Abstract
Hemophagocytic lymphohistiocytosis (HLH) is an uncommon yet potentially devastating
systemic disease, arising from uncontrolled activation of the immune system. While
the primary form of this disease can be caused by genetic mutation(s), the secondary
form may be triggered by infection and hematologic, malignant, and metabolic conditions.
The diagnosis of HLH remains a clinical challenge due to nonspecific symptoms. Proper
diagnosis is significantly more difficult among patients with acute leukemia who have
received chemotherapy. The objective of this study is to describe three unique cases
of secondary HLH, describe the specific treatment, and improve the awareness of this
condition. Two patients with acute myeloid leukemia (AML) and one with acute lymphoblastic
leukemia were diagnosed with HLH, having fulfilled the criteria as outlined in the
HLH-2004 protocol. They then received HLH-specific treatment. Two patients passed
– one from refractory HLH and one from primary disease (i.e., AML) – and one patient
remains alive 22 months after her allogeneic bone marrow transplant. The diagnosis
of HLH requires the presence of any five of the eight criteria. Due to its heterogeneous
presentation, it remains imperative that treating clinicians remain cognizant about
HLH so that prompt diagnosis may allow appropriate treatment.
Keywords
Acute leukemia - ferritin - hemophagocytic lymphohistiocytosis
