Chikungunya Arthritis in the Americas

Chikungunya is a mosquito-borne viral illness that leads to chronic joint pain in approximately one half of patients. The mechanisms leading to long term arthritis in humans has not been well established. There is some evidence from animal studies that activated macrophages with persistent viral infection may play a role in chronic arthritis however these mechanisms have not yet been identified in humans. It is hypothesized that activated macrophages harboring persistent active chikungunya virus are responsible for chronic arthritis and joint pain in patients. The focus of this proposal is to evaluate synovial fluid and blood for direct viral persistence and activated macrophages that may clarify the mechanism of inflammatory injury. The results of this study will be directly applicable to tailoring trials of therapeutics.

Chikungunya is rapidly spreading throughout the Americas and causes debilitating chronic arthritis in approximately one fourth of patients. There is currently no standard treatment for chikungunya arthritis, and the mechanisms leading to this chronic arthritis are unclear. Further characterization of the disease pathophysiology is needed in order to guide evaluation of potential therapeutics. It is hypothesized that chronic chikungunya arthritis is due to persistence of active virus in the synovial fluid where macrophages serve as a viral reservoir. The predominance of activated macrophages in persistently infected tissue and the presence of viral genome within these macrophages in non-human primates makes our hypothesis plausible. To test this hypothesis, this study has three Specific Aims. Aim 1, describe host characteristics affect susceptibility to severe or persistent arthritis. Aim 2, determine if chikungunya virus persists in synovial fluid and synovial fluid macrophages in humans as shown in non-human primates. Aim 3, investigate how these macrophages may be activated and modulated by cytokines. To date, these pathophysiologic factors have not been well characterized in humans. Information gained from this study can directly lead to recommendations for the further evaluation of antiviral versus immune modulating medications.

Eligibility Criteria:
Inclusion Criteria:

* There will be three cohorts of patients.

  * Cohort 1 Chronic chikungunya: Twenty participants with chronic chikungunya with knee effusion defined as continued knee joint effusion at least three months after diagnosis of chikungunya.
  * Cohort 2 Acute chikungunya: Ten participants with acute chikungunya defined as clinical symptoms of chikungunya with acute fever \>38°C and joint pain within 10 days the onset of symptoms without other more likely diagnosis or laboratory confirmed chikungunya.
  * Cohort 3 Healthy controls: Five healthy participants will participate that will provide baseline measurements of the cytokine profile and mononuclear cell sample recovery.

All subjects will be adults ≥18 years old. Cohort 1 participants will only be enrolled in the study if they have a knee effusion at baseline presentation. Laboratory confirmation of chikungunya includes positive viral PCR or positive IgM antibody. All patients will be able to understand and give informed consent in Spanish.

Exclusion Criteria:

* Participants will be excluded if they have a known bleeding disorders or if they are on warfarin, clopidogrel, and ticagrelor therapy they will be excluded for increased bleeding risk.
* The study will also exclude children, adults unable to give consent, prisoners, and pregnant women.