It was also observed that the DHFR mutant strain (401 T > C) was frequently associated with patients presenting with pneumonia (other group; 9/11, 81%), followed by 66% in patients with malignant disorders, 60% in patients with autoimmune disorders or immune deficiencies and 20% in patients with HIV seropositivity (Table 3). The gene discussed is DHFR; the disease is pneumonia.