Rituximab in Systemic Lupus Erythematosus: Transient Effects on Autoimmunity Associated Lymphocyte Phenotypes and Implications for Immunogenicity

Abstract

B cell abnormalities are common in systemic lupus erythematosus (SLE), and include expansion of double negative (DN) and age-associated-like B cells (ABC-like). We aimed to investigate rituximab (RTX) effects on DN and ABC-like B-cell subsets and, when possible, also secondary effects on T cells. Fifteen SLE patients, fulfilling the ACR 1982 criteria, starting RTX and followed longitudinally up to two years, were analyzed for B- and T- lymphocyte subsets using multicolor flow cytometry. DN were defined as IgD-CD27- and ABC-like as CD11c+CD21- within the DN gate. Additional phenotyping was performed adding CXCR5 in the B-cell panel. Cellular changes were further analyzed in the context of the generation of anti-drug antibodies (ADA) against RTX and clinical information. The SLE patients were mainly females (86.6%), of median age 36.7 (29.8-49.4) years and disease duration of 6.1 (1.6-11.8) years. Within the DN subset, ABC-like (IgD-CD27-CD11c+CD21-) B cell frequency reduced from baseline median level of 20.4% to 11.3% (p=0.03), at early follow-up. The DN B cells were further subdivided based on CXCR5 expression. Significant shifts were observed at the early follow-up in the DN2 sub-cluster (CD11c+CXCR5-), which reduced significantly (-15.4 percentage points, p=0.02) and in the recently described DN3 (CD11c-CXCR5-) which increased (+13 percentage points, p=0.03). SLE patients treated with RTX are at high risk of developing ADA. In our cohort, the presence of ADA at 6 months was associated with lower frequencies of DN cells and to a more pronounced expansion of plasmablasts at early follow-up. The frequency of follicular helper T cells (TFH, CD4+PD-1+CXCR5+) and of peripheral helper T cells (TPH, CD4+PD-1+CXCR5-) did not change after RTX. A sub-cluster of PD-1highCD4+ T cells showed a significant decrease at later follow-up compared to early follow-up (p=0.0039). It is well appreciated that RTX transiently influences B cells. Here, we extend these observations to cell phenotypes which are believed to directly contribute to autoimmunity in SLE. We show early transient effects of RTX on ABC-like memory B cells, later effects on PD-1high CD4+ cells, and possible implications for RTX immunogenicity. Further insight in such effects and their monitoring may be of clinical relevance.

T peripheral helper cells in autoimmune diseases: What do we know?

“…Meanwhile, IFN-a-induced Tph cells could induce B cell differentiation into plasmablasts (60). In contrast, one study found no significant alteration in Tph cells after treatment with rituximab, suggesting that Tph cells do not change in response to disease activity (61). SS is a systemic autoimmune disease which is characterized by lymphocytic infiltration of exocrine glands, mainly salivary and lacrimal glands (79).…”

“…Mounting studies have been conducted to investigate the physiological role and mechanisms of Tph cells, predominantly focusing on autoimmune diseases (shown in Table 1 ), including RA ( 6 , 7 , 48 , 52 – 54 ), SLE ( 26 , 55 – 61 ), SS ( 62 – 66 ), IgG4-related disease (IgG4-RD) ( 64 , 67 ), type 1 diabetes (T1D) ( 68 , 69 ), primary biliary cirrhosis (PBC) ( 70 ), immunoglobulin A nephropathy (IgAN) ( 71 ), juvenile idiopathic arthritis (JIA) ( 72 ), autoimmune hepatitis (AIH) ( 73 ), dermatomyositis (DM) ( 74 ), celiac disease (CeD) ( 58 ), systemic sclerosis (SSc) ( 58 ), autoimmune bowel disease (IBD) ( 75 ), and psoriasis vulgaris (PV) ( 76 ). Notably, most studies elucidated altered frequencies of Tph cells and their correlation with disease activity, and they analyzed only cTph cells because of the relative difficulty in obtaining tissue samples.…”

“…Meanwhile, IFN-α-induced Tph cells could induce B cell differentiation into plasmablasts ( 60 ). In contrast, one study found no significant alteration in Tph cells after treatment with rituximab, suggesting that Tph cells do not change in response to disease activity ( 61 ).…”

Age/autoimmunity-associated B cells in inflammatory arthritis: An emerging therapeutic target

“…found that belimumab, a monoclonal antibody targeting the B cell cytokine BAFF, can decrease the ABCs with early clinical improvements in SLE in a prospective cohort study ( 101 ). Consistent with these findings, another clinical study showed that SLE patients who received rituximab treatment had a reduction of ABCs frequency at early follow-up ( 54 ). Besides, it was found that ABCs were reduced following plasma exchange treatment with a reduction in all immunoglobulin subsets in the circulation in patients with MS ( 102 ).…”

Off-label use of rituximab in patients with systemic lupus erythematosus with extrarenal disease activity: a retrospective study and literature review

“…CD19+ B cell depletion is a marker for rituximab’s biologic effect and, despite some authors ( 41 ) have found an association with disease remission and clinical response, this has not always been the case. The effect of rituximab on B cells is transient and some variability across patients in the response is expected, which can be partially explained by the reduction of the frequency of specific B cell subsets and phenotypes that can differ between patients ( 53 ). The study by Jónsdóttir et al showed that patients with low baseline levels of CD19-positive lymphocytes can also respond to depletion with rituximab, due to the lack of correlation between peripheral blood and the rest of the population of CD19-positive B cells in the lymphoid tissues ( 20 ).…”