Serum procalcitonin levels in newly diagnosed classical Hodgkin Lymphoma (cHL): Correlation with other inflammatory biomarkers
In the recent years procalcitonin (PCT) has emerged as a useful biomarker for the diagnosis of sepsis and bacterial infection. Inflammatory markers are elevated in the majority of patients with cHL, a finding that may cause diagnostic issues. Ongoing infection rarely coexists with HL at the time of diagnosis. PCT levels might be helpful in differentiating bacterial infection from non-bacterial, disease-related inflammation, which are both characterized by elevated CRP levels.
Materials and Methods:
In order to assess whether and to what extent the underlying chronic inflammatory condition is associated with elevated PCT levels, we collected data on serum PCT levels and other routine inflammation markers in newly diagnosed cHL patients. Values <0.50 ng/mL were considered normal; 0.10-0.50 ng/mL were normal/detectable, while <0.10 ng/mL were normal/undetectable. Serum PCT levels were considered elevated if exceeded the cut-off of 0.50 ng/mL.
Among 137 patients diagnosed with cHL between April 2010 and August 2015, 55 had B-symptoms (40%), ESR was ≥50 mm/h in 77/130 (59%) and 116 patients (85%) had elevated CRP; the median CRP was 38.1 mg/L (range;2.97-328.0). The median serum ferritin was 154.10 ng/ml (range;7-6709) and leukocytosis (WBC ≥15x109/L) was recorded in 20 (15%) patients. Serum PCT levels were normal in the vast majority of the patients [normal/undetectable 94/137(68.5%) and detectable 41/137(30%)] with median value <0.10 ng/ml (<0.10-15.90). Only 2 patients had elevated PCT levels (1.5%). Patients who had serum PCT<0.10 ng/ml had lower median CRP [25.75; range(2.97-203.0)] compared to patients with PCT ≥0.10 ng/ml who had median CRP of 92.50 mg/L(range;3.34-328.0; p<0.001). Almost all patients (40/41, 97.6%) with detectable PCT levels had also elevated CRP. Compared to patients with normal/undetectable levels, those with PCT ≥0.10 ng/ml had more frequently advanced disease (83%), B symptoms (73%), ESR≥50 (82%), anemia (81%), hypoalbuminemia (90%), leukocytosis (27%) and higher serum ferritin, haptoglobin and a2-globulin levels.
This is the first study showing that the inflammatory condition characterizing cHL is not associated with serum PCT elevations although CRP levels are elevated in 85% of them. Consequently, normal serum PCT levels may rule out the diagnostic possibility of occult infection, thus preventing extensive evaluation, which may further delay in treatment initiation.