2. Case Presentation
We previously reported two cases with chikungunya fever after traveling
to Cook Island.3 The elevated serum IL-6, IL-17,
IL-21, and IL-23 levels have been reported in patient with chronic
arthritis after chikungunya fever [1,2]. Recent findings in psoriatic
arthritis revealed the elevated serum IL-36 during arthritis
[4]. IL-36 is a relatively newly found cytokine belonging to the IL-1
family, whose involvement in various diseases is still poorly
understood. In the current study, to evaluate the involvement of IL-36
in patients with chikungunya fever, stocked serum from the previously
reported two cases [1] at the initial visit, 7 days, and 56 days later
were used to measure IL-36α and IL-36βconcentration. Two cases were
siblings, and the brother developed pain in his neck and ankle joints on
the second day back to Japan, but fever was not detected. Sister
developed fever soon after returning to Japan, with severe arthralgia
and leg edema. The arthralgia persisted for about a year. IL-36α and
IL-36β were measured in the patient’s serum using human IL-36α/IL-1F6
and IL-36β/IL-1F8 DuoSet ELISA® (R&D Systems,
Minneapolis, MN, USA). At the initial visit, IL-36α was higher in the
sister, who had more fever and arthralgia symptoms than her brother. 7
days later, both had higher levels than at the initial visit, but the
brother, whose symptoms of Chikungunya fever appeared later, had a
larger increase than at the initial visit. After 56 days, both decreased
to about half of the peak value. IL-36β was highest at the first visit
for both patients and gradually decreased (Figure 1).