A repeat bone marrow biopsy and the first and second bone biopsies were compared ( Figure 2 and Figure 3 ). The first and second bone marrow biopsies were also critically compared (Figure 3) . The latter showing a substantive increase in hematophagocytes compared to the former. In addition, a lumbar puncture showed an elevated protein level (109 mg/dL) with a lymphocytic pleocytosis (12 WBC with 100% lymphocytes). These findings suggested central nervous system HLH involvement. Table 1: Initial laboratory values  Table 2 : Evolution of laboratory values Figure 1 : Illustration of key laboratory value evolution Figure 2 : Bone marrow aspirate; Wright stain postanakinra Figure 3 : CD 163 immunohistochemical stain of bone marrow biopsy