Is Post-Vaccination IgG Predictive of Mortality in Systemic Vasculitis?

Total immunoglobulin G (IgG) and B-cell counts predicted infection rates and response to vaccination in patients with systemic vasculitis, according to recent data published in Arthritis Care & Research. Vaccination in patients with systemic vasculitis in remission appeared to be safe, with vaccination responses found to be predictive of all-cause mortality.

The researchers followed 92 patients for a median follow-up of 4.6 years (interquartile range [IQR]: 3.6 to 4.8 years). Patients with systemic vasculitis in remission were vaccinated with pneumococcal 7-valent conjugate (Prevnar®, Pfizer), Haemophilus influenza and meningococcal group C conjugate vaccine (Menitorix®, GlaxoSmithKline), and meningococcal polysaccharide groups A, C, Y, and W135 (ACWY VAc Nimenrix®, enveo® GlaxoSmithkline) vaccines.

Study researchers performed a subset analysis comparing total IgG and antibody titers against specific antigens and lymphocytes before the vaccination. They then measured post-vaccination antibody titers at 4 weeks and 2 years, calculating antibody responses. Infection and mortality rates were also collected prospectively after vaccination.

After a median of 2 years, the overall infection rate was 0.4 infections per patient per year (IQR: 0.2 to 1.3). The researchers found that reduced serum IgG, B cell count, and CD4+ cell counts predicted poor vaccine response and infection, but they did not predict mortality.

A median of 46% (IQR: 39% to 58%) of patients responded to each individual antigen, although the investigators noted that the overall the response rates to individual vaccine antigens were highly variable. In addition, vaccine response, age, and reduced renal function were independent predictors of all-cause mortality in multivariate analysis.

“This study suggests the vaccination score provides useful information on the health of the immune system and provides a surrogate marker of poor immune response, which may identify those patients potentially benefitting from a reduction in immunosuppression,” the authors wrote. “For those who require long-term immunosuppression due to continued disease activity, these data may help identify those patients who require additional intervention to reduce risk of infection.”

Summary and Clinical Applicability

The researchers found that older patients with poor renal function and low vaccine response to have the highest risk of all-cause mortality, and patients with low B cell counts and IgG levels had the greatest risk of infection. The results of the study confirmed the association of poor renal function and continued immunosuppression with increased risk of infection.

“Using these biomarkers as risk stratification may allow identification of patients who may benefit from immunosuppresion withdrawal if appropriate and/or the use of additional therapies, such as IVIG, as a way to reduce infection and mortality,” the authors noted.

Limitations and Disclosures

The authors note that the study did not investigate the changes in infection rates in response to vaccination due to the large sample size. They also included the meningitis vaccination in this study, which might limit the applicability of the vaccine response score, but the response to the memningitis vaccine provided important information about the immune system’s ability to response to polysaccharide vaccines.

Dr Richter has received consulting fees, speaking fees, and/or honoraria from Pfizer. Dr Goldblatt has received consulting fees, speaking fees, and/or honoraria from GlaxoSmithKline, Merck, Novartis, Pfizer, and Sanofi Pasteur.

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