Relationship of Treg/Th17 balance with HBeAg change in HBeAg-positive chronic hepatitis B patients receiving telbivudine antiviral treatment: A longitudinal observational study

Creatine kinase elevation in chronic hepatitis B patients with telbivudine therapy: influence of telbivudine plasma concentration and single nucleotide polymorphisms of TK2, RRM2B, and NME4

PURPOSE

To study the correlations of genetic variants of telbivudine phosphorylase kinases and telbivudine plasma concentration with creatine kinase elevation in chronic hepatitis B patients who received telbivudine.

METHODS

An observational study was performed in China chronic hepatitis B patients receiving telbivudine therapy at 600 mg once daily. Plasma concentration was measured 12 h after taking telbivudine using ultra-performance liquid chromatography-tandem mass spectrometry and SNPs located in RRM2B, TK2, and NME4 was detected by MALDI-TOF mass spectrometry. All statistical analyses were performed with R 4.3.1 and all graphs were drawn by Origin 2023b and P value < 0.05 was considered statistically significant.

RESULTS

A total of 140 patients receiving telbivudine therapy were recruited with a median plasma concentration of 952.49 (781.07-1238.98) ng/mL. The value of plasma concentration was proportional to the grade of creatine kinase elevation and the best telbivudine plasma concentration threshold to discriminate the grade 3/4 CK elevation was 1336.61 ng/mL. Multivariate analysis revealed that plasma concentration and rs3826160 were the independent risk factor of telbivudine-induced creatine kinase elevation. Patients with TC and CC genotype in rs3826160 not only had a higher incidence of creatine kinase elevation but also a higher plasma concentration than TT genotype carriers.

CONCLUSION

Chronic hepatitis B patients with TC and CC genotype in rs3826160 have high telbivudine plasma concentration are at risk of elevated creatine kinase.

The Connection between MiR-122 and Lymphocytes in Patients Receiving Treatment for Chronic Hepatitis B Virus Infection

New molecular predictors for the response to treatment in HBV (hepatitis B virus) infection are assessed. Among them is miR-122. Our article searches the connection between miR-122 and the counts of lymphocytes in chronic HBV patients receiving treatment. We included the sera of 38 Romanian subjects with chronic HBV infection (20 receiving treatment and 18 not receiving treatment) and 5 healthy controls. The expression of miR-122 was determined using RT-PCR (real-time PCR) and a 2-ΔΔCT method. Two systematic analyses were also performed on databases (PUBMED, Web of Science, and Science Direct), eliminating systematic reviews, editorials, letters to editors, meta-analyses, reviews, conference proceedings, or pre-print manuscripts. We included human-based articles following the PRISMA criteria and the Newcastle Ottawa Assessment Scale for Case-Control and Cohort studies. R 4.2.2 was used for statistics, and MIENTURNET and STRING were used for the bioinformatic analysis. Our results showed a link between the variations in the expression of miR-122 and the counts of lymphocytes in HBV Romanian patients receiving therapy. Treatment influenced miR-122 and the lymphocyte numbers. This is the first study with these results, and it may lead to a new perspective on the inter-relationships between microRNAs and therapy in HBV patients.

Interleukin-21 modulates balance between regulatory T cells and T-helper 17 cells in chronic hepatitis B virus infection

BACKGROUND

Chronic HBV infection is always accompanied by differences in the balance between regulatory T cells (Tregs) and T-helper 17 (Th17) cells in infection phases. IL-21 plays an important role in the progression of chronic HBV infection. Thus, the aim of our study was to investigate the role of the regulatory function of IL-21 in maintaining the balance between Tregs and Th17 cells in chronic HBV infection.

METHODS

Twenty-five chronic HBV-infected patients in the immune-tolerant (IT) phase and 23 chronic hepatitis B (CHB) patients were recruited in this study. Cytokines production was measured by ELISA. The mRNA expression levels were determined by qPCR. CD4+T cells were stimulated with or without IL-21. Tregs and Th17 cells were measured by flow cytometry. pSTAT3 and STAT3 expression was assessed by Western blotting.

