IF EVER there was a telling illustration of the power of the immune system, it came in 2006. Six men in a trial of an experimental drug made by the company TeGenero became critically ill after suffering a catastrophic over-stimulation of the immune system. The T-cells, the 鈥渕aster regulators鈥� of the body鈥檚 immune system, had turned against it.
Now it seems we may have a 鈥渟hadow鈥� immune system ruled by B cells, usually portrayed as foot soldiers that do the bidding of T-cells. Tinkering with this aspect of the immune system (page 6) could yield new ways of treating autoimmune diseases and cancer. But, exciting as this is, let鈥檚 not forget the TeGenero story. We must understand shadow immunity much better before we can even think of tweaking it in people.