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, regardless of administration route (e.g., oral, intramuscular, subcutaneous); 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.