Fig 1: Elevated sULBP2 levels in patients with moderate COVID-19. (A) Serum levels of sULBP2 at the clinically most symptomatic time point during hospitalization were measured in the mild (n = 11) and moderate (n = 16) groups using the Human ULBP2 SimpleStep ELISA® Kit. White circles and black circles represent individual patient values for the mild group and moderate group, respectively. Horizontal bars indicate the mean values. Statistical significance is denoted as **p < 0.01. (B) A volcano plot generated to compare the mild and moderate cases at the clinically most symptomatic time point using the levels of 24 serum markers and sULBP2. The y-axis represents −log10 (q-value), whereas the x-axis represents log2 fold change (FC), where FC is defined as the mean value in moderate cases divided by the mean value in mild cases. The dashed line represents nominal p = 0.05, indicating that serum markers above the line are significant without multiple comparison correction. Statistical analyses were conducted using the Mann–Whitney U test for comparisons between disease severity group. White squares indicate that the serum markers the remained significant after false discovery rate (FDR) correction performed using the two-stage linear step-up procedure of Benjamini, Krieger, and Yekutieli, whereas the black squares indicate those that were not significant. A threshold of q < 0.05 was considered statistically significant.