Varicella zoster virus (VZV)-specific immunity and subclinical VZV reactivation in patients with autoimmune diseases

Elucidating the causal nexus between antibody-mediated immunity and autoimmune diseases: Insights from bidirectional mendelian randomization, gene expression profiling, and drug sensitivity analysis

OBJECTIVE

This study aimed to elucidate the causal relationships between antibodies and autoimmune diseases using Mendelian randomization (MR).

METHODS

Data on 46 antibodies were obtained from genome-wide association studies (GWAS). Autoimmune disease data were sourced from the FinnGen consortium and the IEU OpenGWAS project. Inverse-variance weighted (IVW) analysis was the primary method, supplemented by heterogeneity and sensitivity analyses. We also examined gene expression near significant SNPs and conducted drug sensitivity analyses.

RESULTS

Antibodies and autoimmune diseases exhibit diverse interactions. Antibodies produced after Polyomavirus infection tend to increase the risk of several autoimmune diseases, while those following Human herpesvirus 6 infection generally reduce it. The impact of Helicobacter pylori infection varies, with different antibodies affecting autoimmune diseases in distinct ways. Overall, antibodies significantly influence the risk of developing autoimmune diseases, whereas autoimmune diseases have a lesser impact on antibody levels. Gene expression and drug sensitivity analyses identified multiple genes and drugs as potential treatment options for ankylosing spondylitis (AS), with the AIF1 gene being particularly promising.

CONCLUSIONS

Bidirectional MR analysis confirms complex causal relationships between various antibodies and autoimmune diseases, revealing intricate patterns of post-infection antibody interactions. Several drugs and genes, notably AIF1, show potential as candidates for AS treatment, offering new avenues for research. Further exploration of the underlying mechanisms is necessary.

Obstructive sleep apnea and its association with humoral immunity against varicella zoster virus

OBJECTIVE

This study aimed to evaluate the association between obstructive sleep apnea (OSA) and humoral immunity to varicella zoster virus (VZV).

METHODS

This retrospective cohort study included patients who underwent polysomnography and concurrently agreed for blood collection between January 2018 and February 2021. Habitual snorers and patients with severe obstructive sleep apnea were evaluated to compare the VZV immunoglobulin G (IgG) antibody titer between habitual snorer group and OSA group. Correlation between VZV IgG antibody titer and various sleep related respiratory parameters were also evaluated.

RESULTS

We found that the VZV IgG antibody titer of the habitual snorer group (n = 60) was significantly higher than that of the severe OSA group (n = 54) (244.1 ± 80.9 and 163.09 ± 48.39, respectively. Data are presented as mean ± standard deviation, P < 0.001). According to Spearman's correlation analysis, the VZV IgG antibody titer was moderately negatively correlated with apnea hypopnea index (r = -0.477, P < 0.001), apnea index (r = -0.496, P < 0.001), hypopnea index (r = -0.398, P < 0.001), respiratory disturbance index (r = -0.467, P < 0.001), arousal index (r = -0.467, P < 0.001) and oxygen desaturation index (r = -0.475, P < 0.001). Minimal oxygen saturation was moderately positively correlated with VZV IgG antibody titer (r = 0.474, P < 0.001).

CONCLUSION

Humoral immunity to VZV is significantly reduced in patients with severe OSA, and VZV IgG antibody titer was inversely correlated with respiratory events during sleep.

Are Viral Infections Key Inducers of Autoimmune Diseases? Focus on Epstein–Barr Virus

It is generally accepted that certain viral infections can trigger the development of autoimmune diseases. However, the exact mechanisms by which these viruses induce autoimmunity are still not understood. In this review, we first describe hypothetical mechanisms by which viruses induce some representative autoimmune diseases. Then, we focus on Epstein–Barr virus (EBV) and discuss its role in the pathogenesis of rheumatoid arthritis (RA). The discussion is mainly based on our own previous findings that (A) EBV DNA and its products EBV-encoded small RNA (EBER) and latent membrane protein 1 (LMP1) are present in the synovial lesions of RA, (B) mRNA expression of the signaling lymphocytic activation molecule-associated protein (SAP)/SH2D1A gene that plays a critical role in cellular immune responses to EBV is reduced in the peripheral T cells of patients with RA, and (C) EBV infection of mice reconstituted with human immune system components (humanized mice) induced erosive arthritis that is pathologically similar to RA. Additionally, environmental factors may contribute to EBV reactivation as follows: Porphyromonas gingivalis peptidylarginine deiminase (PAD), an enzyme required for citrullination, engenders antigens leading to the production of citrullinated peptides both in the gingiva and synovium. Anti-citrullinated peptides autoantibody is an important marker for diagnosis and disease activity of RA. These findings, as well as various results obtained by other researchers, strongly suggest that EBV is directly involved in the pathogenesis of RA, a typical autoimmune disease.