sCD163 as a Potential Biomarker in Guillain- Barré Syndrome

Guillain- Barré syndrome (GBS) is an acute inflammatory demyelinating polyneuropathy (AIDP) that often is triggered by an infection. GBS is characterized by progressing weakness and numbness and loss of tendon reflexes. It can also include tingling sensation in the legs and arms. These symptoms occur due to an autoimmune attack on the myelin resulting in demyelination. The diagnosis is given by electrophysiological examination and clinical presentation. GBS is treated with intravenous immunoglobulin (IVIG) or plasma exchange (PE). The specific mechanism is not fully understood, but it is believed that the antibodies produced against the myelin, is eliminated to avoid further damage to the peripheral nerves. IVIG is slightly safer and easier to give than PE. However, both treatments are equally effective. They both need to be given during the first few weeks of symptoms.

Most patients recover completely, while others must ease symptoms and reduce the duration of illness by several treatments. Moreover, the initial phase of GBS is followed by a long recovery period where intensive neurorehabilitation is important. Some people will not recover completely from GBS and experience long-term complications such as not being able to walk unaided, loss of sensation causing lack of coordination and balance. It is estimated around 20% of people with GBS still experience some muscle weakness after three years. Some may also have persistent fatigue. In rare cases, complications can be life threatening, particularly in the acute phase.

GBS is one of the neurological emergencies, where patients need to be examined closely during the initial acute phase of the illness. Many studies have been performed to elucidate the mechanism of neuropathy in Guillain Barré syndrome but treatment remains disappointing. There are findings of autoantibodies against gangliosides, myelin proteins such as PO- glycoprotein, P2 basic protein and PMP22 and to nodal and paranodal proteins, such as NF155 and NF186.

Cluster of differentiation 163 (CD-163) - a new way to measure GBS CD-163 is a scavenger receptor (recognizes and uptakes macromolecules), which marks the monocyte-macrophage activation. CD163 works for macrophages as a receptor for haemoglobin-haptoglobin complexes. The soluble form of the receptor is called sCD163 and is found in plasma, where it is up regulated in a large range of inflammatory diseases.

Values, which are increased strongly (<20mg/l), are seen in diseases like macrophage activating syndrome, haemophagocytic syndrome and acute hepatic failure. Furthermore, the level of sCD163 reflects the activity of the disease. Patients with increasing and high values are found to have unfavourable prognosis. Increased values (5-20 mg/l) are seen in hepatic disease, sepsis and Gaucher´s disease. Septic patients with values greater than 10mg/l have a 10 times greater risk of fatal outcome. Values, which are slightly increased (3-5 mg/l), are often seen in inflammatory of infectious conditions and in cancer.