What does an elevated Beta-2 microglobulin (β2-microglobulin) level indicate?

From the Guidelines

Elevated Beta-2 microglobulin (β2-microglobulin) levels are a prognostic indicator of various lymphoproliferative disorders, including multiple myeloma and lymphoma.

Key Points

• In the context of multiple myeloma, a β2-microglobulin level greater than 3.5 mg/L is associated with a poorer prognosis, and may guide treatment decisions, such as the use of novel agents like lenalidomide (25mg/day, days 1-21 of a 28-day cycle) or bortezomib (1.3mg/m2, days 1,4,8, and 11 of a 21-day cycle) 1.
• The International Staging System (ISS) is based on easily obtained laboratory measures (serum β2-microglobulin and serum albumin) and is easier to use than the Durie-Salmon Staging System for patients with previously untreated MM 1.
• Prolonged elevation of β2-microglobulin levels, defined as greater than 5.5 mg/L for more than 6 months, may also indicate disease progression or relapse 1.
• The level of β2-microglobulin reflects the tumor mass and is now considered a standard measure of the tumor burden 1.
• Elevated β2-microglobulin levels are associated with high-risk chromosomal abnormalities, such as t(4;14), t(14;16), and 17p13 deletion, detected by FISH 1.
• The Revised International Staging System (R-ISS) includes serum β2-microglobulin and serum albumin and prognostic information obtained from the LDH and high-risk chromosomal abnormalities detected by FISH and is the preferred staging approach 1.

From the Research

Elevated Beta-2 Microglobulin Levels

Elevated Beta-2 microglobulin (β2-microglobulin) levels are associated with various lymphoproliferative disorders, including:

• Multiple myeloma 2, 3, 4
• Lymphoma 2, 5
• Acute lymphocytic leukemia 2

Prognostic Significance

Elevated β2-microglobulin levels are indicative of poor prognosis in several lymphoproliferative disorders, including:

• Multiple myeloma, where high levels are associated with a higher tumor burden and poorer survival 3, 4
• Acute lymphocytic leukemia, where high levels are associated with a lower complete response rate, worse survival, and a higher association with central nervous system leukemia 2
• Hodgkin's lymphoma, where elevated levels are associated with inferior overall survival 5

Association with Disease Characteristics

Elevated β2-microglobulin levels are associated with various disease characteristics, including:

• Older age 2, 5
• Elevated creatinine, bilirubin, and alkaline phosphatase levels 2
• Low albumin levels 2
• B-cell disease 2
• Advanced stage 3, 5
• High lactate dehydrogenase levels 5

Monitoring and Treatment

Monitoring serum β2-microglobulin levels may provide significant prognostic information in adults with acute lymphocytic leukemia and multiple myeloma, and should be included in their pretreatment evaluation 2, 3. However, the role of β2-microglobulin in staging or prognosis of MALT-type lymphoma is unclear 6.