Patients with known or suspected immunologically-mediated kidney diseases, including but not limited to, nephrotic syndrome, glomerulonephritis, membranous nephropathy, lupus nephritis, and nephritis associated with other systemic or connective tissue disorders, will be evaluated at the Clinical Center. Patients who have immunologically-mediated diseases with potential for kidney disease will be evaluated as well. Studies will include characterization of the clinical and laboratory features of these disorders, studies of natural history and complications, evaluation of responses to standard treatment, and determination of the patients' eligibility to enter other experimental diagnostic or therapeutic protocols. Patients may be asked to contribute blood and/or urine samples for immunological research studies.