HLA-DR Expression Level in CD8+ T Cells Correlates With the Severity of Children With Acute Infectious Mononucleosis

Infectious mononucleosis: new concepts in clinical presentation, epidemiology, and host response

PURPOSE OF REVIEW

Infectious mononucleosis (IM) is an infectious disease that presents clinically in only a small percentage of individuals despite almost universal infection with the causative agent. Here, we review the latest concepts in the clinical presentation, epidemiology, and host response of this disease.

RECENT FINDINGS

Several recently published papers/reviews describe IM as a condition caused by one of several etiologic agents including, cytomegalovirus (HHV-5), Roseola virus (HHV-6) and Toxoplasmosis amongst others; this review focuses on IM as solely caused by the human herpes virus 4 (HHV-4). Since the initial discovery of the virus in the 1960s and its subsequent discovery as the primary etiologic agent for IM it has been associated with several human cancers and autoimmune disorders. Recent published findings show a correlation between HHV-4 and the autoimmune disorder, multiple sclerosis (MS), suggesting earlier IM could possibly act as a causative factor. Considering the important links being made with IM to so many cancers and autoimmune disorders it is surprising that a standard investigative procedure has yet to be determined for this disease. A standard approach to the investigation of IM would ensure more cases are diagnosed, particularly atypical cases, this would benefit epidemiological studies, and more immediately help practitioners distinguish viral from bacterial throat infections, enabling them to treat accordingly.

SUMMARY

The understanding of the latest concepts in clinical presentation, epidemiology and host response to IM would benefit greatly from the introduction of a standard procedure for its investigation and diagnosis.

Comparison of immune responses in children with infectious mononucleosis caused by Epstein-Barr virus at different infection stages

INTRODUCTION

Infectious mononucleosis (IM) is a common infectious disease in children mainly caused by Epstein-Barr virus (EBV) infection, followed by abnormal immune response, and resulting in serious complications. However, there are few clinical analyses of immune responses in children with IM at different stages.

METHODS

This study combined EBV serological test and EBV DNA test to diagnose the infection status of children with IM, and the infection status was divided into primary acute IM infection (AIM), primary late IM infection (LIM) and reactivation IM infection (RIM).

RESULTS

The results revealed that the absolute numbers of leukocytes and CD8+ T lymphocytes in primary IM infection were significantly higher than those in reactivation infection, while the frequencies of CD4+ T lymphocytes and B cells were significantly lower than those in reactivation infection. In addition, the activities of ALT, AST, α-HBDH and LDH in liver function indicators in primary infection were significantly increased compared with reactivation infection. Similarly, the EBV DNA levels of the primary infection were significantly higher than that of the reactivation infection.

CONCLUSION

There are differences in immune response at different stages of infection, which can provide guidance for effective treatment in children with IM infection.

Expression and Clinical Significance of Peripheral Blood IL-17A, IL-22, Tim-3, and gal-9 in Children with Infectious Mononucleosis

To investigate the expression and clinical significance of peripheral blood interleukin (IL)-17A, IL-22, T cell immunoglobulin molecule-3 (Tim-3), and galectin-9 (gal-9) in children with infectious mononucleosis (IM) caused by the Epstein-Barr virus (EBV). Peripheral blood of 54 children with IM (case group) was collected and divided into a liver damage group and a non-liver damage group. During the same period, 20 healthy children were in the control group. IL-17A and IL-22 were measured by enzyme-linked immunosorbent assay. Real-time quantitative polymerase chain reaction was used to measure the mRNA expression of Tim-3 and gal-9. Their correlation with clinical indicators was then analyzed. The IL-17A expression level was higher in the case group than in the control group, while Tim-3, gal-9, and IL-22 were lower than those in the control group. Tim-3 was positively correlated with gal-9, but negatively correlated with IL-17A. Tim-3 and gal-9 were positively correlated with CD4+/CD8+ cells. Conversely, they were negatively correlated with CD3+, CD3+CD8+, white blood cell, lymphocyte (L), alanine transaminase (ALT), aspartate transaminase (AST), glutamyl transpeptidase (GGT), and lactate dehydrogenase (LDH). In the case group, IL-17A was positively correlated with L, GGT, and LDH, but negatively correlated with the natural killer (NK) cell count. IL-17A and IL-22 were positively correlated with CD3+, CD3+CD8+, ALT, and AST, but they were negatively correlated with the ratio of CD4+/CD8+. In the liver damage group, IL-17A, IL-22, CD3+, CD3+CD8+, immunoglobulin A (IgA), IgG, IgM, L, ALT, AST, GGT, LDH, and α-hydroxybutyrate levels were higher than those in the non-liver damage group. However, Tim-3, gal-9, the ratio of CD4+/CD8+, and NK were lower than those in the non-liver damage group. IL-17A, IL-22, Tim-3, and gal-9 are involved in the immune pathogenesis of IM caused by EBV infection in children, which may be related to immune liver injury.

Characteristics of immunological events in Epstein-Barr virus infection in children with infectious mononucleosis

BACKGROUNDS & AIMS

Epstein-Barr virus (EBV) infection occurs commonly in children and may cause acute infectious mononucleosis (AIM) and various malignant diseases. Host immune responses are key players in the resistance to EBV infection. We here assessed the immunological events and laboratory indicators of EBV infection, as well as determined the clinical usefulness of evaluating the severity and efficacy of antiviral therapy in AIM patients.

