Spare parts for sick people

Title

Creator

Owen, Ray D.

Language

English

Source

Panorama XII (10) October 1960

Year

1960

Rights

In Copyright - Educational Use Permitted

Fulltext

As automatic as that! Spare Parts for SICK PEOPLE By Ray D. Owen When a car or bicycle washing machine needs repairing you take it to a mechanic with the idea that if he finds a part that is worn out or broken, he will almost always able to replace that part. Imagine how important it would be if it were also possible to replace parts of human be ings that had worn out, or that had been destroyed by disease, or gone “wild” as in particular kinds of cancer. Within the next hundred years—perhaps rather early in that interval—it is very possible that a lively market will develop for good used parts for the human body. Of course, the kinds of sub stitutions of parts now possible are very limited. If a person needs a blood transfusion, it is a simple matter to transfuse the right kind of compatible blood into his veins. But unless his bo dy is able to make the blood he needs, he wlil require another transfusion soon, and then an other. The transfused blood doesn’t settle down and make more blood like itself. It is a “dead-end” tissue; it is used up and disappears. Somewhat similarly, if a per son needs to grow bone in a par ticular place, it is possible to take part of another person’s bone and put it in that area, and new bone will often grow there. But this can be done with bone that has been boiled, frozen, or dried. Dead bone works because it provides only the inert scaf 82 Panorama folding onto which the host’s cells grow, producing more bone of their own. In fact, there are very few kinds of tissues that can be transplanted successfully from one individual to another, to grow and function in their new home. The reason for this is that the animal body has a kind of machinery to recognize things. This is the machinery of im munity. It recognizes the for eign, invading germ and res ponds by destroying that germ. When we have a foreign tissue transplant from another indivi dual, the body isn’t capable of making a moral judgment as to whether the foreign material is going to be good or bad for it; it recognizes simply that the ma terial is foreign and destroys it. It is possible to transplant ■ living, , growing, surviving tissue from one person to anoth er—if they are identical twins. Identical twins are so much alike, having the same heredity, that their bodies do not recog nize each other’s tissues as for eign. But in the ordinary case, if a person has a burn and needs a skin transplant to cover it, the surgeon will take skin from somewhere on that person’s own body, because only that skin will be accepted. So the problem in developing a market for good used parts for the human body is: How can we evade or control the immunolo gical reaction—the recognition and response to foreign material —when there is need for a tis sue or organ transplant? We don’t have the answer now. But we have some rather promising leads. One of the leads is, in part, derived from some observations made with my colleagues at the University of Wisconsin about 15 years ago. We were working on blood broups of dairy cattle and a very interesting and un usual case came to our attention. It happened that, on a farm in aryland, a breeder of pure bred Guernseys bred a Guern sey cow one morning to the Guernsey bull on the farm. By accident, that same day the cow was bred again to the beef bull—a white-faced Hereford— on the same farm. At the end of the proper period, the cow gave birth to twin calves. They were a remarkable pair of twins because, while one was a fe male and looked as a Guernsey should, the other was a bull and had the dominant white-faced marking of Hereford. It seemed evident, just -from looking at this pair, that they were twins with different fath ers. But when we tested their bloods, we found that their blood types were identical. This was hard to believe because October 1960 83 they could not have been iden tical twins; they were of op posite sex, and it was evident that apparently had different fathers. J TUDYING them a little furthu er, we found out why their bloods gave the same reactions. There were two different kind of blood cells there, just as there should have been for two dif ferent kinds individuals. One kind of blood cells was marked with the characteristics, inherit ed from the Hereford bull. The other kind was marked with the characteristics which came from the Guernsey. The cow had therefore evi dently produced two eggs and one of the eggs had been fer tilized by a Hereford sperm, the other by a Guernsey sperm. Both of the twins had a mixture of both of these kinds of blood cells. Nowk that shouldn’t have been so surprising either, be cause it had been known for a long time that twin cattle usual ly have a common circulation; their blood vessels join, and they give each other reciprocal transfusions of blood continu ously during much of their embyronic lives. So, we might even expect to find that two calves bom as twins have mixed blood. But the surprising thing was that, when we tested these twins again six months later, and again at the end of the year, and again over several years, they stayed the way they had been at birth. In other words, it wasn’t just a matter of blood transfusion, with the transfused blood disap pearing. There had been a per sistent transplantation of bloodforming tissue between these calves while they were embryos. And this is interesting because it means that when a transplant, ed tissue is introduced to an in dividual while he is still very young (in the embryo, in this case) his body is not able to re cognize the tissue as foreign and doesn’t rescond to it and destroy it. Instead, his body continues to accept this material as his own. A little while later some peo ple in England showed that it was possible to make skin grafts between non-identical twin cat tle. And more recently some Scandinavian workers perform ed successful kidney transplants. So bovine fraternal twins really lack the abiilty to recognize what is different in each other. Not long ago a similar case was found in a human be ing. A “Mrs. McK.” came into a British blood bank to give a pint of blood. When the sam ple was typed, it was found that Mrs. McK. had unusual blood. Her blood behaved mainly as type A, but not all her cells had the A antigen. Quite a large proportion behaved as though 84 Panorama they were O. And the O cells lacked another antigen called Kell that was present in the A cells. Her blood was apparently a mixture. Mrs. McK. was asked (with the twin cattle in mind), “Are you by any chance a twin?” “Yes,” she replied, “I was a twin, but my twin brother died more than 20 years ago when he was a baby.” It was possible to do a com plete job of blood typing on the long-dead twin brother because descendants of his cells that had been transplanted into