The relationship between Chlamydia pneumoniae infection and CD4/CD8 ratio, lymphocyte subsets in middle-aged and elderly individuals

Distribution and clinical significance of circulating CD8+CD28- regulatory T cells in the peripheral blood of patients with pulmonary tuberculosis

Background

Regulatory T cells (Treg cells) in the peripheral blood of patients with pulmonary tuberculosis (PTB) may be closely related to the progression of PTB. In this study, the distribution characteristics and clinical importance of CD8⁺CD28⁻ Treg cells in patients with tuberculosis were systematically analyzed, and the role and importance of CD8⁺CD28⁻ Treg cells in influencing the immune response and progression of tuberculosis were discussed, which will provide immunological indices and reference values for the clinical diagnosis of tuberculosis.

Methods

Flow cytometry, sputum smears and computed tomography imaging were used to analyze the distribution characteristics of CD8⁺CD28⁻ Treg cells in the peripheral blood of patients with PTB and the correlation between CD8⁺CD28⁻Treg cells and clinical and immune indices.

Results

The percentages of CD4⁺CD25^high and CD8⁺CD28⁻ Treg cells in the peripheral blood of patients with PTB were significantly higher than those in the healthy control (HC) group. Further analysis showed that the percentage of CD4⁺CD25^highTreg cells in the Stage II group was significantly higher than that in the HC group. The percentages of CD4⁺CD25^high and CD8⁺CD28⁻ Treg cells increased significantly in patients in the Stage II group. The proportion of CD8⁺CD28⁻ Treg cells was directly proportional to the degree of positivity in sputum smears, while CD4⁺CD25^highTreg cells did not exhibit this trend.

The correlations between the percentage of CD4⁺CD25^high and CD8⁺CD28⁻ Treg cells and the percentage of lymphocyte subsets were examined. The percentage of CD8⁺CD28⁻ Treg cells was negatively correlated with the percentage of CD4⁺T cells and positively correlated with the CD8⁺T cell percentage in the HC and PTB groups. The percentage of CD4 + CD25^highTreg cells was positively correlated with the percentage of CD4⁺T cells only in the PTB group.

Conclusions

This study was the first to show that the proportion of CD8⁺CD28⁻ Treg cells in the peripheral blood of patients with PTB was significantly increased, and the increase in CD8⁺CD28⁻ Treg cells was related to the progression of PTB, which may affect the proportion of immune cell subsets by inhibiting the immune response, resulting in the progression of PTB.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12890-022-02088-7.

Cross Talk Between Natural Killer T and Dendritic Cells and Its Impact on T Cell Responses in Infections

Both innate and adaptive immunity is vital for host defense against infections. Dendritic cells (DCs) are critical for initiating and modulating adaptive immunity, especially for T-cell responses. Natural killer T (NKT) cells are a small population of innate-like T cells distributed in multiple organs. Many studies have suggested that the cross-talk between these two immune cells is critical for immunobiology and host defense mechanisms. Not only can DCs influence the activation/function of NKT cells, but NKT cells can feedback on DCs also, thus modulating the phenotype and function of DCs and DC subsets. This functional feedback of NKT cells on DCs, especially the preferential promoting effect on CD8α+ and CD103+ DC subsets in lymphoid and non-lymphoid tissues, significantly impacts the systemic and local adaptive CD4 and CD8 T cell responses in infections. This review focuses on the two-way interaction between NKT cells and DCs, emphasizing the importance of NKT cell feedback on DCs in bridging innate and adaptive immune responses for host defense purposes.

Clinical significance of changes in serum inflammatory factors in patients with chronic obstructive pulmonary disease and pulmonary infection

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is often accompanied by pulmonary infection, inflammatory responses, decreased immunity, and decreased lung function. The relationships among the pulmonary inflammation index (PII), lung function, and immunity in COPD patients with pulmonary infection remain unclear.

METHODS

This retrospective observational study enrolled 234 participants (patients with COPD and pulmonary infection, patients with COPD without pulmonary infection, and healthy individuals) from January 2017 to December 2019.

RESULTS

Levels of interleukin (IL)-6 were lower and levels of IL-8 were higher in patients with COPD and pulmonary infection. Levels of white blood cells (WBCs), C-reactive protein (CRP), IL-6, IL-8, tumor necrosis factor (TNF)-α and CD8+ cells were higher, while levels of CD3+ and CD4+ cells, the CD4+/CD8+ ratio, forced expiratory volume in 1 s (FEV1), FEV1 % predicted (FEV1%pred), and FEV1/forced vital capacity (FVC) (FEV1%FVC) were lower in patients with COPD and pulmonary infection. Levels of WBCs, CRP, IL-6, IL-8, and TNF-α were negatively associated with FEV1, FEV1%pred and FEV1%FVC.

CONCLUSIONS

Patients with COPD and pulmonary infection have high PIIs, decreased immunity, and poor lung function. PII is closely related to lung function and may represent a useful biomarker for the assessment of patients with COPD and pulmonary infection.