FCGR2B and systemic lupus erythematosus: Interestingly, a polymorphism of FcγRIIb which changes the threonine at position 232 to an isoleucine (I232T) was found to be associated with SLE as positivity for the 232I allele was significantly decreased in SLE patients suggesting a significant association of the 232T/T genotype with SLE [64].