RESULTS

The concentration of IL-21 in the serum of CHB were significantly higher than that in the serum from IT patients, and IL-21 and IL-21R levels in the PBMCs from CHB were higher than those from IT patients. IL-21 promoted Th17 cells differentiation and function but inhibited Treg cells differentiation and function by activating STAT3 signaling pathways, upregulating RORγt expression, downregulating Foxp3 expression, by increasing IL-17and IL-22 secretion, and decreasing TGF-β secretion in chronic HBV infection. The proportion of Tregs and TGF-β concentrations in CHB was significantly lower than that in IT patients. Furthermore, the percentage of Th17 cells and the IL-17 concentration in CHB was markedly higher than that in IT patients, causing a reduction in the Tregs/Th17 ratio in CHB patients.

CONCLUSIONS

Our results suggest that IL-21 may contribute to inflammation in chronic HBV infection by modulating the balance between Treg and Th17 cells.

Effect of prophylactic antiviral intervention on T cell immunity in hepatitis B virus-infected pregnant women

BACKGROUND

Antiviral intervention in hepatitis B virus (HBV)-infected pregnant women can effectively reduce mother-to-child transmission. However, the immunological characteristics of pregnant women with chronic HBV infection and the effects of antiviral intervention during pregnancy on maternal immune response remain unknown. We aimed to investigate these effects by comparing mothers who received antiviral intervention during pregnancy with those who did not.

METHODS

Pregnant women positive for hepatitis B surface antigen and hepatitis B e-antigen (HBsAg⁺ HBeAg⁺) were enrolled at delivery, including 34 received prophylactic antiviral intervention during pregnancy (AVI mothers) and 15 did not (NAVI mothers). T lymphocyte phenotypes and functions were analysed using flow cytometry.

RESULTS

At delivery, maternal regulatory T cell (Treg) frequency in AVI mothers was significantly higher than that in NAVI mothers (P < 0.002), and CD4⁺ T cells in AVI mothers displayed a decreased ability to secrete IFN-γ (P = 0.005) and IL-21 (P = 0.043), but an increased ability to secrete IL-10 and IL-4 (P = 0.040 and P = 0.036), which represented a higher Treg frequency, enhanced Th2 response and suppressed Th1 response. Treg frequency among AVI mothers was correlated negatively with serum HBsAg and HBeAg levels. After delivery, the ability of CD4⁺ T cells or CD8⁺ T cells to secrete IFN-γ or IL-10 was similar and no significant difference in Treg frequency was found between the two groups.

CONCLUSIONS

Prophylactic antiviral intervention during pregnancy has an effect on T cell immunity in pregnant women, which was characterised by increased maternal Treg frequency, enhanced Th2 response and suppressed Th1 response at delivery.

Recovery of host adaptive immune function promoted the reduction of hepatitis B surface antigen in nucleoside analog-experienced chronic hepatitis B patients with low hepatitis B surface antigen levels

