FCER2 and Menkes disease: Furthermore, MD patients had more circulating CD4+ cells (mean 44.22% ± 8.86) than controls (mean 39.49 ± 4.85; p < 0.05), increased CD4+/CD8+ cell ratio (MD 1.65 ± 0.71, controls 1.22 ± 0.24; p < 0.05), more circulating CD23+ cells (MD mean 10.09% ± 3.96, controls 6.82% ± 1.88; p < 0.05), and elevated blood concentrations of interleukin–4 (IL-4) (MD mean IL4 6.35 pg./mL ± 6.20, controls 2.67 pg./mL ± 0.65; p < 0.05).