Duffy (Fy), DARC, and neutropenia among women from the United States, Europe and the Caribbean.

Neutropenia associated with race/ethnicity has essentially been unexplained and, although thought to be benign, may affect therapy for cancer or other illnesses. A recent study linked a single nucleotide polymorphism (SNP) (rs2814778) in the Duffy antigen/receptor chemokine gene (DARC) with white blood cell count. We therefore analysed the association of the rs2814778 CC, TC and TT genotypes with absolute neutrophil count (ANC) among asymptomatic women from the Caribbean, Europe and the United States. Among 261 study participants, 33/47 women from Barbados/Trinidad-Tobago, 34/49 from Haiti, 26/37 from Jamaica, and 29/38 US-born black women, but only 4/50 from the Dominican Republic and 0/40 US- or European-born whites (P = 0.0001) had the CC genotype. In a linear regression model that included percentage African ancestry, national origin, cytokines, socio-economic factors and the ELA2 rs57834246 SNP, only the DARC rs2814778 genotype and C-reactive protein were associated with ANC (P < 0.0001). Women with the CC genotype had lower ANC than other women. Further research is needed on the associations of rs2814778 genotype with neutropenia and treatment delay in the setting of cancer. A better understanding of these associations may help to improve cancer outcomes among individuals of African ancestry.

Neutropenia in 6 ethnic groups from the Caribbean and the U.S.

BACKGROUND: Low white blood cell counts (WBC) or absolute neutrophil counts (ANC) may delay or prevent the completion of appropriate chemotherapy, especially among women receiving adjuvant therapy for breast and colon cancer, and affect cancer survival. Because race/ethnicity is also associated with survival, the authors compared WBC and ANC in healthy American-born women of African descent and European descent, and women from Barbados/Trinidad-Tobago, the Dominican Republic, Haiti, and Jamaica. METHODS: Blood samples from 261 healthy women ages 20 to 70 years were tested for WBC with differential, cytokine and growth factor levels, and ancestry informative and neutrophil elastase polymorphisms. The authors analyzed the association between neutropenia and serum WBC growth factor levels, cytokine levels, and neutrophil elastase c199a polymorphism. RESULTS: The median WBC and ANC differed among the 6 groups (P < .01 for WBC and P < .0001 for ANC). Dominicans were found to have higher median WBC and ANC than all other groups (P < .03). Neutropenia (ANC < 1500 cu/mm) was observed among 2.7% to 12.5% of the groups of predominantly African descent; no other groups were found to have neutropenia (P < .05). Granulocyte-colony-stimulating factor was found to be lower in white women, but tumor necrosis factor-alpha and C-reactive protein were not found to be correlated with ethnicity. Women of African origin were more likely to have polymorphisms of African ancestry (P < .001) and c199a alleles (P < .0001), which were also associated with low ANC levels. CONCLUSIONS: In the current study, the authors observed a strong association between neutropenia and African descent among asymptomatic women from the U.S. and the Caribbean. Among women of African descent who develop a malignancy, this association may contribute to racial disparities in treatment and outcomes.

Neutropenia in 6 ethnic groups from the Caribbean and the U.S.

BACKGROUND: Low white blood cell counts (WBC) or absolute neutrophil counts (ANC) may delay or prevent the completion of appropriate chemotherapy, especially among women receiving adjuvant therapy for breast and colon cancer, and affect cancer survival. Because race/ethnicity is also associated with survival, the authors compared WBC and ANC in healthy American-born women of African descent and European descent, and women from Barbados/Trinidad-Tobago, the Dominican Republic, Haiti, and Jamaica. METHODS: Blood samples from 261 healthy women ages 20 to 70 years were tested for WBC with differential, cytokine and growth factor levels, and ancestry informative and neutrophil elastase polymorphisms. The authors analyzed the association between neutropenia and serum WBC growth factor levels, cytokine levels, and neutrophil elastase c199a polymorphism. RESULTS: The median WBC and ANC differed among the 6 groups (P < .01 for WBC and P < .0001 for ANC). Dominicans were found to have higher median WBC and ANC than all other groups (P < .03). Neutropenia (ANC < 1500 cu/mm) was observed among 2.7% to 12.5% of the groups of predominantly African descent; no other groups were found to have neutropenia (P < .05). Granulocyte-colony-stimulating factor was found to be lower in white women, but tumor necrosis factor-alpha and C-reactive protein were not found to be correlated with ethnicity. Women of African origin were more likely to have polymorphisms of African ancestry (P < .001) and c199a alleles (P < .0001), which were also associated with low ANC levels. CONCLUSIONS: In the current study, the authors observed a strong association between neutropenia and African descent among asymptomatic women from the U.S. and the Caribbean. Among women of African descent who develop a malignancy, this association may contribute to racial disparities in treatment and outcomes.