A 46-year-old woman, with no known underlying medical conditions, was admitted for a septic shock with acute respiratory distress syndrome. Influenza A non-H1N1 virus infection was confirmed by PCR on a respiratory sample with a high suspicion of bacterial co-infection despite negative bacterial culture.

Laboratory tests revealed microcytic anemia (8 g/dl, mean cell volume 70 fl) and profound thrombopenia (13 G/L). Reticulocyte count was down to 5 G/L. No hemolysis was observed (total bilirubin 10 μmol/l, haptoglobin 2.52 g/l, lactate deshydrogenase 347 IU/L). Fibrinogen concentration was 7.13 g/l. Triglyceride level was 10.48 mmol/L. Despite iron deficiency (iron concentration 1 μmol/L, total iron binding capacity 37 μmol/L, transferrin saturation coefficient 3%), ferritin concentration was unexpectedly in the normal range (169 μg/L).

A myelogram revealed an erythroblastopenia (2% of erythroblast) and a hemophagocytic syndrome (Fig. 1). Parvovirus B19 PCR was negative. No other cause than flu infection was suspected. All PCR tests for respiratory viruses or intracellular bacteria were negative. She received a 7-day course of oseltamivir, cefotaxime, and spiramycin and recovered within 10 days. The platelet count and hemoglobin normalized within 8 and 34 days, respectively.

Fig. 1
figure 1

Bone marrow aspirate showing hemophagocytosis and increased histiocytes. a–d May–Grünwald–Giemsa (MGG) stain; a–c ×1000, d ×100. a, b MGG stain of bone marrow showing histiocytes phagocytizing neutrophils (arrows). c MGG stain of bone marrow illustrating macrophages with erythrocytes and platelets (arrowhead). d MGG stain shows increased histiocytes and erythroblastopenia

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To our knowledge, this is the first reported case of erythroblastopenia and hemophagocytic syndrome related to influenza virus infection.