The frequency of CD4+CD28null cells among the IPF patients destined for poor outcomes here are also highly comparable to the proportions of these cells among lung transplant recipients with chronic rejection who had similarly guarded prognoses [20], and is even greater than in many other disease conditions wherein these particular lymphocytes have been implicated in pathogenesis [21]–[34]. The gene discussed is CD4; the disease is idiopathic pulmonary fibrosis.