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. 2015 Jan 14;83(2):646–660. doi: 10.1128/IAI.02398-14

TABLE 2.

Antibody responses to P. falciparum merozoite antigens and prospective risk of symptomatic malaria with a density of >2,500/μla

Antigen, antibody (responder level) Value(s) for P. falciparum (density > 2,500/μl)
IRRb 95% CI P aIRRc 95% CI P aIRR-FOId 95% CI P
MSP1-19
    IgG (M) 1.27 0.93, 1.73 0.129 1.04 0.75, 1.45 0.818 0.95 0.74, 1.22 0.669
    IgG (H) 1.11 0.81, 1.52 0.517 0.99 0.74, 1.33 0.955 0.91 0.72, 1.16 0.465
    IgG1 (M) 1.21 0.90, 1.63 0.21 1.15 0.86, 1.55 0.35 1.00 0.79, 1.27 0.988
    IgG1 (H) 0.83 0.59, 1.15 0.259 0.84 0.63, 1.12 0.229 0.81 0.61, 1.06 0.127
    IgG3 (M) 1.13 0.83, 1.55 0.428 1.16 0.87, 1.56 0.319 1.02 0.79, 1.30 0.903
    IgG3 (H) 1.09 0.80, 1.47 0.596 1.12 0.80, 1.57 0.506 0.87 0.67, 1.13 0.293
    IgM (M) 0.97 0.73, 1.31 0.858 0.95 0.72, 1.25 0.724 1.04 0.81, 1.35 0.750
    IgM (H) 0.88 0.65, 1.20 0.43 0.90 0.65, 1.24 0.518 0.93 0.73, 1.18 0.541
MSP2 3D7
    IgG(M) 1.34 0.95, 1.89 0.092 1.12 0.79, 1.58 0.528 1.21 0.92 1.58 0.178
    IgG (H) 1.72 1.28, 2.33 <0.001 1.19 0.80, 1.77 0.399 1.13 0.86, 1.48 0.381
    IgG1(M) 1.10 0.77, 1.58 0.594 0.96 0.65, 1.42 0.836 0.97 0.73, 1.28 0.829
    IgG1(H) 1.66 1.21, 2.27 0.002 1.18 0.77, 1.81 0.458 1.07 0.81, 1.40 0.633
    IgG3 (M) 1.51 1.07, 2.13 0.018 1.52 1.07, 2.16 0.019 1.17 0.89, 1.55 0.253
    IgG3 (H) 1.91 1.40, 2.61 <0.001 1.35 0.89, 2.04 0.161 1.11 0.85, 1.47 0.436
    IgM (M) 0.85 0.61, 1.19 0.352 0.80 0.58, 1.10 0.177 0.92 0.70, 1.22 0.583
    IgM (H) 1.29 0.96, 1.73 0.092 1.10 0.80, 1.50 0.559 1.10 0.85, 1.42 0.480
MSP2 FC27
    IgG (M) 1.52 1.07, 2.17 0.019 1.36 0.96, 1.93 0.08 1.26 0.95, 1.67 0.111
    IgG (H) 1.99 1.44, 2.74 <0.001 1.48 0.98, 2.24 0.06 1.24 0.92, 1.67 0.162
    IgG1 (M) 1.54 1.09, 2.16 0.014 1.31 0.90, 1.89 0.161 1.19 0.90, 1.57 0.222
    IgG1 (H) 2.18 1.62, 2.93 <0.001 1.74 1.22, 2.49 0.002 1.32 1.00, 1.75 0.050
    IgG3 (M) 1.52 1.08, 2.15 0.017 1.48 1.04, 2.10 0.03 1.29 0.99, 1.69 0.062
    IgG3 (H) 2.17 1.58, 2.98 <0.001 1.62 1.08, 2.42 0.02 1.33 0.99, 1.80 0.060
    IgM (M) 0.91 0.66, 1.25 0.561 0.89 0.65, 1.24 0.5 0.92 0.72, 1.17 0.506
    IgM (H) 1.29 0.96, 1.73 0.086 1.12 0.79, 1.57 0.528 0.97 0.75, 1.25 0.806
AMA-1-3D7
    IgG (M) 1.49 1.08, 2.07 0.015 1.36 0.99, 1.87 0.058 1.28 0.97, 1.69 0.076
    IgG (H) 2.15 1.56, 2.96 <0.001 1.66 1.07, 2.58 0.023 1.29 0.97, 1.72 0.084
    IgG1 (M) 1.13 0.82, 1.55 0.445 1.04 0.75, 1.44 0.809 1.01 0.77, 1.33 0.922
    IgG1 (H) 1.72 1.29, 2.28 <0.001 1.25 0.88, 1.78 0.214 1.11 0.86, 1.43 0.409
    IgG3 (M) 1.55 1.11, 2.16 0.01 1.58 1.14, 2.19 0.006 1.43 1.09, 1.88 0.010
    IgG3 (H) 2.26 1.67, 3.05 <0.001 1.94 1.31, 2.87 0.001 1.44 1.09, 1.90 0.009
    IgM (M) 0.90 0.68, 1.19 0.459 0.99 0.73, 1.33 0.932 0.91 0.71, 1.16 0.438
    IgM (H) 0.77 0.56, 1.06 0.11 0.84 0.63, 1.14 0.265 0.86 0.66, 1.12 0.266
    All (H)e 1.45 0.99, 2.13 0.058 1.23 0.82, 1.85 0.316 1.21 0.84, 1.74 0.317
a

Antibody levels were grouped into tertiles and related to the prospective incidence of symptomatic P. falciparum malaria. High-level antibody responders (designated H) or medium-level antibody responders (designated M) were compared to low-level responders for each antigen. CI, confidence interval. Boldface data represent statistically significant associations (P < 0.05).

b

Values represent incidence rate ratio (IRR).

c

Adjustments were performed for the variables of village (11 categories), month (6 categories), year (continuous variable), age (continuous), P. falciparum infection status at the start of the interval (0 and 1), prior drug use (2 categories), and average ITN use (continuous) as defined previously (aIRR) (39).

d

Adjustments were performed to account only for differences in exposure as defined previously (aIRR-FOI) (32).

e

The prospective risk of malaria during the study follow-up period was examined in 16 individuals who were high-level responders for all antigens and was compared with the results determined for the rest of the cohort.