Inclusion Criteria:
* Fulfilling EFNS/PNS criteria for definite, probable or pure motor CIDP.
* No previous treatment with IVIG or SCIG.
* Age ≥ 18.
* ODSS ≥ 2 - either (arm/leg): 1/1, 2/0 or 0/2 at the time of inclusion.
Clinical criteria for typical CIDP
* Chronically progressive, stepwise, or recurrent symmetric proximal and distal weakness and sensory dysfunction of all extremities, developing over at least 2 months; cranial nerves may be affected.
* Absent or reduced tendon reflexes in all extremities.
Criteria for pure motor CIDP • Pure motor affection; otherwise as for typical CIDP.
Electrophysiological criteria for CIDP
1. Motor distal latency prolongation ≥50% above ULN in two nerves (excluding median neuropathy at the wrist from carpal tunnel syndrome), or
2. Reduction of motor conduction velocity ≥30% below LLN in two nerves, or
3. Prolongation of F-wave latency ≥30% above ULN in two nerves (≥50% if amplitude of distal negative peak CMAP ≤80% of LLN values), or
4. Absence of F-waves in two nerves of these nerves have distal negative peak CMAP amplitudes ≥20% of LLN + ≥1 other demyelinating parameter in ≥1 other nerve, or
5. Partial motor conduction block: ≥50% amplitude reduction of the proximal negative peak CMAP relative to distal, if distal negative peak CMAP \>20% of LLN, in two nerves, or in one nerve + ≥1 other demyelinating parameter in ≥1 other nerve, or
6. Abnormal dispersion (≥30% duration increase between the proximal and distal negative peak CMAP) in ≥2 nerves, or
7. Distal CMAP duration (interval between onset of the first negative peak an return to baseline of the last negative peak) increase in ≥1 nerve (median ≥6.6 ms, ulnar ≥6.7 ms, peroneal ≥7.6 ms, tibial ≥8.8 ms) + ≥1 other demyelinating parameter in ≥1 other nerve
Electrophysiological criteria for probable CIDP
(a) ≥30% amplitude reduction of the proximal negative peak CMAP relative to distal, excluding the posterior tibial nerve, if distal negative peak CMAP ≥20% of LLN, in two nerves, or in one nerve + ≥1 other demyelinating parameter in ≥1 other nerve
Exclusion Criteria:
* Other causes of neuropathy
* Increased risk of thromboembolism
* Pregnancy (Plasma HCG is tested at inclusion in all fertile women)
* Breast feeding
* Malignancy
* Severe medical disease
* Other immune modulating treatment than low dose steroid (prednisolon \< 25 mg daily) within the last 6 months prior to inclusion
* Hepatitis B or C or HIV infection (screening at inclusion)
* Known IgA deficiency
* Known allergy to consents in PRIVIGEN or HIZENTRA
* Body weight \> 120 kg
After treatment initiation:
* Pregnancy
* Serious medical disease that affects treatment or examinations
* Non-compliance to treatment
* Initiation of other immune modulating therapy
* Unacceptable side effects
* Withdrawal of consent to participate (drop-out)
