| Total CAP | Nonsevere CAP PSI 1–3 | Severe CAP PSI 4–5 | Healthy controls | |
| Subjects n | 20 | 10 | 10 | 10 |
| Age years | 60.6±19 | 54.5±18.4 | 66.6±15.8 | 54.8±5.7 |
| Sex | ||||
| Male | 13 (65) | 6 (60) | 7 (70) | 6 (60) |
| Female | 7 (35) | 4 (40) | 3 (30) | 4 (40) |
| Smoking | 8 (40) | 4 (40) | 4 (40) | 4 (40) |
| Comorbidity# | N/A | |||
| COPD | 5 (25) | 4 (40) | 1 (10) | |
| Heart disease | 6 (30) | 1 (10) | 5 (50) | |
| Neurological disorder | 4 (20) | 1 (10) | 3 (30) | |
| Chronic renal disease | 1 (5) | 1 (10) | ||
| Diabetes mellitus | 2 (10) | 1 (10) | 1 (10) | |
| PSI class | N/A | |||
| I | 3 (15) | 3 (30) | ||
| II | 5 (25) | 5 (50) | ||
| III | 2 (10) | 2 (20) | ||
| IV | 6 (30) | 6 (60) | ||
| V | 4 (20) | 4 (40) | ||
| Mechanical ventilation | 4 (20) | 4 (40) | N/A | |
| Mortality | 2 (10) | 2 (20) | N/A | |
| Bacteraemia | 5 (25) | 1 (10) | 4 (40) | N/A |
| Prior antibiotic use | 5 (25) | 3 (30) | 2 (20) | N/A |
| ICS | 5 (25) | 4 (40) | 1 (10) | N/A |
| Microbiological species | 14 (70) | 7 (70) | 7 (70) | N/A |
| Streptococcus pneumoniae | 7 (35) | 3 (30) | 4 (40) | |
| Stenotrophomonas maltophilia | 1 (5) | 1 (10) | ||
| Pseudomonas aeruginosa | 1 (5) | 1 (10) | ||
| Streptococcus pyogenes | 1 (5) | 1 (10) | ||
| Staphylococcus aureus | 1 (5) | 1 (10) | ||
| Haemophilus influenzae | 1 (5) | 1 (10) | ||
| H1N1 | 1 (5) | 1 (10) | ||
| Adenovirus | 1 (5) | 1 (10) | ||
| Unknown | 6 (30) | 3 (30) | 3 (30) |
Data are presented as mean±sd or n (%), unless otherwise stated. CAP: community-acquired pneumonia; PSI: pneumonia severity index; COPD: chronic obstructive pulmonary disease; ICS: inhaled corticosteroids; N/A: not applicable. #: Some patients had more than one comorbidity.