Introduction

A 82-year-old man presented with asthenia, dyspnea and fever for 2 days and was admitted from the emergency department to our intensive care unit with acute hypoxemic respiratory failure. His past medical history included a myeloperoxidase-antineutrophil cytoplasmic autoantibody-associated vasculitis with renal impairment, diagnosed 4 years earlier and treated with steroids and methotrexate for 2 years, resulting in a persistent chronic kidney disease. Following admission and endotracheal intubation for mechanical ventilation, a thoracic CT-scan (see Supplementary material) disclosed bilateral interstitial lung infiltrates, with multiple patterns including micronodules, ground-glass and tree-in-bud opacities. Bronchoalveolar lavage (BAL) was performed in the right middle lobe (75 mL/150 mL). Macroscopic examination of BAL fluid revealed a pink color; microscopic examination (Fig. 1) revealed a total cell count (220 cell/µL) in the normal range, but a high lymphocyte differential count (24%, CD3 82% and CD19 2%) with a CD4/CD8 T-cell ratio of 1.7. A complete microbiological workup was performed, which allowed to diagnose COVID-19 pneumonia, without concomitant bacterial infection. No recurrence of vasculitis was identified. Despite symptomatic treatment, the patient died after 13 days in the ICU. Here, we point out the high lymphocyte count in BAL fluid during COVID-19 pneumonia. Data about alveolar cellularity in this novel viral infection are urgently needed, which may provide clues for testing immunomodulatory treatments [1] in the most severely affected patients.

Fig. 1
figure 1

May-Grunwald Giemsa stained cells from bronchoalveolar lavage fluid after cytocentrifugation (40X). Black arrow: lymphocyte; white arrow: macrophage; arrowhead: neutrophil

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