A new study may help us understand why some patients get
better and other don’t. This topical
study: Serum Inflammatory Mediators as Markers of Human Lyme Disease Activity, was
published in PLOS one-- the lead authors are from Johns Hopkins University. All
published Lyme studies have had problems with patient selection. Patient groups
are selected because they are supposed to have the same thing. IDSA criteria
are generally used. The group in this study had early Lyme associated with EM
rash. As I have discussed previously,
most patients with acute Lyme do not present with a rash; and more to the
point, most patients with chronic Lyme are not diagnosed in a timely fashion.
Nonetheless, this study conveys important information.
This study demonstrates the exist of two distinct patient
populations who have very different immunological responses to infection with
Borrelia burgdorferi (Lyme) – one group has a robust response based on
measurements of cytokines and markers of inflammation; the other group has a
minimal immunological reaction using the same indicators. The two groups have
very different clinical outcomes.
I am pleased by a change in verbiage/terminology. In this
study the authors use the words PTLDS, post-treatment Lyme disease syndrome,
which replaces the old term PLDS, post-Lyme disease syndrome. This small change
leaves the door open to the notion that Lyme organisms may persist after
treatment. And here we are dealing with acute patients treated early in the course
of the illness.
The study measures molecules which moderate immune
responses. The immune system is tasked
with finding offending invaders, like germs, and eradicating them by a host of
complex mechanisms and devices. (Seek out and destroy) This study measures the messengers that help
direct the traffic of the immune system – sending signals to an assortment of
cells, telling them where to go and when.
The authors note the immune system alone is unable to
eradicate Lyme infection and that late-stage arthritis develops in many
patients. They describe a subset of patients who develop antibiotic refractory
disease 12 months or more. The dogma that host immune responses is the major
factor in such cases is discussed, but, from the mouse model -- another possibility
is discussed. “Delays in the generation
of long-lived plasma cells (the cells that make antibodies) and a weak, largely
IgM response (sound familiar) may be part of a Lyme (Borrelia burdorferi)
strategy to avoid clearance.”(Yet another mechanism of survival). The authors reflect that residual antigen or
infection in some treated patient may explain the persistence of symptoms, in
post-treatment Lyme disease, but state: “this is a very controversial area.”
The scientists measures many molecules that traffic immune
cells, with names like: CCL1 9, CXCL 19, CXCL 10, CRP, SAA, IL-1a, IL-18, IL33,
IL6, TNF alpha, and others.
Two distinct responses were identified. On groups showed
high levels of these markers of immune response while the other showed low
levels of these markers.
One particular mediator of inflammation, IL-6 remained
elevated in patients with late stage Lyme which the authors found surprising. These patients with post-treatment,
symptomatic Lyme disease showed immunological evidence of persistent
inflammation – or infection.
The group of patient with a high level of reaction
(cytokines, chemokines) had lower WBC counts, increased liver function counts
and higher levels of markers of inflammation such as CRP. This group produced
Lyme antibodies, or seroconverted. This group showed clinical remission. The group with low level reactions to the same
molecules did not share these features: these patients had a tendency not to
seroconvert. This group of patients was more likely to develop post treatment
symptoms like chronic joint pain.
This study has clearly identified a subset patient who are
more likely to develop chronic Lyme disease even after IDSA recommended
treatment for stage one disease. This study sheds light on why many patients
are seronegative (do not make antibodies) or have weak IgM responses as we
commonly see. This study lays the foundation for the development of a test
which helps us predict which patients need more help early on -- those who are
at higher risk for developing chronic disease.
On another note…
Another scientist’s face is displayed in a Johns
Hopkins University magazine in an article which states he has beliefs contrary
to the IDSA and that he believes in Lyme persiters which might respond to a
drug for tuberculosis. The article say that while these ideas would not be
controversial regarding tuberculosis they are very controversial when mentioned
in the context of Lyme disease.