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The association of Neoehrlichia mikurensis infection with polymyalgia rheumatica

Christine Lingblom1,2, Sofia Sundvall3, Kerstin Andersson4

  • 1Department of Clinical Microbiology, Sahlgrenska University Hospital, Gothenburg, Sweden. christine.lingblom@microbio.gu.se.

Infection
|July 10, 2026
PubMed

Insights

Polymyalgia rheumatica (PMR) patients infected with Neoehrlichia mikurensis showed distinct inflammatory profiles and vascular autoantibodies. The study did not confirm N. mikurensis as a trigger for PMR.

Area of Science:

  • Infectious Diseases
  • Rheumatology
  • Immunology

Background:

  • Neoehrlichia mikurensis is a tick-borne bacterium linked to vascular endothelium infections and PMR-like symptoms.
  • Polymyalgia rheumatica (PMR) is an inflammatory condition with an unknown cause, potentially linked to infectious agents.

Purpose of the Study:

  • To investigate a potential association between PMR and Neoehrlichia mikurensis infection.
  • To analyze clinical and immunological differences in PMR patients with and without N. mikurensis infection.

Main Methods:

  • PCR and serology were used to detect N. mikurensis infection in 142 PMR patients and 56 controls.
  • Serum samples were analyzed for anti-endothelial cell antibodies (AECA) and 38 inflammatory markers.
  • Multivariate pattern recognition methods were applied for data analysis.

Main Results:

  • No significant difference in N. mikurensis prevalence was found between PMR patients (5.6%) and controls (5.4%).
  • PMR patients with N. mikurensis infection exhibited elevated IgM AECA and IL-1β, with lower levels of IGFBP4, cystatin C, and angiopoietin-1.
  • A significant correlation was observed between IgM antibodies to N. mikurensis and IgM AECA (r=0.50, P<0.0001).

Conclusions:

  • PMR patients infected with N. mikurensis present with vascular autoantibodies and a unique inflammatory signature.
  • The study could not definitively establish whether N. mikurensis infection triggers or modulates PMR development.
Keywords:
Neoehrlichia mikurensisAngiopoietin-1Anti-endothelial cell antibodiesCystatinCInsulin-like growth factor-binding protein 4Interleukin-1ßPolymyalgia rheumatica

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