Figure 3: Assessment of HNA antigens in 1994 CDC and ICC CFS/ME patients. Expression of human neutrophil antigens HNA1, HNA2, HNA4 and HNA5 were examined in all participants following staining of whole blood samples with monoclonal antibodies specific for neutrophils. Data represents means ± SEM. * represents level of significance where P-values are less than 0.05 and the lines indicate significance between groups.