Kannan,
There is no journal entry for this transation:-
1) When the Kidney is being donated the record will be in the Hospital Manangement software(Generally Known as HIMS)/register to record such type of transaction. Same as Blood Bank, where the blood stock is maintained and not in the books of accounts as the value cannot be measured in monetary terms.
2) All Hospitals generally have packages for such treatments, like wise Kidney transplantation will have a package of its own.
3) When the Kidney is used to a patient the package amount itself will be charged and considered as In-Patient Income.
Hence, in any case there is no sale/purchase of kidney in the books of accounts.
One should distinguish between Organ Trading and Organ Donation. Organs are donated (Eg: Liver, Kidney, Eyes. apart from organ Blood Donation), therefore the question of illegal transaction does not arise.