Macrophage Activation Syndrome: A Report of Two Cases and a Literature Review

Table 1

Diagnostic criteria for macrophage activation syndrome: HLH-2004—revised diagnostic guidelines for HLH10.

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The diagnosis of HLH can be established if one of the two criteria below is met

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(1) A molecular diagnosis consistent with HLH (i.e., reported mutations found in either PRF1 or MUNC13-4), or

(2) Diagnostic criteria for HLH are fulfilled (i.e., at least five of the eight criteria listed below are present)

 (a) Persistent fever

 (b) Splenomegaly

 (c) Cytopenia (affecting ≥ 2 of 3 lineages in the peripheral blood)

  (i) Hemoglobin < 90 g/L (in infants < 4 weeks: <100 g/L)

  (ii) Platelets < 100 × 10⁹/L

  (iii) Neutrophils < 1.0 × 10⁹/L

 (d) Hypertriglyceremia and/or hypofibrinogenemia

  (i) Fasting triglycerides ≥ 3.0 mmol/L (i.e., ≥265 mg/dl)

  (ii) Fibrinogen ≤ 1.5 g/L

 (e) Hemophagocytosis in bone marrow or spleen or lymph nodes, no evidence of malignancy

 (f) Serum ferritin ≥ 500 µg/L (i.e., 500 ng/ml)

 (g) Low or absent NK cell activity (according to local laboratory reference)

 (h) Increased serum sIL2Rα (according to local laboratory reference)

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If hemophagocytic activity is not proven at the time of presentation, further search for hemophagocytic activity is encouraged. If the bone marrow specimen is not conclusive, material may be obtained from other organs. Table 1 is copied from Henter et al. [17].