• Assessment of immune responses
  
• Clinical response in PND patients who are treated with Tacrolimus and Prednisone
  

• Collection and archiving of serum and lymphocytes for future studies on the mechanism of neuronal autoimmunity.
  

Patients typically spend two to three weeks as in-patients at the Rockefeller University Hospital. Patients will have a complete history as well as complete general and neurologic examinations, and will be assessed for baseline neurologic, hepatic, hematopoietic, cardiovascular, pulmonary, and renal function (including 24 hour creatinine clearance). Eligible patients will then have a lumbar puncture (spinal tap) and a leukapheresis, a procedure like blood donation during which white blood cells are removed but red blood cells are returned. Tacrolimus will be given in two divided oral doses, in conjunction with oral prednisone. Patients will be treated for up to three weeks, at which time they will be discontinued from treatment with tacrolimus and prednisone unless they have shown definite signs of a beneficial clinical response. Patients will have electrolyte, metabolic, and hematologic measurements, peak and trough serum tacrolimus levels, renal function, and neurologic status serially monitored, requiring approximately one tablespoon of blood per assay. Patients who cannot tolerate tacrolimus without renal dysfunction will be terminated from protocol. Repeat leukapheresis and/or large volume blood draw, and lumbar puncture may be performed either during or after the in-patient stay, with the patient's consent. Patients will be followed after leaving the hospital to monitor for clinical changes and for drug side-effects.

Inclusion Criteria:

• Patients diagnosed with Paraneoplastic Disorder

Exclusion Criteria:

• Metastasis (spread) of cancer to brain, History of additional active malignancy other than non-melanoma skin cancer, History of Hepatitis B, Hepatitis C, HIV or Syphilis.