Hepatitis B surface antigen (HBsAg) seroclearance is an optimal therapeutic endpoint, as it reflects the amount of covalently closed circular DNA. The exact mechanisms that contribute to HBsAg reduction are not completely understood. We evaluated adaptive immunity in nucleoside analog-experienced chronic hepatitis B (CHB) patients with low HBsAg levels who received oral antiviral therapy. One hundred and ninety-five CHB patients had hepatitis B virus (HBV) DNA ≤ 1000 IU/ml and HBsAg < 3000 IU/ml for longer than one year of antiviral therapy. According to HBsAg levels, they were divided into Group 1 (HBsAg reduction ≥ 0.5 log₁₀) and Group 2 (HBsAg reduction < 0.5 log₁₀). Cytokines, adaptive immune cells, and molecular markers in peripheral blood were detected at follow-up times. In total, 38 (19.5%) of the 195 patients achieved HBsAg reduction ≥ 0.5 log₁₀. IL4, IL5, IL10, TGF β, IL17, and PD-1 decreased gradually in these patients. HBsAg reduction had a link to the change in ICOSL⁺CD19⁺ B cells and CD40L⁺CXCR5⁺CD4⁺ Tfh cells. More CD8⁺ naive T lymphocytes differentiated into CD4⁺ T_CMs, CD8⁺ T_CMs and CD8⁺ T_EMs in Group 1. Meanwhile, Group 1 exhibited elevated Th1 and Th1/Th2 levels and reduced levels of Treg versus those in Group 2. With the reduction in HBsAg, the imbalance of T-cell subsets was partially corrected; the immune activity of T cells was enhanced, and the state of immune exhaustion was alleviated to a certain extent.

[Effects of hepatitis B virus on Th17, Treg and Th17/Treg ratio in different alanine aminetransferase stages]

OBJECTIVE

To evaluate the effects of hepatitis B virus (HBV) on helper T lymphocytes 17 (Th17), regulatory T lymphocyte (Treg) and Th17/Treg ratio in chronic hepatitis B patients in different alanine aminetransferase (ALT) stages.

METHODS

In the study, 336 chronic hepatitis B patients in the first hospital of Lanzhou University were analyzed. The hepatitis B antigen antibody parameters were measured by chemiluminescence immunoassay analyzer, the liver function parameters were measured by automatic biochemical analyzer, the HBV loads were measured by quantitative PCR, Th17, Treg and Th17/Treg ratios were detected by flow cytometry. Among them, 111 cases (ALT < 40 U/L) of ALT were normal hepatitis B, 108 cases of chronic hepatitis B with ALT above normal upper limit and < 2 times higher (40 U/L≤ALT < 80 U/L), and 117 cases of chronic hepatitis B with ALT above 2 times normal upper limit (80 U/L≤ALT). According to the viral load, they were divided into low replication group with HBV DNA < 4.0 lg copies/mL, medium replication group with 4.0 lg copies/mL≤HBV DNA < 6.0 lg copies/mL and high replication group with HBV DNA ≥ 6.0 lg copies / mL. Dunnett T3 variance analysis were used to analyze the effects of HBV on Th17, Treg and Th17/Treg ratio in the chronic hepatitis B patients in different ALT stages. The changes of virological and immunological indexes before and after treatment were observed for 24 weeks of antiviral therapy in the hepatitis B patients with ALT≥double upper limit of normal group.

RESULTS

In the ALT normal group, different virus load HBV had minor effects on Th17, Treg and Th17/Treg ratio. In the ALT≥2 times upper limit of normal group, with the virus load increased, Th17 (3.18%±0.79% in low replication group, 3.78%±0.92% in medium replication group and 4.57%±1.15% in high replication group), Treg cells (5.52%±1.58% in low replication group, 5.89%±1.84% in medium replication group and 6.37%±2.35% in high replication group) and their ratio Th17/Treg (0.57±0.25 in low replication group, 0.65±0.29 in medium replication group and 0.73±0.36 in high replication group) were significantly increased (P < 0.05). After entecavir treatment 24 weeks, the patient' s HBV-DNA decreased significantly, Th17 (3.89%±1.02% vs. 2.06%±0.46%), Treg (6.02%±2.03% vs. 5.06%±1.25%), Th17/Treg ratio (0.65±0.28 vs. 0.41±0.14) decreased significantly (P < 0.05).

CONCLUSION

Investigation on the effects of HBV on Th17 and Treg cells and their ratios in different ALT states can clarify the effects of HBV on the body from the immunological perspective and can further understand the ALT grouping for antiviral treatment theoretical significance, which is helpful for clinical treatment.

