Tracy Kleef, with her son Nathan.

Reliant on the blood of strangers ... Tracy Kleef with her son Nathan.

Nathan was a great baby. He always slept and ate well; we had no problems at all for the first year. But it wasn't long after the 12-month mark that he started getting odd illnesses. First, he had a simple scratch that turned into an abscess that had a staph infection, then there was a bad ear infection. No matter what oral antibiotics we put him on, he couldn't recover. Then he started getting little mouth ulcers and he wasn't eating much. Then he stopped breastfeeding for 24 hours and I had to take him to emergency.

I wasn't too worried at first, but when all the heads of departments started checking him for cancers and things like that I got scared. Eventually, they told me he had X-linked hyper-IgM syndrome, which is a primary immune disorder that affects one in 500,000 male children. They gave me an article about it that was mostly positive, but at the end it said for those with his particular primary immune deficiency, 75 percent died before they were 25 due to lung infections. Luckily I read it after I'd put Nathan to bed, because I just broke down. I was sitting on the floor of the bathroom in tears, trying to keep quiet. Mitchell, our other son who's now four, had already been diagnosed with autism. So finding out that life wasn't going to be easy for either of them was really the low point.

My husband, Andrew, was the strong one, even though, like me, he was shocked and confused. I remember him saying, "That article is 10 years old; antibiotics have improved and the quality of treatments is better."

Nathan's disorder means his little body is incapable of making the antibodies it needs to fight off bacterial infections, of which there are millions. From what I've read of other patients, you're dealing with it most of your days, so for Nathan it's a life of needles, of taking antibiotics every day, of being very careful and of staying away from places that are full of bacteria, like pools or waiting rooms in doctors' surgeries.

At first, Andrew and I walked in fear. We were scared about taking him into groups of children, and we wanted to stay in the house so we wouldn't be around bacteria. But that was when we didn't know about the treatment he now gets - an intravenous immunoglobulin (IVIg) called Intragam, which is a blood plasma product that wards off a lot of infections - and how well he would respond.

We've been one of the lucky ones because he's flourishing from the treatment. He's now two years old, happy, growing properly and back to eating, sleeping and walking. Obviously, we have to be cautious because he's still prone to bad chest infections and infections that cause liver damage and lung damage, but while he's healthy we try to get him to lead as much of a normal life as possible. Also, Nathan qualifies for a bone marrow transplant that can possibly cure him, and Mitchell is a match, so we'll most likely be looking down that path in the future.

I administer his treatment myself at home. Basically, I need to stick a needle into his stomach fat for three hours, once a week. He sleeps for an hour and a half of that, but it's still awful having to do it. I get very anxious beforehand, but it has to be done.

With Mitchell, whenever there's a change in his environment he gets very anxious. So when Nathan's in hospital and I'm not around, he doesn't react well. But thankfully I have a great set of grandparents on both sides and a fantastic sister, and they help out with babysitting. Without the support of our families, it would be almost impossible.

We're looking to start Nathan off one day a week at daycare, if we can get him through winter healthy. He's a very social kid; I'll take him to pick up Mitchell at day care and he'll just take off to play with the kids, so we need to put him in circumstances where he can be around other kids as much as possible. We need to let him lead a normal life, otherwise what sort of life is it?

Sometimes I feel that life is unfair. Not every day; at the moment Nathan is extremely healthy and Mitchell is doing so well. But you still look at other people and think, "How come they've got it so easy?" You have a vision of your kids growing up, getting married, having kids and living full lives, but when these sorts of things happen you're not sure of the future, so there is grief involved in that adjustment. You just have to take each day as it comes, take Mitchell to his therapies and stick needles into Nathan when you have to. There's nothing else you can do.

It takes plasma from eight blood donors, or four plasma donors, to make 200 millilitres of Intragam. Nathan's only on 15 millilitres a week, so it takes three blood donors for his monthly treatment at his current weight, which will continue to rise as he gets older.

I worry about shortages in supply. All my family donate blood, and I get frustrated that one in three people need blood or plasma products or platelets in their lifetime, but only one in 30 donate. We thank donors every time we have an infusion, because Nathan wouldn't be here if it wasn't for them.

Call 13 14 95 to find out more about being a blood donor or go to donateblood.com.au.

This article first appeared in Sunday Life.