Do you catch every bug going? A top-up of fresh blood could be the answer

Margaret Bennett has always seemed to pick up more than her fair share of infections, but had always assumed it was due to her job teaching young children.

'I loved my job, but five-year-olds are not known for their attention to hygiene and would sometimes sneeze all over you,' says Margaret, now 61, from Birmingham.

For years, Margaret suffered constant bouts of throat infections, sinusitis, chest infections and conjunctivitis. She would often have half a dozen courses of antibiotics a year - though she noticed none of her colleagues seemed to be affected.

Always ill: After many years of ill heath, Margaret Bennett, 61, was diagnosed with Common Variable Immune Deficiency (CVID)


But it wasn't just that Margaret got everything going: even vaccinations didn't seem to work.

At the age of 28, Margaret was pregnant with her first child and teaching in a school where there was an outbreak of German measles. 'The headteacher was concerned about whether it was safe for me to be in school,' Margaret recalls, 'because the disease can cause serious damage to a baby.

'But I knew I'd had a vaccination fairly recently because all Birmingham teachers were given a booster, so I felt confident to carry on teaching.'

Then, 30 weeks into her pregnancy, Margaret was given alarming news. A routine blood test showed she had none of the antibodies known to protect against German measles. It seemed her vaccination hadn't worked.

'It was very frightening to think that if I had caught German measles, my daughter could have been born blind or deaf.'

Happily, her baby was fine - but Margaret was none the wiser about why the vaccine hadn't worked.

In fact, her experience is far from unusual. Thousands of people suffer similar problems with their immune system and are 'locked in a cycle of repeated infections and trapped into a permanent state of poor health', according to Dr Aarnoud Huissoon, consultant immunologist at Heartlands Hospital, Birmingham.

While many people have episodes where their immune system seems sluggish and they get more than their fair share of infections, usually this lasts only for a matter of months. Improving diet and sleep patterns, and reducing stress levels, can all help restore a 'sluggish' but otherwise normal immune system.

However, some people, like Margaret, have a chronically poor immune system. She had so many bouts of tonsillitis that, unusually, she had her tonsils removed at the age of 40 - a fairly rare step in adults.

Bodies count: CVID is the body's inability to produce antibodies in response to an infection


'People kept saying to me: “As a teacher, you are just more exposed to infections” - but by this stage I was querying the rationale because I could see my colleagues weren't affected in the same way.'

By the age of 51, Margaret made a simple comment during a consultation about an ear infection with her GP which sowed the seeds for a diagnosis at last.

'I said to my GP: “I just seem to have a really rubbish immune system.” He looked at me and said there was a test I should have.'

The GP ordered a test of Margaret's immunoglobulin levels.

Immunoglobulin is the term used to describe the total collection of antibodies each one of us has to fight infection. This can be measured by FISH tests (full blood count, immunoglobins, serum complement and HIV tests).

The test is measured as immunoglobulin per litre, with 'normal' ranging from six to 16 per litre. Margaret's result was four.

'I was pretty shocked because my GP called me on my mobile. He said he had never seen anything like it and described my immune system as “barely functioning”.'


'It explained everything,' says Margaret. 'I realised I must have had this for more than 30 years.'

He told Margaret she might have a disorder called Common Variable Immune Deficiency (CVID). This meant her body was not able to produce antibodies in response to an infection

It is the persistence of the infections which suggests possible CVID, rather than a temporary bout of bad health.

'I had never heard of it,' says Margaret, 'but there was also some relief because I knew that my GP had been talking to a haematologist and I was worried I might have leukaemia.'

Although children have been diagnosed with CVID (after long bouts of infections and failure to put on weight and thrive), most commonly it occurs at two peak ages - in the 20s, and 40s and 50s.

'It is normal for the immune system to have some times when it doesn't seem to be working as well as normal,' says Dr Huissoon. 'What we are concerned about is a pattern of severe, unusual, persistent and recurrent infections.'

Margaret's diagnosis was confirmed at Heartlands Hospital in Birmingham, two weeks after her immunoglobulin test.


Estimates put the number of people affected in the UK at 6,000, although the true figure could be even higher.

'Having CVID initially doesn't make you extremely unwell,' says Dr Huissoon. 'The infections you get are the typical problems which mean people are in and out of GP surgeries a lot.

'But over time it becomes more serious, because you are not producing the antibodies you need to stay healthy in the long term.

'There is a very serious cumulative effect. Many people with CVID end up with hearing loss due to repeated ear infections,  or scarred lungs following chest infections.'

People are frequently diagnosed with CVID only after being hospitalised with pneumonia. Some degree of eyesight loss is also common as a result of recurrent and increasingly severe eye infections.

'The tragedy is that if the signs had been picked up, these people could have been diagnosed earlier and this damage avoided,' says  Dr Huissoon.

Dr Huissoon carried out a study of 355 patients with CVID looking at the amount of time it took to reach a diagnosis. For a quarter of patients, it took more than seven years. The majority had been treated in chest clinics or ear, nose and throat services, but questions about immunity were not considered.

'When a person develops CVID, the impact tends to be gradual rather than dramatic,' explains Dr Huissoon. 'Also, GPs think immune system problems must be present from childhood, and therefore they don't consider an underlying immune system problem or offer the FISH test.'

He recommends the test be offered to any patient prescribed antibiotics more than five times in a single year.

The treatment for CVID is therapy to replace the immunoglobulin that the patient's body cannot produce. This involves having infusions every three weeks for the rest of the patient's life. Each infusion involves plasma from more than 1,000 donors.

'We need a large number of donors because this provides the best antibodies,' says Dr Huissoon.
The treatment needs to be repeated regularly because antibodies have a short life. Within three weeks, half will have died.

'It took about nine months for the therapy really to take effect,' says Margaret. 'But, once it did, it transformed my life. I can go 18 months now without falling ill. I've even been to Peru with my husband, which has been an ambition since I was 14. It was wonderful.'

For the avoidance of confusion, we are happy to make clear that CVID is treated with immunoglobulin G, which is a clear liquid, extracted from blood plasma.