杏吧原创

A protein produced by the malaria parasite can trigger an aggressive and torturous form of cancer called Burkitt鈥檚 lymphoma, according to new research.

Although Burkitt鈥檚 lymphoma rarely strikes in rich countries such as the US, the disease accounts for the vast majority of malignancies suffered by children in equatorial Africa, outnumbering all other forms of tumours combined in many parts of the region.

The illness causes horrendous suffering. Immune cells turn cancerous and tumours develop in the lymph nodes, often making the tongue swell and cheeks bulge. One doctor described a youngster with the illness as resembling 鈥渁 gargoyle not a child鈥�.

The deformities make it increasingly difficult for patients to eat. Burkitt鈥檚 lymphoma proves fatal in parts of sub-Saharan Africa where access to necessary medication remains limited.

杏吧原创s believe that Epstein-Barr virus (EBV), which commonly causes mononucleosis 鈥� also known as glandular fever or 鈥渢he kissing disease鈥� 鈥� can cause this type of lymphoma. But the virus typically remains dormant, and thus relatively harmless, in the body after inserting itself into the carrier鈥檚 DNA.

Reactivated virus

Arnaud Ch锚ne at the Karolinska Institute in Stockholm, Sweden, and colleagues investigated a theory that a protein produced by the malaria parasite 鈥� called CIDR1 鈥� may reactivate EBV.

In a laboratory dish, Ch锚ne鈥檚 team exposed the immune cells of healthy African children, who tested positive for the Epstein-Barr virus, to CIDR1. In a separate laboratory dish they exposed the same cells to another parasite-related protein for comparison.

Within the span of three days the levels of EBV in the CIDR1-exposed cells was five times that in the control dish. Moreover, there were twice as many immune cells in the dish containing CIDR1.

This suggests that CIDR1 can reactivate the Epstein Barr virus, which in turn creates a massive overproduction of immune cells leading to lymphoma, the researchers say.

Access problems

The finding also hints at why adults in equatorial Africa do not develop Burkitt鈥檚 lymphoma anywhere near as frequently as children there. 鈥淚f you get malaria first [before the Epstein-Barr virus], then you acquire some immunity to malaria after that. So if you are exposed again the parasite cannot stimulate the overproduction of cells鈥� that leads to lymphoma, suggests Qijun Chen, who helped carry out the study.

Burkitt鈥檚 lymphoma can be treated with chemotherapy and antibody therapy. But many patients and their families face great difficulties in gaining access to appropriate care 鈥渟ince 99% of children with the tumour live in rural settings, often miles away from roads,鈥� paediatrician John Phillips explained in an essay published in late 2006 (Lancet, vol 368, p 2251).

Chen says that one way to reduce the number of cases of Burkitt鈥檚 lymphoma might be to intensify efforts to curb the malaria epidemic.

Journal reference: PLoS Pathogens (DOI: 10.1371/journal.ppat.0030080)