In the second observation, IgG concentration was positively correlated with the infection index reported by 69 participants (Spearman R = 0.47; p < 0.0001); then IgA concentration was positively correlated with both infection index (Spearman R = 0.44; p < 0.0001) and age (Spearman R = 0.17; p = 0.026). The gene discussed is CD79A; the disease is infection.