Histological subtypes of rheumatoid arthritis-associated lymphoproliferative disorders: Serological and Epstein-Barr virus findings.

OBJECTIVES

Lymphoproliferative disorders (LPDs) in patients with rheumatoid arthritis (RA) are thought to develop through two major mechanisms: chronic inflammation and immunosuppression. This study aimed to investigate the relationship between histological subtypes and two representative biomarkers, rheumatoid factor (RF) and Epstein-Barr virus-encoded RNA in situ hybridisation (EBER-ISH), in RA-associated LPD (RA-LPD).

METHODS

We retrospectively analysed patients with clinically diagnosed RA-LPD who underwent tissue biopsy at a single institution. Histological subtypes were classified as classic Hodgkin lymphoma (CHL), monomorphic LPD (Mono-LPD), polymorphic LPD (Poly-LPD), or reactive lymphoid hyperplasia/normal variant (RLH/NV). RF levels and EBER-ISH results were compared across groups.

RESULTS

A total of 69 RA-LPD patients were included in the analysis. RF levels differed significantly across the four histological subtypes (P = .024), with the highest median level observed in the Mono-LPD group. EBER-ISH positivity differed significantly among the subtypes (P < .001), with a significantly higher rate in Poly-LPD compared to Mono-LPD and RLH/NV. Mono-LPD tended to show high RF titres and EBER-ISH negativity, whereas Poly-LPD and CHL were characterised by low RF titres and high EBER-ISH positivity.

CONCLUSIONS

RF and EBER-ISH status differed among histological subtypes of RA-LPD, and their combined assessment may help explain its histological diversity.