TreatmentUpdate 68, Volume 8, No 4; May-June 1996
Sean Hosein

The immune system makes at least 3 types of interferon:

* interferon-alpha

* interferon-beta

* interferon-gamma

Interferon-alpha is made up of a mixture of sub-types such as:

* interferon-alpha2

* interferon-alpha1

When attacked by a virus, the immune system makes natural interferon-alpha which is a mix of perhaps 20 sub-types. Examples of products containing a mix of these sub-types of interferon-alpha include:

* Alferon N(R) (interferon-alpha n3)--Interferon Sciences

* Wellferon(R) (interferon-alpha n1)--Glaxo Wellcome

Since natural interferon-alpha contains a mixture of sub-types, some researchers think that it may be better tolerated and possibly more effective than products containing just one sub-type.

Symptom-free HIV infection

Researchers in the USA conducted a study using 20 HIV-infected subjects who had an average of 566 CD4+ cells. The purpose of their study was to test the safety of a new natural interferon-alpha product called Alferonr (interferon-alpha n3). Subjects were told to inject various doses of this form of interferon-alpha three times weekly over a period of up to 5 months. The drug was well tolerated. Only one subject reported symptoms of a flu-like syndrome--tiredness, bone, joint and muscle pain. Those subjects taking 44 million units/week had production of HIV decrease to approximately 1/100 of their pre-study values. CD4+ cell counts remained stable for a period of 22 months following the study even though subjects received interferon-alpha for only 5 months.

The anti-HIV effect of Alferonr is encouraging. However, until clinical trials are conducted, researchers cannot be certain that this form of interferon is beneficial to subjects with HIV infection. Technicians could not detect anti-interferon-alpha n3 antibodies in the blood samples from subjects. When people are treated with interferon-alpha products such as interferon-alpha2a, or interferon-alpha2b, they can develop antibodies that attack those forms of interferon and weaken its effect.

Research on hepatitis C

In at least one study comparing the effect of natural interferon-alpha (Wellferonr) against highly purified sub-types such as interferon-alpha2a , doctors did not find any significant benefit from one form over the other.

REFERENCES:

1. Cellular and molecular immunology. Abul K Abbas, Andrew H Lichtman and Jordon S Pober. 2nd edition. WB Saunders Company c 1994 . Printed in USA. Philadelphia, Penn.

2. Antonelli G, Currenti M, Turriziani O, and Dianzani F. Neutralizing antibodies to interferon-alpha: relative frequency in patients treated with different interferon preparations. Journal of Infectious Diseases 1991;163:882-885.

3. Skillman Dr, Malone JL, Decker CF, et al. Phase I trial of interferon-alpha-n3 in early stage Human Immunodeficiency virus type 1 disease: evidence for drug safety, tolerance, and antiviral activity. Journal of Infectious Diseases 1996;173:1104-1107.

4. Rumi MG, Romero R, Paravicini ML, et al. Randomized comparative study of recombinant alpha and lymphoblastoid interferon in patients with chronic active hepatitis C. Journal of Hepatology 1994;18:527-530.

5. Swindells S, Baldwin T, Kelly C, et al. Regulation and characterization of the interferon-alpha present in patients with advanced Human Immunodeficiency Virus type 1 disease. Journal of Interferon and Cytokine Research 1996;16:127-137.

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