The impact of lymphoid memory cells in different ages of COVID-19 patients

Investigation of IL-6 serum level in COVID-19 patients with positive COVID-19 IgG/IgM antibody titers to check inflammation and disease progression

OBJECTIVE

The SARS-CoV-2, the cause of coronavirus disease 2019 (COVID-19), leads to severe pathogenicity and high mortality among different communities around the world. Therefore, it is important to understand the mechanisms of virus pathogenesis and the immune system's response to prevent the further spread of this virus. This study was aimed to evaluate the relationship between the serum level of interleukin 6 and positive IgG and IgM antibody levels in patients with COVID-19 to investigate inflammation and disease progression.

METHODS & MATERIALS

In this study, 10 ml of EDTA blood samples were taken from 414 COVID-19 patients. Then, the plasma was separated and the levels of IgM and IgG antibodies and interleukin 6 cytokine were evaluated by ELISA and chemiluminescence methods, respectively. All data were analyzed by SPSS 22 and GraphPad prism 9 software at the significance level of P < 0.05.

RESULTS

The results of this study showed that there was no significant difference in the expression of IgM and IgG antibodies between men and women. Also, a significant increase in the mean expression of IL-6 was observed only in the high concentration range (100-〉1000 pg/ml) in men compared to women (P < 0.001). In addition, in the female population, all three concentration ranges (negative, medium, and high) of IL-6 have the highest correlation with high titers (>10 U/ml) of IgM and IgG antibodies. While, in men, all three concentration ranges of IL-6 had the highest correlation with > 10 U/ml IgM antibody titers, but in the case of IgG, the highest correlation between different concentrations of IL-6 was observed with the negative or moderate titers of this antibody and there was an inverse relationship with the high titers of IgG (>10 U/ml).

CONCLUSION

As a result, the relationship between different serum levels of cytokine IL-6 with different titers of IgM and IgG antibodies was observed in both male and female populations. In general, it can be concluded that the correlation between different concentrations of IL-6 with different IgM titers was similar in both men and women, but in the case of different IgG titers, this correlation was higher in women than men.

Incidence and outcome of SARS-CoV-2 infection in a pediatric kidney transplant recipient cohort from a single center in Northern Italy

BACKGROUND

Concern about SARS-CoV-2 infection has increased over the possible effects on immunocompromised patients. Among them, recipients of solid organ transplantation deserve special attention. Data from the adult population suggest they may be at high risk for developing severe COVID-19, but little data are available for pediatric solid organ transplantation recipients.

METHODS

From March 2020 to April 2021, KT recipients aged <21 years, routinely managed at our center, who underwent RT-PCR testing with nasopharyngeal swabs to detect SARS-CoV-2 infection, were studied. Tests were performed according to clinical and/or epidemiological criteria.

RESULTS

One hundred one transplanted patients were managed at our center during the observation period. Among this population, 57 patients were tested for SARS-CoV-2 infection with a RT-PCR test and were subsequently enrolled. A total of 111 swabs were performed. Twelve out of the 57 patients tested (21.1%) had a positive RT-PCR test result. Among the positive patients, eight were symptomatic (66.7%). Median duration of symptoms and RT-PCR positivity was two days (IQR 1-2.25) and 17 days (IQR 11-27.25), respectively. No patients required specific treatment or IS therapy reduction; no one was admitted to hospital.

CONCLUSIONS

Our data show that pediatric renal transplant recipients are at low risk of clinically relevant COVID-19, as is the healthy age-related population. On the contrary, our results differed substantially from those seen in adult SOT recipient populations that have a high incidence and an even earlier and higher mortality rate.

SARS-CoV-2 triggering autoimmune diseases

Autoimmunity, hyperstimulation of the immune system, can be caused by a variety of reasons. Viruses are thought to be important environmental elements that contribute to the development of autoimmune antibodies. It seems that viruses cause autoimmunity with mechanisms such as molecular mimicry, bystander activation of T cells, transient immunosuppression, and inflammation, which has also been seen in post-Covid-19 autoimmunity. Infection of respiratory epithelium by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) dysregulates the immune response, triggers both innate and acquired immunity that led to the immune system's hyperactivation, excessive cytokine secretion known as “cytokine storm,” and finally acute respiratory distress syndrome (ARDS) associated with high mortality. Any factor in the body that triggers chronic inflammation can contribute to autoimmune disease, which has been documented during the Covid-19 pandemic. It has been observed that some patients produce autoantibody and autoreactive CD4⁺ and CD8⁺ T cells, leading to the loss of self-tolerance. However, there is a scarcity of evidence defining the precise molecular interaction between the virus and the immune system to elicit autoreactivity. Here, we present a review of the relevant immunological findings in Covid-19 and the current reports of autoimmune disease associated with the disease.