CD40L and IL-4 lymph node-associated signals protect B cells from rituximab-induced ADCC via KIR and NKG2A
CD40L and IL-4 lymph node-associated signals protect B cells from rituximab-induced ADCC via KIR and NKG2A
Autoreactive B cells that remain in lymphatic tissue after anti-CD20 antibody therapy are considered a major contributing factor to relapse in patients with autoimmune diseases. Natural killer (NK) cells contribute to the depletion of autoreactive B cells by anti-CD20 antibodies via antibody-dependent cellular cytotoxicity (ADCC). However, the impact of germinal centre–associated signals CD40 ligand (CD40L) and interleukin-4 (IL-4) on ADCC was unknown. This study used a combination of flow cytometry, immunohistochemistry, and ex vivo functional assays using peripheral blood mononuclear cells to investigate how CD40L and IL-4 affect NK cell–B cell interactions. CD40L and IL-4 significantly upregulate human leukocyte antigen (HLA)-E and total HLA Class I expression on the surface of B cells from healthy donors, as well as patients with rheumatoid arthritis and systemic lupus erythematosus. The upregulation of HLA-E and total HLA functions to inhibit B-cell depletion by NK cell–mediated ADCC induced by rituximab via NKG2A and killer cell immunoglobulin-like receptors (KIR). Moreover, B cells that have differentiated through the germinal centre have higher expression of HLA-E and total HLA compared with naive B cells and are more resistant to depletion by rituximab. In accordance with this, blockade of NKG2A and inhibitory KIRs by monalizumab and lirilumab, respectively, increased antibody-dependent cellular cytotoxicity against autologous B cells in vitro. Overall, this study identifies a novel mechanism of resistance of B cells to NK cell cytotoxicity and indicates that blockade of the HLA-E:NKG2A and HLA:KIR checkpoint axes could be beneficial for improving B-cell depletion in patients with autoimmune diseases.
antibodies, autoimmunity, natural killer cells
Graham, Lara V.
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Foxall, Russell B.
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Ashton-Key, Margaret
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Khakoo, Salim I.
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Sayegh, Souraya
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Leandro, Maria
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Reddy, Venkat R.
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Cragg, Mark S.
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Blunt, Matthew D.
b1109de3-6045-4bc3-bd77-6cf26504697d
13 January 2026
Graham, Lara V.
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Foxall, Russell B.
cfe3a818-a281-4bcb-8889-e1d0b591117c
Ashton-Key, Margaret
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Khakoo, Salim I.
6c16d2f5-ae80-4d9b-9100-6bfb34ad0273
Sayegh, Souraya
b7bdac06-931d-4f5c-bc78-8c75369dcac4
Leandro, Maria
f6423fa5-324c-4cc2-a661-74c1b54b0b4b
Reddy, Venkat R.
cbab0de2-8fc1-42f0-abe1-5806b06f696c
Cragg, Mark S.
ec97f80e-f3c8-49b7-a960-20dff648b78c
Blunt, Matthew D.
b1109de3-6045-4bc3-bd77-6cf26504697d
Graham, Lara V., Foxall, Russell B., Ashton-Key, Margaret, Khakoo, Salim I., Sayegh, Souraya, Leandro, Maria, Reddy, Venkat R., Cragg, Mark S. and Blunt, Matthew D.
(2026)
CD40L and IL-4 lymph node-associated signals protect B cells from rituximab-induced ADCC via KIR and NKG2A.
Clinical and Experimental Immunology, 220 (1), [uxag001].
(doi:10.1093/cei/uxag001).
Abstract
Autoreactive B cells that remain in lymphatic tissue after anti-CD20 antibody therapy are considered a major contributing factor to relapse in patients with autoimmune diseases. Natural killer (NK) cells contribute to the depletion of autoreactive B cells by anti-CD20 antibodies via antibody-dependent cellular cytotoxicity (ADCC). However, the impact of germinal centre–associated signals CD40 ligand (CD40L) and interleukin-4 (IL-4) on ADCC was unknown. This study used a combination of flow cytometry, immunohistochemistry, and ex vivo functional assays using peripheral blood mononuclear cells to investigate how CD40L and IL-4 affect NK cell–B cell interactions. CD40L and IL-4 significantly upregulate human leukocyte antigen (HLA)-E and total HLA Class I expression on the surface of B cells from healthy donors, as well as patients with rheumatoid arthritis and systemic lupus erythematosus. The upregulation of HLA-E and total HLA functions to inhibit B-cell depletion by NK cell–mediated ADCC induced by rituximab via NKG2A and killer cell immunoglobulin-like receptors (KIR). Moreover, B cells that have differentiated through the germinal centre have higher expression of HLA-E and total HLA compared with naive B cells and are more resistant to depletion by rituximab. In accordance with this, blockade of NKG2A and inhibitory KIRs by monalizumab and lirilumab, respectively, increased antibody-dependent cellular cytotoxicity against autologous B cells in vitro. Overall, this study identifies a novel mechanism of resistance of B cells to NK cell cytotoxicity and indicates that blockade of the HLA-E:NKG2A and HLA:KIR checkpoint axes could be beneficial for improving B-cell depletion in patients with autoimmune diseases.
Text
uxag001
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Accepted/In Press date: 18 December 2025
e-pub ahead of print date: 13 January 2026
Published date: 13 January 2026
Keywords:
antibodies, autoimmunity, natural killer cells
Identifiers
Local EPrints ID: 509856
URI: http://eprints.soton.ac.uk/id/eprint/509856
ISSN: 0009-9104
PURE UUID: a66e50ae-bc64-46b9-9e61-bb36f0fba7d9
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Date deposited: 09 Mar 2026 17:32
Last modified: 14 Mar 2026 03:15
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Contributors
Author:
Lara V. Graham
Author:
Russell B. Foxall
Author:
Margaret Ashton-Key
Author:
Souraya Sayegh
Author:
Maria Leandro
Author:
Venkat R. Reddy
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