How Repeated Strep Infections May Drive Neuroinflammation in PANDAS

New research might explain why repeated Group A Strep (GAS) infections trigger neuroinflammation in children and adolescents suffering from PANDAS and Sydenham's chorea (SC).

Columbia University researchers from the Dr. Agalliu Lab discovered that specialized white blood cells frequently associated with autoimmunity (Th17 cells) produce a signaling molecule (IL-17A) that communicates with white blood cells in the brain (microglia). These microglia then transmit the signal to critical blood-brain barrier cells (endothelial cells), causing them to become leaky.

Their data suggest that this cell communication is partly responsible for the neuroinflammation observed in children and adolescents exposed to repeated GAS infections (PANDAS and SC), as it causes the brain's blood vessels to become leaky.

The IL-17A cytokine also plays an important role in controlling GAS infections. Thus, therapeutically, "...targeting this pathway may complement existing therapeutic strategies for chronic SC/PANDAS in the absence of active infection."

We and others in the PANDAS/PANS community are excited that Dr. Agaillu and colleagues used the words "post-streptococcal encephalitis," as the concept that GAS infections can cause encephalitis is lost on many health care professionals.

We thank these talented researchers for their contribution toward understanding the pathological drivers of PANDAS and Sydenham's chorea.

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