Variations of S-100B in early phases of head trauma

Background

S-100 protein is an acidic calcium-binding protein found in astroglia and Schwann cells. Recently, there have been several reports on the relation of the severity of head injury and serum S-100B protein levels in trauma patients, but there are few reports about time course of S-100B protein in the early phase of head injury. In many previous reports, S-100B was reported in units of μg/l. Lately, a new device (YK-150) was developed that can measure serum S-100B protein in pg/ml units.

Objective

We showed the course of the concentration of serum S-100B in the acute phase of head injury using the YK-150.

Patients and methods

S-100B serum levels were determined in 10 patients (eight men, two women; mean ± SD, 50.1 ± 20.2 years). There were two cases of severe head injuries (Glasgow Coma Scale [GCS] < 9). Blood samples were taken on admission, 24 and 48 hours after the traumas. Serum S-100B protein concentrations (pg/ml) were measured by ELISA (Yanaihara Industry, Tokyo, Japan).

Results

Initial serum S-100B concentrations were elevated (minimum, 790 pg/ml; maximum, 7,749,669 pg/ml; mean, 979,666 pg/ml). All patients whose serum S-100B concentrations compared with the first-time value decreased at the second point, 24 hours after injury (minimum, 10.1 pg/ml; maximum, 16,990 pg/ml; mean, 5994 pg/ml). After 48 hours, only two patients showed an increase of serum S-100B concentrations and one of these showed the highest level of serum S-100B and died on day 28 (Fig. 1).

Figure 1

Discussion and conclusion

Many studies have been done on S-100B that have shown the relation between initial data and poor prognosis. We have also shown patients with slight head injuries who were conscious (GCS > 8) and whose elevated serum S-100B concentrations decreased in the next 24 hours. We suspect it was only the cerebral cell damage that caused the initial increase of serum S-100B concentrations in these head injuries. If there is no secondary brain damage, serum S-100B concentrations will immediately decrease. The YK-150 (Human S-100B ELISA kit) can measure serum S-100B concentrations in 22 ± 4 hours. Using the YK-150, if we can detect a slight variation in early-phase secondary brain damage, we can accurately predict what changes will take place in the patient; and if so, YK-150's efficacy will spread even further.