Autoimmune disorders in patients with hairy cell leukemia: are they more common than previously thought?

Background: For a number of decades, hairy cell leukemia (HCL) has been linked with polyarthritis, vasculitis, symptomatic cytopenias and thrombosis in the medical literature. Notwithstanding, the significance of these associations has not been well understood. Therefore, we have decided to analyze them further.
Methods: We provide herein a comprehensive literature review of the prevalence of autoimmune disorders in patients with HCL. Most relevant publications were identified through searching the PubMed/Medline database for articles published from inception to February 2014.
Findings: Perhaps due to the rarity of HCL, scientific literature on autoimmune conditions in patients with HCL consists mainly of published case series and isolated reports. Our analysis identified increased prevalence of various autoimmune conditions in patients with HCL, including various vasculitides, immune cytopenias and antiphospholipid antibody syndrome (APS) among others.
Conclusions: Presence of certain autoimmune disorders should increase the suspicion of HCL in an appropriate clinico-laboratory context. Conversely, the diagnosis of HCL should prompt early recognition of certain autoimmune disorders if clinical suspicion exists. While some of these autoimmune diseases are thought to be secondary to the dysfunctional immune response associated with underlying malignant process, others could be primary and might even play a role in the HCL pathogenesis. The autoimmune complications can pose important clinical problems for the HCL patients. Therefore, a catalogue of these problems is important for alerting physicians to watch for them and diagnose them promptly.