Tolerability of home subcutaneous immunoglobulin (ScIG) for replacement therapy for hypogammaglobulinemia in allogeneic HCT patients. A financial analysis comparing the cost of ScIG with intravenous immunoglobulin (IVIG) will also be performed.

The purpose of the study is to determine whether home subcutaneous immunoglobulin (ScIG) is tolerated as replacement therapy for hypogammaglobulinemia in patients that have undergone allogeneic hematopoietic cell transplantation (alloHCT). Secondary objective is to perform a financial analysis comparing the cost of ScIG with intravenous immunoglobulin (IVIG). The study hypothesis is that home based SCIG treatment is applicable and tolerated well for replacement treatment in alloHCT patients. This will be examined in two sets of patients recruited: A) Patients already on IVIG replacement therapy and B) Newly diagnosed patients with hypogammaglobulinemia. Economic analysis will be performed by comparing the cost with an equal number of patients retrospectively determined to have undergone treatment with IVIG.

Inclusion Criteria:

• Age over 18 years
• Patients at least 100 days post allogeneic hematopoietic cell transplantation for any benign or malignant hematological disease, from a related or unrelated donor
• Patients who are already established on regular IVIG
• Patients eligible for immunoglobulin replacement with an IgG <7mg/L, or normal IgG total but IgG2 or IgG4 below normal
• Patients with IgG =>7g/L but with at least 2 prior episodes of bacterial infection (proven or suspected eg. sinusitis diagnosed on CT)
• No other medical condition which would preclude treatment with immunoglobulin
• Willing to participate and sign informed consent

Exclusion Criteria:

• Previous serious adverse reaction from IVIG or products from Hizentra (polysorbate)
• Other serious medical or psychiatric disorders which may interfere with the patient's ability to participate in the study, or interfere with study assessment (e.g. advanced congestive heart failure, severe liver disease, renal failure, disease relapse or secondary malignancy, schizophrenia, paranoid psychosis)