The Commodification of the "Human" Body

Spoiler Alert! Don't read if you haven't finished the novel completely. I don't want to give anything away!

In Kazuo Ishiguro's novel Never Let Me Go, the main characters Kath, Ruth, and Tommy are raised in a mysterious boarding school somewhere in the English countryside. Through the novel, which is told in flashback's through Kath's perspective, they develop from children into adults. They go about their lives knowing they are meant for something greater and knowing that someday they will begin donating their vital organs to others. By the way did I forget to mention they are clones?!
Throughout the novel, Kath and her friends only attain so much knowledge about their true purpose and at the end, they still do not obtain all of the facts about why they were created and why they are treated the why they are.
The issue of commodities and commodification comes in to play when we think about Kath, Ruth, and Tommy as commodities themselves. According to Marx commodities comes into existence through two reasons, one, to satisfy a human need and two, due to the effort of human labor (664). He also states that, "the products of labor become commodities, social things whose qualities are at the same time perceptible and imperceptible" (664). Using these two ideas from Marx, I wish to discuss Kath and friends in terms of commodities.
As a product of human labor, a clone, and having been created to fulfill a societal need, organ donation, Kath and her companions would qualify as commodities according to Marx. However, unlike a table, which is inanimate, Ishiguro's reoccurring question of the humanity of clones like Kath, complicates Marx's theory and evokes millions of questions, which the novel debates, as to what is makes us human?
If it is our abilities to produce products through hours of labor which are relevant to society, than would not Kath and her friends, through the production of vital organs be considered as human? Because the can "create" something that society needs?
Another point would be in regards to the art work the Hailsham students are prompted to create. While the aesthetic pleasure of viewing art is not a commodity; the fact that Kath creates something through labor and that it is valued based on the system at Hailsham cannot be overlooked. The question it implies however, is whether this example is a "mock" or created system which mirrors the production of commodities in the real world? Does Ishiguro use the Hailsham Exchanges as symbolic of the real life system which commodifies the bodies of Kath and the other clones?