Blood parameters

Immunological Parameters

Immunological parameters are determined by analyzing the absolute numbers of lymphocytes, quantitative and qualitative changes in the composition of lymphocyte subsets, concentration of cytokines in serum, (IL)-1b, interferon (IFN)-alpha, IFN-gamma, (TNF)-alpha, MCP-1, IL-6, IL-8, IL-10, IL-12p70, IL-17A, IL-18, IL-23, and IL-33) and functional activities of T cells and natural killer cells. A metric of immune age was adapted to our data by approximation using principal component regression based on the composition of lymphocyte subsets (natural killer and T cells, CD4+, CD8+, and CD8+CD28 T cells). Additionally, peripheral blood mononuclear cells (CD14 positive monocytes) as well as proteins (C-reactive protein), RNA, and DNA are extracted.

Metabolic Parameters

From venous blood ammonia concentration, leucocytes, erythrocytes, hematocrit, monocytes, lymphocytes, cell volume, thrombocytes, triglycerides, cholesterol, high- and low-density lipoprotein cholesterol, glycosylated hemoglobin, glucose, C-reactive protein, and creatinine are measured. Later, choline, betaine, and glycerophosphocholine will be measured. Additionally, a urine sample is collected early in the morning before starting the tests, from which creatinine and calcium oxalate are extracted.


The presence of a latent Toxoplasma gondii infection is explored using specific IgG antibodies. In the follow-up testing, a measure of COVID-19 antibodies will also be obtained.

Genetic Parameters (SNPs)

Isolation of genomic DNA of leukocytes is performed according to standard procedures. Several genetic polymorphisms potentially related to the structure and function of the central nervous system are selected. Following SNPs were analyzed: Apo-E4, BDNF Val66Met, COMT-1, COMT-2 Val158Met, DRD2, DRD1 48 A/G, CHRNA6-1, CHRNA6-3, CHRNB3-1, CHRNB3-2, GPCPD1, GRIN2A, GRIN2B, IL-1beta, IL-12A, TNF-alpha. In current analyses, we evaluate polygenic scores (PGS) since, based on the findings of several recent large-scale GWAS (genome-wide association studies).

Endocrine Parameters

If possible, a hair sample is taken from which hair cortisol concentrations are measured as an index of long-term stress.