and CD73 expressed by CD4+ T cells and Tregs in the peripheral blood of the subjects. The results of the present study demonstrated an increased frequency of CD4+Foxp3+IL­17+ T cells in moderate to severe asthma. A deficiency in CD39 expressed on the surface of CD4+ T cells and Tregs was observed in asthma patients. The expression of CD39 and CD73 on the surface of CD4+ T cells and Tregs was negatively correlated with the number of Th17 cells. These results indicated that the plasticity of Tregs transforming to IL­17+Foxp3+CD4+ T cells, the reduced frequency of CD39+ Tregs and less effective suppression of IL­17 production by residual CD39+ Tregs leads to an imbalance of Th17 and Tregs in asthma. Therefore, enhanced CD39 activity is hypothesized to prevent the progression of asthma.

[Comparison of transient evoked otoacoustic emissions in newborns and adults with frequency specific approach].

OBJECTIVE: To investigate the difference of transient evoked otoacoustic emissions (TEOAE) between neonates and adults with the frequency-specific approach. METHODS: TEOAE were recorded from 112 newborns (62 females, 58 males) who passed hearing screening, and 32 adults (17 females, 15 males) tested with pure-tone threshold equal or less than 20 dBHL. Band reproducibility, signal-to-noise rate (SNR) of frequency-band and half-octave frequency analysis of TEOAE amplitude was recorded respectively. RESULTS: Significant differences were found in two groups, the higher entire TEOAE level found in newborn [(15.18 +/- 4.39) dB SPL] was higher than that of adults group [(9.51 +/- 4.12) dB SPL, P < 0.05]. The lowest wave reproducibility and SNR were in first frequency band (0.8 kHz) for neonate, and then, in last frequency band (4.0 kHz) were for young adults. For newborns, the highest band reproducibility and SNR were presented at fourth frequency band (3.2 kHz). However, for adults, the highest band reproducibility and SNR were presented at second frequency band (1.5 kHz). Frequency space of the SNR response peaks between neonates and adults was 1.7 kHz. The level difference was 7.09 dB SPL. Half octave frequency analysis shows a TEOAE response peaks in neonates was (10.50 +/- 5.09) dB SPL at the 2828 Hz, and in adults, it was (2.84 +/- 5.33) dB SPL at the 1414 Hz. Frequency space of the TEOAE response peaks between neonates and adults was 1414 Hz. Level differences of TEOAE response peaks was 7.66 dB SPL. TEOAE response peak in adult appear at 1.5 kHz, and then dropped down correlated to increase of frequency. From the first to the last testing frequency band, the difference of TEOAE level between neonate and adult was found to increase correlated to increase of frequency. CONCLUSIONS: TEOAE response level in newborn is higher than that in adult group. Further, the decrease of TEOAE response level presented more sharpens with the frequency increasing in adult. The frequency of TEOAE response peak in neonate (3.2 kHz) is higher than adult (1.5 kHz). The level of TEOAE response peak is also greater than adult.