IL-2

a Simple Facts Sheet from The Network

For more information about clinical trials of treatments for HIV infection currently enrolling see the clinical trials page Drugs for treating HIV.

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Interleukin-2, or IL-2, is a substance the body naturally makes that controls the growth and function of many types of cells. IL-2 helps the immune system produce cells whose job is to get rid of infected or cancerous cells. T4 cells need IL-2 to thrive. Without IL-2, activated T4 helper cells die.

Ten years ago, people with AIDS were given IL-2 in much higher doses than are being tested now. The results were disastrous. People became sick and died. Although most of the people with AIDS who took the drug were very sick in the first place, it appeared that the drug didn't help, and probably made things worse. Since that time, work on IL-2 has continued.

In previous studies of IL-2, a significant increase in T4 cells was seen for a short period and for as long as the drug was continued. The side effects were very toxic. Hopefully, the way the drug is now being tested will help avoid some of the side effects such as fevers, chills and an overall sick feeling. Scientists are fine tuning how IL-2 is given, including how much and when and for how long.

A recent study of IL-2 enrolled 60 people with T4 cells over 200. People were divided into two groups. The first group of 31 people received anti-HIV drugs (AZT, ddI, ddC or d4T, alone or in two-drug combinations) along with intravenous infusions of IL-2. The IL-2 infusions were given for five days every 2 months. The IL-2 dose was originally 18 million IU (International Units) a day, but by the end of the study most people were getting about 8 million IUs a day because of side effects.

People in the IL-2 group had an average of 428 T4 cells when they started the study. After 12 months the average T4 cell count of this group had increased to 916. One person in this group dropped out before receiving any IL-2, five people dropped out of the study due to side effects, and one person died of AIDS related complications.

The second group of 29 people in this study received anti-HIV drugs (AZT, ddI, ddC or d4T, alone or in two-drug combinations), but no IL-2. This group started the study with an average T4 cell count of 406. After 12 months, the average T4 cell count had gone down to 349.

There has been concern that IL-2 may increase the level of HIV in the body. In this study the levels of virus, known as viral load, stayed about the same in both groups.

In terms of side effects, in the IL-2 group 90% of people experienced fatigue or feeling unwell, 20% experienced headache, diarrhea, and inflammation of the mouth. Other side effects in the IL-2 group included abdominal pain, fever and sinus congestion. One person experienced toxicity to the heart.

It has been reported that two people that were originally in the IL-2 group have died, as compared to five people who were originally in the group not receiving IL-2. However, at least two of these five people received IL-2 after the first year of the study was completed, so there can not be said to be an important difference in number of deaths between the two groups.

T4 cells are one way of measuring the health of the immune system. But it is not always known if increased numbers of T4 cells caused by a treatment may actually help someone stay healthy or live longer. Because of this fact, a longer, larger trial of IL-2 is planned to see if the treatment will actually improve health and extend life.

Some people have begun on their own to inject themselves with IL-2, which is available by prescription for people with cancer. This is very dangerous. We don't recommend it. We strongly encourage the supervision of a trained medical professional. Until more is known about IL-2, how to best use the drug and what it actually does to the immune system, we encourage people who are considering using the drug to carefully weigh all the benefits and risks.

For more information on currently enrolling studies of IL-2, call the Network at (800) 734-7104.

Possible side effects of IL-2 include fatigue, nausea, vomiting, fever, chills, headache, muscle aches, shortness of breath, low blood pressure and kidney and liver damage.

The Simple Facts Project is a program of The Network. If you need help finding out whether or not a specific drug or therapy is covered by private or public insurance, contact The Network at (800) 734-7104. This information does not intend to promote or endorse any specific treatment for any health related condition.