In the blood stage malaria caused by the rodent parasite, Plasmodium chabaudi, the spleen CD4+ T cell population expands quickly, secretes considerable amounts of interferon-γ (IFN-γ) and helps B cells to produce high quantities of polyclonal immunoglobulin (Ig) M and IgG2a [6], [7], [8]. This evidence concerns the gene CD4 and malaria.