A Study of MB-CART19.1 Cellular Therapy for People With Central Nervous System Lymphoma (CNSL)

Inclusion Criteria: * Men and women who are at least 18 years of age on the day of consenting to the study. * Histologically documented primary or secondary central nervous system lymphoma of DLBCL subtype * Relapsed/refractory primary or secondary CNSL patients. All relapsed//refractory patients need to have received at least one prior CNS-directed methotrexate-based therapy. There is no restriction on the number of recurrences. * For relapsed patients, parenchymal lesions must have unequivocal evidence of disease progression on imaging (MRI of the brain or head CT) within 21 days of study consent. * For refractory patients, there must be residual disease after their last line of therapy. * For patients with leptomeningeal disease only, CSF cytology and/or flow cytometry must document CSF findings consistent with CSF involvement by lymphoma and/or imaging findings consistent with CSF disease within 21 days of study registration (at the discretion of the investigator). * Creatinine Clearance ≥ 40 ml/min/m2, direct bilirubin ≤2.0 mg/100 ml, AST and ALT ≤3.0x upper limit of normal (ULN) * Adequate pulmonary function as assessed by ≥90% oxygen saturation on room air by pulse oximetry. * Must be able to tolerate both MRI and CT scans * Must be able to tolerate lumbar puncture and/or Ommaya taps * Must have been either off corticosteroids, or on a stable or decreasing dose of dexamethasone equivalent ≤ 2 mg daily for 7 days before apheresis and 72 hours prior to CAR T cell infusi…