Plasma PTX3 levels in sickle cell disease patients, during vaso occlusion and acute chest syndrome (data from Saudi population)

Background: Sickle cell disease (SCD) is a chronic, incurable hereditary disease. The vaso-occlusive crisis (VOC) is the most frequently occurring acute complication in sickle cell patients and accounts for the majority of SCD-related hospital admissions. Another major complication is the potentially fatal acute chest syndrome (ACS). The prototypic long pentraxin-3 (PTX3), an acute phase protein and a key component of innate immunity, is linked to ischemia-induced inflammation, a condition incriminated in SCD complications.

Aim: To investigate the expression of PTX3 in stable SCD and VOC patients and to assess its relation to the development and progression of ACS.

Subjects and methods: We conducted this study on 160 patients with confirmed SCD (20 stable SCD and 140 in VOC), and 10 healthy age- and sex-matched controls. Patients were diagnosed as SCD by high-performance liquid chromatography. PTX3 levels were assessed using enzyme-linked immunosorbant assay.

Results: In the stable state, all 20 SCD patients had PTX3 levels (range = 0.9-2.1 ng/ml; median = 1.1) comparable to those of healthy controls (range = 0.8-2.0 ng/ml; median = 1.0) (P > 0.05). During the VOC, plasma PTX3 significantly increased (range = 8.7-37.2 ng/ml; median = 22.3) (P < 0.01). Out of 140 VOC patients, 15 (10.7%) developed ACS and four required mechanical ventilation, of which two died. The median plasma level of PTX3 (22.3 ng/ml) was set as a cut-off value to stratify patients into low- and high-PTX3 expressers. Of the 140 VOC patients, 43 (30.7%) had PTX3 levels >22.3 ng/ml, of these, 13 patients developed ACS (13/43; 30.2%); of the remaining 97 patients who had PTX3 ≤22.3 ng/ml, only two patients (2/97; 2.1%) progressed to ACS, with a further increment in PTX3 in all of them. PTX3 levels were correlated with length of hospital stay in VOC patients and markers of lung injury in ACS patients.

Conclusion: PTX3 levels were higher in SCD patients in VOC, being associated with longer hospital stay. Higher initial PTX3 concentrations were related to the development of ACS with a further increase in PTX3 levels observed upon progression to ACS. Thus, PTX3 could be used as a subjective method to predict occurrence and severity of SCD acute complications.