Isita started the second cycle of immunotherapy on Thursday. As she sailed through the first cycle without major side-effects, we hoped that it might be even easier this time. But she immediately developed a persistent dry cough.

Somehow, the antibodies provoke a tightening of the airway. They are giving her regular doses of adrenaline through a nebuliser – a bit like treating asthma – and also piriton,which makes her sleepy. Each time the cough gets too much, they reduce the dosage of antibodies to one-eighth and slowly build it up again over a day, so that her body can gradually acclimatise to their effect. For the past three days she has had, on average, one quarter of the full dose. So she will certainly be in hospital for a fortnight or more, rather than just 10 days.

While we are keen to spend as much time as possible at home, this is far from the top priority. It is much more important that she completes this cycle and is fit to do the third, fourth and fifth as well.

Looking on the bright side, this cough is a fairly common side-effect and the specialist nurses have experience at dealing with it. Also, there is no sign of the more serious and distressing problem of neuropathic pain. We pray to avoid that entirely.

It is hardly surprising that this amazing medicine is having some unwanted effects on Isita’s body in addition to its incredible benefit. What she is being given is a drug called Dinutuximab. In scientific terms this is a “chimeric human-murine anti-GD2 monoclonal antibody”.

This needs some unpacking. The chimera (I just looked up on Wikipedia) is a portmanteau beast of ancient Greek myth – a lion, with a goat’s head sprouting from its middle and a snake’s head tail. Well, the magical monster we are injecting into Isita is half-human, half-mouse – not an obvious combination to inspire dread or wonder, but miraculous nevertheless. In the way that a regular antibody’s job is to gobble up a specific virus, this wee sleekit tim’rous cowrin’ beastie gobbles up neuroblastoma cells, identified as they are by a protein called GD2. I think monoclonal means that all the antibodies were cloned from a single parent cell.

Similar antibodies are now being used to save the lives of people with all kinds of cancer. We are fortunate that it is available for Isita as the gravest threat for her is that a new tumour should now appear. If this were to happen it would not come from the original tumour, which we hope is all but dead, but from neuroblastoma cells at large in her body that have survived chemotherapy and are therefore immune to it. Such a relapse would be very hard to treat. If any such devil cells exist, mouse-man is out to kill them.