Inclusion Criteria:  Donors must fulfil criteria for blood- and plasma donation according to Council of Europe's "Guide to the preparation, use and quality assurance of blood components" (14) and "Veileder i transfusjonsmedisin" (16) Age: 18-64 years Sex: Men Estimated blood volume > 4 500 ml Weight >50 kg Donors must have performed at least one plasmapheresis earlier (start at least 2 months after last donation) Good vein quality for plasmapheresis Total serum protein>60 g/L Serum IgG>6.0 g/L Haemoglobin>13.5 g/dL  Exclusion Criteria:  Hct >50 %. Medications or medical history not compatible with blood- or plasma donations, for example treatment with ACE inhibitors, according to guidelines in inclusion criteria