Bioinformatic Analysis of Prognostic and Immune-Related Genes in Pancreatic Cancer

Pancreatic cancer (PC) is a malignant tumor with poor prognosis. The poor effect of surgery and chemotherapy makes the research of immunotherapy target molecules significant. Therefore, identifying the new molecular targets of PC is important for patients. In our study, we systematically analyzed molecular correlates of pancreatic cancer by bioinformatic analysis. We characterized differentially expressed analysis based on the TCGA pancreatic cancer dataset. Then, univariate Cox regression was employed to screen out overall survival- (OS-) related DEGs. Based on these genes, we established a risk signature by the multivariate Cox regression model. The ICGC cohort and GSE62452 cohort were used to validate the reliability of the risk signature. The impact of T lymphocyte-related genes from risk signature was confirmed in PC. Here, we observed the correlation between the T lymphocyte-related genes and the expression level of targeted therapy. We established a five-mRNA (LY6D, ANLN, ZNF488, MYEOV, and SCN11A) prognostic risk signature. Next, we identified ANLN and MYEOV that were associated with T lymphocyte infiltrations (P < 0.05). High ANLN and MYEOV expression levels had a poorer prognosis in decreased T lymphocyte subgroup in PC. Correlation analysis between ANLN and MYEOV and immunomodulators showed that ANLN and MYEOV may have potential value in pancreatic cancer immunotherapy.

Combination of pegylated interferon-alpha and nucleos(t)ide analogue treatment enhances the activity of natural killer cells in nucleos(t)ide analogue experienced chronic hepatitis B patients

A combination of pegylated interferon-alpha (peg-IFN-α) and nucleos(t)ides analogue (NA) therapy can effectively reduce hepatitis B surface antigen (HBsAg), especially in NA-experienced chronic hepatitis B (CHB) patients. However, the immune mechanism of this therapy is unclear. Forty NA-experienced CHB patients were enrolled into this study. The frequencies of peripheral blood natural killer (NK) cells, dendritic cells (DCs), CD4⁺ T cells, CD8⁺ T cells, T helper (Th) cells, regulatory T cells (T_reg ), B cells and follicular T helper (Tfh) cells were evaluated by flow cytometry. Seven of the 40 patients converted to peg-IFN-α combined with NA treatment, while the other 33 continued to NA therapy. The decrease in HBsAg was more pronounced in the combination treatment group, and only patients receiving combination treatment achieved HBsAg loss. The frequency and absolute number of CD56^bright NK cells in the combination treatment group increased significantly compared with the NA treatment group, whereas the CD56^dim NK cells were decreased. In the NA treatment group, the proportions of CD4⁺ T_N , CD8⁺ T_N , CD19⁺ B and cytotoxic T lymphocyte antigen-4 (CTLA-4)⁺ CD4⁺ T cells were increased, while the proportions of CD4⁺ T_EM , CD8⁺ T_EM , CD25⁺ CD4⁺ T_reg , CD25^high CD4⁺ T_reg , CD127^low CD25⁺ T_reg , programmed cell death 1 (PD-1)⁺ CD4⁺ T, PD-1⁺ CD8⁺ T, CTLA-4⁺ CD8⁺ T, CCR4⁺ CD25⁺ T_reg and CCR4⁺ CD25^high T_reg cells were decreased after therapy. For NA-experienced CHB patients who achieved low HBsAg levels, combination treatment is more likely to result in HBsAg decline and HBsAg clearance by increasing the activity of CD56^bright NK cells.

HBV promotes the recruitment of IL-17 secreting T cells via chemokines CCL22 and CCL17

BACKGROUND AND AIMS

Little is known about the mechanisms of IL-17 secreting T cells accumulation in HBV-transfected livers. Here, we investigated the role of the chemokines CCL17, CCL20 and CCL22 in this process.

