The immunology of Parkinson’s disease

Abstract

Parkinson’s disease (PD) is the second most common neurodegenerative disorder which affects 6.1 million people worldwide. The neuropathological hallmarks include the loss of dopaminergic neurons in the substantia nigra, the presence of Lewy bodies and Lewy neurites caused by α-synuclein aggregation, and neuroinflammation in the brain. The prodromal phase happens years before the onset of PD during which time many patients show gastro-intestinal symptoms. These symptoms are in support of Braak’s theory and model where pathological α‐synuclein propagates from the gut to the brain. Importantly, immune responses play a determinant role in the pathogenesis of Parkinson’s disease. The innate immune responses triggered by microglia can cause neuronal death and disease progression. In addition, T cells infiltrate into the brains of PD patients and become involved in the adaptive immune responses. Interestingly, α‐synuclein is associated with both innate and adaptive immune responses by directly interacting with microglia and T cells. Here, we give a detailed review of the immunobiology of Parkinson’s disease, focusing on the role α-synuclein in the gut-brain axis hypothesis, the innate and adaptive immune responses involved in the disease, and current treatments.

Current Advances of Plant-Based Vaccines for Neurodegenerative Diseases

“…In particular, PD is the world’s second most prevalent neurodegenerative condition, affecting at least 6.1 million people worldwide. The neuropathology of this ailment is distinguished by dopaminergic neuron death in the substantia nigra, neuroinflammation, and by the occurrence of Lewy bodies and Lewy neurites induced by α-syn aggregation [ 107 ]. PD patients manifest motor symptoms, including bradykinesia, tremor, postural instability, and rigidity, as well as non-motor symptoms, involving sleep disorders, sensory disorders, cognitive impairment, psychotic symptoms, and mood disturbances [ 108 ].…”

Neuroimmune interactions in health and disease

“…The review by Zhu et al describe immune responses in the pathogenesis of Parkinson's disease where the innate immune responses triggered by microglia can cause neuronal death and disease progression. 7 The review also examines the role that T cells infiltrating the brains of Parkinson's disease patients and the role of α-synuclein reactive T cells. Macular degeneration is a neurodegenerative disease of the retina and one of the most common causes of blindness in the world.…”

The reciprocal interactions between microglia and T cells in Parkinson’s disease: a double-edged sword

“…Among them, immunological studies suggest that PD results from an imbalance in the immune system homeostasis in pathological processes in PD patients and related animal models [ 25 – 27 ]. Compared to controls, immune cells infiltrate the brain parenchyma and peripheral tissues, causing a release of large amounts of inflammatory and regulatory factors [ 26 , 27 ]. Furthermore, the activation of pre-existing immune cells in the brain also promotes the damage of dopaminergic neurons and exacerbates the progression of the disease [ 8 , 28 ].…”