METHODS: A sandwich ELISA using B. malayi soluble antigen was employed to detect antifilarial IgG4 antibodies in serum samples of 330 individuals who comprised 88 healthy individuals from nonendemic areas, 15 B. malayi microfilaraemic cases, 22 individuals with soil-transmitted helminthiases, 9 elephantiasis cases and 196 residents from a B. malayi-endemic area. An O.D. value of > 0.420 at serum dilution of 1:400 was used as the cut-off point. This cut-off point was obtained by taking the mean optical density (0.252 + 4 S.E.) of 36 negative sera which had O.D. values greater than 0.1 at serum dilution of 1:400.
RESULTS: All 15 microfilaraemic persons were positive for antifilarial IgG4 antibody. Non-endemic normals, soil-transmitted helminth infected persons and chronic elephantiasis cases were negative for antifilarial IgG4 antibody. Of the 196 individuals from the filaria endemic area, 37 (18.8%) demonstrated presence of antifilarial IgG4 antibodies; and only eight individuals (4.1%) were positive for microfilariae. All eight microfilaraemic individuals were also positive for antifilarial IgG4 antibodies.
CONCLUSION: Antifilarial IgG4-ELISA could detect 4.6 times more positive cases than the microfilaria detection method. With appropriate cut-off values that eliminate cross-reactivities, this serological tool is very useful for Brugia malayi prevalence surveys and diagnosis.
METHODOLOGY: During this study, enzyme activity was measured in 53/59 (89.8%) hospital-diagnosed G6PD-deficient neonates (34 Malays, 12 Chinese, and seven other ethnic groups) born consecutively in the Kuala Lumpur Maternity Hospital. All neonates, except one, were males.
RESULTS: The mean level of enzyme activity of the 52 males G6PD-deficient neonates (0.47 iu/g Hb, 95% confidence intervals: 0.37, 0.57) was less than 10% of that of normal Malaysian male neonates. The enzyme activity of the only female G6PD-deficient infant, at 1.11 iu/g Hb, was 12.5% of the mean G6PD enzyme activity of normal females.
CONCLUSION: Our results showed that G6PD deficiency in Malaysian neonates predominantly affects males and is usually severe.