Correspondence Financial Disclosure: The authors declare that they have no relevant financial interests.
LETTERS TO THE EDITOR Rituximab and B-Cell Return in ANCA-Associated Vasculitis To the Editor: New insights into the pathogenesis of autoimmune diseases have implications for therapy.1 One such new therapeutic approach is the use of B-cell–depleting therapy, as discussed by Kallenberg et al.1 In ANCA-associated vasculitis (AAV), rituximab has been found to be beneficial.2 However, in the RAVE (Rituximab in ANCA-Associated Vasculitis) trial, one-third of the patients (n 5 24) treated with rituximab experienced a relapse within the first 18 months of remission.2 The relapse was preceded by B-cell return in 21 of 24 patients. Importantly, B cells also returned in the two-thirds of patients treated with rituximab who did not experience a relapse.2 The question is: how do we identify patients at risk for relapse when B cells return? Rituximab depletes B cells, including proinflammatory IL-61/TNF-a1 B cells (Bpro) and anti-inflammatory IL-101 regulatory B cells (Bregs). B cells usually repopulate after 9-18 months.2-4 Bregs control proinflammatory T cells and are diminished in AAV.3,5 Our own preliminary data indicate that frequent relapsers have an imbalance of proinflammatory T cells versus Bregs when compared with nonrelapsers (Table 1). Cohort studies indicate that B-cell repopulation after depletion resets the balance of pro-/antiinflammatory B and T cells, thus restoring immune tolerance.3,6,7 In patients with AAV who relapse after rituximab, Bpros may be the dominant repopulated B-cell population, with a relative deficit of Bregs. Because the return of B cells itself does not predict relapse, analyzing the cytokine profile of the returning B cells may be useful to determine B-cell subsets. In addition, understanding the molecular mechanisms controlling the secretion of cytokines by B cells may help find novel drug targets for autoimmune diseases. Benjamin Wilde, MD,1,2 Oliver Witzke, MD2 Jan Willem Cohen Tervaert, MD, PhD1 1 University Hospital Maastricht Maastricht, the Netherlands 2 University Duisburg-Essen, University Hospital Essen Essen, Germany
Acknowledgements This work was funded by a grant of the Deutsche Forschungsgemeinschaft (DFG), Wi-3723/1-1 awarded to Dr Wilde. Table 1. Immunologic Profile of Untreated PR3-ANCA–Positive Patients in Remission Stratified by Disease Course TH17:Breg TH17:Treg TH17:TH10 Ratio Ratio Ratio
TH1:TH2 Ratio
Relapsers (n 5 4) 0$5 6 0.08 Nonrelapsers (n 5 5) 0$2 6 0.06
0$6 6 0.20 0$2 6 0.07
7$0 6 1.57 2$5 6 0.37 3$3 6 0.71 3$3 6 0.80
P
0.1
0.03
0.06
0.6
Note: Data are expressed as mean 6 SEM. All patients had disease duration of at least 4 years; patients were untreated at time of sampling. Abbreviations and definitions: Breg, regulatory B cells; nonrelapsers, patients in stable long-term remission who never had a relapse; NS, not significant; PR3-ANCA, proteinase 3–antineutrophil cytoplasmic antibody; relapsers, patients with at least 1 disease flare within 4 years of diagnosis; Treg, regulatory helper T cells; TH1, IFN-g1 helper T cells; TH2, IL-41 helper T cells; TH10, IL-101 helper T cells, TH17, IL-17A1 helper T cells.
