Table 1.

Characteristics of patient groups and healthy controls

CharacteristicActive n=24Remission n=19Healthy Controls n=68P Valuea
Age58 (48,68)c58 (38,66)c34 (25,46)b<0.001
 Female11 (46%)13 (68%)41 (60%)
 White19 (79%)14 (74%)48 (71%)
 MPO8 (33%)12 (63%)
 PR316 (67%)7 (37%)
 GPA10 (42%)8 (42%)
 MPA8 (33%)10 (53%)
 Renal limited6 (25%)1 (5%)
Organ involvementN/A
 Upper respiratory12 (50%)14 (74%)0.13
 Pulmonary14 (58%)11 (58%)>0.99
 Renal15 (94%)14 (93%)>0.99
Peak serum creatinine at disease onset (mg/dl)3 (1,5)3 (1,5)N/A0.97
BVAS12 (7,16)0 (0,0)N/A<0.001
%CD5+ B cells17 (11,28)b26 (21,36)c28 (21,35)c0.003
ANCA titer (U/ml)d43 (98)19 (67)N/A0.36
MPO-ANCA titer (U/ml)50 (19,71)19 (8,37)N/A0.11
PR3-ANCA titer (U/ml)102 (50,162)117 (76,121)N/A0.94
  • Data are summarized as n (%) or median with interquartile range. B cell data are reported as a percentage of CD19+ B cells. MPO, myeloperoxidase; PR3, proteinase 3; GPA, granulomatosis with polyangiitis; MPA, microscopic polyangiitis; BVAS, Birmingham Vasculitis Activity Score.

  • a P values were calculated by Kruskal-Wallis test for comparison in three groups and Wilcoxon two-sample test for two groups.

  • b,c Different superscript letters indicate a statistically significant difference between groups after a Bonferroni correction (P < 0.02).

  • d ANCA titer indicates the MPO-ANCA titer for MPO-ANCA patients or the PR3-ANCA titer for PR-3 patients combined together as a group for all patients in either remission or active disease. ANCA titers were determined by the McLendon Clinical Laboratories at the University of North Carolina using ELISA kits specific for either MPO or PR3 (Inova Diagnostics, San Diego, CA). Negative titers are ≤ 20 U/ml.