Characteristics and prognosis of non-spontaneously regressing immunodeficiency-associated lymphoproliferative disorders in patients with rheumatoid arthritis after methotrexate discontinuation

ObjectiveTo investigate the risk factors and prognosis of non-spontaneously regressing immunodeficiency-associated lymphoproliferative disorders (LPDs) after methotrexate (MTX) discontinuation in patients with rheumatoid arthritis (RA). MethodsWe retrospectively reviewed medical records of 38 patients with MTX-associated LPD and compared the characteristics of those with and without spontaneous regression (SR) of LPDs (SR versus non-SR groups: n = 22 versus 16) and of survivors and non-survivors in the non-SR group (n = 5 deaths). ResultsThe SR and non-SR groups were comparable regarding age, sex, RA duration and activity, MTX use duration and dose, LPD stage and histological characteristics (lymphoma types and Epstein-Barr encoding region in situ hybridisation positivity). However, the non-SR group had significantly higher lactate dehydrogenase (LDH) levels at LPD diagnosis and lower lymphocyte recovery 1 month after MTX withdrawal. Multivariate analysis revealed poor lymphocyte recovery 1 month after MTX withdrawal as a risk factor for non-SR (odds ratio: 7.12; p = 0.02). Log-rank test showed that elevated LDH levels (>250 U/L) were significantly associated with death (p = 0.02). ConclusionsLack of lymphocyte recovery 1 month after MTX discontinuation was a risk factor for non-spontaneously regressive LPD. High LDH level was associated with death in these cases.