The hazy shadowing of ground-glass changes seen in PCP are a reflection of the exuberant host inflammatory response that is triggered by P. jirovecii attachment to alveolar pneumocytes and extracellular matrix proteins,30 with resultant interstitial thickening, partial alveolar exudative filling, air displacement and/or alveolar collapse.23 The neutrophil- and CD8+-driven immune reaction that incites lung injury and contributes to respiratory failure in PCP31 occurs paradoxically in patients with advanced immunodeficiencies. Here, CD8A is linked to pneumocystosis.