Deregulated Fcγ receptor expression in patients with CIDP

OBJECTIVE To evaluate the expression of activating and inhibitory Fc-gamma receptors (FcγRs) before and during clinically effective therapy with IV immunoglobulin (IVIg) in patients with chronic inflammatory demyelinating polyneuropathy (CIDP). METHODS Peripheral blood leukocyte subsets, including classical CD14(high)CD16(-) and nonclassical inflammatory CD14(low)CD16(+) monocytes as well as naive CD19(+)CD27(-) and memory CD19(+)CD27(+) B cells, were obtained at baseline and monitored at 2 and 4-8 weeks after initiation of IVIg therapy. RESULTS Compared with healthy donors matched by age and sex, patients with CIDP showed increased expression levels of the activating high-affinity FcγR1 on CD14(high)CD16(-) (p < 0.001) and CD14(low)CD16(+) monocytes (p < 0.001). Expression of the activating low-affinity FcγRIIA was increased on CD14(low)CD16(+) monocytes (p = 0.023). Conversely, expression of the inhibitory FcγRIIB was reduced on naive (p = 0.009) and memory (p = 0.002) B cells as well as on CD14(high)CD16(-) monocytes (p = 0.046). Clinically effective IVIg therapy partially restored deregulated FcγR expression on B cell subsets and monocytes. CONCLUSIONS The FcγR regulatory system is disturbed in patients with CIDP. Balancing activating vs inhibitory FcγR expression might provide a clinical benefit for patients with CIDP.