A low CD4 cell count is associated with increased mortality risk, even if people are taking virologically effective HIV therapy, an international team of investigators report in the online edition ofClinical Infectious Diseases. People with incomplete CD4 count recovery – a count below 200 cells/mm3 – despite three years of treatment with virologic suppression had a more than two-fold increase in their mortality risk compared to people with more robust immune reconstitution.
“We identified older age, transmission via male heterosexual sex or IDU [injecting drug use], lower CD4 count at start of the suppressed period and longer time from initiation of cART [combination antiretroviral therapy] to start of the virally suppressed period as risk factors for incomplete CD4 cell recovery,” write the authors.
They believe their findings underline the importance of earlier HIV diagnosis and the prompt initiation of therapy. The investigators also urge that patients with incomplete CD4 count recovery should be closely monitored for certain diseases, including hepatitis and non-HIV-related cancers.
Modern antiretroviral therapy is very effective at suppressing viral load. This control of HIV replication allows the immune system to strengthen and CD4 count to increase. People with virologic and immunologic responses to HIV therapy now have a normal life expectancy.
However, it is well known that a significant proportion of people taking anti-HIV drugs do not have a robust increase in their CD4 count, even though treatment is controlling viral load. The clinical consequences of this discordant response to treatment are unclear.
Investigators from Europe and North America therefore designed a study to elucidate the factors associated with an incomplete CD4 response to HIV therapy in people with long-term virologic suppression. They also compared mortality rates according to CD4 count and analysed the relationship between incomplete immune recovery and specific causes of death.