A woman, whose ovaries had failed due to damage caused by chemotherapy and radiotherapy, has received a successful ovarian transplant from her genetically non-identical sister.
The transplant restored her ovarian function, she started to menstruate and, after a year, doctors were able to recover two mature oocytes from her ovaries and fertilise them to produce two embryos.
This first case of a successful transplantation of ovarian tissue between two non-identical sisters is reported in the journal Human Reproduction today (Thursday 2 August). Professor Jacques Donnez, head of the department of gynaecology and professor and chairman at the Catholic University of Louvain in Brussels, Belgium, led the team that carried out the work.
In 1990, when she was 20, doctors treated Teresa Alvaro for beta-thalassemia, an inherited blood disorder characterised by reduced or absent haemoglobin, which is the oxygen-carrying protein in red blood cells. She received chemotherapy and radiotherapy before having a bone marrow transplant from her 17-year-old sister, Sandra Alvaro, who had an identically matched tissue type (human leukocyte antigen (HLA) type), which meant that Teresa's immune system would not recognise her sister's bone marrow as foreign and reject it.
The treatment was successful and Teresa was cured. However, in 1990 there were no procedures available for preserving her fertility before commencement of the treatment by, for instance, removing and freezing her eggs or ovarian tissue. The treatment caused complete ovarian failure, and her ovaries never recovered.
In July 2005, now aged 35, Teresa consulted Prof Donnez and his colleagues about the possibility of ovarian tissue transplantation from her sister to give her a chance of becoming pregnant.
Prof Donnez said: "Having already provided bone marrow in 1990, her sister, who was now aged 32 and had never become pregnant, badly wanted to help her sister by donating some of her own ovarian tissue.
"Although the option of oocyte donation from the sister to the patient was discussed, the patient refused this option. She preferred a transplant because she wanted to be responsible for the follicular maturation and considered that it was more natural than egg donation, for which her sister would have to undergo ovarian stimulation with follicle stimulating hormones and then oocyte retrieval. In addition, her sister had asked expressly to be the tissue donor and had refused to undergo ovarian stimulation for oocyte donation."
Analysis of the sisters HLA type showed that their genetically different cells coexisted successfully together (chimaerism) and that, therefore, no immuno-suppressive treatment would be required to prevent the ovarian graft being rejected. The earlier bone marrow transplant and resulting mixing of the sisters cells meant that Teresa's immune system would recognise Sandra's ovarian tissue as 'self' rather than foreign.
In February 2006, Teresa and Sandra were anaesthetised together and three small sections of ovarian tissue were removed from Sandra via laparoscopy and within less than a minute were being sewn on to one of Teresa's atrophied ovaries, also via laparoscopy. The sisters were discharged from hospital the day after surgery.