METHODS

We enrolled 88 children with EBV infection. The immune environment was defined by immunological events such as frequencies of lymphocyte subsets, phenotypes of T cells, and their ability to secrete cytokines, and so on. This environment was analyzed in EBV-infected children with different viral loads and in children in different phases of infectious mononucleosis (IM) from disease onset to convalescence.

RESULTS

Children with AIM had higher frequencies of CD3⁺ T and CD8⁺ T cells, but lower frequencies of CD4⁺ T cells and CD19⁺ B cells. In these children, the expression of CD62L was lower and that of CTLA-4 and PD-1 was higher on T cells. EBV exposure induced granzyme B expression, but reduced IFN-γ secretion, by CD8⁺ T cells, whereas NK cells exhibited reduced granzyme B expression and increased IFN-γ secretion. The frequency of CD8⁺ T cells was positively correlated with the EBV DNA load, whereas the frequencies of CD4⁺ T cells and B cells were negatively correlated. During the convalescent phase of IM, CD8⁺ T cell frequency and CD62L expression on T cells were restored. Moreover, patient serum levels of IL-4, IL-6, IL-10, and IFN-γ were considerably lower throughout the convalescent phase than throughout the acute phase.

CONCLUSION

Robust expansion of CD8⁺ T cells, accompanied by CD62L downregulation, PD-1 and CTLA-4 upregulation on T cells, enhanced granzyme B production, and impaired IFN-γ secretion, is a typical characteristic of immunological events in children with AIM. Noncytolytic and cytolytic effector functions of CD8⁺ T cells are regulated in an oscillatory manner. Furthermore, the AST level, number of CD8⁺ T cells, and CD62L expression on T cells may act as markers related to IM severity and the effectiveness of antiviral treatment.

Positive correlation between VCA-IgM and Th1/Th2 immunocytokines in children with infectious mononucleosis

OBJECTIVE

To analyze the correlation between immunoglobulin M (IgM) against viral capsid antigen (VCA) of Epstein-Barr virus (EBV) and T helper 1 and 2 (Th1/Th2) immunocytokines (ICKs) in children with infectious mononucleosis (IM).

METHODS

This is a retrospective study. A total of 40 children with IM treated in our hospital from August 2019 to August 2021 were included in the research group, and another 42 children with upper respiratory tract infection treated during the same period were selected as the control group. The VCA-IgM positive (+) rate and Th1/Th2 ICKs in two groups were detected, and the correlation of VCA-IgM with Th1/Th2 ICKs in IM patients was analyzed.

RESULTS

The research group was found to have an evidently higher VCA-IgM+ rate than the control group. Moreover, the accuracy of VCA-IgM in detecting IM was as high as 91.46%. In addition, tumor necrosis factor-α (TNF-α), interferon-γ (IFN-γ), interleukin (IL)-6 and IL-10 presented markedly elevated levels in the research group than in the control group, and in VCA-IgM negative (-) patients compared with VCA-IgM+ patients. There was a positive connection between VCA-IgM and Th1/Th2 ICKs.

CONCLUSIONS

IM children showed high VCA-IgM+ rate and imbalance of Th1/Th2 ICKs, and their VCA-IgM and Th1/Th2 ICKs are positively correlated. In addition, VCA-IgM has certain diagnostic value for IM.

The reference ranges and characteristics of lymphocyte parameters and the correlation between lymphocyte parameters and routine health indicators in adults from China

Background

Assessment of immune function is of key importance in recognition of disease or healthy status, which still faces challenge in clinical practice. We conducted a 10-center study to investigate lymphocyte parameters including the number, phenotype and IFN-γ-producing ability, and routine laboratory indicators by using the standard method.

Results

Although the heterogeneity of lymphocyte parameters was widely found, we have established the normal ranges of these parameters by using pooled data which showed no significant difference among centers. Cluster analysis of 35 parameters found 3 interesting clusters which represented different immunological status. Cluster 1 (parameters: IFN-γ⁺CD4⁺ T cell percentage and IFN-γ⁺CD8⁺ T cell percentage) represented current lymphocyte function, which was associated with indicators such as body mass index and red blood cell; Cluster 2 (parameters: NK cell number and CD45RA⁺CD4⁺ T cell percentage) represented potential of lymphocytes, which was associated with indicators such as albumin and high-density lipoprotein. Cluster 3 (parameters: HLA-DR⁺CD8⁺ T cell percentage) represented inflammatory status, which was associated with indicators such as low-density lipoprotein, globulin and age. Correlation analysis found that nutritional indicator albumin is significantly positively correlated with lymphocyte potential. Triglyceride and body mass index were positively correlated with current lymphocyte function rather than lymphocyte potential. The loss of CD8⁺ T cells was extremely pronounced with increasing age and was one of the most important factors to cause immunosenescence, which may be associated with increased glucose.

Conclusions

We have established the normal ranges of lymphocyte parameters in different areas. This study elucidates the key indicators used to reflect the current function or potential of lymphocytes, which may provide a valuable clue for how to keep immunity healthy.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12979-022-00298-5.