Sustained Humoral Immunity After SFTS | Tropical Medicine

Here’s a breakdown of the key information from the provided text regarding Severe Fever with Thrombocytopenia Syndrome (SFTS) and potential treatments:

Key Findings & Information:

* SFTS Treatment Challenges: Currently, there are no effective treatments for SFTS.
* Favipiravir (T-705) – Mixed Results:

* Showed efficacy in animal models (mouse studies – references 31 & 32).
* Failed to significantly reduce mortality in a human study (multicenter,non-randomized,uncontrolled,single-arm study – reference 8).
* Long-Lasting Immunity: Memory B cells specific to the SFTSV gn protein were found in 75% of recovered patients, and these persisted for up to 6 years and 7 months after infection (Figure 4c).
* Potential for Antibody Therapy: The persistence of these memory B cells suggests that developing recombinant neutralizing monoclonal antibodies from them could be a promising avenue for new SFTS therapies.
* Antibody Maintainance – Beyond B Cells: Neutralizing antibodies were still present in some patients (4/16) even without detectable memory B cells. This suggests long-lived plasma cells (LLPCs) play a role in maintaining antibody responses independently of memory B cells (reference 33). A study in non-human primates supports this idea.

In essence, the text highlights the need for new SFTS treatments and points to the potential of leveraging the body’s own immune response (specifically, antibodies derived from memory B cells and the role of long-lived plasma cells) to develop those therapies.