Pruritus is most often secondary to dermatitis but can also occur without skin lesions, it is called pruritus sine materia. The causes of pruritus sine materia are various: haematological (myeloproliferative neoplasia ...), hepatic (cholestasis ...), renal (chronic renal failure, dialysis), endocrine (iron deficiency ...), secondary to drug intake ... or idiopathic when no cause is found.

Gammapathies are among the causes of pruritus sine materia, and as such electrophoresis of serum proteins is usually part of the pruritus assessment to look for monoclonal gammopathy (MGUS, multiple myeloma, Waldenström disease). However, there is very little data on the frequency of pruritus in patients with monoclonal gammopathy and the characteristics of this pruritus. So the aim of this study is to compare the frequency of pruritus between patients with monoclonal gammapathy and controls

Inclusion Criteria for case :

Major patient Realized Serum protein electrophoresis between 2014 and 2017 Hematology follow-up at Brest CHR Positive monoclonal gammopathy Non-opposition formulated

Inclusion Criteria for Control :

Major patient Realized Serum protein electrophoresis between 2014 and 2017 Hematology follow-up at Brest CHR Negative gammopathy Non-opposition formulated

Exclusion Criteria:

Minor patient Major protected Patient with another haemopathy secreting a monoclonal immunoglobulin (lymphoma, LLC ...) Physical or mental incapacity Refusal to participe

Patients who had serum protein electrophoresis at Brest CHRU between 2014 and 2017, with and without gammapathy.

All collected data that underlie results in a publication

Data will be available after the publication of result and ending three years maximum following the last visit of the last patient

Data access requests will be reviewed by the internal committee of Brest UH. requestors will be required to sign and complete a data access agreement