That might be a factor, but this work is specifically on B cells in the gastrointestinal tract. There are definitely interactions with the gut biome and B cells

That might be a factor, but this work is specifically on B cells in the gastrointestinal tract. There are definitely interactions with the gut biome and B cells though, see eg https://www.ncbi.nlm.nih.gov/pubmed/31462512 https://www.ncbi.nlm.nih.gov/pubmed/31462512