Inclusion Criteria:

* Capable of understanding the investigational nature, potential risks and benefits of the study, and able to provide valid informed consent
* For patients with medical incapacity or impaired consciousness such that they are not able to give fully informed voluntary consent, the subjects' legal representative must sign an institutional review board (IRB) approved informed consent document prior to the initiation of any screening or study-specific procedures
* Participants must be 18 years of age or older
* Participants will receive an Food and Drug Administration (FDA)-approved CD19-CAR T-cell product for the treatment of hematologic malignancies. Patients receiving an FDA-approved product are eligible even if the product is being administered as part of a clinical trial or expanded access program (e.g., product is 'out of specification'; concomitant anti-tumor treatment such as acalabrutinib)
* Serum total IgG \< 600mg/dL within the prior three months
* SUBSEQUENT INFUSIONS: Received an FDA-approved CD19-CAR T-cell product for the treatment of hematologic malignancies.

Exclusion Criteria:

* Primary congenital selective IgA deficiency
* Prior serious adverse event/s related to intravenous immune globulin (IVIG) administration
* Known serious allergy to any component of IVIG
* Has a history or current evidence of any condition, therapy, lab abnormality, or other circumstance that might confound the results of the study or interfere with the patient's ability to participate for the full duration of the study or would put the patient at undue risk as judged by the investigator, such that it is not in the best interest of the patient to participate in this study
* SUBSEQUENT INFUSIONS: Ongoing symptoms of cytokine release syndrome (CRS) and/or immune effector cell-associated neurotoxicity syndrome (ICANS) meeting criteria for grade 3 or higher
* SUBSEQUENT INFUSIONS: Primary congenital selective IgA deficiency
* SUBSEQUENT INFUSIONS: Has a history or current evidence of any condition, therapy, lab abnormality, or other circumstance that might confound the results of the study or interfere with the patient's ability to participate for the full duration of the study or would put the patient at undue risk as judged by the Investigator, such that it is not in the best interest of the patient to participate in this study
* SUBSEQUENT INFUSIONS: Receipt of additional therapy for persistence or relapse of the patient's primary malignancy
* SUBSEQUENT INFUSIONS: Receipt of bone marrow transplant (allogeneic or autologous)
* SUBSEQUENT INFUSIONS: Any serious adverse event (SAE), clinically significant adverse event (AE), severe laboratory abnormality, intercurrent illness, or other medical condition that indicates to the Investigator that continued participation is not in the best interest of the participant