In a C57BL/6 knockin (KI) mouse model of the 5' region of the haplotype I FcγRIIb gene (FcγRIIbNZB), FcγRIIb failed to be upregulated on activated and GC B cells resulting in enhanced early GC responses and low auto-Ab production without kidney disease as discussed later in more detail (11). Here, FCGR2B is linked to kidney disorder.