his twin sister still survived in her body giving rise to blood cells in large numbers. Here again, a successful transplant had occurred be cause the recipient at the time was an embryo. Of course, Mrs. McK. and her brother were fra ternal twins; there is no implica tion that Mrs. McQ. has two fathers. A few years ago a group of workers in England found a way of putting this kind of si tuation on a controlled, labora tory basis. These were the same workers that did the skin trans plants in twin cattle, mentioned above, but in this work they used mice and chickens. Does this suggest any recipe for human practice? Looking ahead in a rather starry-eyed way to the next hundred years, we could say, “Perhaps.” It may even happen that when two ba bies are born, cells will they can still accept them, so that each of these babies grows up as a walking “tissue bank” for the other. However, they may well be a situation with dangers in it that we don’t recognize, so we would hesitate to attempt such applications to human ba bies as yet. There may be special cases where these experiments could be justified. For instance, there are certain kinds of anemia the person is genetically unable to produce the amount of blood that he needs because of an in herent defect in his blood-for ming tissue. If, when this per son is a baby, we inject normal blood-forming cells into him from another individual, it might well be that these would be accepted as a transplant to provide a source of normal cells to take the place of his own de fective ones. Actually, the first steps in this research have already been accomplished with mice. Dr. Elizabeth Russell of the Roscoe B. Jackson Memorial Labora tory in Bar Harbor, Me., by ma king transplants, has succeeded in saving the lives of mice that are genetically severe anemics. UU hen you look at the ” broader picture it is ob vious that the treating of very young babies in this way is not October 1960 85 a general solution to the prob lem we are discussing. If you need a tissue transplant now because something is badly wrong in you, it doesn’t help to say you could have been in jected with some kind of cell when you were a baby. What we need to solve this problem is way of suppressing and controlling the immune response in a normal adult. And it is with that in mind that a great deal of searching is going on now in laboratories all over the world. Again, we have some leads. One of them deals with very large amounts of X-ray irradia tion, or with particular kinds of chemicals which mimic the ef fects of radiation on animals. If, for example, a mouse is given 900 or 950 roentgens of total body radiation (a very high dose) it will die in a week or 10 days. But if, after the X-ray, this mouse is injected with bone marrow cells from another mouse, then he lives. This has two points of signi ficance for us. The first is that the life of the mouse has been saved by this kind of treatment. Looking toward a future in which we can expect increased use of high energy irradiation, and possible catastrophes from this, we could be very much in terested in saving the lives of individuals who have been ex posed by accident to these kill ing rays. The second point is that the X-rays have had the effect of permitting the individual to re ceive a tissue transplant that his body would ordinarily re ject. The X rays, or the chemi cals that mimic the effects of X rays, have inactivated the an imal’s ability to give an im mune response; the recognition and response machinery has been destroyed. So he accepts the tissue transplant that will save his life. Some animal experiments of this kind have been made re cently at Oak Ridge National Laboratory. An ordinary mouse colored mouse was given a le thal dose of X rays and then in jected with bone marorw from a rat. The mouse doesn’t look realy normal any more because for one thing, the X rays have killed the cells in his hair that produce pigment, so that hair is almost white. The X rays have also had some other effects on the mouse which the injection of bone marrow has not correct ed, but the main thing is that this mouse is alive and well. And within him are rat blood cells. Now, a rat is a very dif ferent kind of animal than a mouse—a different genus and species. It is remarkable that this mouse can live with all of his red blood cells derived from an animal so foreign to him. What are the prospects in ” this field for the next 86 Panorama hundred years? We now have blood banks for blood transfu sions. We have some tissue banks for keeping tissues like bone, that don’t have to live and grow in a new host. I think we can predict that in the relatively near future we will develop tissue banks for storing the kinds of tissue banks to live and grow in the foreign host. When we do, the vista that opens before us is overwhelm ing. Think, for example, of a dia betic—a person who lacks the ability to make insulin in the is let cells in his pancreas. The diabetic goes through his life being injected repeatedly with insulin from animals. How much better it might be if, instead of injecting the insulin, we could provide the diabetic with nor mal tissue, itself capable of mak. ing insulin in the diabetic’s body under physiological conditions. Or take the matter of trans planting healthy blood-forming tissues into the anemic indivi dual. Or suppose we could des troy the diseased cells in leuke mia (where a particular kind of cell goes wild) and replace them with normal ones. There are many examples that might be cited. But the ho rizon is even broader than that. If in the course of our search we find ways of controlling the transplantation-immune r e a c - tion, the way might be opened to treament of many of the more serious aspects of important dis eases. Many diseases have bad side effects from the struggle that is going on between the host’s im mune machinery and the for eign invading germ. In many al lergies, as well, the immune ma chinery goes wrong and causes bad reactions. Of we find a way to control this kind of reaction, the diseases of hypersensitivity may come under control, and we can do humanity a great deal of good. Frankenstein created a mons. ter. Mary Shelley, second wife of the poet Shelley, in the fan tasy she published in 1818, had Frankenstein say, “The dissect ing room and the slaughter house furnished many of my materials.” Our aim, a used parts market for the human body, is not to create a monster. Instead, we will serve desirable and prac tical aims—the needs of man. More than that, our effort will be to understand; and in this effort no one can predict what areas of human difficulty will yield to the understanding to be contributed by research in tissue transplantation in the next hundred years, or how far this research will help us to pro gress to ultimate comprehen sion of the essential mysteries of life. October 1960 87

pages

82-87

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