B Cell Characteristics at Baseline Predict Vaccination Response in RTX Treated Patients

Background

Vaccination is considered as most efficient strategy in controlling SARS-CoV-2 pandemic spread. Nevertheless, patients with autoimmune inflammatory rheumatic diseases receiving rituximab (RTX) are at increased risk to fail humoral and cellular responses upon vaccination. The ability to predict vaccination responses is essential to guide adequate safety and optimal protection in these patients.

Methods

B- and T- cell data before vaccination were evaluated for characteristics predicting vaccine responses in altogether 15 patients with autoimmune inflammatory rheumatic diseases receiving RTX. Eleven patients with rheumatoid arthritis (RA) on other therapies, 11 kidney transplant recipients (KTR) on regular immunosuppression and 15 healthy controls (HC) served as controls. A multidimensional analysis of B cell subsets via UMAP algorithm and a correlation matrix were performed in order to identify predictive markers of response in patients under RTX therapy.

Results

Significant differences regarding absolute B cell counts and specific subset distribution pattern between the groups were identified at baseline. In this context, the majority of B cells from vaccination responders of the RTX group (RTX IgG+) were naïve and transitional B cells, whereas vaccination non-responders (RTX IgG-) carried preferentially plasmablasts and double negative (CD27-IgD-) B cells. Moreover, there was a positive correlation between neutralizing antibodies and B cells expressing HLA-DR and CXCR5 as well as an inverse correlation with CD95 expression and CD21low expression by B cells among vaccination responders.

Summary

Substantial repopulation of the naïve B cell compartment after RTX therapy appeared to be essential for an adequate vaccination response, which seem to require the additional capability of antigen presentation and germinal center formation. Moreover, expression of exhaustion markers represent negative predictors of vaccination responses.

Rituximab for remission induction in elderly patients with ANCA-associated vasculitis

OBJECTIVES

Advancing age is a risk factor for treatment-related side effects and mortality in AAV patients treated with cyclophosphamide (CYC) and glucocorticoids (GC) for remission induction. The efficacy and safety of rituximab (RTX) in elderly AAV patients has not been well described.

METHODS

We performed a single center retrospective review of 31 consecutive AAV patients aged 60 or more at the time of RTX use for remission induction. All patients received RTX with GC for remission induction. Four patients received concomitant CYC for a mean duration of 52 days. We evaluated clinical and laboratory variables at diagnosis, rates of complete remission defined as Birmingham Vasculitis Activity Score/Wegener's Granulomatosis (BVAS/WG) = 0 and patient survival, renal survival, infections requiring hospitalization, and vasculitis relapse 24 months following RTX use.

RESULTS

Of the 31 patients, 77% were Caucasian, 68% female, mean age was 71 ± 6 years, 58% were MPO ANCA positive, and 42% had relapsing disease. The mean BVAS/WG score entry was 4.4 ± 1.5, 71% had glomerulonephritis (GN) and 10% had alveolar hemorrhage. The mean baseline e-GFR was 40 ± 28ml/min/1.73m(2). Thirty patients achieved remission with a mean time to remission of 57 ± 27 days. The single patient with refractory vasculitis responded to CYC. The mean prednisone dose at 6 months was 5.6 ± 4mg. Remission maintenance therapy was started within 12 months of RTX induction in 6 patients (4 with RTX, 1 with azathioprine, and 1 with mycophenolate mofetil). One patient suffered a limited relapse 10 months post RTX use. Among the 22 patients with GN at baseline, 1 developed ESRD. One-year patient survival among 25 patients with at least 1 year of follow-up was 100%. There were no episodes of infusion reaction or leukopenia. There were 3 episodes of bacterial pneumonia, 1 episode of candida pneumonia, and 1 episode of disseminated cutaneous zoster.

CONCLUSIONS

This study demonstrates that rituximab is effective for remission induction in elderly patients with AAV. Furthermore, we observed a high incidence of infectious complications. Our experience was limited by its retrospective design, and further studies are needed to evaluate the efficacy and safety of RTX in elderly AAV patients.