Molecular Mechanisms of T Helper Cell Differentiation and Functional Specialization

Th cells, which orchestrate immune responses to various pathogens, differentiate from naïve CD4 T cells into several subsets that stimulate and regulate immune responses against various types of pathogens, as well as a variety of immune-related diseases. Decades of research have revealed that the fate decision processes are controlled by cytokines, cytokine receptor signaling, and master transcription factors that drive the differentiation programs. Since the Th1 and Th2 paradigm was proposed, many subsets have been added to the list. In this review, I will summarize these events, including the fate decision processes, subset functions, transcriptional regulation, metabolic regulation, and plasticity and heterogeneity. I will also introduce current topics of interest.

In Response to Author: COVID-19 and T Cells: Do T Cells Really Matter?

How to cite this article: Vadi S, Pednekar A, Suthar D, Sanwalka N, Ghodke K, Rabade N. In Response to Author: COVID-19 and T Cells: Do T Cells Really Matter? Indian J Crit Care Med 2023;27(1):76.

Recovery of lymphocyte subpopulations is incomplete in the long-term setting in pediatric solid tumor survivors

BACKGROUND

Childhood cancer survivors (CCSs) may have comorbidities including a long-term abnormality in the immune system. Immune reconstitution in CCSs after treatment for acute leukemia has been reported previously, while analyses of immune reconstitution in CCSs with solid tumors have been limited.

METHODS

Childhood cancer survivors who received chemotherapy for solid tumors and who visited University of Tsukuba Hospital between November 2019 and March 2021 were included the study. Peripheral blood was collected for flow cytometry analysis.

RESULTS

Forty-nine samples from 35 CCSs (18 male, 17 female) were included in the study. High-dose chemotherapy and cerebral spinal irradiation were conducted in 14 CCSs (40%) and in five CCSs (14%), respectively. The median time between the completion of chemotherapy and the collection of the present samples was 15.0 months (range, 0-286 months). The total lymphocyte count, B cells, and CD8-positive T cells recovered to the normal range of controls (NR-CTLs) in 0 (0%), four (66.7%), and four (66.7%) of six samples at 0-3 months after the completion of chemotherapy, and in three (60%), four (80%), and three (60%) of five samples at 3-12 months after the completion of chemotherapy, respectively. Meanwhile, CD4-positive T cells remained lower than NR-CTLs in 0 (0%) of six samples, one (20%) of five samples, and seven (63.7%) of 11 samples at 0-3, 3-12 and 12-60 months after the completion of chemotherapy, respectively.

CONCLUSIONS

Recovery to the NR-CTLs was rapidly achieved in B cells and CD8-positive T cells, while the recovery was slower and incomplete in CD4-positive T cells. Careful observation of infection in long-term follow-up clinics is needed.

Comparative study of yeast selenium vs. sodium selenite on growth performance, nutrient digestibility, anti-inflammatory and anti-oxidative activity in weaned piglets challenged by Salmonella typhimurium

The present study was conducted to investigate the effects of dietary supplementation of selenium from different sources on the growth performance, nutrient digestibility, and blood immune indices of piglets orally challenged with Salmonella typhimurium (ST). In a 2 × 2 factorial arrangement, 32 piglets (6.43 ± 0.54 kg of body mass) were assigned into four groups with or without dietary inclusion of sodium selenite (SS) or yeast selenium (YS) and with or without ST challenge (5 ml 1 × 109 cfu/ml ST or 5 ml saline) on d 13. In each period, YS increased average daily feed intake and average daily gain but did not reach statistical significance. During the challenged stage, piglets fed YS had higher digestibility of dry matter, crude protein, crude fat, and YS reduced the amount of Escherichia coli in feces. Additionally, YS regulated the composition of T-lymphocyte subset and influenced the production of inflammatory cytokines. In conclusion, in this study selenium-enriched yeast was more effective in enhancing nutrient digestibility, and inhibiting inflammation and oxidative stress by inducing the activity of the lymphocytes, expression of antioxidant enzymes and so on.

