Elevated Systemic and Parasite-Antigen Stimulated Levels of Type III IFNs in a Chronic Helminth Infection and Reversal Following Anthelmintic Treatment

Unique cellular immune signatures of multisystem inflammatory syndrome in children

The clinical presentation of MIS-C overlaps with other infectious/non-infectious diseases such as acute COVID-19, Kawasaki disease, acute dengue, enteric fever, and systemic lupus erythematosus. We examined the ex-vivo cellular parameters with the aim of distinguishing MIS-C from other syndromes with overlapping clinical presentations. MIS-C children differed from children with non-MIS-C conditions by having increased numbers of naïve CD8+ T cells, naïve, immature and atypical memory B cells and diminished numbers of transitional memory, stem cell memory, central and effector memory CD4+ and CD8+ T cells, classical, activated memory B and plasma cells and monocyte (intermediate and non-classical) and dendritic cell (plasmacytoid and myeloid) subsets. All of the above alterations were significantly reversed at 6-9 months post-recovery in MIS-C. Thus, MIS-C is characterized by a distinct cellular signature that distinguishes it from other syndromes with overlapping clinical presentations. Trial Registration: ClinicalTrials.gov clinicaltrial.gov. No: NCT04844242.

Restoration of dendritic cell homeostasis and Type I/Type III interferon levels in convalescent COVID-19 individuals

Background

Plasmacytoid and myeloid dendritic cells play a vital role in the protection against viral infections. In COVID-19, there is an impairment of dendritic cell (DC) function and interferon secretion which has been correlated with disease severity.

Results

In this study, we described the frequency of DC subsets and the plasma levels of Type I (IFNα, IFNβ) and Type III Interferons (IFNλ1), IFNλ2) and IFNλ3) in seven groups of COVID-19 individuals, classified based on days since RT-PCR confirmation of SARS-CoV2 infection. Our data shows that the frequencies of pDC and mDC increase from Days 15–30 to Days 61–90 and plateau thereafter. Similarly, the levels of IFNα, IFNβ, IFNλ1, IFNλ2 and IFNλ3 increase from Days 15–30 to Days 61–90 and plateau thereafter. COVID-19 patients with severe disease exhibit diminished frequencies of pDC and mDC and decreased levels of IFNα, IFNβ, IFNλ1, IFNλ2 and IFNλ3. Finally, the percentages of DC subsets positively correlated with the levels of Type I and Type III IFNs.

Conclusion

Thus, our study provides evidence of restoration of homeostatic levels in DC subset frequencies and circulating levels of Type I and Type III IFNs in convalescent COVID-19 individuals.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12865-022-00526-z.

Plasmacytoid Dendritic Cells Facilitate Th Cell Cytokine Responses throughout Schistosoma mansoni Infection

Plasmacytoid dendritic cells (pDCs) are potent producers of type I IFN (IFN-I) during viral infection and respond to IFN-I in a positive feedback loop that promotes their function. IFN-I shapes dendritic cell responses during helminth infection, impacting their ability to support Th2 responses. However, the role of pDCs in type 2 inflammation is unclear. Previous studies have shown that pDCs are dispensable for hepatic or splenic Th2 responses during the early stages of murine infection with the trematode Schistosoma mansoni at the onset of parasite egg laying. However, during S. mansoni infection, an ongoing Th2 response against mature parasite eggs is required to protect the liver and intestine from acute damage and how pDCs participate in immune responses to eggs and adult worms in various tissues beyond acute infection remains unclear. We now show that pDCs are required for optimal Th2 cytokine production in response to S. mansoni eggs in the intestinal-draining mesenteric lymph nodes throughout infection and for egg-specific IFN-γ at later time points of infection. Further, pDC depletion at chronic stages of infection led to increased hepatic and splenic pathology as well as abrogated Th2 cell cytokine production and activation in the liver. In vitro, mesenteric lymph node pDCs supported Th2 cell responses from infection-experienced CD4+ T cells, a process dependent on pDC IFN-I responsiveness, yet independent of Ag. Together, these data highlight a previously unappreciated role for pDCs and IFN-I in maintaining and reinforcing type 2 immunity in the lymph nodes and inflamed tissue during helminth infection.

Association of previous schistosome infection with fatty liver and coronary heart disease: A cross-sectional study in china

BACKGROUND

More than 11 million people were estimated to have been infected by Schistosoma japonicum in China before the 1950s. However, few studies have been conducted to evaluate the longitudinal effects of previous schistosome infection (PSI).

OBJECTIVE

We aimed to evaluate the association of PSI with fatty liver and coronary heart disease in China.

METHODS

A cross-sectional study was conducted in regions which were all reportedly heavily endemic for S japonicum in China. All data were collected using a questionnaire administered and health examinations by well-trained medical professionals. 2867 participants aged 40 years and older were enrolled. Among these, 731 patients with PSI were selected as study subjects and 2136 subjects served as controls. Comparisons between groups were performed with or without an adjustment for a covariate, using Student's t tests for continuous variables and chi-square testing for categorical variables. Multivariable logistic models were used to estimate the associations between PSI and fatty liver or coronary heart disease.

RESULTS

The PSI participants had significantly lower levels of triglyceride, low-density lipoprotein cholesterol, fasting blood glucose, uric acid, serum creatinine, urea nitrogen, platelet, total protein and globulin as well as a lower prevalence of fatty liver (13.3% vs 53.6%, P < .001) and coronary heart disease (3.4% vs 6.0%, P < .05) compared with the uninfected, contemporaneous controls (without PSI), whereas the PSI participants had higher levels of high-density lipoprotein cholesterol, direct bilirubin and a higher prevalence of hepatic dysfunction compared with those without PSI (P < .05).

CONCLUSION

We found PSI significantly negatively associated with fatty liver and coronary heart disease. However, further studies on schistosomiasis may provide new directions for prevention and treatment of fatty liver and coronary heart disease.