Attempts at immune reconstitution have been made using
interleukin 2, interferons, thymic factors or bone marrow
transplantation.
These have not been notably successful and remain potentially harmful, since the very factors which activate T-cells will also activate HIV replication. In vivo, activation of CD4 cells is caused by stimulation with antigens in the form of micro-organisms or vaccines.
This suggests that it is sensible to treat intercurrent infections promptly and provides a rationale for prophylactic chemotherapy for pneumocystis. In some studies, vaccination (for example with influenza vaccine) has been shown to be enough of an antigenic stimulus to increase HIV replication. The advent of highly activated antiretroviral therapy (HAART) has enabled the viral load to be enormously reduced, but the difficulty of maintaining this type of therapy over long periods has led to a search for strategies to complement drug treatment.
Two observations are pertinent, the first is that even after 2–3 years of HAART treatment, latent virus can still be detected and the second is that antiviral immune responses decline during treatment. It has therefore been suggested first that latent virus should be “flushed out” by activation of the immune system with anti-CD3 antibody or interleukin 2 while still continuing drug treatment. Secondly vaccination against HIV should be instituted to prevent recrudescence of low level infection. Both strategies are being actively investigated.
These have not been notably successful and remain potentially harmful, since the very factors which activate T-cells will also activate HIV replication. In vivo, activation of CD4 cells is caused by stimulation with antigens in the form of micro-organisms or vaccines.
This suggests that it is sensible to treat intercurrent infections promptly and provides a rationale for prophylactic chemotherapy for pneumocystis. In some studies, vaccination (for example with influenza vaccine) has been shown to be enough of an antigenic stimulus to increase HIV replication. The advent of highly activated antiretroviral therapy (HAART) has enabled the viral load to be enormously reduced, but the difficulty of maintaining this type of therapy over long periods has led to a search for strategies to complement drug treatment.
Two observations are pertinent, the first is that even after 2–3 years of HAART treatment, latent virus can still be detected and the second is that antiviral immune responses decline during treatment. It has therefore been suggested first that latent virus should be “flushed out” by activation of the immune system with anti-CD3 antibody or interleukin 2 while still continuing drug treatment. Secondly vaccination against HIV should be instituted to prevent recrudescence of low level infection. Both strategies are being actively investigated.
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