• Clinical response rate at 3 and 6 months [ Designated as safety issue: No ]
  
• Progression-free survival [ Designated as safety issue: No ]
  
• Grade II-IV and grade III-IV infusion-related toxicities [ Designated as safety issue: Yes ]
  

• Antibody dependent cell mediated cytotoxicity and effector cell phenotype analysis compared with clinical response at baseline, 4 weeks, and 3 months [ Designated as safety issue: No ]
  
• Soluble CD20 fragments or CD20-containing membrane fragments and clinical response compared at baseline, 4 weeks, and 3 months [ Designated as safety issue: No ]
  
• Phenotype analysis of CD16 and CD32 on natural killer cells compared with clinical response [ Designated as safety issue: No ]
  
• Rituximab pharmacokinetics and clinical response compared at baseline, 4 weeks, and 3 months [ Designated as safety issue: No ]
  

OBJECTIVES:

Primary

• Determine the clinical response rate and progression-free survival at 3 and 6 months in patients with CD20-positive low-grade B-cell non-Hodgkin's lymphoma treated with rituximab and dexamethasone.
• Determine the rates of grade II-IV and grade III-IV toxicity of this regimen in these patients.

Secondary

• Correlate the antibody dependent cell mediated cytotoxicity, effector cell phenotype analysis, and soluble CD20 fragments or CD20-containing membrane fragments at baseline, 4 weeks, and 3 months with clinical response in patients treated with this regimen.
• Correlate phenotype analysis of CD16 and CD32 on natural killer cells with clinical response in patients treated with this regimen.
• Correlate rituximab pharmacokinetics at baseline, 4 weeks, and 3 months with clinical response in patients treated with this regimen.

OUTLINE: This is multicenter study.

Patients receive dexamethasone IV over 30 minutes and rituximab IV once weekly for 4 weeks in the absence of unacceptable toxicity. Patients with progressive disease at the 6-month follow-up visit may be retreated on this protocol with dexamethasone and rituximab.

After completion of study treatment, patients are followed at 3 and 6 months and then every 6 months until disease progression.

PROJECTED ACCRUAL: Approximately 40-96 patients (20-52 with previously treated or relapsed disease and 20-44 with previously untreated disease) will be accrued for this study within 2-3 years.