KEEP praying for Joshua.

That's the message from the Hartley family as eldest son Josh goes back into hospital after his post-transplant recovery took a turn for the worse.

The 12-year-old Romsey schoolboy was taken into Southampton General Hospital after developing signs that his body was rejecting the vital bone marrow transplant.

He's been in the city hospital since last Thursday - and today the brave Romsey School pupil will undergo a minor operation as doctors try to discover the cause of his illness.

In June, Joshua received a bone marrow transplant at London's Great Ormond Street Hospital from mum Allison.

It was the only cure for one of the world's rarest genetic disorders which Josh and his three brothers were all diagnosed with at the end of last year.

But last week, Josh who was recovering at home, developed high temperatures, a rash and swelling in his hands.

They were all signs that his body was starting to reject the transplant.

He was taken to Southampton General, where doctors said he was suffering from a combination of mild Graft versus Host Disease and a stomach bug.

Today, surgeons will take a biopsy from his bowels to try to understand more about the problem.

But dad David said the family remained positive.

"Joshua is OK but very tired, his nights are quite disturbed. It's a real shame as it seemed to us that he had turned a corner, with only occasional sickness and great weight gain.

"But we see these as setbacks only. It's a long walk we're facing."

He added: "It's a real battle in the Hartley household at the moment. Please pray that we will see an end to this and that he can get back on with his recovery."

Eight-year-old Daniel is due to go for his life-saving transplant at the end of October.

Luke, four, and Nathan, ten, who also suffer from X-linked Lymphoproliferative disease (XLP), discovered earlier this summer that a donor had been found for them, too.

The pair are due to travel to Great Ormond Street for their transplants next year.