Relationship Between Immunosuppressive Treatment Status and Clinical Course of Parkinson's Disease

Inclusion criteria for the study group: 1. Diagnosis of Parkinson's disease according to the International Parkinson and Movement Disorder Society Clinical Diagnostic Criteria for Parkinson's disease; 2. Immunosuppressive medication use - medication taken regularly, which we have defined as administered at a dose and frequency effective for the indicated disease, for over 12 months, systemic administration route (oral, intramuscular, subcutaneous, intravenous and inhaled); The most commonly used immunosuppressive drugs that we anticipate will be used by the study group participants include: glucocorticosteroids (GC) - budesonide, cortisone, dexamethasone, hydrocortisone, methylprednisolone, prednisolone, prednisone, triamcinolone; calcineurin inhibitors - tacrolimus, cyclosporine; inosine monophosphate dehydrogenase (IMDH) inhibitors - azathioprine, leflunomide, mycophenolate; mammalian target of rapamycin (mTOR) inhibitors - sirolimus, everolimus; biologics - abatacept, adalimumab, anakinra, certolizumab, etanercept, infliximab, ixekizumab, natalizumab, rituximab, secukinumab, tocilizumab, ustekinumab, vedolizumab; antimetabolites - methotrexate; inclusion of participants taking immunosuppressive drugs not listed above will be considered individually; 3. Provision of informed consent to participate in the study. Inclusion criteria for the control group: 1. Diagnosis of Parkinson's disease according to the International Parkinson and Movement Disorder Society Clinical Diagnostic Criteria for Parkinson's Disease; 2. No history of regular use of immunosuppressive medications; 3. Provision of informed consent to participate in the study. Exclusion criteria for the study group: 1. Immunosuppressive drug administration at an ad hoc basis (i.e. when symptoms occur) or irregularly (i.e. drug taken at an inappropriate dose and/or with a regularity ineffective for the indicated disease); 2. Use of immunosuppressive drugs for a period of less than 12 months; 3. Ineffective treatment of the disease requiring the use of immunosuppressive drugs (no improvement/progression of disease symptoms); Additional exclusion criteria for both the study and control groups: 1. Advanced cancer; severe heart failure; severe renal failure; untreated autoimmune disease; active inflammation; diseases that impair drug absorption/metabolism; 2. Dementia; 3. Failure/inability to provide informed consent.