1 Which one of the following is not a part of the diagnostic cri- teria for HLH?
a) Fever ≥38.5
c) Peripheral blood cytopenia, with at least two of the follow- ing: haemoglobin <9 g/dL (for infants <4 weeks, haemoglo- bin <10 g/dL); platelets <100 000/μL; and absolute neutrophil count <1000/μL
d) High C-reactive protein (CRP) and erythrocyte sedimenta- tion rate (ESR)
e) Ferritin >500 ng/mL
2 HLH is a condition of abnormal immune activation causing excessive inﬂammation and tissue destruction in the body. Which one of the following is not associated with HLH?
a) Genetic defects
c) Rheumatological disorders
e) Severe eczema
3 Which one of the following is untrue regarding HLH?
a) Infection is a common trigger both in those with primary and secondary cases.
b) It can be caused by genetic defects, infections, malignancy or autoimmune conditions.
c) HLH can be controlled with antimicrobials, steroids, intrave- nous immuneglobulin, chemotherapeutic agents in some cases and haemopoietic stem cell transplant (HSCT) in genetic and other conditions.
d) Prompt initiation of treatment for HLH is essential for the survival of affected patients.
e) HSCT is always the treatment of choice.
1 Answer: d. CRP and ESR can be raised due to the underlying condition; however, it is not a diagnostic criterion for HLH. Please refer to the discussion section (Box 1) for detailed diagnostic criteria for HLH.
2 Answer: e. HLH can be caused by genetic defect or secondary to infections, autoimmune conditions and malignancy. Severe eczema is not a known cause of HLH. Patients with HLH can have a single episode or relapsing episodes. Infection is a common trig- ger in genetic (primary) as well as sporadic (secondary) cases, with viral infections being the most common trigger, especially with Epstein–Barr virus, although any infection can trigger the disease. Other triggers include Kawasaki disease, malignancy, rheumato- logical disorders or human immunodeﬁciency virus infection.
3Answer: e. HSCT is not always the treatment of choice as second- ary HLH may respond to the treatment of underlying conditions.