To Normalize or Not? Dilute Russell Viper Venom Time testing

Introduction/Objective

Background: Antiphospholipid antibodies bind phospholipid bound proteins. Criteria for diagnosis of the antiphospholipid syndrome includes detection of either a lupus anticoagulant (LA) or anticardiolipin/anti B2GP1 antibodies and thrombotic events or pregnancy loss. Functional LA is detected by prolonged dRVVT clotting time (dCT) of patient plasma in the presence of limited phospholipid (screen) followed by a 1:1 mix of patient and normal pooled plasma to rule out procoagulant deficiency (mix). Confirmation is achieved by addition of excess phospholipid shortening the dCT and increasing the screen/confirm ratio (SCR). Normalization involves testing pooled reference plasma to determine the SCR with an added calculation step to correct for reagent/instrument differences. We compared the SCR in patient plasma with that obtained using reference plasma to determine impact on clinical decision making.

Methods/Case Report

Methods: 404 patients had dRVVT testing (STAGO STA-R Evolution) from 09/2021 to 05/2022. Positive screens (≥51 seconds) underwent mixing studies followed by confirmatory tests (>=46 seconds). The dRVVT of reference pooled plasma was also measured (George King Normal Pooled Plasma). A positive conventional or normalized SCR was defined as an SCR > 1.2 and comparison was by the paired t test.

Results (if a Case Study enter NA)

6.4% (26) of the 404 samples tested were confirmed positive for LA by both methods, out of which 12 had a clinical history of thrombosis. Although a statistically significant difference between the two groups (p=0.0096) was found, the magnitude of absolute SCR differences (0.1s) was within total allowable error limits and there was 100% concordance of positive and negative results between the 2 groups.

Conclusion

There is no clinically significant difference between the two groups. Normalization had no benefit in our patient population, therefore no need for the extra calculation step. Others have reported that normalization is useful for inter-method and inter-laboratory studies and not for within method LA detection consistent with our results.

Ethnically mismatched cord blood transplants in African Americans: the Saint Louis Cord Blood Bank experience

BACKGROUND

For ethnic minority patients where a suitably matched BM or peripheral blood donor is frequently unavailable, cord blood offers an opportunity for hematopoietic stem cell transplantation. Focused recruitment of ethnic minorities for cord blood donation has been proposed as the preferred strategy to improve access for minority recipients to cord blood for transplantation. The aim of this study was to evaluate cord blood characteristics for Caucasian and African American donors and the success of ethnically mismatched UC blood transplantation in African American recipients.

METHODS

Retrospective data analysis was performed comparing the characteristics of 556 cord blood units from African American and Caucasian donors. The outcomes of 18 African American ethnically mismatched transplant recipients were compared with a paired sample of 18 ethnically matched Caucasian recipients.

RESULTS

The fraction of collected units meeting acceptability criteria from African Americans was significantly lower compared with Caucasians (P = <0.0001). Additionally, African Americans had a significantly lower post-processing total nucleated cell count (TNC) compared with Caucasians (P=0.007) but there were no other significant differences in conventionally measured product characteristics. In the transplant analysis, there was no difference in overall survival at 1 year (P=0.85) or time to neutrophil engraftment (P=0.92) between the two patient populations.

DISCUSSION

At comparable levels of TNC dose and HLA matching, the use of ethnically mismatched UC blood units as a source for allogeneic unrelated transplant can result in successful transplant outcomes for African American patients.

Keratan sulphate levels in mucopolysaccharidoses and mucolipidoses

The mucopolysaccharidoses (MPS) is characterized by accumulation of glycosaminoglycans (GAGs), and mucolipidosis (ML) by accumulation of GAGs and sphingolipids. Each type of MPS accumulates specific GAGs. The lysosomal enzymes N-acetylgalactosamine-6-sulphate sulphatase and beta-galactosidase involve the stepwise degradation of keratan sulphate (KS). Deficiency of these enzymes results in elevation of KS levels in the body fluids and in tissues, leading to MPS IV disease. In this study, we evaluated blood and urine KS levels in types of MPS and ML other than MPS IV. Eighty-five plasma samples came from MPS I (n = 18), MPS II (n = 28), MPS III (n = 20), MPS VI (n = 3), MPS VII (n = 5) and ML (n = 11) patients while 127 urine samples came from MPS I (n = 34), MPS II (n = 34), MPS III (n = 32), MPS VI (n = 7), MPS VII (n = 9) and ML (n = 11) patients. KS levels were determined using the ELISA method. Plasma KS levels varied with age in both control and patient populations. In all age groups, the mean values of plasma KS in MPS and ML patients were significantly higher than those in the age-matched controls. Plasma KS values in four newborn patients were above the mean + 2SD of the age-matched controls (mean, 41 ng/ml). Overall, 85.9% of individual values in non-type IV MPS and ML patients were above the mean + 2SD of the age-matched controls. For urine KS levels, 24.4% of individual values in patients were above the mean + 2SD of the age-matched controls. In conclusion, KS in blood is elevated in each type of non-type IV MPS examined, in contrast to the conventional understanding. This finding suggests that measurement of KS level provides a new diagnostic biomarker in a wide variety of mucopolysaccharidoses and mucolipidoses in addition to MPS IV.

