Low heritability of neopterin in the Old Order Amish

• Published in: Journal of neuroimmunology
• Main Authors: Raheja, Uttam K, Stephens, Sarah H, Fuchs, Dietmar, Pavlovich, Mary A, Mohyuddin, Hira, Yousufi, Hassaan, Ryan, Kathleen, O'Connell, Jeff, Brenner, Lisa A, Punzalan, Cecile, Lowry, Christopher A, Hoisington, Andrew J, Nijjar, Gursharon K, Groer, Maureen, Shuldiner, Alan R, Pollin, Toni I, Stiller, John W, Mitchell, Braxton D, Postolache, Teodor T
• Format: Journal Article
• Language: English
• Published: 2017
• Subjects: Allergy and Immunology; Neurology; Biomarkers; Heritability; Neopterin; Old Order Amish; Psychiatric disorders
• ISSN: 0165-5728
• DOI: 10.1016/j.jneuroim.2017.02.016

Abstract Background Neopterin is a biomarker for cell-mediated immunity and oxidative stress, and a potential biomarker for psychiatric disorders such as depression. Heritability of immune markers is important for understanding their usefulness as potential trait versus state indicators in neuropsychiatric disorders. We examined the heritability of neopterin in Old Order Amish adults. Methods Fasting blood draw was obtained in 2,015 Amish individuals 18 years of age or above. Plasma neopterin levels were determined using enzyme-linked immunosorbent assay. Quantitative genetic procedures were used to estimate heritability of neopterin with adjustment for age, gender, and household. Results Mean plasma neopterin (± SD) was 6.2 (± 3.0) nmol/L (range 3.2–48.9 nmol/L). Heritability of log-neopterin was estimated at 0.08 unadjusted (p = 0.01) and 0.07 after adjusting for age, gender, and household (p = 0.03). The shared household effect was 0.06 (p < 0.02). Conclusions We found a significant low heritability of neopterin in contrast to the moderate to high heritability previously reported for other inflammatory markers such as C-reactive protein, antigen-specific immunoglobulins, and cytokines. Household effects were also significant, but small. The remaining non-household related environmental factors may be more important for pathogen and allergen exposure or for exposure to environmental microorganisms that limit inappropriate inflammation, than household and heritability related factors. Considering its low heritability, neopterin may be a useful marker to document the longitudinal course, naturalistic and interventional, of cellular immune responses and oxidative stress.