Terri,
The benefit of using Herceptin in an uncompromised immune system is thought to be via "Natural Killer" (NK) cells. These cells are noticeably reduced following most chemo. I did read an abstract:
http://www.ncbi.nlm.nih.gov/sites/en...&dopt=Abstract Titled "Paclitaxel probably enhances cytotoxicity of natural killer cells against breast carcinoma cells by increasing perforin production," which may explain the positive results seen when combining paclitaxel with Herceptin.
Hope this helps,
Hopeful