http://www.niaid.nih.gov/final/immun/immun.htm (from NIH) http://www.niaid.nih.gov/final/immds/immds.htm (immunologic diseases from NIH) http://www.cancerresearch.org/immhow.html (from Cancer Research Institute) http://www.niaid.nih.gov/publications/autoimmune/work.htm ( autoimmune disease from National Institutes of Health) http://www.sciencemuseum.org.uk/exhibitions/lifecycle/112.asp and http://www.sciencemuseum.org.uk/exhibitions/lifecycle/105.asp (from a British Science Museum -- with great images) http://www.cdc.gov/nip/publications/fs/gen/howvpd.htm (from CDC) http://www.canadian-health-network.ca/servlet/ContentServer? cid=1007411&pagename=CHN- RCS%2FCHNResource%2FFAQCHNResourceTemplate&c=CHNResource&lang=En (from Canadian Health Network) Hope that these help remove some confusion. [Posted in FML issue 4641]