Voluntarily terminated by PI due to lack of feasibility.

The investigators propose to study novel targets of rituximab in podocytes, with a particular focus on recurrent focal segmental glomerulosclerosis (FSGS). The proposed study has strong clinical implications, since it may extend the approved indications for rituximab treatment to recurrent FSGS as well as to other proteinuric diseases. Furthermore, it will offer new insights into the role of sphyngomyelin related enzymes in podocyte function in health and disease, thus allowing the identification of novel targets for antiproteinuric drug development. Finally, the proposed study offers the opportunity to identify a correlation between the patient's specific clinical outcome and the experimental results obtained after exposing podocytes to patient sera in the presence or absence of rituximab. Therefore, it may lead to the development of an assay for the pre-transplant identification of patients at high-risk for recurrent disease and, among them, may allow the identification of those patients that will respond to rituximab.

A total of 60 patients will be enrolled in the study.

Inclusion:

1. Patient has been fully informed and has signed a dated IRB-approval informed consent form.
2. Age 7-65 years.
3. Male and Females diagnosed of FSGS by kidney biopsy. Kidney biopsy report is not required once the physician confirms the diagnosis. Transcribed reports from referring physicians are also valid.

Exclusion:

1. Recipient or donor is seropositive for human immunodeficiency virus (HIV), Hepatitis C viruses, or Hepatitis B virus antigenemia.
2. Patient has a current malignancy or a history of malignancy (within the past 5 years), except non-metastatic basal or squamous cell carcinoma of the skin that has been treated successfully or carcinoma in situ of the cervix that has been treated successfully.
3. Patient has uncontrolled concomitant infections and/or severe diarrhea, vomiting, active upper gastro-intestinal tract malabsorption or an active peptic ulcer or any other unstable medical condition that could interfere with study objectives.
4. Patient is pregnant or lactating.
5. Patient has any form of substance abuse, psychiatric disorder or a condition that, in opinion of the investigator, may invalidate communication with the investigator.
6. Patients with a defined genetic cause of FSGS.

1 year