What other than cancer can cause a low white blood count and loss of weight
Low white blood count can be caused by infections and immune disorders such as Lupus or HIV or an infection of the immune system due to chemotherapy. It can also be caused by Leishmaniasis, which is due to a bite from an infected sand fly. Wilson's disease which is a genetic disorder can also cause the low count since it leads to liver malfunction. You can go to, http://www.livestrong.com/article/152636-what-are-the-causes-of-low-white-blood-cell-count-weight-loss/, to get more information on this.
Aids I think