Ruxolitinib side effects include the most frequent hematological toxicity along with a more recently evidenced immunosuppressive activity, interfering both with the innate and adaptive immunity, and several cases of reactivation of latent infections by opportunistic agents in patients in treatment with ruxolitinib have been published in the last years. Several pathophysiological mechanisms may explain an association between ruxolitinib and opportunistic infections. From what we know, the only case of an isolated lymph node TBC reactivation in a ruxolitinib-treated myelofibrosis (MF) patient was reported by Patil et al. in 2016 [Int J Med Sci Public Health. 2017;6(3):1]. Other 10 cases describing TBC reactivations in MF patients assuming ruxolitinib and successfully treated with 4-drug anti-TBC therapy are available in the literature to date. The case we reported describes an isolated lymph nodal TBC reactivation in a patient with the diagnosis of post-essential thrombocythemia-MF during ruxolitinib treatment after a long course of interferon-a (IFN-α2b) assumed for the previous diagnosis of ET. The case we report teaches that lymphadenopathy with or without constitutional symptoms developing during ruxolitinib therapy should be considered as a possible manifestation of a TBC reactivation in patients with a previous positive TBC-exposure test. In these cases, Ziel-Nielsen testing on urine and sputum has to be performed to rule out infectiousness and eventually isolate the patient. Moreover, previous long-time exposition to IFN-α2b may be related with a higher risk for TBC reactivation in these subset of patients. We encourage reevaluation of the cohorts of patients treated with ruxolitinib in previous and current large prospective studies to study the possible correlation between previous exposition to IFN-α2b and TBC reactivation.
Keywords: Infection; Myelofibrosis; Reactivation; Ruxolitinib; TBC; Tuberculosis.
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