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References 1. Kallenberg CG, Stegeman CA, Abdulahad WH, Heeringa P. Pathogenesis of ANCA-associated vasculitis: new possibilities for intervention. Am J Kidney Dis. 2013;62(6):1176-1187. 2. Specks U, Merkel PA, Seo P, et al. Efficacy of remissioninduction regimens for ANCA-associated vasculitis. N Engl J Med. 2013;369(5):417-427. 3. Lund FE, Randall TD. Effector and regulatory B cells: modulators of CD41 T cell immunity. Nat Rev Immunol. 2013;10(4):236-247. 4. Leandro MJ, Cambridge G, Ehrenstein MR, Edwards JCW. Reconstitution of peripheral blood B cells after depletion with rituximab in patients with rheumatoid arthritis. Arthritis Rheum. 2006;54(2):613-620. 5. Wilde B, Thewissen M, Damoiseaux J, et al. Regulatory B cells in ANCA-associated vasculitis. Ann Rheum Dis. 2013;72(8): 1416-1419. 6. Barr TA, Shen P, Brown S, et al. B cell depletion therapy ameliorates autoimmune disease through ablation of IL-6–producing B cells. J Exp Med. 2012;(5):1001-1010. 7. Sun F, Ladha SS, Yang L, et al. Interleukin-10 producing B cells and their association with responsiveness to rituximab in myasthenia gravis. Muscle Nerve. 2014;49(4):487-494. Ó 2014 by the National Kidney Foundation, Inc. http://dx.doi.org/10.1053/j.ajkd.2013.11.029
In Reply to ‘Rituximab and B-Cell Return in ANCAAssociated Vasculitis’ We appreciate the constructive comments of Wilde et al1 on our review.2 In their letter, the authors propose that analyzing the cytokine profile of regulatory (IL-101) and effector (IL-61/TNFa1) B cells that return after rituximab treatment is a useful method to predict disease relapse. Although we support this type of analysis in general, we also acknowledge that this approach has certain limitations. As is well known, the cytokine profile of B cells is identified indirectly following ex vivo exposure to oligonucleotides containing the immunostimulatory CpG motif for 66 hours, with restimulation by phorbol 12-myristate 13-acetate/ ionomycin for another 4 hours. Wilde et al3 analyzed regulatory B cells in ANCA-associated vasculitis (AAV) in this way. However, this type of analysis requires a large amount of B cells, which is not available in most cases following B-cell depletion caused by rituximab. In addition, ex vivo stimulation may change the normal distribution of B-cell subsets, which may lead to a flawed conclusion. In this regard, Bunch et al4 recently have noted that declining percentages of CD51 B cells after rituximab treatment were associated with a shorter time to disease relapse in patients with AAV. These CD51 B cells were noted to be IL-10–producing regulatory cells.5,6 The practical approach of determining CD51 B cells following rituximab treatment seems to be more efficient than ex vivo culturing of B cells followed by intracellular cytokine detection because CD5 is a surface marker and no stimulation is required for quantifying these B-cell subsets. Therefore, determination of the percentage of CD51 B cells following rituximab
Am J Kidney Dis. 2014;63(6):1066-1075
LETTERS TO THE EDITOR Rituximab and B-Cell Return in ANCA-Associated Vasculitis To the Editor: New insights into the pathogenesis of autoimmune diseases have implications for therapy.1 One such new therapeutic approach is the use of B-cell–depleting therapy, as discussed by Kallenberg et al.1 In ANCA-associated vasculitis (AAV), rituximab has been found to be beneficial.2 However, in the RAVE (Rituximab in ANCA-Associated Vasculitis) trial, one-third of the patients (n 5 24) treated with rituximab experienced a relapse within the first 18 months of remission.2 The relapse was preceded by B-cell return in 21 of 24 patients. Importantly, B cells also returned in the two-thirds of patients treated with rituximab who did not experience a relapse.2 The question is: how do we identify patients at risk for relapse when B cells return? Rituximab depletes B cells, including proinflammatory IL-61/TNF-a1 B cells (Bpro) and anti-inflammatory IL-101 regulatory B cells (Bregs). B cells usually repopulate after 9-18 months.2-4 Bregs control proinflammatory T cells and are diminished in AAV.3,5 Our own preliminary data indicate that frequent relapsers have an imbalance of proinflammatory T cells versus Bregs when compared with nonrelapsers (Table 1). Cohort studies indicate that B-cell repopulation after depletion resets the balance of pro-/antiinflammatory B and T cells, thus restoring immune tolerance.3,6,7 In patients with AAV who relapse after rituximab, Bpros may be the dominant repopulated B-cell population, with a relative deficit of Bregs. Because the return of B cells itself does not predict relapse, analyzing the cytokine profile of the returning B cells may be useful to determine B-cell subsets. In addition, understanding the molecular mechanisms controlling the secretion of cytokines by B cells may help find novel drug targets for autoimmune diseases. Benjamin Wilde, MD,1,2 Oliver Witzke, MD2 Jan Willem Cohen Tervaert, MD, PhD1 1 University Hospital Maastricht Maastricht, the Netherlands 2 University Duisburg-Essen, University Hospital Essen Essen, Germany
Acknowledgements This work was funded by a grant of the Deutsche Forschungsgemeinschaft (DFG), Wi-3723/1-1 awarded to Dr Wilde. Table 1. Immunologic Profile of Untreated PR3-ANCA–Positive Patients in Remission Stratified by Disease Course TH17:Breg TH17:Treg TH17:TH10 Ratio Ratio Ratio
TH1:TH2 Ratio
Relapsers (n 5 4) 0$5 6 0.08 Nonrelapsers (n 5 5) 0$2 6 0.06
0$6 6 0.20 0$2 6 0.07
7$0 6 1.57 2$5 6 0.37 3$3 6 0.71 3$3 6 0.80
P
0.1
0.03
0.06
0.6
Note: Data are expressed as mean 6 SEM. All patients had disease duration of at least 4 years; patients were untreated at time of sampling. Abbreviations and definitions: Breg, regulatory B cells; nonrelapsers, patients in stable long-term remission who never had a relapse; NS, not significant; PR3-ANCA, proteinase 3–antineutrophil cytoplasmic antibody; relapsers, patients with at least 1 disease flare within 4 years of diagnosis; Treg, regulatory helper T cells; TH1, IFN-g1 helper T cells; TH2, IL-41 helper T cells; TH10, IL-101 helper T cells, TH17, IL-17A1 helper T cells.