[Brain derived neurotrophic factor enhances the role of mesenchymal stem cells in inhibiting follicular helper T cells]

目的

探讨脑源性神经营养因子（BDNF）增强间充质干细胞（MSC）抑制滤泡辅助性T细胞（Tfh细胞）的作用及机制。

方法

ELISA法检测MSC培养上清中吲哚胺2,3-二加氧酶（IDO）、IL-10、TGF-β和IL-21的含量；采集健康志愿者的外周血标本，采用人淋巴细胞分离液分离外周血中的淋巴细胞；采用Transwell小室进行MSC和淋巴细胞共培养，流式细胞术检测CD4⁺CXCR5⁺ Tfh细胞及其亚群的比例。

结果

①BDNF组（BDNF刺激的MSC）培养上清IL-10、TGF-β、IDO浓度均高于对照组（加入等体积磷酸盐缓冲液）[IL-10：（42.1±4.4）ng/ml对（19.3±2.1）ng/ml，t=4.761，P=0.009；TGF-β：（13.9±1.7）ng/ml对（5.3±0.6）ng/ml，t=5.129，P=0.008；IDO：（441.3±56.9）ng/ml对（226.7±37.6）ng/ml，t=3.130，P=0.035]；②BDNF组（淋巴细胞与BDNF刺激的MSC共培养）与MSC组（淋巴细胞与MSC共培养）比较：CD4⁺CXCR5⁺Tfh细胞比例降低[（3.37±0.21）%对（6.51±0.27）%，t=9.353，P<0.001]，CD4⁺ CXCR5⁺ CXCR3⁺ CCR6⁻Tfh1细胞比例升高[（41.14±2.04）%对（26.72±2.57）%，t=4.383，P=0.012]，CD4⁺CXCR5⁺CXCR3⁻CCR6⁻Tfh2细胞和CD4⁺CXCR5⁺CXCR3⁻CCR6⁺Tfh17细胞比例降低[Tfh2：（30.16±5.38）%对（43.26±4.11）%，t=4.426，P=0.012；Tfh17：（15.61±1.52）%对（22.32±0.72）%，t=4.202，P=0.014]，CD4⁺CXCR5⁺Foxp3⁺ Tfr细胞比例升高[（4.95±0.22）%对（2.32±0.16）%，t=10.241，P<0.001]，淋巴细胞培养上清中IL-21浓度降低[（0.28±0.03）ng/ml对（0.85±0.08）ng/ml，t=6.675，P=0.003]。

结论

BDNF能够增强MSC抑制Tfh细胞的作用，机制是抑制淋巴细胞中Tfh细胞比例升高及其向Tfh2和Tfh17亚群的分化。

Potential Predictors for Serofast State after Treatment among HIV-Negative Persons with Syphilis in China: A Systematic Review and Meta-Analysis

BACKGROUND

Several studies have been conducted in China in order to investigate the potential predictors of serofast state after treatment among syphilitic patients. However, there is a remarkable diversity among the results. This meta-analysis was conducted to assess potential predictors of serofast among syphilitic patients in China.

METHODS

International and national electronic databases were searched up to September 2013. Reference lists of retrieved articles were also reviewed. Cohort or case-control studies addressing risk factors of serofast among syphilitic patients were included in this study.

RESULTS

We assessed 27 separate studies involving overall 6682 HIV-negative participants with syphilis of which 1962 remained in the serofast state. The serofast was positively associated with older age(P trend=0.001), female(summary risk ratio[sRR]=1.50, 95%CI:1.34-;1.68), latent syphilis(sRRlatent vs primary=3.17, 95%CI: 2.66-;3.77; sRRlatent vs secondary=2.00, 95%CI: 1.48-;2.69) as well as non-penicillin treatment(sRR =2.99, 95%CI:2.45-;3.67), but negatively associated with higher baseline titers(sRR>1:32 vs ≤1:32=0.63, 95%CI: 0.54-;0.75). Compared with healthy group and serological cure group, respectively, the levels of CD4 (+), IL-2, and IL-6 among serofast patients were decreased (standardized mean difference[SMD]<0, P<0.05), but the levels of CD8(+) and IL-10 were increased(SMD>0, P<0.05). Some studies also hinted the serofast was associated with subtypes i of treponema pallidum(TP) repeat gene (RR i vs d=4.67,95%CI: 1.31-;16.69) and TP occult infection.

CONCLUSION

The age, gender, stage of infection, baseline titers, treatment drug, cellular immune suppression and disorders, TP occult infection and subtypes i of TP repeat gene should be considered as important predictors of serofast. However, until now the definition and mechanism of serofast has still been not clear.