Macrophage Activation Syndrome

1
Macrophage Activation Syndrome in a Child with
Systemic Juvenile Rheumatoid Arthritis Mina
Hur, M.D., Young Chul Kim, M.D., Kyu Man Lee, M.
D., and Kwang Nam Kim, M.D. Departments of
Laboratory Medicine and Pediatrics, Hallym
University College of Medicine, Seoul, Korea
INTRODUCTION

• Macrophage activation syndrome (MAS) is a severe
  and potentially life-
• threatening complication of rheumatic disorders
  in children, especially those with systemic
  juvenile rheumatoid arthritis (S-JRA).
• MAS is characterized by serious liver disease,
  hematologic abnormalities, coagulopathy, and
  neurologic involvement. Laboratory hallmarks are
  anemia, thrombocytopenia, leukopenia in various
  combinations, evidence of disseminated
  intravascular coagulation (DIC),
  hypertriglyceridemia, increased LDH, and
  hemophagocytosis in bone marrow.
• We describe a 13-month-old boy in whom MAS
  developed as a complication of S-JRA.

CASE REPORT

• He suffered from fever and generalized rash
  followed by multiple joints swelling for four
  months before admission. Physical examination
  revealed cervical lymphadenopathy and
  hepatosplenomegaly. Laboratory findings were
  abnormal liver enzymes, increased triglyceride
  and ferritin levels, coagulopathies resembling
  DIC, anemia, and thrombocytopenia (Table 1).
• Bone marrow (BM) aspiration smear was diluted
  with no marrow particle giving no diagnostic
  information. In BM biopsy, estimated cellularity
  was about 90, which was normocellular for
  age-related value. Granulocytic and
  megakaryocytic hyperplasia were prominent with
  suppressed erythropoiesis. Benign-appearing
  histiocytes were increased and diffusely
  distributed with hemophagocytic features.
  Presence of histiocytes was confirmed with
  positivity of CD68 stain (Fig. 1).
• Clinical and laboratory improvement were
  observed during hospital courses with
  corticosteroid and cyclosporine therapy (Fig. 2
  3).

DISCUSSION

• Immunologic mechanisms causing MAS are still
  unclear. It is thought, however, that T- or NK
  cell dysfunction leads to macrophage activation
  and increased levels of many cytokines
  (specifically, tumor necrosis factor alpha and
  interferon gamma) released by macrophage or
  T-lymphoid cells initiate systemic
  hemophagocytosis.
• This is the third case of MAS associated with
  S-JRA in Koreans, and the first one, in which
  histiocytic hyperplasia was proven in bone
  marrow.

Fig.1. (a) Bone marrow biopsy section illustrates
hypercellular marrow with granulocytic and
megakaryocytic hyperplasia (H E stain, ? 200).
(b) Histiocytic hyperplasia is prominently
observed (CD 68 stain, ? 200).