Immunofluorescence assay for diagnosis of strongyloidiasis in immunocompromised patients

Strongyloides infection screening in transplant candidates: What is the best strategy?

BACKGROUND

The potential that Strongyloides stercoralis infection has to cause major morbidity and high mortality when the disseminated form occurs in transplant patients is of particular concern.

METHODS

In this study, the objective was to observe S. stercoralis infection in patients who are candidates for transplantation by using parasitological, serological, and molecular techniques and to propose an algorithm for the detection of that infection in transplant candidates.

RESULTS

By parasitological techniques, 10% of fecal samples were positive. Anti-Strongyloides antibodies immunoglobulin G were detected in 19.3% and 20.7% of patients by immunofluorescence assay and enzyme-linked immunosorbent assay, respectively. S. stercoralis DNA was observed in 17.3% of samples by conventional polymerase chain reaction and 32.7% of samples by quantitative polymerase chain reaction (qPCR).

CONCLUSION

The set of results allows us to reinforce that a positive result by parasitological techniques and/or qPCR indicates that the specific treatment should be applied. However, the improvement of diagnostic techniques may suggest changes in the screening for strongyloidiasis in these patients.

Ineffectiveness of TF-Test® and Coproplus® Methods in Strongyloides stercoralis Infection Diagnosis

PURPOSE

S. stercoralis diagnosis is currently performed by parasitological methods, mainly by Baermann-Moraes (BM), although Agar Plate Culture (APC) presents a higher sensitivity. New techniques, such as TF-Test® and Coproplus® have been suggested as more practical alternatives. The aim of this study was to evaluate the sensitivity of TF-Test® and Coproplus®, compared with APC, BM and Spontaneous Sedimentation (SS) methods.

METHODS

One-hundred and forty male alcoholic patients, who provided three stools samples collected on alternate days, were included in this study. The most frequently found parasite was S. stercoralis, 20% (28/140), and the most sensitive method was APC, 96.4% (27/28), followed by BM, 89.3% (25/28) and SS, 57.1% (16/28). TF-Test® and Coproplus® presented a sensitivity of 46.4 (13/28) and 39.3% (11/28), respectively. In samples with a parasitic load of 1-10 larvae/g of feces, which occurred in 39.3% (11/28) of the infected patients, both the TF-Test® and Coproplus® methods demonstrated sensitivities of 18.2% (2/11), while APC and BM methods reached a sensitivity of 100% (11/11) (p < 0.05). For other intestinal helminth infections, TF-Test® and Coproplus® sensitivities were 22.2 (4/18) and 11.1% (2/18), respectively, this being lower than the SS, 66.7% (12/18) (p < 0.05). On the other hand, for protozoa infection diagnosis, TF-Test® and Coproplus® presented the highest sensitivities, 62.2 (46/74) and 43.2% (32/74), respectively.

CONCLUSION

TF-Test® and Coproplus® methods presented the lowest sensitivities for S. stercoralis and other helminth infection diagnosis; therefore, they can be indicated for use in parasitological diagnosis, only when associated with other more effective methods of helminth identification.

Membrane Technology for Rapid Point-of-Care Diagnostics for Parasitic Neglected Tropical Diseases

Parasitic neglected tropical diseases (NTDs) affect over one billion people worldwide, with individuals from communities in low-socioeconomic areas being most at risk and suffering the most. Disease management programs are hindered by the lack of infrastructure and resources for clinical sample collection, storage, and transport and a dearth of sensitive diagnostic methods that are inexpensive as well as accurate. Many diagnostic tests and tools have been developed for the parasitic NTDs, but the collection and storage of clinical samples for molecular and immunological diagnosis can be expensive due to storage, transport, and reagent costs, making these procedures untenable in most areas of endemicity. The application of membrane technology, which involves the use of specific membranes for either sample collection and storage or diagnostic procedures, can streamline this process, allowing for long-term sample storage at room temperature. Membrane technology can be used in serology-based diagnostic assays and for nucleic acid purification prior to molecular analysis. This facilitates the development of relatively simple and rapid procedures, although some of these methods, mainly due to costs, lack accessibility in low-socioeconomic regions of endemicity. New immunological procedures and nucleic acid storage, purification, and diagnostics protocols that are simple, rapid, accurate, and cost-effective must be developed as countries progress control efforts toward the elimination of the parasitic NTDs.

Diagnosis of human strongyloidiasis: Application in clinical practice

This review considers the advantages and disadvantages of parasitological techniques, methods of detecting antibodies and antigens, as well as molecular biology techniques in the diagnosis of human strongyloidiasis. In addition, it elucidates the potential of different techniques for rapid and effective detection of clinical cases, thus enabling early treatment and preventing fatal consequences of this helminthiasis.

Inhibition of intervertebral disc disease progression via the circPKNOX1-miR-370-3p-KIAA0355 axis

The molecular mechanism underlying the development of intervertebral disc disease (IVDD) is not completely understood. Circular RNAs (circRNAs) play a significant role in the occurrence and development of various diseases, and studies have shown that circPKNOX1 is involved in the compensatory response of extracellular matrix synthesis and secretion of the nucleus pulposus (NP) cells. However, the mechanism through which circRNAs regulate IVDD progression remains unclear; therefore, in this study, we explored the significance of circPKNOX1 in IVDD. The expression of circRNAs in NP cells of normal and degenerative patients was detected using microarray analysis, and the role of circPKNOX1 in IVDD was confirmed using RT-qPCR. The interaction networks of circRNAs, miRNAs, and miRNA target genes were detected using bioinformatics analysis, RNA fluorescence in situ hybridization, and immunofluorescence analysis. We found that the expression of circPKNOX1 decreased in IVDD cells. The expression of circPKNOX1 in NP cells, observed using RT-qPCR and western blotting, was consistent with that observed using array screening. Overexpression of circPKNOX1 increased the expression of collagen II, aggrecan, and SOX9 and decreased that of ADAMTS4, ADAMTS-5, MMP3, and MMP13. We further demonstrated that circPKNOX1 played the role of a sponge by competitively binding miR-370-3p to reverse the inhibition of KIAA0355 expression. Our findings indicated that circPKNOX1 affected the progression of IVDD by regulating the expression of KIAA0355 via miR-370-3p. Therefore, circPKNOX1-based therapy may serve as an effective IVDD treatment strategy.

Strongyloides hyperinfection following hematopoietic stem cell transplant in a patient with HTLV-1-associated T-cell leukemia

Strongyloides stercoralis has the potential to cause accelerated autoinfection in immunocompromised hosts. Screening tests for strongyloidiasis may be falsely negative in the setting of immunosuppression. We report a case of Strongyloides hyperinfection syndrome in a patient with human T-lymphotropic virus type 1-associated T-cell leukemia early after hematopoietic stem cell transplant. The diagnosis was made by stool ova and parasite examination, despite a negative screening enzyme-linked immunosorbent assay. Because of anticipated prolonged neutropenia, an extended course of treatment was utilized.