9 May 2002
Measles Supresses HIV Replication
by Kate Melville
Replication of human immunodeficiency virus (HIV) is briefly suppressed during acute measles, according to researchers at the Johns Hopkins Bloomberg School of Public Health. A study of HIV-infected children living in Zambia found that HIV levels in the blood were significantly lower while having measles compared to HIV-infected children who did not have measles. The researchers say the only other illness previously reported to suppress HIV is O. tsutsugamushi, which causes scrub typhus. The study appears in the April 15, 2002 issue of The Journal of Infectious Diseases. "We were surprised by these findings, because we expected to see HIV replication increase, not decrease with measles," says the study's lead author William Moss, MD, MPH, assistant research professor of international health and molecular microbiology and immunology at the Johns Hopkins Bloomberg School of Public Health. "Measles is a very immunosuppressive virus. It results in many secondary infections and is a major cause of death among children. Our findings show that measles also triggers intense immune system activation that temporarily suppresses HIV," explains Dr. Moss.
For the study, Dr. Moss and his colleagues followed 93 children diagnosed with measles and HIV at the University Teaching Hospital in Lusaka, Zambia. The children's HIV levels were measured from blood samples taken when they were admitted to the hospital for measles treatment. More samples were taken when the children were discharged from the hospital, and again one month later. They were compared with samples taken from HIV-infected children who did not have measles or other illnesses and with samples from children with measles, but not HIV.
The study found that 33 of the children diagnosed with measles and HIV had a median HIV level of 5,339 copies per milliliter when they first entered the hospital for treatment. The HIV levels increased to 60,121 copies per milliliter when measured at the time of discharge and to 387,148 copies per milliliter one month later. HIV-infected children who did not have acute measles had a median HIV level of 228,454 copies per milliliter.
The researchers also noticed that the CD8 T-cell level, which is an indicator of immune system response, was elevated in the children with both measles and HIV compared to children in the control groups. The increase in the CD8 level occurred during the same time as the suppression of HIV levels.
"More research will be needed with a larger study group to fully understand how measles suppresses HIV and activates the immune system, but our findings may provide clues to understanding both HIV pathogenesis and immunity," says Diane Griffin, MD, PhD, professor and chair of the W. Harry Feinstone Department of Molecular Microbiology and Immunology at the Johns Hopkins Bloomberg School of Public Health.