Cytokine and LL-37 gene expression levels in Bartonella spp. seropositive and seronegative patients of a rheumatology clinic

Purpose: The variation in the immune response to Bartonella spp. infection in humans remains unclear. The present study compares the expression of selected interleukins, cytokines and cathelicidin (LL-37) in rheumatology clinic patients suffering from musculoskeletal symptoms with healthy blood donors. The patients had previously been tested for the presence of Bartonella henselae antibodies. Methods: Gene expression of LL-37, interleukin (IL)-2, IL-4, IL-6, IL-12, interferon-(IFN)-gamma, and tumor necrosis factor (TNF-alpha)-alpha was determined in blood samples using quantitative Polymerase Chain Reaction (qPCR). Statistical analysis was prepared with STATISTICA. Results: Statistically significant differences in the mRNA levels of the tested cytokines (IFN-gamma, TNF-alpha, IL-2, IL-4, IL-6, IL-12; p < 0.0001) were observed between the healthy controls and patients; however, no difference was observed for LL37 mRNA (p = 0.1974). No significant differences in mRNA expression were observed between IgG in anti-Bartonella seropositive and seronegative individuals (p > 0.05). The only significant differences between the Bartonella spp. DNA positive and negative patients, indicated by PCR, were observed for TNF-alpha and IL-12 mRNA (p = 0.0045 and p = 0.0255, respectively). Conclusion: A broadly similar immune response to the tested cytokines was observed among the participants irrespective of anti-Bartonella spp. IgG seropositivity. However, the Bartonella DNA-positive participants demonstrated significantly lower expression of IL-12 and TNF-alpha mRNA; this may indicate that these bacteria have a suppressive influence on the immune system.

Automated summary

This study compared the immune response in rheumatology clinic patients with musculoskeletal symptoms and healthy blood donors, finding significant differences in mRNA levels of tested cytokines, indicating a potential suppressive influence of Bartonella spp. on the immune system.