METHODS

Peripheral blood and liver tissues were obtained from 30 chronic hepatitis B (CHB) patients and 15 healthy volunteers and were evaluated by flow cytometric analysis and immunohistochemistry. Chemokine production by monocyte-derived dendritic cells (MoDCs) cocultured with HBV-transfected or untransfected Huh7 cells was measured by quantitative real-time PCR and enzyme-linked immunosorbent assay. The chemotactic activity of the culture supernatants was also tested.

RESULTS

The proportions of IL-17 secreting CD4 (Th17) and CD8 (Tc17) T cells were both increased in liver and peripheral blood mononuclear cells of CHB patients compared to those in HVs. CHB patients showed higher intrahepatic levels of CCL17 mRNA, CCL22 mRNA, CCR6 mRNA and CCR4 mRNA than HVs. The expression of CCR6 and CCR4 on the surface of Th17 and Tc17 cells in CHB patients was also significantly higher than that in HVs. Significant correlations existed between the CCR4/CCR6 levels and both the alanine transaminase levels and HBV DNA loads. Contact between MoDCs and pBlue-HBV-transfected Huh7 cells induced the expression of CCL17 and CCL22 dependent on the dose of HBV DNA. However, CCL20 expression was lower in CHB patients than in HVs. Transwell experiments showed that upregulation of CCL17 and CCL22 enhanced the migration of IL-17 secreting T cells.

CONCLUSIONS

Contact of HBV-transfected cells with MoDCs induces CCL17 and CCL22 chemokine production, which may favour the recruitment of Th17 and Tc17 cells to liver tissue in CHB. Our results reveal the mechanism of IL-17 secreting T cells recruitment to liver tissue and thus provide new immunotherapy targets for CHB patients.

The effects of nucleoside/nucleotide analogues on host immune cells: the baseline for future immune therapy for HBV?

HBV is a non-cytopathic virus and the progression of liver fibrosis is attributed to the host immune response. Complete suppression of viral replication using nucleotide or nucleoside analogues (NUCs) can prevent most complications related to chronic HBV infection. Unfortunately, antiviral treatment has to be administered lifelong to the majority of patients as HBV persists in the hepatocytes. However, although NUCs are very frequently administered in clinical practice, their effects on vital parts of the host immune response to HBV are not well established. In this review we summarize the currently available data gathered from longitudinal studies that investigated treatment-associated alterations of HBV-specific CD4⁺ and CD8⁺ T-cells, regulatory T-cells and natural killer (NK) cells. These observations are important, as they can guide the design of studies that investigate the efficacy of new immune therapeutic agents. Novel experimental compounds will likely be added to ongoing NUC treatment, which leads to a functional cure in only a small minority of patients.

The serum interleukin-26 level is a potential biomarker for chronical hepatitis B

Proinflammatory interleukin-26 (IL-26) is involved in chronic inflammation; however, the role of IL-26 in chronic hepatitis B (CHB) remains unknown.In this study, serum IL-26 was quantified in a cohort of CHB patients at baseline and during telbivudine (LdT) treatment.Our results showed that the serum IL-26 level was significantly elevated in CHB patients compared with that in healthy controls and was time-dependently decreased during LdT treatment, accompanying hepatitis B e antigen (HBeAg) seroconversion and reduced serum levels of hepatitis B virus (HBV) DNA, aspartate transaminase, and alanine transaminase across baseline and treatment. In addition, the serum level of IL-26 exhibited a similar declining trend to that of T helper 17 (Th17) cell-secreted IL-17 during LdT treatment in CHB patients. The percentage of IL-26-expressing CD4 cells was significantly higher than that of IL-26-expressing CD4 cells isolated from the peripheral blood mononuclear cells of CHB patients, suggesting that serum IL-26 might be mainly released from CD4 T cells. Furthermore, the baseline mRNA levels of IL-26 and orphan nuclear receptor RORγt-an important transcription factor expressed by Th17 cells-were positively correlated and displayed the same declining trend across the baseline and LdT treatment in CHB patients, suggesting that Th17 cells could be a possible cellular source of the increased serum IL-26 in CHB patients.Taken together, our results suggest that serum IL-26, possibly produced by Th17 CD4 cells, is a novel and potential biomarker for CHB prognosis and treatment.

