Persistent Antigen Lyme Arthritis: Infection or Immune Response?

Persistent antigen Lyme arthritis has gained attention following research suggesting that Borrelia burgdorferi peptidoglycan fragments (PG(Bb)) may drive inflammation even after antibiotic treatment.

This raises a critical clinical question: are these symptoms driven by residual immune activation—or by ongoing infection?

According to Jutras and colleagues, PG(Bb) fragments likely “contribute to inflammation during infection and in cases of post-infectious Lyme arthritis.” In a mouse model, the authors found that PG(Bb) alone was sufficient to induce acute arthritis.

Furthermore,

Jutras et al.

suggest that “immune responses to PG(Bb) and autoantigens may contribute to pathology, even after the infection itself has been cleared.” They propose that differences in disease severity may reflect variability in immune responses to PG(Bb).

Author’s note: Jutras and colleagues assume that the infection has resolved. However, there is currently no reliable test that can definitively confirm that a Lyme disease infection has been cleared. This limitation is central to ongoing debates surrounding post-treatment Lyme disease syndrome (PTLDS) and persistent Lyme disease.

Why Does PG(Bb) Persist After Treatment?

A central question raised by the authors is:
How can PG(Bb) material remain in the synovial environment for weeks to months after appropriate antibiotic therapy?

They propose three possible explanations:

1. PG material may remain after bacterial killing.
2. Macrophages may store PG fragments within intracellular vesicles.
3. PG-containing immune complexes may accumulate in synovial fluid.

Based on these hypotheses, the authors suggest managing persistent antigen Lyme arthritis with immune-modulating therapies rather than additional antimicrobial treatment.

Proposed Treatments for Persistent Antigen Lyme Arthritis

To dampen immune responses to PG(Bb), Jutras and colleagues recommend disease-modifying anti-rheumatic drugs, primarily hydroxychloroquine or methotrexate.

They further suggest targeting innate immune responses with medications such as TNF or NF-κB inhibitors for patients with persistent inflammatory arthritis.

[bctt tweet=”Persistent antigen (Borrelia burgdorferi peptidoglycan) may drive ongoing inflammation in Lyme arthritis, according to study.” username=”DrDanielCameron”]

The authors also demonstrate that B. burgdorferi releases PG(Bb) fragments during bacterial growth, raising the possibility that PG(Bb) contributes to broader Lyme disease pathogenesis beyond arthritis alone.

Could Persistent Infection Explain Persistent Antigen?

One critical question remains unaddressed:
Could an active or persistent Lyme infection be driving the continued presence of PG(Bb)?

The authors do not explore this possibility. If persistent infection were considered, alternative treatment strategies—including additional or targeted antimicrobial therapy—might be evaluated alongside immune-modulating approaches.

This distinction—between residual immune activation and ongoing infection—remains one of the most important unresolved questions in chronic Lyme disease.

Dr. Daniel Cameron, MD, MPH
Lyme disease clinician with over 30 years of experience and past president of ILADS.

Symptoms • Testing • Coinfections • Recovery • Pediatric • Prevention