Statistics
After testing for distribution with Komolgorov-Smirnov-test, non-parametric variables were compared by the Mann-Whitney U-test using SPSS software (Version 26.0) (IBM statistic, Chicago USA). Correlations between demographic and immunological parameters were performed using Spearman rank’s correlation coefficient. Numbers of stratified groups were compared using X2 or Fisher’s exacta test. A p-value ≤ 0.05 was considered statistically significant.