Neutropenia associated with rituximab therapy

Area of Science:

• Immunology
• Hematology
• Pharmacology

Background:

• Rituximab is increasingly used for various hematologic and nonhematologic disorders.
• Late-onset neutropenia (LON) has been reported following rituximab or rituximab-based therapies.
• While typically self-limiting, recognizing LON is important due to rituximab's expanding applications.

Purpose of the Study:

• To review the incidence of late-onset neutropenia (LON) after rituximab therapy.
• To explore proposed hypotheses regarding the etiology of rituximab-induced LON.
• To discuss the relationship between B-cell recovery and LON.

Main Methods:

• Literature review of studies reporting late-onset neutropenia following rituximab.
• Exploration of proposed pathogenetic mechanisms for LON.
• Analysis of the role of B-cell reconstitution and granulocyte homeostasis.

Main Results:

• Proposed mechanisms for LON include antineutrophil antibodies, LGL expansion, and aberrant B-cell recovery.
• An alternative hypothesis suggests LON results from granulocyte homeostasis perturbations due to B-cell recovery and SDF-1 interactions.
• LON is a distinct biologic phenomenon occurring weeks to months after rituximab administration.

Conclusions:

• Late-onset neutropenia (LON) following rituximab is a distinct phenomenon linked to B-cell recovery.
• While frequent, LON is generally self-limiting with rare significant clinical sequelae.
• Understanding LON is important for managing patients receiving rituximab therapy.