Beta2-Microglobulin as a Diagnostic Marker in Cerebrospinal Fluid: A Follow-Up Study

Beta2-Microglobulin (B2-m) is a low molecular weight protein occurring in all body fluids. Its concentration increases in various pathologies. Increased values in cerebrospinal fluid (CSF) are ascribed to an activation of immune system. A large body of literature on monitoring B2-m levels in cerebrospinal fluid is currently available. While most groups of patients described are numerous enough, what is badly needed is a comparison of diagnostical subgroups of defined neurological entities in reasonably large groups.

Using immunoturbidimetry, the reaserchers from Department of Neurology, RHG City Hospital, Czech Republic examined concentrations of beta2-microglobulin in cerebrospinal fluid in a large group of 6274 patients with defined neurological diseases to clarify a biological behavior of this marker.

Cell counts, total protein, albumin, glucose, lactic acid, immunoglobulins concentrations, and isofocusing (IEF) were also evaluated. They found substantial changes of CSF B2-m concentrations in purulent meningitis, leptomeningeal metastasis, viral meningitis/encephalitis, and neuroborreliosis, while in multiple sclerosis these changes were not significant. Intrathecal synthesis and immune activation were present in these clinical entities. A new normative study enables better understanding of beta2-microglobulin behavior in CSF.

Results from this study demonstatred higher values of B2-m in cerebrospinal fluid are present in the pathological group. There was a statistically significant difference between the control group and the pathological group (P< 0.001). Beta2-microglobulin values are the highest in the group with bacterial meningitis/encephalitis.

The difference between groups with bacterial and viral meningitis/encephalitis is very important, because that means the CSF B2-m value allows distinguishing between these etiological diagnoses and contributes to early targeted therapy. Group with the second highest CSF B2-m values, the group of brain tumours and malignant infiltrations, is statistically different from the control group and groups with multiple sclerosis, and polyneuritis/polyneuropathies. But there is no difference among this group and group with viral meningitis/encephalitis, neuroborreliosis, scavenger reaction, that is, values of CSF B2-m are similar in these groups. The results from this study confirm that 𝛽2-m behaves in cerebrospinal fluid as an inflammatory marker or a tumour marker. Elevated 𝛽2-mCSF values should lead to a suspicion of CNS inflammation or malignant infiltration, even if no tumorous cells are present in cerebrospinal fluid.

Svatonova J, Borecka K, Adam P, Lanska V. Beta2-Microglobulin as a Diagnostic Marker in Cerebrospinal Fluid: A Follow-Up Study. Hindawi. 2014;2014:1-6.