Inclusion Criteria:
1. Male or female, aged 2 to 65 years.
2. Patients with confirmed diagnosis of primary immunodeficiency, predominantly antibody deficient, or common variable immunodeficiency (CVID) with a history of hypogammaglobulinemia (i.e., IgG\<500 mg/dl) or X-linked agammaglobulinemia (XLA).
3. Treatment naive patients eligible to receive intravenous immunoglobulin or, patients already on intravenous immunoglobulin infusions every 3 or every 4 weeks for ≥6 months at a dose aimed to be between 200 and 800 mg/kg with at least two documented IgG trough levels in the previous two infusions before enrolment in the study.
4. The screening laboratory tests must meet the following criteria:
1. WBC ≥3.5 x 109/L
2. Neutrophils ≥1.5 x 109/L
3. Platelets ≥100 x 109/L
4. Serum transaminase ≤2 times the upper limit of normal
5. Alkaline phosphatase levels ≤2 times the upper limit of normal
6. Serum creatinine ≤150 µmol/L (≤1.7mg/dl)
5. Patients must be able to adhere to the study visit schedule and other protocol requirements.
6. If subject is a female and is
a. -of child bearing potential, she should be practicing an acceptable method of birth control for the duration of tl1e study as suggested by the investigator, such as a combination of male condom with either cap, diaphragm or sponge with spermicide (double barrier method), intrauterine device (IUD), or abstinence OR surgically sterile, bilateral tubal ligation done at least 6 months before the study should be documented
7. Patients/LAR must be capable of giving informed consent, and written consent must have been obtained prior to any study procedures.
Exclusion Criteria:
1. Pregnant women, nursing mothers or a planned pregnancy within 18 months of participation.
2. Patients requires any blood transfusion during the study.
3. Patients with T-cell related Severe combined immunodeficiency.
4. Patients with secondary immunodeficiency diseases
5. History or presence of any form of cancer prior to enrollment.
6. History of any autoimmune disease
7. Positive at screening for any markers of infectious blood borne viruses
8. History of adverse or allergic reactions to other IgG or blood products
9. Patients with selective IgA deficiency or antibodies IgA
10. History of acute renal failure or severe renal impairment, or deep venous thrombosis which in the opinion of the Investigator, may place the patient at unacceptable risk for study participation and may prevent the patient from completing the study.
11. History of congestive heart failure \[New York Heart Association class III/IV\] or unstable angina
12. Recent history of migraine, hyperprolinemia, and lymphoid malignancy.
13. Requirement for use of glucocorticosteroids above 0.15 mg of prednisone equivalent/kg/day and other immunosupressive drugs as concomitant medication.
14. History or presence of any medical or psychiatric condition or disease, or laboratory abnormality that, in the opinion of the Investigator, may place the patient at unacceptable risk for study participation and may prevent the patient from completing the study.
15. Participation in any clinical study within the previous 3 months
16. Patient, who in the opinion of the Investigator, is not suitable for participation in the clinical study
