The family of a Chester teenager battling cancer are praying for a miracle after the 18-year-old took a turn for the worse.

Despite her 10-year-old sister Maisy donating her bone marrow in the hope of saving her life, Jessica Versey, who was diagnosed with acute myeloid leukaemia in May this year, has damage to her vital organs following aggressive chemotherapy treatment.

The former Queen’s Park High School student, of Hatton Road, Blacon , remains in hospital where she is sleeping most of the time with her family at her bedside.

The sad news comes just weeks after Maisy successfully underwent rare surgery to transplant her stem cells to her sister, which the family prayed would save the teenager’s life.

But speaking on behalf of the Verseys, Kate Northcott, who runs the Pamela Northcott Fund which features a teenage cancer support service, asked everyone to keep Jessica in their prayers.

“Her family thought it was only right, and what Jess would want, to be honest and not sugar coat the situation to let people know that beautiful Jess is struggling right now,” she said. “As we hoped, heroic little sister Maisy’s stem cells were perfect and the stem cell transplant, although gruelling, went to plan.

“But sadly in the past week, it has become apparent the aggressive chemotherapy given prior to the transplant has seriously damaged Jess’ vital organs. The transplant team are doing all they can to keep Jess comfortable and pain free. She is sleeping most of the time and her family are with her.”

Kate added: “Jess’ parents would like to thank the staff at the Royal Liverpool University Hospital Transplant Unit and to all of the amazing well wishers. They ask that you keep precious Jess in your thoughts and prayers during this extremely difficult time.”

Last month Jessica told The Chronicle how grateful she was to her little sister, who had wanted to be her donor from ‘day one’.

Maisy was honoured as Young Person of the Year at the 2014 Trinity Mirror Scottish Power Your Champions Awards earlier this month.

Jessica said at the time: “She always used to say how exciting it would be to be able to help me and when we found out, I was in hospital so I rang Maisy and told her the news. I honestly wish I could have recorded it, as she squealed down the phone and kept shouting and screaming with excitement,” she said.

“Then she started crying and my dad had to take the phone off her; it was a very special moment. Once she settled down she sent me a beautiful text saying how happy she was to be a match and how much she loved me.

“She’s honestly the most amazing girl I’ve ever met; her understanding of the situation and how she takes it in her stride is amazing – I couldn’t be more proud.”