SEX DIFFERENCES IN ANTIBODY LEVELS IN ALZHEIMER'S DISEASE

Abstract

Tau protein is one of the cytoskeletal neuronal proteins and under some pathological conditions it can be released into the extracellular fluid. One of promising therapeutic options for Alzheimer disease (AD) is tau vaccination. Therefore we aimed to find out corresponding immunologic background in normal population and in patients with AD prior to vaccination. We measured anti-tau antibodies using ELISA in serum samples from AD patients fulfilling NIA-AA criteria and age- and sex- matched cognitively normal controls (NC) in two independent experiments (firstly, 36 AD vs 34 NC, secondly, 30 AD vs 30 NC). We used different tau antigens involved in AD pathology or resembling brain tau protein: the longest isoform (441 amino acids), the shortest isoform (“fetal" 352 amino acids), two misdisordered forms of tau protein (151-391 3R and 151-391 4R), a cleaved form (151-421 amino acids) and native bovine tau protein. Levels of serum anti-tau antibodies did not differ between the AD patients and the controls in both experiments. Moreover, anti-tau levels were independent of age in both NC groups. Interestingly, we found some differences depending on gender and the used antigen. We noticed that anti-tau antibody levels were in opposite direction in male and female population which could have an influence on statistics. We found similar immunological background of anti-tau antibodies in serum from individuals with AD or without it. Gender changes in serum anti-tau antibodies due to AD should be taken into consideration in tau vaccination interventions. The size of our groups does not allows us to perform rigorous statistical analysis and our preliminary findings should be validated on larger sample. The study was supported by grant GAČR P304/12/G069 and GAČR 13-26601S, IGA NT 13183 and MH CZ - DRO (PCP, 00023752), UK 266705/SVV/2014.