Role of Foxp3/Treg and RORγt/Th17 imbalance in chronic hepatitis B virus infection

A wide range of immune-mediated liver damage can be seen during infection with hepatitis B virus (HBV). Failure of HBV immune clearance leads to chronic hepatitis and greatly increases the risk of liver cirrhosis and hepatocellular carcinoma. Recently, there have been many studies on the relationship between the outcome of HBV infection and the immune status of patients. The immune response of T lymphocytes in HBV infection plays an important role, especially the imbalance of regulatory T cells (Treg)/Helper T cell 17 (Th17). The imbalance between the Treg and Th17 is an important mechanism of persistent HBV infection and inflammatory injury of the liver. To better reveal the underlying mechanisms, we systematically review the roles of Treg and Th17 and discuss the relationship between Treg and Th17 during HBV infection as well as the changes in the two related specific transcription factors, retinoid-related orphan nuclear receptor γt (RORγt) and forkhead/winged helix family transcription factor 3 (Foxp3). The research on HBV immunotargeting therapy in recent years has suggested the role of Foxp3/Treg and RORγt/Th17 imbalance in HBV infection. Such findings provide new ideas for the treatment of chronic hepatitis B.

Interleukin-35 modulates the balance between viral specific CD4+CD25+CD127dim/- regulatory T cells and T helper 17 cells in chronic hepatitis B virus infection

Background

Interleukin (IL)-35 regulates imbalance between regulatory T cells (Tregs) and T helper (Th) 17 cells, leading to an important modulator in autoimmune disorder, cancer, and infectious diseases. Our previous study revealed an immunosuppressive activity of IL-35 in chronic hepatitis B virus (HBV) infection. Thus, the aim of the current study was to investigate the role of regulatory function of IL-35 to viral specific Tregs/Th17 cells balance in chronic HBV infection.

Methods

A total of 44 HLA-A2 restricted chronic HBV infected patients, including 21 of chronic hepatitis B (CHB) and 23 of asymptomatic HBV carriers (ASC) were enrolled. Purified CD4⁺ T cells or CD4⁺CD25⁺CD127^dim/− Tregs were stimulated with recombinant IL-35. HBV core antigen specific Tregs and Th17 cells were determined by flow cytometry. FoxP3 and RORγt mRNA was measured by real-time PCR. Cytokines production (IL-10 and IL-17) was investigated by ELISA.

Results

Peripheral viral specific Tregs was comparable between CHB and ASC. However, increased percentage of viral specific Th17 cells was found in CHB, leading to the reduction of Tregs/Th17 ratio in CHB patients. IL-35 stimulation elevated viral specific Tregs, but not Th17 cells frequency, in both CHB and ASC, resulting in the elevation of Tregs/Th17 ratio in both groups. This process was accompanied by increased expression of FoxP3 mRNA and IL-10 production, and decreased IL-17 secretion and STAT3 phosphorylation in purified CD4⁺ T cells. Moreover, IL-35 stimulation inhibited viral specific Th17-like phenotype differentiation from Tregs in CHB patients. Effective anti-HBV therapy did not affect viral specific Tregs/Th17 cells frequency or IL-35 expression in CHB patients, however, reduced responsiveness of CD4⁺ T cells or Tregs to IL-35 stimulation in vitro.

Conclusion

Our findings indicated that IL-35 regulation to viral specific Tregs/Th17 balance may contribute to viral persistence in chronic HBV infection.

