ObjectiveTo compare the expressive differences of plasma Kerbs von den lungen-6 (KL-6) in patients with idiopathic interstitial pneumonia (IIP) and connective tissue disease associated secondary interstitial pneumonia (CTD-SIP), and analyze the clinical significances.MethodsThe clinical data and peripheral blood of 399 inpatients with interstitial pneumonia and 50 healthy controls were collected from January 2011 to December 2014 in Nanjing Drum Tower Hospital. The level of plasma KL-6 was measured by chemiluminescence immunoassay method. The subjects were divided into IIP (n=233) group and CTD-SIP (n=166) group, usual interstitial pneumonia (UIP) pattern and non-UIP pattern, and stable (S) UIP group and acute exacerbation (AE) UIP group. Statistical analyses were performed by using IBM SPSS 19.0 (SPSS, Inc., Chicago IL, USA) to compare the differences of plasma KL-6 in groups.ResultsThere were more male subjects (61.8%) in the IIP group, and the average age of (62.3±12.5) years was significantly older (both P<0.01). Plasma KL-6 levels in the IIP ［(1 822.7±1 505.2) U/ml) and the CTD-SIP group ［(1 846.7±1 625.3) U/ml］ were significantly higher than the healthy control group ［(190.2±88.7) U/ml］ (both P<0.001). However, there was no any difference of KL-6, white blood cell count (WBC), lactate dehydrogenase (LDH), C-reactive protein (CRP) and erythrocyte sedimentation rate between the IIP and the CTD-SIP group. The level of plasma KL-6 was positively correlated to WBC, LDH and CRP in the IIP group (r=0.159, P=0.016; r=0.380, P<0.001; r=0.158, P=0.015, respectively); and it was positively correlated to LDH and CRP in the IIP group (r=0.187, P=0.016 and r=0.068, P=0.032) in the CTD-SIP group. There was no significant difference of plasma KL-6 between the UIP and non-UIP subgroups (P>0.05). The difference of plasma KL-6 between the S-UIP and AE-UIP subgroup was significant (P<0.001 and P=0.023). There was no any significant difference of plasma KL-6 among the subgroups with CTD patients (primary Sj?gren’s syndrome, n=90; rheumatoid arthritis, n=20; polymyositis/dermatomyositis, n=26; undifferentiated connective tissue disease, n=10; anti-neutrophil cytoplasmic antibody associated vasculitis, n=15 and systemic sclerosis, n=5) (P=0.785 2).ConclusionsPlasma KL-6 may be a useful biomarker for interstitial pneumonia. It can show the disease activities, but is not able to distinguish IIP from SIP.
Objective To investigate the colonization, risk factors and prognosis of Pneumocystis jirovecii (P.jirovecii) colonization in patients with Pulmonary alveolar proteinosis (PAP). Methods The patients with Pulmonary alveolar proteinosis who were admitted to the Department of Respiratory and Critical Care Medicine, Nanjing Drum Tower Hospital from March 2019 to December 2022 were retrospectively analyzed. Polymerase chain reaction/next-generation metagenomic sequencing were used to detect the colonization of P. jirovecii in bronchoalveolar lavage fluid, and then to investigate the colonization rate, risk factors and outcome of P. jirovecii in PAP patients. Results A total of 25 patients were included in the study, of which 7 were colonized by P. jirovecii (28.0%). The rate of using antibiotics before admission in the colonizing group was significantly higher than that in the non-colonizing group (85.7% vs 33.3%, P=0.030). Total blood lymphocytes (1.4×109/L vs. 1.8×109/L, P=0.048), CD3+T cells (0.83×109/L vs. 1.34×109/L, P=0.010), CD4+T cells (0.48×109/L vs. 0.85×109/L, P=0.010) were significantly lower than those in the non-colonizing group, lactate dehydrogenase (469.9 U/L vs. 277.3 U/L, P=0.005) was significantly higher than those in the non-colonizing group. A higher proportion of colonizing group required combination therapy (57.1% vs. 11.1%, P=0.032); but there was no significant difference in the percentage of whole-lung ground-glass opacification, lung function, oxygen index and outcome. Lactate dehydrogenase was positively correlated with the percentage of whole-lung ground-glass opacification of PAP, but negatively correlated with oxygen index, percentage of predicted forced vital capacity and percentage of predicted diffusion capacity for carbon monoxide. Conclusions The colonization rate of P. jirovecii in PAP patients was high. Reduced lymphocyte count in peripheral blood of PAP patients and antibiotic use before diagnosing were risk factors for P. jirovecii colonization.
