Gene knockout results in increasing mouse spleen weight and reducing % eosinophi - (May/19/2014 )

Dear experts in immunology,

Recently our lab generated a gene knockout mouse. The KO animals are fertile and look completely normal except that they have heavier spleens and lower % eosinophils, which, we hope, are phenotypes. However, eosinophil #/uL in KO animal blood is not significantly different from that in wild type control mouse blood. 

In case that a gene KO causes the spleen heavier or reduce % eosinophils, what test/experiments can I try? Since I and my lab have very limited knowledge on immunology, I need some help from immunology experts.

Thanks in advance.

Cancerous

Well you know what gene you knockouted.. there must have been some hypothesis, what does this gene does. If it's a signal pathway gene, in which processes and in which tissues it is involved..