Universität zu Köln

Schenk, Julia Katharina (2024). Cytokine-producing peripheral blood mononuclear cells (PBMCs) for discrimination of vertebral osteomyelitis and degenerative spinal diseases. PhD thesis, Universität zu Köln.

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Abstract

Vertebral osteomyelitis (VO) is a rare but dreaded disease of the spine. A major challenge lies in its earliest possible diagnosis and treatment. The average time between the first symptoms and a final diagnosis ranges between 2 and 6 months. These difficulties can lead to a highly acute course with neurological deficits, sepsis, organ failure and may result in death. Previous work in our group showed that IL-6, IL-8, IL-12, and VEGF were candidate cytokines for the discrimination of vertebral osteomyelitis and degenerative spinal diseases. The aim of the present study was to gain an understanding of the immune cells responsible for the production of these candidate cytokines along with the associated changes in immune cells during vertebral osteomyelitis. This approach may enable a clear differentiation between vertebral osteomyelitis and degenerative spinal diseases. Therefore, the levels of cytokine-producing peripheral mononuclear blood cells (PBMCs) were measured via fluorescence activated cell sorting (FACS). The study was a single-center-control study performed at the Orthopedic Department of the University of Cologne in co-operation with the Department for Internal Medicine I and the Center for Molecular Medicine Cologne (CMMC) between 2015 and 2019. Inclusion criteria were medical need for operative stabilization due to VO or erosive osteochondrosis and exclusion criteria were autoimmune diseases, chronic infections or active cancer. A total number of 36 patients were included in the study: 16 patients being part of the VO group and 20 patients with erosive osteochondrosis in the control group. The average age was 68.8 years and 62.5 % of the VO group were male. There were two time points of blood drawing, one before surgery (pre-OP) and one 40-56 days after surgery (post-OP). For both groups at both timepoints, FACS analysis was conducted, and seven cell populations were screened, namely lymphocytes, B-cells, T-cells, which were then divided into CD4 T-cells and CD8 T-cells as well as NK-cells, and monocytes. The results were statistically analyzed via paired t-test within the groups and a two-sample-t-test (method of Satterthwaite) to detect the differences between the VO group and the control group. Furthermore, similarity matrices were created for B-cells, T-cells, and monocytes for both study groups at both time points to determine co-regulatory processes. IL-6-positive cells were produced by all cell populations analyzed but there were no significant differences between both study groups at the pre-operative time point. The similarity matrices showed positive correlations of IL-6 with VEGF and/or IL-12 pre-OP. Monocytes showed by far the highest number of IL-8-positive cells compared to other cell populations analyzed and the proportion of CD8+ T-cells in the VO patients was significantly lower than in the controls pre-OP. There was a significant higher number of IL-12-positive lymphocytes in the VO group than in the controls pre-OP. IL-12 showed positive correlations with IL-6 and VEGF in the similarity matrices. VEGF-positive cells showed the most significant differences between both study groups pre-OP, whereby the proportion of positive cells was higher in the VO group than in the controls (lymphocytes, B-cells, T-cells, and CD8+ T-cells). In addition, the number of VEGF-positive cells was the highest in comparison to the other cytokine-positive cell populations and VEGF showed positive correlations with IL-6, IL-8, and IL-12 in the similarity matrices pre-OP. Based on the present results, a clear differentiation between vertebral osteomyelitis and degenerative spinal disease is possible pre-operatively, especially with the IL-8-positive CD8+ T-cells, IL-12-positive lymphocytes, and VEGF-positive cells (lymphocytes, B-cells, T-cells, and CD8+ T-cells).

Item Type:	Thesis (PhD thesis)
Creators:	Creators Email ORCID ORCID Put Code Schenk, Julia Katharina UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-727628
Date:	2024
Language:	English
Faculty:	Faculty of Medicine
Divisions:	Zentrum für Molekulare Medizin
Subjects:	Medical sciences Medicine
Uncontrolled Keywords:	Keywords Language vertebral osteomyelitis English peripheral mononuclear blood cells English orthopedic surgery English cytokine-producing PBMCs English bacterial infection English
Date of oral exam:	28 February 2024
Referee:	Name Academic Title Mahabir-Brenner, E. Professorin Dr. sc. agr. Suárez, I. Privatdozentin Dr. med.
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/72762