GIFT showed that neutrophil-specific autoantibodies were produced by the patient, and the amount of autoantibody inversely correlated with the patient’s neutrophil counts.

The presence of an autoantibody to a novel antigen on immature myeloid cells or NVP-BKM120 mouse neutrophils is the likely the cause of severe neutropenia in this patient with KS. Kawasaki syndrome (KS) is an acute febrile illness that presents with systemic vasculitis and is associated with a high incidence of coronary artery abnormalities (CAA) [1, 2]. High-dose intravenous immunoglobulin (IVIG) therapy is effective and reduces the incidence of CAA [3]. Although haematological abnormalities, including leukocytosis, thrombocytosis and anaemia associated with KS, have been reported [4], there are only a few publications reporting severe neutropenia [5–7]. Neutropenia is defined as an absolute neutrophil count (ANC) of <1500/mm3, while severe neutropenia, observed in 1.0% of patients with KS [6], has an ANC of <500/mm3. Neutropenia was observed approximately 3–4 weeks after onset of KS [7]. Neutropenia during the subacute phase of KS has been ascribed to the transient inhibition of GM-CSF production [7], downregulation of inflammatory cytokines such

as interleukin (IL)-1β, IL-6 and tumour necrosis factor-α (neutrophil apoptosis inhibitors) [8, 9], the administration of aspirin selleck chemical or IVIG therapy [10, 11] and the possible relation of Vasopressin Receptor the production of antibodies that bind to neutrophils [12]. However, the detailed mechanisms behind neutropenia in KS have not been fully elucidated. Here, we describe a patient with KS whose disease was complicated with severe transient neutropenia. Bone marrow examination revealed developmental arrest at the early myelocyte stage, and flow cytometric analysis showed the presence of autoantibodies that bound to immature CD13-positive myeloid cells. We speculated that this specific antibody bound to premature myeloid cells or peripheral neutrophils and contributed

to the transient severe neutropenia of the patient. The aim of this study was to clarify the mechanisms of neutropenia in KS, using a combination of the granulocyte immunofluorescence test (GIFT) and flow cytometry. Patient report.  A previously healthy 2-year-old boy was admitted to a neighbourhood hospital suffering with fever, lymphadenopathy and fatigue (Fig. 1). Laboratory findings revealed a white blood cell count (WBC) of 24,700/mm3 and C-reactive protein (CRP) of 19.8 mg/dl. He was diagnosed with bacterial lymphadenitis and treated with Panipenem/Betamipron (PAPM/BP). On the fifth day of illness, he developed a skin rash, reddening of lips and conjunctival injection and was then diagnosed with KS.