Gene Therapy: Blue Smoke & Mirrors?
by Jake (Juneau, AK)

Dear Ed: The big hope for a psoriasis cure right now appears to be gene therapy. I am baffled by it all and wonder if you or anyone else who visits Flake HQ can enlighten me. As I understand it, there seems to be some evidence that a particular gene or genes ALLOWS us to get psoriasis, but how it is initially triggered and just what it may look like once it's triggered may or may not be related to the gene. Am I correct so far? Most of what I know about genes I learned from that little animated sequence near the beginning of JURASSIC PARK, the movie, so consider me basically uninformed. But isn't it true that every cell in our bodies contains our complete genetic makeup? How do you replace bad genes that are everywhere in your body?... I sometimes get the feeling that so-called gene therapy resides somewhere between science fact and science fiction. -Jake

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Ed's Response:

Dear Jake: Usually I find books and articles written by physicians to be about as indigestible as the medicines they prescribe; however, I've found two quasi-illuminating sites on the Web about so-called "gene therapy":

http://nimnet51.nimr.mrc.ac.uk/mhe95/genether.htm
http://www.the-scientist.library.upenn.edu/yr1996/jan/gene_960122.html

Read them in the order I've presented them here. The first is an article by Peter Rigby from something called the "Mill Hill Essays 1995 | National Institute for Medical Research," which I deduce from the URL is in the United Kingdom somewhere. Rigby tries hard and mostly succeeds in writing for the lay reader. The second is really an interview with James Wilson from the University of Pennsylvania. It's evident both the interviewer and Mr. Wilson know a lot more about gene therapy than you or me, and the interview appears to be directed at some body of readers more knowledgable than us, too.

My belief after reading these two articles ("conclusion" would imply a precision of understanding I'm sure I don't possess) is as follows:

(1) IF -- and this is a BIG if -- a gene or genes can be definitely ID'd as the cause of psoriasis, and IF it can be determined that something is wrong with this gene or genes, then...

(2) Scientists will probably be able to identify, isolate, and reproduce the "normal" variant of the same gene from people who do NOT have psoriasis.

(3) But then they have to determine WHERE in the body the replacement gene must go. Not all genes are relevant to all tissues and organs even though all genes are present in all cells except sperm and egg cells (a.k.a. "germ cells," which each carry half a complete set). I'm not sure we know, yet, in just what organ our psoriasis-gene goes to work -- though the entire immune system is suspect and involves many organs and tissue-types.

(4) And finally they will have to figure out a way to deliver the new gene to the right place. So-called "vectors," which have been derived from viruses, are the current delivery vehicle, and as of 1995 (Rigby's article) researchers were having problems getting corrected genes into human subjects.


We also need to bear in mind that the big boys in gene therapy research don't appear to be focusing on diseases like psoriasis. Rigby writes very openly about the prospective high costs of gene therapy -- even when they get it to work predictably. As usual with psoriasis research, treatments are apt to be happy accidents deriving from work on other ailments. As a target market the population of psoriatics isn't too attractive, at least not in comparison to cancer, AIDS, muscular dystrophy, cystic fibrosis and many others.

As my research yielded nothing more current than 1995, gene therapy in general by mid-1997 is probably less "science fiction" than my references may suggest. Nonetheless, any gene therapy route to a psoriasis cure is probably not imminent.

Anyone else reading this who has something to add, correct or update is invited to email me. (Pssst! NPF staffers! Any late breaking news from Dallas?) -Ed

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