van der Woude, D. | Search bioRxiv

bioRxiv2023

Autoreactive B cells in rheumatoid arthritis consist of activated CXCR3+ memory B cells and plasmablasts

Many autoimmune diseases (AIDs) are characterized by persistence of autoreactive B cell responses which is often directly implicated in disease pathogenesis. How and why these cells are generated or how they are maintained for years is largely unknown. Rheumatoid arthritis is among the most common AIDs and characterized by autoantibodies recognizing proteins with post-translational modifications (PTMs). This PTM-directed, autoreactive B cell compartment is ill defined. Here, we visualized the B cell response against the three main types of PTM antigens implicated in RA by spectral flow cytometry. Our results show extensive cross-reactivity of autoreactive B cells against all three PTM antigens (citrulline, homocitrulline and acetyllysine). Unsupervised clustering revealed several distinct memory B cell (mBC) populations. Autoreactive cells clustered with the most recently activated, class-switched mBC phenotype, expressing high CD80, low CD24 and low CD21. Notably, patients also harbored large fractions of autoreactive plasmablasts (PB). Both PTM-directed mBC and PB showed high expression of CXCR3, a receptor for chemokines abundantly present in arthritic joints. Together, our data provide novel, detailed insight into the biology of B cell autoreactivity and its remarkable, seemingly exhaustless persistence in a prominent human AID.

immunology↗

bioRxiv2021

ACPA-IgG variable domain glycosylation increases before the onset of rheumatoid arthritis and stabilizes thereafter; a cross-sectional study encompassing over 1500 samples

ObjectiveThe autoimmune response in rheumatoid arthritis (RA) is marked by anti-citrullinated protein antibodies (ACPA). A remarkable feature of ACPA-IgG is the abundant expression of N-linked glycans in the variable domain. Nonetheless, the presence of ACPA variable domain glycans (VDG) across disease stages and its response to therapy is poorly described. To understand its dynamics, we investigated the abundance of ACPA-IgG VDG in 1574 samples from individuals in different clinical disease stages. MethodsUsing liquid chromatography, we analyzed ACPA-IgG VDG profiles of 7 different cohorts from Japan, Canada, the Netherlands and Sweden. We assessed 184 healthy, 228 pre-symptomatic, 277 arthralgia, 305 patients at RA-onset and 117 RA-patients 4, 8 and 12 months after disease onset. Additionally, we measured VDG of 234 samples from RA-patients that did or did not achieve long-term drug-free remission (DFR) during up to 16 years follow-up. ResultsOur data show that ACPA-IgG VDG significantly increases (p<0.0001) towards disease-onset and associates with ACPA-levels and epitope spreading pre-diagnosis. A slight increase in VDG was observed in established RA and a moderate influence of treatment. Individuals who later achieved DFR displayed reduced ACPA-IgG VDG already at RA-onset. ConclusionThe abundance of ACPA-IgG VDG rises towards RA-onset and correlates with maturation of the ACPA-response. Although, ACPA-IgG VDG levels are rather stable in established disease, a lower degree at RA-onset correlates with DFR. Even though the underlying biological mechanisms are still elusive, our data support the concept that VDG relates to an expansion of the ACPA-response pre-disease and contributes to disease-development.

immunology↗