Effect of WSP, a Chinese Herbal Formula, on Th17/Treg Ratio and HBeAg Seroconversion in Telbivudine-Treated HBeAg-Positive Chronic Hepatitis B Patients with High Baseline ALT Levels (20-30 Times the ULN)

Chronic hepatitis B (CHB) is a global health problem. Clinically, many patients have baseline alanine aminotransferase (ALT) levels above 20 times the upper limit of normal (ULN), but there are few reports about these patients. The prospective randomized placebo-controlled clinical study was designed to investigate the effect of WSP, a Chinese herbal formula, on telbivudine- (LDT-) treated HBeAg-positive CHB patients with high baseline ALT levels (20–30 times the ULN) and kidney-yang deficiency syndrome. Eligible patients were randomized to receive LDT 600 mg/day in combination with WSP (treatment group) or placebo granules (control group) 16.28 g/day for 52 weeks. The results showed that HBeAg seroconversion (SC) rate (44.1%) in the treatment group (n=34) was significantly superior to that (20.6%) in the control group (n=34) at 52 weeks (P < 0.05). Meanwhile, WSP could promote HBV DNA negative conversion (85.3% versus 61.8%, P < 0.05) and ALT normalization (94.1% versus 76.5%, P < 0.05) compared with the placebo. There were no drug-related serious adverse events. During the treatment, the peripheral blood Th17/Treg ratio first increased and then decreased in the treatment group and reached the peak at 12 weeks (P < 0.05). At 12, 24, 36, and 52 weeks, Th17/Treg ratio in the treatment group was better than those in the control group (all P < 0.05). In addition, the patients (n=22) with HBeAg SC had higher Th17/Treg ratio than the patients (n=46) without SC at 12 weeks (0.68±0.26 versus 0.43±0.18, P < 0.001). In conclusion, WSP could safely enhance HBeAg SC and promote HBV DNA negative conversion and ALT normalization in LDT-treated HBeAg-positive CHB patients with high baseline ALT levels (20–30 times the ULN) and kidney-yang deficiency syndrome. Th17/Treg ratio was not only related to the mechanisms of WSP but also a good predictor of 52-week HBeAg SC.

Contribution of Regulatory T Cells in Nucleotide-Binding Oligomerization Domain 2 Response to Influenza Virus Infection

Influenza A virus (IAV) is recognized to cause severe pulmonary illnesses in humans, particularly in elderly and children. One of the features associated with IAV infection is an excessive lung inflammation due to an uncontrolled immune response. The nucleotide-binding oligomerization domain 2 (NOD2) receptor is known to recognize ssRNA viruses such as IAV, but its role in the inflammatory process during viral infections remains to be clarified. In a previous report, we have shown that activation of NOD2 with muramyl dipeptide (MDP) significantly reduces both viral loads and lung inflammation and also improves pulmonary function during IAV infection. These findings prompted us to further investigate whether NOD2 receptor may contribute to regulate inflammation during viral infection. In the present study, we show that administration of MDP to mice infected with IAV stimulates the migration of regulatory T (Treg) cells to the lungs. Such a presence of Treg cells was also accompanied with a reduction of neutrophils in the lungs during IAV infection, which correlated, with a significant decrease of Th17 cells. In our model, Treg cell recruitment is dependent of CXCL12 and CCL5 chemokines. Moreover, we show that the presence of Ly6C^low patrolling monocytes is required for Treg cells mobilization to the lung of mice treated with MDP. In fact, following monocyte depletion by administration of clodronate liposome, mobilization of Treg cells to the lungs of treated mice was found to occur when circulating Ly6C^low monocytes begin to reemerge. In addition, we also detected an increased production of TGF-β, a cytokine contributing to Treg activity when blood Ly6C^low monocytes are restored. Together, our results demonstrate that MDP treatment can promote an anti-inflammatory environment through the mobilization of Treg cells to the lung, a mechanism that requires the presence of Ly6C^low monocytes during IAV infection. Overall, our results suggest that activation of NOD2 receptor could be an appealing approach to control pulmonary inflammation in patients infected with IAV.