Evaluation of saliva-based diagnostic test kit for routine detection of antibodies to HIV.

The study was carried out to determine the reliability of a saliva based test kit for routine detection of HIV antibodies. 150 paired plasma and saliva samples were collected from 50 patients who were known to be positive for HIV-I and 100 others whose HIV serostatus were previously unknown. All the plasma samples were tested for HIV antibodies using Novopath Immunoblot Technique (as the gold standard), Wellcozyme (Murex) ELISA, Latex Agglutination Test (Capillus) and SeroCard Kit. The saliva samples were screened for HIV antibodies using SalivaCard Test Kit. All the 50 known positive patients tested positive when retested with immunoblot and 9 of 100 whose serostatus were unknown also tested positive giving a total of 59 positive results and 91 negative results. Of the 59 positive results, 59, 57, 58 and 47 were correctly identified as true positives by Wellcozyme, Capillus, SeroCard and SalivaCard respectively. Of the 91 negatives, 90, 91, 90 and 85 were correctly identified as true negatives respectively. Sensitivities in the same order were 100%, 97%, 98.3% and 79.7% whilst specificities were 98.9%, 100%, 98.9% and 97.8%. Whereas evaluation parameters for Wellcozyme, Capillus and SeroCard test kits met the criteria for licensure of a test kit as a routine test method for HIV antibody detection, the SalivaCard values fell far short of the stipulated criteria. The Sensitivity, Test Efficiency and Positive Predictive Values of 79.7%, 88% and 67.8% respectively obtained for SalivaCard are too low and the test kit cannot be recommended for routine use as HIV antibody detection kit.

Application of polymerase chain reaction to the prenatal diagnosis of sickle cell anaemia in Nigeria.

Although sickle-cell disease is very common in Nigeria, control by prenatal testing is lacking. The polymerase chain reaction-based technology combined with chorionic villi sampling has enabled us to offer prenatal diagnosis of sickle cell disease to 50 pregnant women who were at risk of bearing children with sickle cell anaemia. DNA was extracted from the villus and subjected to either PCR and restriction enzyme (Dde I) analysis (36 samples) or to PCR-ARMS procedure (12 samples) or to both procedures when the results by the first procedure were equivocal (2 samples). The genotypic distribution was 13AA, 25AS and 11SS. In one case, it was not possible to determine the genotype of the villi by both methods. A post delivery genotype analysis confirms the correctness of prenatal diagnosis in all the 42 subjects that has so far reported. The results clearly demonstrate the usefulness of the PCR method in the prenatal diagnosis of sickle-cell anaemia in this environment.

Leucocyte ascorbic acid levels in Nigerian children with protein-energy malnutrition.

Leucocyte ascorbic acid (LAA) levels were estimated in 26 Nigerian infants and preschool children with protein energy malnutrition (PEM) in order to ascertain their ascorbic acid status. The children included eight with kwashiorkor, 12 with marasmus and six with marasmic kwashiorkor. The mean (SD) LAA level of 13.7 (8.2) micrograms/10(8) leucocytes in the malnourished children did not vary significantly from the mean level of 14.4 (8.8) micrograms/10(8) leucocytes found in 26 age-matched controls, and the values were unrelated to the presence or absence of megaloblastic change in the 14 bone marrows examined. It was concluded that ascorbic acid deficiency was not prevalent amongst children with PEM in Lagos, and was therefore not usually contributory to the anaemia, megaloblastic changes or other features of the syndrome seen in Nigerian children in Lagos.