Evaluation of seven rapid HIV tests to detect HIV-exposure and seroreversion during infancy.

BACKGROUND: Failure to determine the HIV status of all pregnant women impedes progress in preventing and treating paediatric HIV because vertically exposed infants are not identified for prophylaxis, early HIV diagnosis and care. OBJECTIVES: To assess the performance of rapid HIV tests in comparison to a laboratory-based HIV ELISA test for determining HIV-exposure and excluding HIV infection during infancy. STUDY DESIGN: Seven rapid HIV tests were evaluated on 2266 stored samples from 116 HIV-exposed infants of known HIV status at four ages during infancy. The HIV ELISA for each sample was the standard against which rapid results were assessed to establish HIV-exposure. RESULTS: Rapid tests did not perform uniformly during infancy. For detecting HIV-exposure the sensitivity of most rapid tests to 3 months of age approached that of an HIV ELISA however only Determine maintained this sensitivity (99.7%) throughout infancy. For excluding HIV infection (i.e. for correctly identifying HIV-uninfected infants) the specificity of all rapid tests except Determine exceeded that of the HIV ELISA from 7 months of age. CONCLUSIONS: The use of rapid tests in infancy could improve identification and care of HIV-exposed infants. Further evaluation under field conditions is required before rapid tests can be incorporated into evidence-based diagnostic algorithms.

Low risk of contamination with automated and manual excision of dried blood spots for HIV DNA PCR testing in the routine laboratory.

In low resource settings the inability to diagnose HIV in infants early presents a major obstacle to providing care for HIV-infected children. Dried blood spot samples offer a solution to the scarcity of skills available for venesecting young infants but pose challenges to laboratories because their processing requirements are distinct from that of the liquid blood samples widely used for viral detection assays. Different methods of excising 287 paired HIV-positive and HIV-negative dried blood spot samples (n=574) for testing by the Roche Amplicor HIV-1 DNA assay version 1.5 were assessed. A manual punch in conjunction with three different cleaning protocols (n=372) and an automated punch (BSD 1000 GenePunch) using a single cleaning protocol (n=202) was assessed for the risk of cross contamination between samples. A single false positive result obtained using the automated punch may have been attributable to contamination during the excision step of the assay. Excision of dried blood spot samples is associated with a very low risk of cross contamination regardless of the instrument or cleaning intervention used. The process of excising dried blood spot samples should not compromise the results of HIV viral detection assays performed on dried blood spots in routine laboratories which is encouraging for increasing access to an accurate diagnosis of HIV in infants.

Modulation of integrin-linked kinase (ILK) expression in human oesophageal squamous cell carcinoma cell lines by the EGF and TGFbeta1 growth factors.

BACKGROUND: Integrin-linked kinase (ILK) is a ubiquitously expressed protein kinase that has emerged as one of the points of convergence between integrin- and growth factor-signalling pathways. RESULTS: In this study we identify the ILK isoform expressed in five human oesophageal squamous cell carcinoma cell lines of South African origin as ILK1, and demonstrate its cellular distribution. ILK expression, although similar in the majority of the cell lines, did show variation. Furthermore, the ILK expressed was shown to be catalytically functional. The effect of growth factors on ILK expression was examined. An increase in ILK expression, following EGF and TGFbeta1 exposure, was a trend across all the five oesophageal carcinoma cell lines tested. CONCLUSION: These results suggest that growth factor modulation of ILK expression relies on the internalisation/recycling of growth factor receptors and stimulation of the PI3K pathway, which may have implications with regards to cell adhesion and tumourigenesis.