Table 2

Associations of ancestry and ACKR1 genotype (rs2814778) with haemoglobin, white cell and platelet counts in patients with SLE

Haematological parametersAll patients with SLE (n=764)AA patients with SLE (n=190)
EA n=574AA n=190P value*ACKR1-CT/TT n=57ACKR1-CC n=133P value†
Median haemoglobin (g/dL)12.9 (11.8–13.7)11.5 (10.4–12.5)2.2E-1611.8 (10.5–12.6)11.4 (10.4–12.5)0.53
Lowest haemoglobin (g/dL)11.2 (9.0–12.6)9.3 (7.6–11.1)6.6E-139.1 (7.5–11.1)9.5 (7.7–11.1)0.78
Ever anaemia (%)380 (66.2)168 (88.4)3.7E-950 (87.7)118 (88.7)0.84
Median white cell counts (103/mm3)6.7 (5.4–8.2)5.9 (4.7–7.1)2.1E-66.8 (5.6–8.4)5.5 (4.4–6.7)1.1E-4
Lowest white cell counts (103/mm3)4.6 (3.4–5.9)3.5 (2.5–5.0)1.1E-94.3 (3.3–6.0)3.1 (2.3–4.4)5.0E-4
Ever leucopenia (%)211 (36.8)114 (60.0)1.9E-824 (42.1)90 (67.7)9.8E-4
Median neutrophil counts (103/mm3)‡4.4 (3.3–5.6)3.7 (2.6–4.9)3.3E-64.3 (3.8–4.8)3.2 (2.4–4.4)2.2E-5
Lowest neutrophil counts (103/mm3)‡2.8 (2.0–3.2)2.0 (1.2–2.4)2.5E-92.7 (1.9–3.8)1.8 (1.1–2.7)2.9E-4
Ever neutropenia (%)‡58 (11.6)61 (34.7)6.4E-128 (15.1)53 (43.1)3.4E-8
Median platelet count (103/mm3)245 (201–291)250 (202–314)0.13257 (202–307)247 (202–315)0.88
Lowest platelet count (103/mm3)187 (138–236)178 (114–233)0.26170 (115–249)181 (114–227)0.74
Ever thrombocytopenic (%)76 (13.2)42 (22.2)0.00412 (21.1)30 (22.6)0.82
  • Data shown as median (IQR) or number (per cent).

  • Leucopenia defined as a white cell count <4000/mm3; neutropenia as neutrophil count <1500/mm3; thrombocytopenia as platelet count <100 000/mm3; and anaemia as haemoglobin <12 g/dL in females and Hb <13.5 g/dL in males.

  • *P value for EA versus AA.

  • †P value for CC versus CT/TT genotype in AA patients with SLE.

  • ‡Neutrophil counts were not available in 77 patients of EA and in 14 of AA (10 with ACKR1-CC).

  • AA, African ancestry; EA, European ancestry.