Multiplex bead assay for serum samples from children in Haiti enrolled in a drug study for the treatment of lymphatic filariasis

Abstract

A multiplex bead assay (MBA) was used to analyze serum samples collected longitudinally from children enrolled in a drug trial for treatment of filariasis in Leogane, Haiti. Recombinant antigens Bm14 and Bm33 from Brugia malayi, third polar tube protein (PTP3) from Encephalitozoon cuniculi, and merozoite surface protein-1(19) (MSP-1(19)) from Plasmodium falciparum were coupled to carboxylated polystyrene microspheres. IgG responses to PTP3 and MSP-1(19) were not affected by albendazole (ALB), diethylcarbamazine (DEC), or combination of diethylcarbamazine and albendazole (DEC/ALB). However, IgG and IgG4 responses to Bm14 and Bm33 were significantly decreased (P < 0.001) by DEC and DEC/ALB treatment. Antibody responses to Bm14 and Bm33 decreased after DEC treatment (but not placebo) among children who were negative for microfilaremia and antigenemia at baseline, suggesting that these children harbored early stages of infection. The MBA is an excellent serologic technique for multiple antigens that offers substantial advantages over single-antigen based enzyme-linked immunosorbent assay in mass drug administration studies for monitoring changes in antibody levels.

Figure 1.

IgG4 and IgG responses to Bm14 for children of different infection groups, Haiti. Closed and opened box and whisker plots represent IgG4 responses from 95 children and IgG responses from 148 children, respectively. On the left are time points A, B, and C for children who received diethylcarbamazine (DEC) or DEC/albendazole (ALB) and on the right are time points A, B, and C for children who received placebo or ALB alone. A, Negative microfilaremia and antigenemia (MF–/Og4C3–) children. B, Positive antigenemia (Og4C3+) children, who include 37% (19 of 52) positive for MF. *Denotes significantly lower levels of IgG4 or IgG responses to Bm14 at time points B or C compared with time point A in the same treatment group and same infection status. Horizontal bars in box: low, 25%; middle, median; upper, 75%. Low whisker, 5%; upper whisker, 95%. Outliers are indicated by closed circles. The number of children is listed above the box.

Figure 2.

IgG4 and IgG responses to Bm33 for children of different infection groups, Haiti. Closed and opened box and whisker plots represent IgG4 responses from 95 children and IgG responses from 148 children, respectively. On the left are time points A, B, and C for children who received diethylcarbamazine (DEC) or DEC/albendazole (ALB) and on the right are time points A, B, and C on children who received placebo or ALB alone. A, Negative microfilaremia and antigenemia (MF–/Og4C3–) children; B, Positive antigenemia (Og4C3+) children, who include 37% (19 of 52) positive for MF. *Denotes significantly lower levels of IgG4 or IgG responses to Bm33 at time points B or C compared with time point A in the same treatment group and same infection status. Horizontal bars in box: low, 25%; middle, median; upper, 75%. Low whisker, 5%; upper whisker, 95%. Outliers are indicated by closed circles. The number of children is listed above the box.

Figure 3.

IgG4 and IgG responses to Bm14 and Bm33 for children positive for microfilaremia and antigenemia (MF+/Og4C3+), Haiti. A total of 9 MF+/Og4C3+ children (3 treated with diethylcarbamazine [DEC] or DEC/albendazole [ALB] and 6 treated with placebo or ALB) were tested for IgG4 responses, and a total of 19 MF+/Og4C3 + children (7 treated with DEC or DEC/ALB and 12 treated with placebo or ALB) were tested for IgG responses. Closed and opened box and whisker plots represent IgG4 and IgG responses, respectively. On the left are time points A, B, and C for children who received DEC or DEC/ALB and on the right are time points A, B, and C for children who received placebo or ALB alone. A, IgG4 and IgG responses to Bm14. B, IgG4 and IgG responses to Bm33. Horizontal bars in box: low, 25%; middle, median; upper, 75%. Low whisker, 5%; upper whisker, 95%. Outliers are indicated by closed circles. The number of children is listed above the box. Boxes with no whiskers are less than nine children.