> Her result was that the microplastic particles she studied were too large to interact with T cells.

Her "result" of what? Was there an actual experiment and what was its scope or was this by surveying literature?

Microplastics are of a pretty large range of size, and then there are nanoplastics below that.

I'm also not an expert, but a quick search shows a number of results of microplastics affecting T cells, some directly and some in terms of immune signaling, so this negative result doesn't seem that definitive.

(as usual, the difficulty is in teasing out in vivo effects)