Effects of oral glucocorticoid therapy on CD4+CD25+CD127- and CD4+CD25high T cell levels in asthmatic patients

Establishing a high microbial load maternal-offspring asthma model in adult mice

BACKGROUND

Although it is widely accepted that the "hygiene hypothesis" explains the increased incidence of asthma, the lack of suitable animal models hinders further in-depth studies of the underlying molecular immune mechanisms. Therefore, we aimed to develop a robust mouse asthma model to investigate the role of bacteria in preventing asthma.

METHODS

BALB/c female mice were fed a mixture of eight common bacterial lysates (BL; Broncho-Vaxom®) and a commercial probiotic (Bifidobacterium tetravaccine tablets) at different concentrations before and during pregnancy to simulate different microbial load levels. Faeces from the mother mice were subjected to bacterial 16S rRNA sequencing to quantify the maternal microbial load. TLR2/4 expression and the proportion of regulatory T cells (Tregs) in the intestinal tract of female mice were determined, and the safety of the microbial load was evaluated. An asthma model was established in the offspring mice after weaning, and the extent of pulmonary pathological changes and Treg proportion were evaluated.

RESULTS

A BL concentration of 1 mg/kg enriched the intestinal flora, increased the proportion of Tregs, and increased the expression of TLR2/4 in the maternal mice. The proportion of peripheral blood Tregs was increased, whereas the risk of asthma decreased only in the offspring from mothers with a high microbial load relative to control mice.

CONCLUSION

This study established a safe and stable high microbial load maternal-offspring mouse asthma model, laying the foundation for a study on the molecular mechanism underlying the protective effects of a high microbial load against asthma.

Regulatory T Cell Responses to High-Dose Methylprednisolone in Active Systemic Lupus Erythematosus

BACKGROUND/PURPOSE

A slight increase in the proportion of circulating regulatory T (Treg) cells has been reported in systemic lupus erythematosus (SLE) patients taking oral prednisone. The effects of intravenous (IV) high dose methylprednisolone (MP) on Tregs have not yet been described, especially in active SLE.

METHODS

We prospectively analyzed the proportion of circulating CD4+ Treg cell subsets defined as follows: (1) naïve Treg (nTreg) FoxP3lowCD45RA+ cells; (2) effector Treg (eTreg) FoxP3highCD45RA- cells; and (3) non-suppressive FoxP3lowCD45RA- cells (non-regulatory Foxp3low T cells). Peripheral blood mononuclear cells of patients with active SLE were analyzed before the first infusion of IV high dose MP (day 0) and the following days (day 1, day 2, ±day 3 and ±day 8). The activity of SLE was assessed by the SLEDAI score.

RESULTS

Seventeen patients were included. Following MP infusions, the median (range) percentage of eTregs significantly increased from 1.62% (0.53-8.43) at day 0 to 2.80% (0.83-14.60) at day 1 (p = 0.003 versus day 0), 4.64% (0.50-12.40) at day 2 (p = 0.06 versus day 1) and 7.50% (1.02-20.70) at day 3 (p = 0.008 versus day 2), and declined to baseline values at day 8. Expanding eTreg cells were actively proliferating, as they expressed Ki-67. The frequency of non-regulatory FoxP3low T cells decreased from 6.39% (3.20-17.70) at day 0 to 4.74% (1.03-9.72) at day 2 (p = 0.005); nTreg frequency did not change. All patients clinically improved immediately after MP pulses. The absence of flare after one year of follow up was associated with a higher frequency of eTregs at day 2.

CONCLUSION

IV high dose MP induces a rapid, dramatic and transient increase in circulating regulatory T cells. This increase may participate in the preventive effect of MP on subsequent flares in SLE.

