Washington University. US: A mosquito-borne virus that has spread to the Caribbean and Central
and South America and has caused isolated infections in Florida often
causes joint pain and swelling similar to that seen in patients with
rheumatoid arthritis.
Researchers at Washington University School of Medicine
in St. Louis also found that blood tests of patients with the
Chikungunya virus and those with rheumatoid arthritis can produce
similar results. This may lead some patients with the virus to be
misdiagnosed.
The findings, reported in the January issue of Arthritis and
Rheumatology, underscore the need for doctors to obtain detailed travel
and medical histories from patients being evaluated for rheumatoid
arthritis. Such details could help distinguish between the two
conditions.
“For now, good travel histories of patients are among the best diagnostic tools for physicians,” said senior author Wayne Yokoyama,
MD, the Sam and Audrey Loew Levin Professor of Medicine. “Recent travel
to the Caribbean, Central and South America, Africa, India or other
areas where the virus is prevalent should raise suspicions of
Chikungunya infection. In addition, the disease typically starts with
high fever and abrupt onset of severe pain in the joints, which are not
usually seen with rheumatoid arthritis.”
The global spread of the Chickungunya virus suggests that the disease
is likely to be a diagnostic challenge in the years ahead. Physicians
treat rheumatoid arthritis with drugs that suppress the immune system,
but it’s not yet known whether that approach will help or harm patients
with Chikungunya virus.
The virus is spread by infected mosquitoes and first was identified
60 years ago in eastern Africa. Since then, it has spread to many parts
of the world.
In 2014, more than 2,000 people in the United States developed the
infection after traveling abroad, mostly to the Caribbean. That same
year, the Centers for Disease Control and Prevention reported 11 cases
of Chikungunya infection among people living in Florida who had not
traveled outside the United States, suggesting that mosquitoes in that
state were spreading the virus.
In most patients, the infection causes a fever, rash and severe joint
pain in the hands, feet, knees, neck and elbows. The fever and rash
typically subside in seven to 10 days, but symptoms of arthritis may
persist for 12-15 months in up to 60 percent of patients. Some patients’
symptoms persist for up to three years.
For the study, lead author Jonathan Miner, MD, PhD, a rheumatology
fellow, studied 10 St. Louis-area residents who traveled in June 2014 to
Haiti, where they were infected with Chikungunya virus. The patients
were evaluated seven to 10 weeks after the onset of symptoms. During
that time, eight patients developed persistent arthritis, several with
joint pain so severe they had difficulty walking.
“All eight patients with Chikungunya-related arthritis met the
American College of Rheumatology’s criteria for a diagnosis of
rheumatoid arthritis,” Miner said. “Their recent travel to Haiti led us
to suspect they had Chikungunya virus infections.”
As a comparison, the study also included healthy subjects and
patients newly diagnosed with rheumatoid arthritis who had not yet
received treatment.
Laboratory tests that measured levels of specialized immune cells in
the blood showed additional similarities between Chikungunya virus
infection and rheumatoid arthritis, including elevated levels of
specialized T cells, which suggest, despite the persistence of symptoms,
that the immune system has recognized and is fighting the virus. These
studies were performed on state-of-the-art instruments in the
university’s newly established Center for Human Immunology and
Immunotherapy Programs.
To positively identify Chikungunya virus, the researchers performed
highly specialized tests of the immune system, with results that showed
antibodies against the Chikungunya virus in patients’ blood. Such
testing is only available at the CDC and in research laboratories.
According to Yokoyama, a Howard Hughes Medical Institute
investigator, the similarities between Chikungunya virus infection and
rheumatoid arthritis suggest that learning more about the virus may help
scientists better understand rheumatoid arthritis, which affects about
one in every 100 people worldwide.
Said co-author Deborah Lenschow, MD, PhD, associate professor of medicine and of pathology and immunology: “We’re
anticipating that Chikungunya virus will spread broadly in the United
States, so it’s important to develop better tools for diagnosis,
prevention and treatment.”
The researchers also have established a Chikungunya registry at chikv.dom.wustl.edu to build a database of cases for studying the virus in more detail.
This work was supported by The Foundation for Barnes-Jewish Hospital and the Howard Hughes Medical Institute.
Miner
JJ, Aw-Yeang H-X, Fox JM, Taffner S, Malkova ON, Oh ST, Kim AHJ,
Diamond MS, Lenschow DJ, Yokoyama WM. Chikungunya viral arthritis in the
United States: A mimic of seronegative rheumatoid arthritis. Arthritis
& Rheumatology, DOI 10.1002/art.39027.