ObjectiveTo explore the clinical value of the soluble urokinase type plasminogen activator receptor (suPAR) level in bronchoalveolar lavage fluid (BALF) for evaluateting the disease severity and prognosis of severe community-acquired pneumonia (SCAP). MethodsEighty-four patients with SCAP were recruited as a SCAP group from the respiratory department, ICU and RICU between April 2014 and April 2016. According to their organ dysfunction, the SCAP patients were subdivided into a MODS group and a non-MODS group. Depending on the treatment response on the 7th day of treatment, they were subdivided into an effective group and an ineffective group. According to the survival condition within 28 days, they were subdivided into a survival group and a death group. Meanwhile, 50 cases with non-severe common community acquired pneumonia were recruited as a control group. On the admission day, all cases were evaluated by PSI score and APACHE Ⅱscore. The serum suPAR level were detected by ELISA on the 1st day in hospital. The suPAR and procalcitonin (PCT) levels in the patient's BALF and serum were detected on the 1st, 3rd, 7th day, discharge or death day. The symptoms and signs, biochemical and pulmonary imaging changes were also observed. ResultsThere were no differences in the sex, age, body weight, duration of pneumonia, or complicated diseases such as hypertension, coronary heart disease and cerebral vascular diseases between the SCAP group and the control group (all P > 0.05). The suPAR levels in serum and BALF of the SCAP group were higher than those of the control group with significant differences (all P < 0.05). The suPAR level in BALF was obviously higher than that in serum in the SCAP group with significant difference (P < 0.05), and slightly higher than that in serum in the control group with no significant difference (P > 0.05). The level of suPAR in BALF of the MODS group was significantly higher than that in the non-MODS group with significant difference (P < 0.05), but there was no significant difference in the PCT level between the two groups (P > 0.05). The suPAR level in the ineffective treatment group was significantly higher than that in the effective treatment group on the 7th day in hospital with significant difference (P < 0.05). The suPAR levels in BALF of the death group were higher than those in the survival group at each time point after admittion with significant difference (all P < 0.05), and the PCT levels had no significant difference between the two groups within 1 week of each time point (all P > 0.05). The suPAR level in BALF of the SCAP group was positively correlated with APACHEⅡ score and PSI score (r=0.578, P=0.0085; r=0.565, P=0.0071), and plasma PCT level was weakly correlated with the APACHEⅡ score and PSI score (r1=-0.0137, r2=-0.0152). ConclusionThe SuPAR level in BALF of patients with SCAP is closely related to the severity and prognosis, and can be used as an index to assess the severity and prognosis.