Development of asthmatic response upon bronchial allergen challenge is associated with dynamic changes of interleukin-10-producing and interleukin-10-responding CD4+ T cells

The role of adaptive immune system in regulation of asthmatic responses remains elusive. Here, we performed a comprehensive time-course analysis of mutual relationships between development of asthmatic response following allergen challenge and changes in several CD4+ T cell subsets which we characterized as either releasing interleukin-10 (CD4+CD25−CD127− and CD4+CD25+CD127+ T cells) or responding to IL-10 (CD4+ T cell subsets expressing CD210). Patients that developed asthmatic reaction were described as responders (R) whereas the others were named non-responders (NR). In R, in contrast to NR, at 6 h, we demonstrated significant expansion of CD4+CD25−CD127− T cells which was followed by drop to baseline values at 24 h. In contrast, in R, we observed decrease in numbers of CD4+CD25+CD127+ and CD4+CD25−CD127+ T cells at 24 h. Interestingly, at baseline, despite comparable IL-10 levels, R presented with lower levels of all CD4+ T cell subsets expressing CD210. In R, the numbers of CD4+CD210+ T cell subsets were further decreased following bronchial challenge which was paralleled by decrease in IL-10 serum levels. Altogether, our data suggest that dynamic interactions between IL-10-producing and IL-10-responding CD4+ T cells could contribute to pathogenesis of asthmatic responses in atopic individuals.

Dissecting the regulatory microenvironment of a large animal model of non-Hodgkin lymphoma: evidence of a negative prognostic impact of FOXP3+ T cells in canine B cell lymphoma

The cancer microenvironment plays a pivotal role in oncogenesis, containing a number of regulatory cells that attenuate the anti-neoplastic immune response. While the negative prognostic impact of regulatory T cells (Tregs) in the context of most solid tissue tumors is well established, their role in lymphoid malignancies remains unclear. T cells expressing FOXP3 and Helios were documented in the fine needle aspirates of affected lymph nodes of dogs with spontaneous multicentric B cell lymphoma (BCL), proposed to be a model for human non-Hodgkin lymphoma. Multivariable analysis revealed that the frequency of lymph node FOXP3⁺ T cells was an independent negative prognostic factor, impacting both progression-free survival (hazard ratio 1.10; p = 0.01) and overall survival (hazard ratio 1.61; p = 0.01) when comparing dogs showing higher than the median FOXP3 expression with those showing the median value of FOXP3 expression or less. Taken together, these data suggest the existence of a population of Tregs operational in canine multicentric BCL that resembles thymic Tregs, which we speculate are co-opted by the tumor from the periphery. We suggest that canine multicentric BCL represents a robust large animal model of human diffuse large BCL, showing clinical, cytological and immunophenotypic similarities with the disease in man, allowing comparative studies of immunoregulatory mechanisms.

Significance of the frequency of CD4+CD25+CD127- T-cells in patients with pulmonary tuberculosis and diabetes mellitus

BACKGROUND AND OBJECTIVE

Pulmonary tuberculosis and diabetes mellitus (DM) are closely associated. The objective of this study was to determine whether the expression of CD4+CD25+CD127- T-cells (regulatory T-cells (Treg)) is associated with diabetic pulmonary tuberculosis.

METHODS

Flow cytometry was used to determine the frequencies of CD4+CD25+ and CD4+CD25+CD127- T-cells in peripheral blood, bronchoalveolar lavage fluid (BALF) and pleural effusions from 120 patients (30 with pulmonary tuberculosis and DM (TBDM), 30 with pulmonary tuberculosis without DM (TB), 30 with tuberculous pleurisy without DM (TBP) and 30 healthy volunteers). The concentrations of interferon (IFN)-γ and interleukin (IL)-10 in BALF and pleural effusions were determined by enzyme-linked immunosorbent assay.

RESULTS

Treg frequencies in peripheral blood were significantly higher in patients with TBDM, TB and TBP than in the control group, with the frequency in TBDM being the highest (P < 0.01 for all). In TBP patients, Treg frequencies were significantly lower in pleural effusions than in peripheral blood. In TB patients, Treg frequencies in BALF and peripheral blood were not significantly different. However, in TBDM patients, Treg frequencies were significantly higher in BALF than in peripheral blood. IL-10 expression was significantly higher, and IFN-γ expression was significantly lower in BALF of TBDM patients compared with BALF and pleural effusions of TB patients.

CONCLUSIONS

In patients with pulmonary tuberculosis and DM, the imbalance between Treg and effector T-cells at pathological sites may be associated with weakened immunity and clinical manifestations of TB.