Detecting Human CD34 + and CD34 - Hematopoietic Stem and Progenitor Cells Using a Sysmex Automated Hematology Analyzer

In clinical medicine, particularly in the newly developing stem cell therapies required to support the practice of regenerative medicine, the measurement of both CD34+ and CD34- hematopoietic stem cells (HSC)/hematopoietic progenitor cells (HPC) is important in obtaining more accurate information about the total HSC/HPC content in various stem/progenitor cell sources. We report the results of an investigation into methods of detecting CD34+ and CD34- HSC/HPC using the immature information (IMI) channel incorporated into the Sysmex XE-2100 and SE-9000 automated hematology analyzers. In this study, CD34+ and CD34- HSC/HPC were separated by immunologic methods and quantified by flow cytometry (FACScan) and IMI channel analysis. In addition, CD34-/CD133+ HSC were prepared by a sequential antibody-based positive selection strategy. These cells appeared in the same area as CD34+ cells in the IMI channel of the automated hematology analyzer. These findings confirmed that an automated hematology analyzer can be used to measure both CD34+ and CD34- HSC. These results may explain the difference in HSC/HPC counts sometimes observed between the automated hematology analyzer and flow cytometric methods for CD34+ measurement. The results of this study demonstrated the potential of automated cell counting methods for measuring HSC content in cellular products for both research and clinical applications.

Case report. Diagnosis of early HIV-1 infection

The diagnosis of acute infection with human immunodeficiency virus (HIV) presents a challenge for the primary care provider. We present a case of early HIV infection and discuss the limitations of the currently established diagnostic algorithm for HIV infection. We conclude that alternative diagnostic testing for human immunodeficiency virus type 1 (HIV-1) RNA is warranted in certain clinical settings. Appropriate, early diagnosis of HIV infection may improve the patient's outcome and provide additional public health benefits by reducing transmission of disease.

Diagnostic testing for HIV type 1 RNA in seronegative blood

We studied the feasibility of routine diagnostic testing for HIV-1 RNA at a publicly funded testing site. HIV-1 RNA was determined with a commercial polymerase chain reaction assay in pooled seronegative blood samples submitted for HIV testing to a public health laboratory. Recovery of HIV-1 RNA from the samples was estimated as at least 8% of viral RNA that was found in freshly prepared plasma. We estimated that screening for HIV-1 RNA in serum pools would result in the identification of blood specimens from more than 95% of acutely infected patients. The frequency of HIV-1 RNA in seronegative blood samples was estimated to be between 19 and 601 per 10(6) submitted specimens. The ratio of HIV-1 RNA positive and seronegative samples to specimens with HIV-1 antibodies confirmed by Western blot was estimated to be between 0.2% and 6.6%. The reagent costs for identifying 1 HIV-infected blood sample were 10-fold higher with the commercially available HIV-1 RNA assay compared with the HIV antibody enzyme-linked immunosorbent assay. Diagnostic testing for HIV-1 RNA may be warranted in high-risk populations since acutely infected patients may benefit most from anti-retroviral therapy and are thought to contribute disproportionately to the HIV epidemic.

Fatality due to acute hydrofluoric acid exposure

Although hydrofluoric acid burns are frequent, fatality is rare. In the case of massive exposure, the prognosis is generally poor. We present two fatal cases resulting from extensive exposure to hydrofluoric acid which produced acute systemic metabolic acidosis with profound hypocalcemia and hypomagnesemia. Both patients died within three hours after the exposure. The current knowledge of treatment for severe hydrofluoric acid burns is reviewed and the importance of prevention and prompt recognition for proper treatment is emphasized.