Compounding for the Treatment of COVID-19 and Long COVID, Part 3: The Role of Toll-like Receptors in SARS-CoV-2 Infection and COVID Development.

Toll-like receptors, which are type I transmembrane proteins and pattern recognition receptors found on cell surfaces and in intracellular membranes, serve as central mediators of both initial innate-immune responses and secondary adaptive/acquired-immune responses. Toll-like receptor 4, the activation of which leads to the synthesis of proinflammatory cytokines and chemokines, has been shown to have a vital role in the innate immune response to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. In our practice of pharmaceutical compounding, we noted that some individuals with coronavirus disease- 2019 (COVID-19) or long COVID achieved limited or no benefit from commercially manufactured treatments designed to alleviate symptoms and enable recovery. We suggest that in such cases, a compounded formulation, which can be easily customized to provide that support, may be of benefit. This article provides a brief review of the ways in which toll-like receptors in general, and toll-like receptor 4 in particular, affect the development and progression of SARS-CoV-2 infection and COVID-19, especially with respect to the human respiratory and central nervous systems and people rendered vulnerable by a comorbid condition (diabetes, obesity) or age. Instructions for compounding 2 customized preparations useful in the treatment of COVID-19 and long COVID are also provided.