Serum Thymus and Activation-Regulated Chemokine Level Monitoring May Predict Disease Relapse Detected by PET Scan after Reduced-Intensity Allogeneic Stem Cell Transplantation in Patients with Hodgkin Lymphoma

Patients with relapsed and refractory Hodgkin lymphoma (HL) may experience long-term survival after allogeneic stem cell transplantation (alloSCT), but disease recurrence represents the main cause of treatment failure. Positron-emission tomography (PET)-positive patients after alloSCT have a dismal outcome. Serum thymus and activation-regulated chemokine (TARC) is produced by Reed-Sternberg cells and may be a marker of disease. Our study aimed at assessing whether TARC levels after alloSCf correlated with disease status and whether TARC monitoring could increase the ability to predict relapse. Twenty-four patients were evaluated in a prospective observational study. TARC serum level and PET were assessed before and after alloSCf during the follow-up (median, 30 months; range, 2 to 54). Before alloSCT, the median TARC level was 721 pg/mL (range, 209 to 1332) in PET-negative patients and 2542 pg/mL (range, 94 to 13,870) in PET-positive patients. After alloSCT, TARC was 620 pg/mL (range, 12 to 4333) in persistently PET-negative patients compared with 22,397 pg/mL (range, 602 to 106,578) in PET-positive patients (P <.0001). In 7 patients who relapsed after alloSCT, TARC level increased progressively even before PET became positive, with a median fold increase of 3.19 (range, 1.66 to 7.11) at relapse. The cut-off value of 1726 pg/mL had a sensitivity of 100% and a specificity of 71% for PET positivity. Patients with at least 1 TARC value above 1726 pg/mL during the first year after alloSCf had a worse progression-free survival (P =.031). In conclusion, TARC was correlated with disease status and its monitoring may be able to predict PET positivity after alloSCT, thus potentially allowing an early immune manipulation. 2014 American Society for Blood and Marrow Transplantation.