The study titled “Risk of Severe Infections Associated with Immunoglobulin Deficiency Under Rituximab Therapy in Immune Mediated Inflammatory Diseases” conducted by Claire Rempenault and colleagues, explored the connection between severe infections and immunoglobulin (Ig) deficiency in patients treated with Rituximab (RTX) for immune-mediated inflammatory diseases (IMIDs). These diseases include conditions like rheumatoid arthritis, lupus, and several types of vasculitis. The study was retrospective and observational, focused on patients at the CHU Montpellier who received at least one RTX infusion in 2017.

The researchers followed 311 patients until either the occurrence of a severe infection, death, or the end of the study in May 2020. They categorized patients based on their Ig levels into three groups: those with existing Ig deficiency before RTX treatment, those who developed Ig deficiency after starting RTX, and those with normal Ig levels throughout the study.

The findings revealed that 9.4% of patients had a pre-existing Ig deficiency, and 22% developed an Ig deficiency after beginning RTX treatment. Interestingly, patients with prevalent Ig deficiency often used glucocorticoids (a type of steroid), which was associated with a lower baseline Ig level.

Despite concerns, the study found no statistically significant increased risk of severe infections among patients with Ig deficiency (whether pre-existing or acquired) compared to those with normal Ig levels. Factors like chronic lung disease, higher glucocorticoid doses, and disease activity during follow-up were linked to a higher infection risk, rather than Ig deficiency alone.

The conclusion of the study suggested that while RTX-induced Ig deficiency does not significantly elevate the risk of severe infections, each patient’s risk should still be individually assessed, especially considering other factors like glucocorticoid use and existing lung conditions.