• INCLUSION CRITERIA:

  1. All subjects must fulfill the published criteria for the diagnosis of ALPS (documented nonmalignant lymphadenopathy and/or splenomegaly of at least 1-year duration; greater than1% TCR alpha/beta+ CD4-CD8- T cells in the peripheral blood). This must include clinically documented lymphadenopathy involving more than 2 nodes in more than 1 regional group of nodes measuring greater than 2cm in size and/or a palpable spleen.
  2. Age greater than or equal to 2 years through less than or equal to 70 years.
  3. Must have a personal primary care physician who is willing to follow the protocol required evaluations during the study period.
  4. Must be willing to sign a consent form.
  5. Patients on immunosuppression (e.g., corticosteroid, mycophenolate mofetil, azathioprine, cyclophosphamide) are eligible if the dose of the immunosuppressive drug has been stable for at least 3 months prior to enrollment and their hematologic parameters do not meet the exclusion criteria (1) as outlined below.

EXCLUSION CRITERIA:

1. A hemoglobin concentration of less than 8 gm/dL, a platelet count of less than 75 K/mm(3), or an absolute neutrophil count of less than 500/mm(3), at study entry.
2. Liver disease determined by an alanine aminotransferase (ALT), aspartate aminotransferase (AST), or bilirubin 2.5 times greater than the upper limit of normal.
3. History of pancreatitis by clinical features and/or laboratory abnormalities in the last 12 months.
4. Renal dysfunction determined by a calculated urine creatinine clearance of less than 70 mL/min/1.73 m(2) in children and less than 60 mL/min in adults, or using the Schwartz formula or Levy formula based on serum creatinine.
5. Patients clinically suspected of suffering from urea cycle disorders will be excluded.
6. Patients with history of seizure disorders and/or those already receiving valproic acid will be excluded.
7. Sensitive to or have ever had an allergic reaction to Depakote.
8. Not able to abstain from alcohol during the length of the study.
9. Pregnancy. Female adults and adolescents who have attained menarche must have a negative pregnancy test at study entry and commit to using an acceptable method of barrier or hormonal contraception (e.g., condoms, diaphragms, oral contraceptives, or long acting progestin agents) if sexually active during the study and for 3 months after the last dose of valproic acid.
10. Lactating mothers who are breast feeding their babies will not be eligible.
11. ALPS patients who have been treated with bone marrow toxic chemotherapy regimens for Non-Hodgkin's lymphoma or other malignancies are not eligible for this pilot study.
12. Unwilling or unable to comply with the need to have periodic blood tests to monitor possible side effects of treatment, or other major requirements of this study will be an exclusion criteria.