Measuring the TREC ratio in dried blood spot samples: Intra- and inter-filter paper cards reproducibility

A Critical Review on the Standardization and Quality Assessment of Nonfunctional Laboratory Tests Frequently Used to Identify Inborn Errors of Immunity

Inborn errors of immunity (IEI), which were previously termed primary immunodeficiency diseases, represent a large and growing heterogeneous group of diseases that are mostly monogenic. In addition to increased susceptibility to infections, other clinical phenotypes have recently been associated with IEI, such as autoimmune disorders, severe allergies, autoinflammatory disorders, benign lymphoproliferative diseases, and malignant manifestations. The IUIS 2019 classification comprises 430 distinct defects that, although rare individually, represent a group affecting a significant number of patients, with an overall prevalence of 1:1,200-2,000 in the general population. Early IEI diagnosis is critical for appropriate therapy and genetic counseling, however, this process is deeply dependent on accurate laboratory tests. Despite the striking importance of laboratory data for clinical immunologists, several IEI-relevant immunoassays still lack standardization, including standardized protocols, reference materials, and external quality assessment programs. Moreover, well-established reference values mostly remain to be determined, especially for early ages, when the most severe conditions manifest and diagnosis is critical for patient survival. In this article, we intend to approach the issue of standardization and quality control of the nonfunctional diagnostic tests used for IEI, focusing on those frequently utilized in clinical practice. Herein, we will focus on discussing the issues of nonfunctional immunoassays (flow cytometry, enzyme-linked immunosorbent assays, and turbidimetry/nephelometry, among others), as defined by the pure quantification of proteins or cell subsets without cell activation or cell culture-based methods.

Rapid electrophoretic recovery of DNA from dried blood spots

Large-scale genetic screening of neonatal dried blood spots for episomal DNA has a great potential to lower patient mortality and morbidity through early diagnosis of primary immunodeficiencies. However, DNA extraction from the surface of dried blood spots remains one of the most time consuming, costly, and labor-intensive parts of DNA analysis. In the present study, we developed and optimized a rapid methodology using only 50 V and heat to extract episomal DNA from dried blood spots prepared from diagnostic cord blood samples. This electric field DNA extraction is the first methodology to use an electric field to extract episomal DNA from a dried blood spot. This 25-minute procedure has one of the lowest times for the extraction of episomal DNA found within the literature and this novel procedure not only negates the need for costly treatment and wash steps, but reduces the time of manual procedures by more than 30 min while retaining the 75-80% of the yield. Combined with real-time PCR, this novel method of electric field extraction not only provides an effective tool for the large scale genetic analysis of neonates, but a key step forward in the simplification and standardization of diagnostic testing.

Dysfunction of the thymus in mice with hypertension

The aim of this study was to evaluate thymus function in mice with hypertension. A total of 60 C57BL/6J mice were randomized into control, sham surgery and two-kidney, one-clip groups (n=20 in each). At 4 or 8 weeks after surgery, mice were sacrificed, and blood, spleens, kidneys and thymuses were harvested. The results of reverse transcription-quantitative polymerase chain reaction analysis revealed that the mRNA levels of Forkhead box protein N1 (Foxn1) and autoimmune regulator (AIRE) in the thymus tissue of mice from the HTN group were significantly lower than those from the control group at 4 and 8 weeks (P<0.05). Foxn1 and AIRE expression was also reduced in the sham surgery group at 4 weeks after surgery, but had recovered 4 weeks later. Similar results were observed for the expression of signal-joint T cell receptor excision circles and the percentages of T cell subsets. The present study indicates that impaired thymus function is associated with hypertension in mice, which suggests that thymus function may be a novel target for the treatment of patients with hypertension.

Age estimation via quantification of signal-joint T cell receptor excision circles in Koreans

The estimation of age from biological samples (i.e., remains) at crime scenes could provide useful information about both victims and other persons related to criminal activities. Signal-joint T cell receptor excision circle (sjTREC) levels in peripheral blood decline with age, and negative correlations between sjTREC levels and age have been demonstrated in several ethnic groups. To validate the utility of sjTREC for age estimation in Koreans, Taqman qPCR was used to quantify the sjTREC level in samples obtained from 172 individuals ranging from 16 to 65 years old. We modified the previously reported method by using a shorter amplicon and confirmed the efficiency and utility of this method in this report. Our results showed that the linear negative regression curve between sjTREC levels and age was characterized by r=-0.807 and a standard error of 8.49 years. These results indicate that sjTREC level is an effective age estimation method in Koreans. The value of the standard error of quantification was not different from previous reports for other population groups.