WBC counts according to race/ethnicity and DARC −46C/C genotype. (A) Box-and-whisker plots depicting the distribution of the average of the total WBC counts during disease, in the major ethnic groups represented in the study population. AA indicates African American; EA indicates European American. OT indicates other ethnicities. Numbers at the top are P values obtained by Mann-Whiney tests for the indicated comparisons. N indicates number of subjects. (B) The proportion of subjects with leukopenia (initial WBC count < 4000 cells/mm³) in the indicated racial/ethnic groups. Vertically oriented numbers are significance values obtained by Pearson χ² test. (C) The proportion of AA (n = 397) possessing the indicated DARC T-46C genotype (122 subjects with T/C or T/T and 275 subjects with C/C) who were leukopenic at presentation. The significance value for the comparison was obtained using the Pearson χ² test. (D) The bar charts represent the mean (vertical bars) and 95% confidence intervals (error bars) for the average WBC counts during disease in the indicated racial/ethnic groups according to their DARC T-46C genotype. Numbers at the top are P values obtained by Mann-Whiney tests for the indicated comparisons. N indicates number of subjects. *Too few subjects (1 EA and 3 others), for whom the vertical bars are not shown.