A Multicenter Study to Evaluate the Effect of Rituximab (IDEC-102) on Primary Humoral Response, Recall Response, and Maintenance of Acquired Immunity to Specific Antigens

Inclusion Criteria:

- Signed IRB-approved informed consent.

- Age >/=40 years.

- Men and women of reproductive potential who are following accepted birth control
methods.

- Histologic confirmation of low-grade or follicular, B-cell NHL prior to study entry.

- Relapsed (maximum of 5 relapses) or refractory, low-grade or follicular, CD20+,B-cell
NHL.

- WHO performance status
- Expected survival >/= 1 year.

- Acceptable hematologic status, liver function, renal function, and pulmonary
function.

- Patients must be recovered from all nonhematological toxicities associated with prior
surgery, radiation treatments, chemotherapy, biological therapy, bone marrow
transplant, investigational drugs, or immunotherapy.

- Known history of tetanus toxoid immunization or positive tetanus titer at the
screening visit.

Exclusion Criteria:

- Active autoimmune disease.

- Exposure to rituximab within 12 months prior to Day 1.

- Chemotherapy within 3 months prior to Day 1.

- Previous immunization with tetanus toxoid within 2 years prior to Day 1.

- Previous exposure to KLH.

- Receipt of intravenous or intramuscular immunoglobulin (IVIG or IMIG) within 30 days
of Day 1.

- Known history of hepatitis or other hepatic disease, HIV infection, or AIDS.

- Current use (including "recreational use") of any illicit drugs or history of drug or
alcohol abuse within the 5 years prior to Day 1.

- Prior diagnosis of aggressive NHL or mantle-cell lymphoma.

- Chronic lymphocytic leukemia (CLL).

- Small lymphocytic lymphoma (IWF A) with peripheral blood lymphocyte count > 5,000
cells/mm3.

- History of other primary malignancy, with the exception of squamous cell carcinoma or
basal cell carcinoma of the skin, in situ carcinoma of the cervix, or treated
prostate cancer for which the subject has not been disease free for at least 3 years.

- Serious nonmalignant disease (e.g., congestive heart failure, hydronephrosis);
active, uncontrolled bacterial, viral, or fungal infection; or any other condition
that would compromise protocol objectives in the opinion of the investigator and/or
sponsor.

- Known allergies or contraindications to tetanus toxoid or KLH.

- Known allergy to shellfish.

- Presence of protein-losing enteropathy.

- Major surgery, other than diagnostic surgery, within 4 weeks prior to Day 1.

- Participation in another clinical study with an investigational agent or device
within the last year. The subject cannot participate in any other clinical study with
an investigational agent or device during the course of this study.

- Pregnant or lactating female subjects