This study will be a single center, single-arm, pilot trial. As the study will be registered at clintrials.gov, subjects may be referred from outside physicians. However, all treatment will be done at IU in the GCRC. After meeting inclusion/exclusion criteria and signing the consent, serum for PF levels, and blood for B cell flow cytometry will be obtained. Rituximab (375 mg/m2) will be administered intravenously as per current package label in a facility capable of handling infusion reactions. Subjects would be pre dosed with diphenhydramine and acetaminophen. Solu-Medrol, 1.5 mg/kg would be dosed 1 hour prior to the first dose of rituximab. Three subsequent doses of rituximab will be given at weekly intervals. Study visits will then be conducted monthly thereafter for the 6 months and then every 3 months, at which time, assessments of safety will be made. Efficacy will be determined by monitoring first AM Uprotein/C ratio. Flow cytometry, PF factor, urine proteomics and general blood work including CBC, Chemistry, electrolytes, serum immunoglobulin will also be done. During the second year, subjects would be followed every three months. The primary endpoint will be resolution of proteinuria defined as a Up/C ratio of <0.2. Secondary endpoints will be the number of subjects who achieve partial remission defined at a fall of 50% or more in the Up/C ratio from the pre-treatment baseline; the number of patients who develop a recurrence or increase of proteinuria on samples obtained at least 4 weeks apart; effect of treatment on PF levels; safety as measured by infections and drug infusion reactions. Consideration will be given to a plan of redosing in subjects who relapse after initial response.