[Antiphospholipid antibody-associated hemophagocytic syndrome]

Autoimmune diseases such as systemic lupus erythematosus (SLE) are known to be causative disorders of reactive hemophagocytic syndrome (HPS). We recently encountered a case of HPS associated with the presence of antiphospholipid antibodies (aPL). This patient showed severe thrombocytopenia (0.2 x 10(4)/microliter) and moderate anemia (Hb; 7.6 g/dl). Bone marrow smears showed normal cellularity and an increase in mature-looking histiocytes scattered among the hematopoietic cells, which accounted for approximately 3% of all nucleated cells and were distributed unevenly. These cells showed marked phagocytosis of hematopoietic cells, including megakaryocytes, erythroblasts, and a few neutrophils. In this patient, there is no possible causative factor of HPS (such as viral infection, lymphoma, and systemic lupus erythematosus) except the presence of aPL. There have been no previously reported cases describing the relationship between aPL and HPS. This case indicate that attention should be given to the possibility that certain patients with aPL-associated cytopenia may display accompanying intramedullary hemophagocytic phenomena.