Niehans discovered cell therapy in 1931 by chance, when he replaced a parathyroid gland damaged during an operation with parathyroid cells from a calf, instead of the then customary whole parathyroid implants. He later used the Kuettner approach on a female patient whose parathyroid gland had been erroneously removed by another doctor. As transplant was not possible Niehans injected live cells from the parathyroid of an embryonic ox as a temporary survival technique; this technique was not only well tolerated, but the patient recovered completely and lived for an additional 24 years. Niehans was influenced by the earlier work of Alexis Carrel, who had found that by adding healthy fresh cells to a dying cell colony, the moribund cells acquired new life.
In 1937, influenced by the work of the neurosurgeon Harvey Williams Cushing, Niehans first used cerebral cells, from the hypothalamus and the hypophysis. Beginning in 1948, he also used liver, pancreas, kidney, heart, duodenum, thymus, and spleen cells. In 1949, he began to use lyophilized (freeze-dried) cells, not only fresh ones. In 1953, Prof. Dr. Paul Niehans treated Pope Pius XII, who in gratitude appointed him member of the Papal Academy of Sciences. Due to this success, European physicians slowly began to accept Niehans' work with cell therapy. Cellular therapy was on the way to becoming an accepted regenerative technique in Europe, but not in the United States, where it is not legally available because of safety concerns and lack of proof of its effectiveness.
In 1954, Niehans' classic work, Die Zellulartherapie (Cellular Therapy) was published in German. Swiss publisher Thoune released the English version and update of Niehans' original work which also included papers by researchers from Germany.
Live cell therapy, pioneered in the ’30s by Swiss doctor Paul Niehans is an “organ-specific” approach, which involves harvesting fresh cells from cow or sheep embryo and injecting them directly (intramuscular) on the patient’s buttocks.