Intravenous immunoglobulin (IVIG) is used for treatment of a heterogeneous group of immune related disorders both as immune-replacement and immune-modulating therapy. Sanquin developed a 100 mg/ml IVIg product (Nanogam 100 mg/ml). Patient will receive one infusion with Nanogam 50 mg/ml as they used to (same dose) and subsequently 4 infusions with Nanogam 100 mg/ml (same dose). Aim is to show bioequivalency between the 50 mg/ml and the 100 mg/ml product of Sanquin.

Inclusion Criteria:

• Primary a- or hypogammaglobulinemia, particularly patients with XLA or CVID
• Stabilised on treatment with Nanogam 50 mg/ml with 2-4 weeks intervals in an hospital or at home and willing to be treated with 1 infusion of Nanogam 50 mg/ml and 4 infusions of Nanogam 100 mg/ml at the hospital
• A stable clinical situation (no activity of any other disease; a stable immunoglobulin dose and frequency)
• Age >= 18 years
• The patient has signed the consent form

Exclusion Criteria:

• Known with allergic reactions against human plasma or plasma products
• Having an ongoing progressive disease, including HIV infection
• Pregnancy or lactation
• Known with insufficiency of coronary or cerebral circulation
• Having renal insufficiency (plasma creatinin > 115µmol/L)
• Having IgA deficiency and anti-IgA antibodies have been detected