The possible role of an autoimmune mechanism in the etiopathogenesis of Parkinson’s disease

Application value of peripheral blood IgG and IgM combined with ultrasonic echo parameters of substantia nigra in the diagnosis of Parkinson's disease

We study the clinical value of peripheral blood immunoglobulin G (IgG) and immunoglobulin M (IgM) combined with ultrasonic echo parameters of substantia nigra (SN) in the diagnosis of Parkinson's disease (PD). The clinical data of 121 patients with PD (case group) in our hospital from November 2020 to November 2022 were selected for retrospective analysis, and 9 patients with poor sound transmission of temporal window were excluded. Finally, this study included 112 patients with PD and selected 108 health examination population in the same period (control group). The levels of IgG and IgM in both groups were detected, and ultrasound examination was carried out to observe the structure of SN and obtain strong echo area of SN, midbrain area and strong echo area of SN/midbrain area. The receiver operator characteristic curve of serum IgG and IgM combined with ultrasonic echo parameters of SN in the diagnosis of PD was drawn to evaluate the clinical efficacy of single diagnosis and combined diagnosis. Compared with the control group, the serum levels of IgG and IgM, strong echo area of SN, midbrain area and strong echo area of SN/midbrain area in the case group were obviously higher (P < 0.001), while the folic acid level was notably lower (P < 0.05). The AUC value, Youden index and sensitivity of combined diagnosis were higher than those of single detection. Peripheral blood IgG and IgM combined with ultrasonic echo parameters of SN have high clinical value in the diagnosis of PD, which can provide a new direction for the subsequent diagnosis of PD.

The humoral immune landscape in Parkinson's disease: Unraveling antibody and B cell changes

Parkinson's disease (PD) is a complex neurodegenerative disorder characterized by the accumulation of α-synuclein (α-syn) in the brain and progressive loss of dopaminergic neurons in the substantia nigra (SN) region of the brain. Although the role of neuroinflammation and cellular immunity in PD has been extensively studied, the involvement of humoral immunity mediated by antibodies and B cells has received less attention. This article provides a comprehensive review of the current understanding of humoral immunity in PD. Here, we discuss alterations in B cells in PD, including changes in their number and phenotype. Evidence mostly indicates a decrease in the quantity of B cells in PD, accompanied by a shift in the population from naïve to memory cells. Furthermore, the existence of autoantibodies that target several antigens in PD has been investigated (i.e., anti-α-syn autoantibodies, anti-glial-derived antigen antibodies, anti-Tau antibodies, antineuromelanin antibodies, and antibodies against the renin-angiotensin system). Several autoantibodies are generated in PD, which may either provide protection or have harmful effects on disease progression. Furthermore, we have reviewed studies focusing on the utilization of antibodies as a potential treatment for PD, both in animal and clinical trials. This review sheds light on the intricate interplay between antibodies and the pathological processes in PD, including complement system activation.

Assessing serum anti-nuclear antibodies HEp-2 patterns in synucleinopathies

This study investigates the presence of antinuclear antibodies (ANA) in three primary synucleinopathies - Parkinson's disease (PD), multiple system atrophy (MSA), and dementia with Lewy bodies (DLB), compared to healthy controls. Autoinflammatory disorders typically involve the immune system mistakenly attacking the body's own cells and start producing ANA. There is an increasing body of evidence that immune-mediated inflammation is a pathological feature linked to synucleinopathies. To investigate whether this could be autoimmune mediated we analyzed for ANA in the plasma of 25 MSA, 25 PD, and 17 DLB patients, along with 25 healthy controls, using the ANA HEp-2 indirect immunofluorescence antibody assay (ANA HEp-2 IFA). Contrary to initial expectations, results showed ANA HEp-2 positivity in 12% of PD, 8% of MSA patients, 18% of DLB patients, and 17% of healthy controls, indicating no increased prevalence of ANA in synucleinopathies compared to age-matched healthy individuals. Various ANA HEp-2 patterns were identified, but no specific pattern was associated with individual synucleinopathies. We conclude hereby that synucleinopathies are not associated with detectable presence of ANA in plasma.

Paeoniflorin and Plycyrrhetinic Acid Synergistically Alleviate MPP+/MPTP-Induced Oxidative Stress through Nrf2-Dependent Glutathione Biosynthesis Mechanisms

Recently, combination therapy has proven to be an effective strategy for treating polygenic/multifactorial/complex disorder such as Parkinson's disease (PD). Here, we hypothesized that dual up-regulation of glutamate cysteine ligase (GCL) catalytic subunit (GCLc) and GCL modifier subunit (GCLm) via nuclear factor E2-related factor (Nrf2) contribute to the antioxidant effect of paeoniflorin (PF) synergistically with glycyrrhetinic acid (GA) (henceforth called PF/GA) in the context of MPP⁺/MPTP neurotoxicity. Expectedly, CompuSyn synergism/antagonism analysis showed that PF/GA exerts synergistic neuroprotection. Moreover, the antioxidant effect of PF was significantly enhanced by the combined administration of GA, although GA alone did not confer the effect. Mechanistically, PF triggered extracellular signal-regulated kinase (ERK1/2) phosphorylation, resulting in Nrf2 nuclear translocation from cytoplasmic pool via de novo synthesis in MPP⁺-challenged SH-SY5Y cells. Concomitantly, GA activates Akt which in turn induces nuclear accumulation of Nrf2. Especially, PF/GA up-regulated glutamate-cysteine ligase catalytic subunit (Gclc) and glutamate-cysteine ligase modifier subunit (Gclm) are formed via two separate pathways. Furthermore, these results were confirmed through pathway blockade assays using PD98059 (ERK1/2 inhibitor), LY294002 (phosphatidylinositol-3-kinase inhibitor), and shRNA-induced Nrf2 knockdown. Additionally, using a mouse MPTP-induced model of PD, we demonstrated that PF/GA synergistically ameliorates both motor deficits and oxidative stress in the ventral midbrain. In parallel, PF/GA also up-regulated both GCLc and GCLm expression at levels of transcription and translation. Conversely, antiparkinsonism and antioxidant effects of PF/GA were not observed in Nrf2-knockout MPTP-mice. Collectively, these results show that ERK1/2 and Akt activation contribute to the synergistic antioxidant effect of PF/GA. Hence, PF/GA regimen warrants further preclinical and possible clinical study for PD.