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References 1. Kallenberg CG, Stegeman CA, Abdulahad WH, Heeringa P. Pathogenesis of ANCA-associated vasculitis: new possibilities for intervention. Am J Kidney Dis. 2013;62(6):1176-1187. 2. Specks U, Merkel PA, Seo P, et al. Efficacy of remissioninduction regimens for ANCA-associated vasculitis. N Engl J Med. 2013;369(5):417-427. 3. Lund FE, Randall TD. Effector and regulatory B cells: modulators of CD41 T cell immunity. Nat Rev Immunol. 2013;10(4):236-247. 4. Leandro MJ, Cambridge G, Ehrenstein MR, Edwards JCW. Reconstitution of peripheral blood B cells after depletion with rituximab in patients with rheumatoid arthritis. Arthritis Rheum. 2006;54(2):613-620. 5. Wilde B, Thewissen M, Damoiseaux J, et al. Regulatory B cells in ANCA-associated vasculitis. Ann Rheum Dis. 2013;72(8): 1416-1419. 6. Barr TA, Shen P, Brown S, et al. B cell depletion therapy ameliorates autoimmune disease through ablation of IL-6–producing B cells. J Exp Med. 2012;(5):1001-1010. 7. Sun F, Ladha SS, Yang L, et al. Interleukin-10 producing B cells and their association with responsiveness to rituximab in myasthenia gravis. Muscle Nerve. 2014;49(4):487-494. Ó 2014 by the National Kidney Foundation, Inc. http://dx.doi.org/10.1053/j.ajkd.2013.11.029
In Reply to ‘Rituximab and B-Cell Return in ANCAAssociated Vasculitis’ We appreciate the constructive comments of Wilde et al1 on our review.2 In their letter, the authors propose that analyzing the cytokine profile of regulatory (IL-101) and effector (IL-61/TNFa1) B cells that return after rituximab treatment is a useful method to predict disease relapse. Although we support this type of analysis in general, we also acknowledge that this approach has certain limitations. As is well known, the cytokine profile of B cells is identified indirectly following ex vivo exposure to oligonucleotides containing the immunostimulatory CpG motif for 66 hours, with restimulation by phorbol 12-myristate 13-acetate/ ionomycin for another 4 hours. Wilde et al3 analyzed regulatory B cells in ANCA-associated vasculitis (AAV) in this way. However, this type of analysis requires a large amount of B cells, which is not available in most cases following B-cell depletion caused by rituximab. In addition, ex vivo stimulation may change the normal distribution of B-cell subsets, which may lead to a flawed conclusion. In this regard, Bunch et al4 recently have noted that declining percentages of CD51 B cells after rituximab treatment were associated with a shorter time to disease relapse in patients with AAV. These CD51 B cells were noted to be IL-10–producing regulatory cells.5,6 The practical approach of determining CD51 B cells following rituximab treatment seems to be more efficient than ex vivo culturing of B cells followed by intracellular cytokine detection because CD5 is a surface marker and no stimulation is required for quantifying these B-cell subsets. Therefore, determination of the percentage of CD51 B cells following rituximab
Am J Kidney Dis. 2014;63(6):1066-1075
