What neurological autoimmune disease causes night sweats (just legs)?

Background: I have an unknown autoimmune neurological disorder that affects the my cerebellum. I’ve been to Mayo, and my working diagnosis is autoimmune cerebellar ataxia. But that doesn’t tell me what exactly is the autoimmune cause. I test negative for all known antibodies.

Anyway, a newer symptom is night sweats, but only on my legs. I wake up 3-5 times a night with my legs drenched in sweat. Could that be because of an autoimmune neurological disease? I’m just waiting for that missing puzzle piece that will cause doctors to say, “ah! You have XYZ.”