Do you have research that shows that? What I've read is that there was no real evidence of that.
We discovered the hard-way that my late wife had issues with this. Multiple doctors diagnosed her with both RA and Lupus. When we got the Nightshades out of her diet and switched to more natural based cleaning products, such as Hemp based soap, shampoo and vinegar for cleaning, her symptoms of RA and Lupus went away. An good allergist finds things like this.