HIV viral load assays when used with whole blood perform well as a diagnostic assay for infants

Objective

Over the past several years, only approximately 50% of HIV-exposed infants received an early infant diagnosis test within the first two months of life. While high attrition and mortality account for some of the shortcomings in identifying HIV-infected infants early and putting them on life-saving treatment, fragmented and challenging laboratory systems are an added barrier. We sought to determine the accuracy of using HIV viral load assays for infant diagnosis of HIV.

Methods

We enrolled 866 Ugandan infants between March–April 2018 for this study after initial laboratory diagnosis. The median age was seven months, while 33% of infants were less than three months of age. Study testing was done using either the Roche or Abbott molecular technologies at the Central Public Health Laboratory. Dried blood spot samples were prepared according to manufacturer-recommended protocols for both the qualitative and quantitative assays. Viral load test samples for the Roche assay were processed using two different buffers: phosphate-buffered saline (PBS: free virus elution viral load protocol [FVE]) and Sample Pre-Extraction Reagent (SPEX: qualitative buffer). Dried blood spot samples were processed for both assays on the Abbott using the manufacturer’s standard infant diagnosis protocol. All infants received a qualitative test for clinical management and additional paired quantitative tests.

Results

858 infants were included in the analysis, of which 50% were female. Over 75% of mothers received antiretroviral therapy, while approximately 65% of infants received infant prophylaxis. The Roche SPEX and Abbott technologies had high sensitivity (>95%) and specificity (>98%). The Roche FVE had lower sensitivity (85%) and viral load values.

Conclusions

To simplify and streamline laboratory practices, HIV viral load may be used to diagnose HIV infection in infants, particularly using the Roche SPEX and Abbott technologies.

Extracellular matrix, biotensegrity and tumor microenvironment. An update and overview

The extracellular matrix (ECM) constitutes a three-dimensional network that surrounds all cells, organs and tissues in the body. It forms a biophysical filter for protection, nutrition and cell innervation, as well as the medium for facilitating immune response, angiogenesis, fibrosis and tissue regeneration. It is the mechanism by which mechanical forces are transmitted to the basement membrane which, through the integrins, supports the tensegrity system and activates the epigenetic mechanisms of the cell. A review and update on current knowledge on this topic reveals how disturbance of the ECM leads to a loss of efficient filtering, nutrition, elimination, and cell denervation functions, in addition to loss of regeneration capacity and disorders in mechanotransduction. Furthermore, such disturbance results in a loss of substrate, and with it the ability to provide a proper immune response against tumor, toxic and infectious agents. Reciprocal communication between ECM stromal and parenchymatous cells directs gene expression. The oncogenic capacity of the stroma derives from the associated cells as well as from the tumor cells, the angiogenic microenvironment and from an alteration in tensegrity; all of which are dependent on the ECM. It has been shown that the malignant phenotype is reversible by correction of the altered cues of the ECM.

Comparative study of MLPA-FISH to determine DNA copy number alterations in neuroblastic tumors

Neuroblastoma tumor cells show complex combinations of genetic aberrations, and to date many different methods have been used for their detection. To apply genome-wide techniques, such as Multiplex Ligation-dependent Probe Amplification (MLPA), in routine diagnosis their validation is appropriate and necessary. DNA copy number alterations in 129 cases of neuroblastic tumors were detected using MPLA, and the results validated by Fluorescence In Situ Hybridization (FISH) (MYCN gene, 1p36, 11q and 17q). Kappa index values showed very good concordance between the two techniques in detecting homogeneous MYCN amplification (1); 11q deletion (0.908) and 17q gain (0.922). The validation results showed that MLPA is a highly efficient technique for diagnosis based on the genetic aberrations in relevant regions in neuroblastoma, showing a high concordance with FISH.