Replication of human immunodeficiency virus is briefly suppressed during acute measles, according to researchers at the 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 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 lead author William Moss, an assistant research professor of international health and molecular microbiology and immunology. "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."

For the study, 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 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.

"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, chair of the Department of Molecular Microbiology and Immunology at the Bloomberg School.
--Tim Parsons