The impact of a very high-purity factor VIII concentrate on the immune system of HIV-infected haemophiliacs: a randomized, two-year comparison with a high-purity concentrate.

Randomized and cohort studies have provided evidence confirming the hypothesis, based on in-vitro observations, that the use of very high-purity factor VIII (FVIII) concentrates, either immuoaffinity chromatography purified or produced by recombinant DNA technology, may slow immunological deterioration in human immunodeficiency virus (HIV)-infected haemophiliacs, while high-purity concentrates, produced by ion-exchange chromatography, did not produce a benefit. Even though these data clearly indicate that very high-purity concentrates should be preferred for the replacement therapy of HIV-positive haemophiliacs, there are little data, based on direct comparison, supporting the use of very high-purity concentrates rather than high-purity preparations, which are less expensive. In an attempt to address this issue, we prospectively compared CD4 cell counts and changes of clinical status in 18 HIV-positive haemophiliacs, randomly assigned either to receive the treatment with a very high-purity FVIII concentrate, purified by immunoaffinity chromatography, or a high-purity product, produced by ion-exchange chromatography. All patients had CD4 lymphocyte counts below 300 μL(-1) , were negative for the hepatitis B surface antigen and the HIV p24 antigen, and were receiving antiretroviral treatment with Zidovudine for at least 6 months. There were no significant changes of CD4 cell counts over the 96-week follow-up period or between the two groups. No signficant differences between the two groups were detected in the occurrence of AIDS-defining diagnoses (one in each group). On the whole, no striking benefit is conferred to the immune status of asymptomatic HIV-positive haemophiliacs by using either of these high-purity and very high-purity FVIII concentrates for 96 weeks. Larger prospective randomized trials are needed to establish definitely whether it is necessary to resort to very high-purity concentrates or it is sufficient to use high-purity concentrates to slow the fall of CD4 cell counts that occurs in HIV-positive haemophiliacs. Randomized trials, based on clinical end-points, are also needed to demonstrate whether slowing the fall in CD4 cells results in clinical benefits, delaying the occurrence of AIDS.