Table 2

Comparison of patient groups after treatment with rituximab

CharacteristicGroup 1 (n=7)Group 2 (n=7)Group 3 (n=5)P Valuec
Repopulation with normal %CD5+ B cellsRepopulation with low % CD5+ B cells (≤30%), low remission maintenance medicationaRepopulation with low %CD5+ cells (≤30%), high remission maintenance medicationb
Age59 (32,61)52 (45,59)51 (38,58)0.93
Sex0.03
 Female1 (14%)6 (86%)2 (40%)
Race0.80
 White6 (86%)6 (86%)4 (80)
ANCA0.18
 MPO3 (43%)0 (0%)2 (40%)
 PR34 (57%)6 (86%)3 (60%)
 PR3 and MPO0 (0%)1 (14%)0 (0%)
Disease0.70
 GPA5 (71%)4 (57%)4 (80%)
 MPA1 (14%)3 (43%)1 (20%)
 ANCA GN (renal limited)1 (14%)0 (0%)0 (0%)
Organ involvement
 Upper Respiratory4 (57%)5 (72%)5 (100%)0.35
 Pulmonary5 (71%)7 (100%)3 (60%)0.25
 Renal5 (83%)4 (100)4 (80%)>0.99
Peak serum creatinine at disease onset (mg/dl)1.7 (1.0,2.9)2.5 (1.8,2.9)1.6 (1.2,1.8)0.28
%CD5+ B cells at time of B cell repopulation57 (48,70)d18 (11,31)e23 (13,53)d,e0.02
%CD5+ B cells at last sample available prior to flare34 (27,41)16 (15,18)4 (4,16)0.06
Dose of MMF for remission maintenance (g/day)1.00 (0,1.25)d,e0 (0,1.0)d2.0 (1.5,2.0)e0.007
Time to relapse from rituximab (months)31 (25,48)d17 (12,20)e29 (29,35)d0.002
Time to relapse from B cell repopulation (months)22 (17,36)d7 (3,11)e22 (20,27)d0.002
Total B cell number (x104/ml blood)5.7 (2.4,15.0)1.7 (1.0,3.2)3.9 (2.4,4.5)0.15
ANCA titer (U/ml)f39 (10,95)52 (5,71)8 (6,24)0.28
  • Values for variables examined in patient groups after rituximab therapy are reported as n (%) or median (interquartile range). MPO, myeloperoxidase; PR3, proteinase 3; GPA, granulomatosis with polyangiitis; MPA, microscopic polyangiitis; MMF, mycophenolate mofetil.

  • a One group 2 patient was on cyclosporine (50 mg twice daily) and prednisone (6 mg/day).

  • b One group 3 patient was on MMF (1 g twice daily) and prednisone (10 mg every other day) after rituximab therapy concurrent with seven monthly intravenous doses of cyclophosphamide.

  • c P values were calculated by Fisher exact test for categorical variables and Kruskal-Walls Test for continuous variables.

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

  • f 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 group 1, 2 or 3. 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.