Inclusion Criteria:

- Patients aged from 18 to 70 years

- Written informed consent

- One of the following three criteria:

- Recently diagnosed IgG or IgA monoclonal gammopathy without clinical or
biological features of malignant hemopathy

- IgG or IgA MGUS regardless the date of the diagnosis

- SMM regardless the date of the diagnosis

- Normal blood count, creatininemia and calcemia *

- Bence-Jones proteinuria below 1g/24 hours

- Absence of bone pain

- No clinical or biological features of amyloidosis

- No recurrent episode of infection (more than 2 infections requiring antibiotics in
the previous 6 months) * In case of abnormal blood count, renal failure or
hypercalcemia, patients may be included if an intercurrent cause is identified (for
example anemia associated with iron deficiency)

Diagnostic criteria for MGUS:

- Monoclonal component concentration below 30 g / l AND

- Bone marrow plasmacytosis below 10%

- Bence-Jones proteinuria below 1g/24 hours

- Normal blood count, creatininemia and calcemia *

- Absence of bone lesions on conventional bone radiographies

- No clinical or biological features of amyloidosis

- Absence of hyperviscosity syndrome

- No recurrent episode of infection (more than 2 infections requiring antibiotics in
the previous 6 months) * In case of abnormal blood count, renal failure or
hypercalcemia, patients may be included if an intercurrent cause is identified (for
example anemia associated with iron deficiency)

Diagnostic criteria for SMM:

- Monoclonal component concentration greater than 30 g / l AND / OR

- Bone marrow plasmacytosis greater than 10%

- Bence-Jones proteinuria below 1g/24 hours

- Normal blood count, creatininemia and calcemia *

- Absence of bone lesions on conventional bone radiographies

- No clinical or biological features of amyloidosis

- Absence of hyperviscosity syndrome

- No recurrent episode of infection (more than 2 infections requiring antibiotics in
the previous 6 months) * In case of abnormal blood count, renal failure or
hypercalcemia, patients may be included if an intercurrent cause is identified (for
example anemia associated with iron deficiency)

Exclusion Criteria:

- Patients younger than 18 years

- Patients older than 71 years

- IgM monoclonal gammopathy (regardless of diagnosis)

- Monoclonal gammopathy associated with hematologic malignancies (multiple myeloma,
chronic lymphocytic leukemia, ...)

- Patients with chronic liver disease, autoimmune or neoplastic disease for less than 5
years

- Active viral hepatitis B or C

- HIV seropositive patient

- Pregnant woman

- Breastfeeding woman