Each of these immunopathology biomarkers (sTREM-1 [14–18], alveolar macrophage [19–22], IL-6 [23–25], IL-17 [26–29], CD4 T-cells [30–32], Tregs [33–35], SP-A [36,37] or Caspase-3 [38,39]) has been studied independently to mediate local inflammatory responses in severe pneumonia patients. The gene discussed is CD4; the disease is pneumonia.