Association Serum S100B Protein in Alzheimer's Disease: A Case Control Study from South India

Recent evidence points to a possible link between the inflammatory modulatory protein S100B protein and the pathogenesis of Alzheimer's disease (AD).

To investigate the elevated levels of serum S100B protein among AD in a South Indian cohort and its correlation with severity of cognitive impairment.

A cross-sectional study was conducted with 100 AD patients and 100 age and sex matched healthy controls. Diagnosis of AD was made by a qualified neurologist using NINCDS ADRDA criteria. Measurement of serum S100B protein was performed using solid phase sandwich ELISA method in both cases and controls.

Significantly higher prevalence of elevated serum S100B protein 44(44%) (p<0.0001), hypertension 52(52%) (p=0.02), diabetes mellitus 58(58%) (p=0.002), thyroid dysfunction 28(28%) (p=0.009), positive CRP 46(46%) (p<0.0001) and lower mean Mini-Mental State Examination (MMSE) values 20.4±5.1 (p<0.0001) were seen in AD patients compared to controls. Elevated S100B protein levels were significantly associated with Clinical dementia rating (CDR) score 2(34%) (p=0,05) and score 3 (61.3%) (p=0.03) compared to normal levels. After multivariable logistic regression analysis positive C-Reactive Protein (odds: 3.2; 95%CI: 2.8-9.8)(p=0.001), elevated S100B protein (odds: 9.0;95%CI:2.2-35.8) and diabetes mellitus (odd:1.2;95%CI:1.0-4.9)(p<0.0001), were significantly associated with AD.

In our study, we established an independent association of elevated serum S100B protein levels with AD. Elevated S100B protein levels higher in CDR score 3.