S HORT RE P ORT Comparison between ECL and ELISA for the detection of salivary cortisol and determination of the relationship between cortisol in saliva and serum measured by ECL

ABSTRACT: Salivary cortisol has been increasingly used as a stress biomarker since saliva sampling induces less additional stress than blood sampling. Enzyme-linked immunosorbent assay (ELISA) has been commonly used to measure salivary cortisol in stress related research. Recently, electrochemiluminescence (ECL), a routine immunoassay analyser, has been suggested to measure salivary cortisol. Therefore, the aims of this study are: (1) to compare salivary cortisol level measured by ELISA and ECL and (2) to determine the relationship between salivary cortisol and serum cortisol measured by ECL. Both salivary and serum samples were collected from 83 volunteers for cortisol measurement by ECL analysis. The salivary cortisol value was 3% of that of the serum cortisol. For ECL, the positive correlation between salivary and serum cortisol levels was significant (r = 0.84; p < 0.001). The measurement by two different methods did not show any significant difference (p = 0.5497). The correlation of salivary cortisol values measured by both techniques was significant (r = 0.81; p < 0.001). The result suggests that ECL seems to be more practical and cheaper for salivary cortisol measurement

Significant Association of HLA-B Alleles and Genotypes in Thai Children with Autism Spectrum Disorders: A Case-Control Study

Autism is a severe neurodevelopmental disorder. Many susceptible causative genes have been identified. Most of the previous reports showed the relationship between the Human Leukocyte Antigen (HLA) gene and etiology of autism. In order to identify HLA-B alleles associated with autism in Thai population, we compared the frequency of HLA-B allele in 364 autistic subjects with 952 normal subjects by using a two-stage sequence-specific oligonucleotide probe system (PCR-SSOP) method based on flow-cytometry technology. HLA-B⁎13:02 (P=0.019, OR = 2.229), HLA-B⁎38:02 (P=0.049, OR = 1.628), HLA-B⁎44:03 (P=0.016, OR = 1.645), and HLA-B⁎56:01 (P = 1.78 × 10−4, OR = 4.927) alleles were significantly increased in autistic subjects compared with normal subjects. Moreover, we found that the HLA-B⁎18:02 (P=0.016, OR = 0.375) and HLA-B⁎46:12 (P=0.008, OR = 0.147) alleles were negatively associated with autism when compared to normal controls. Both alleles might have a protective role in disease development. In addition, four HLA-B genotypes of autistic patients had statistically significant relationship with control groups, consisting of HLA-B⁎3905/⁎5801 (P=0.032, OR = 24.697), HLA-B⁎2704/⁎5801 (P=0.022, OR = 6.872), HLA-B⁎3501/⁎4403 (P=0.021, OR = 30.269), and HLA-B⁎1801/⁎4402 (P = 0.017, OR = 13.757). This is the first report on HLA-B associated with Thai autism and may serve as a marker for genetic susceptibility to autism in Thai population