Extracellular NAD⁺ levels are associated with CD203a expression on Th17 cells and predict long-term recurrence-free...

Mortality rates for hepatocellular carcinoma (HCC) remain high, while multimodal treatment approaches offer new perspectives. Here, we investigated the association of extracellular nicotinamide adenine dinucleotide (eNAD⁺) on ecto-nucleotide pyrophosphatase/phosphodiesterase 1 (CD203a, ENPP1 or PC-1) on Th17 cells in relation to the likelihood of HCC recurrence following liver resection.

The study compared heparinized blood plasma samples from 95 patients who underwent liver resection, including 25 patients with HCC and 24 control patients without liver disease. Plasma eNAD⁺ concentrations were determined using a heat-based dichotomous pH extraction method, followed by enzymatic cycling and a colorimetric assay for quantification. Fibrosis was graded histologically using the Desmet score (F0-F4). Surface expression analysis was performed using flow cytometry.

With increasing grades of liver fibrosis predominant in HCC patients, a significant reduction in plasma eNAD⁺ concentrations was measured (p < 0.05). Further, a significant correlation was found between HCC patients and CD203a expression on CD4⁺, CCR4⁺ as well as CCR6⁺ T cells (p < 0.05). Patients who exhibited high proportions of CD203a expressing Th17 cells (CD4⁺, CCR6⁺ CCR4⁺) post surgery were found to be at a sixfold increased risk (HR 6.38, 95% Cl 1.51-27.00) of HCC recurrence and had a median recurrence-free survival of 233 days (p < 0.05), compared to patients with low CD203a expressing Th17 cells (CD4⁺ CCR6⁺ CCR4⁺). Similarly, patients who had a high proportion of CD203a expressing Th17 cells (CD4⁺ CCR6⁺) following surgery had a fivefold increased risk (HR 5.56, 95% Cl 1.58-19.59) of HCC recurrence and a median recurrence-free survival of 334 days (p < 0.05) compared to those with low CD203a expressing Th17 cells (CCR6⁺).

The data indicates that eNAD⁺ levels are decreased in patients with liver fibrosis or cirrhosis. Strikingly, patients with high CD203a expression on Th17 cells had a significantly increased likelihood of recurrence, highlighting its potential as a valuable prognostic marker and a possible therapeutic target.