Infected HbAS volunteers (with less prominent IgM responses [TI]) exhibited 1) lower rates of symptomatic malaria (14% versus 67%), 2) longer pre-patent periods than infected HbAA semi-immune volunteers (Table 2), although the differences in geometric means were not statistically significant,43 and 3) a trend toward higher IgG1, IgG3, and IgG4 levels (TD) for some antigens. This evidence concerns the gene IGHG3 and malaria.