[MRI alterations in immunomodulation]

Area of Science:

• Neurology
• Radiology
• Immunology

Background:

• Immunomodulatory drugs are increasingly used for various conditions, including multiple sclerosis and lymphoproliferative diseases.
• These therapies can lead to opportunistic infections and inflammatory syndromes affecting the brain.
• Accurate diagnosis relies on recognizing specific imaging patterns.

Purpose of the Study:

• To present typical magnetic resonance imaging (MRI) findings associated with diseases induced by immunomodulatory drugs.
• To emphasize the importance of recognizing these patterns in the context of immunosuppressive treatments.
• To raise awareness of potential T-lymphocyte-mediated neurotoxicity.

Main Methods:

• Review of scientific literature focusing on neuroimaging in patients treated with immunomodulatory agents.
• Compilation of characteristic MRI patterns for conditions such as PML, IRIS, methotrexate-associated leukoencephalopathy, and PRES.
• Discussion of the pathomechanisms underlying these imaging findings.

Main Results:

• Progressive multifocal leukoencephalopathy (PML) exhibits a distinct MRI pattern, particularly relevant in multiple sclerosis (MS) patients on natalizumab, fingolimod, rituximab, or fumarate.
• Immune reconstitution inflammatory syndrome (IRIS) can present with overlapping and severe inflammatory changes upon immune system restoration.
• Methotrexate-associated leukoencephalopathy and posterior reversible encephalopathy syndrome (PRES) are other key conditions with identifiable MRI signatures.

Conclusions:

• Recognizing specific MRI patterns is essential for diagnosing drug-induced neurological complications during immunomodulatory therapy.
• Awareness of PML, IRIS, and other entities aids in timely management and can prevent misdiagnosis.
• Immunotherapy targeting T-lymphocytes carries a risk of off-target effects on healthy brain tissue.