Introduction: Autoimmune lymphoproliferative syndrome (ALPS) and
hemophagocytic lymphohistiocytosis (HLH) share clinical and laboratory
features including lymphadenopathy, splenomegaly, and pancytopenia. We
sought to measure αβ double negative T cells (αβ DNT) in a group of
patients with established diagnosis of HLH in relation to disease activity and
severity. Methods: We conducted a follow-up, controlled study that
comprised 25 patients with HLH and 25 healthy matched controls. Patients
were subjected to clinical evaluation and flowcytometric measurement of αβ
DNT Cells at presentation and 9 weeks after start of HLH induction
treatment. Results: In 17 (68%) patients, infection was the trigger of HLH
while the cause was malignancy in three (12%), and rheumatological
disorders in two patients (8%). At enrollment, 15 patients (60%) had αβ
DNT cells levels [median (IQR): 1.71 (1.25-2.12)] that were significantly
higher than the control values [median (IQR): 0.7 (0.4-0.8)] (p<0.001). The
αβ DNT counts of patients were also higher at enrollment as compared to
values at the end of week 9 [median (IQR): 0.76 (0.45-1.17)]; p=0.018.
Survivors (n=8) and non-survivors (n=17) had comparable levels of αβ DNT
cells at enrollment (p=0.861). αβ DNT cell count correlated positively with
ALT (p=0.019) and negatively with CD4/CD8 ratios (p=0.023).
Conclusion: Elevated αβ DNT cell counts might be related to the HLH
process and this implies that mild elevation can exist in HLH and are not
specific to ALPS. Wider scale studies with longer periods of follow up are
needed to validate the results and properly outline the correlation between
both medical conditions.