A number of human proteins, including MIF (which stands for migration inhibitory factor), were long suspected to cause malarial anemia because they are known to reduce red blood cell counts as part of the body's normal response to such inflammatory conditions as rheumatoid arthritis or some cancers.
Using immature blood cell precursors grown in a dish, the research team showed that adding MIF to the cells decreases both the final number and maturity of red blood cells. The researchers believe this effect can lead to anemia.
When infected with plasmodium, mice genetically engineered to lack MIF experience less severe anemia and are more likely to survive. Without MIF around to prevent blood cells from maturing, the mice appear better able to maintain their oxygen carrying capacity and don't lose as much hemoglobin, the protein found in red blood cells responsible for binding to oxygen molecules.
"Demonstrating that MIF clearly contributes to severe anemia suggests new ideas for therapies that can block MIF in malaria patients," says the study's senior author, Richard Bucala, M.D., Ph.D., a professor of medicine at Yale University School of Medicine.
The research team also found different versions of "promoter" DNA sequences next to the MIF gene that control how much MIF protein a cell makes in response to infection. One version of the MIF promoter leads to less MIF protein made, while cells containing another version of the MIF promoter make much more MIF protein. Differences in the MIF promoter also have been linked to the severity of other inflammatory diseases.
The researchers continue to collaborate in an effort to develop drugs that might block MIF and treat severe
Source:Johns Hopkins Medical Institutions