Prevalence of anti-HLA antibodies in COVID-19 convalescent plasma donors: an Indian experience.

BACKGROUND: COVID-19 convalescent plasma is one of the experimental therapies used widely in moderately sick COVID-19 patients. However, there are a few risks involved in plasma transfusion; notably, transfusion-related acute lung injury (TRALI) caused by antibodies against human leukocyte antigens (HLA). This study was designed to assess the prevalence of anti-HLA antibodies in convalescent plasma donors using the single antigen bead method. STUDY DESIGN AND METHODS: This was a hospital-based observational study of consecutive plasma donors. A total of 252 samples were screened for anti-HLA Class I and Class II antibodies using the microbead assay with the identification of anti-HLA Ab in positive samples being performed using a single antigen bead assay. Luminex-based normalized background cutoff ratios of 10.8 for Class I and 6.9 for Class II and mean fluorescence intensity cutoffs of 2500 for Class I and 1500 for Class II were used for screening and the single bead assay, respectively. RESULTS: Of 252 screened samples, 28 (11.1 %) were positive for Class I, Class II or both Class I and Class II anti-HLA antibodies in donors with no history of a previous immunizing event. Moreover, 20/252 (7.9%) donors without any history of prior immunization had specific anti-HLA antibodies of Class I or Class II or both by the single bead assay. CONCLUSIONS: The high prevalence of anti-HLA antibodies in our cohort of donors raises an urgent and immediate need for anti-HLA antibody screening in all convalescent plasma donors for safe therapy of COVID-19 patients.

Perspectives on Rapid Antigen Tests for Downstream Validation and Development of Theranostics.

Point-of-care SARS-CoV-2 rapid antigen tests have proven to be useful over the years and have become more apparent to the public eye during COVID-19 pandemic due to their ease of use, rapid processing and result times, and low cost. Here, we have assessed the effectiveness and accuracy of rapid antigen tests in comparison to the standard real-time polymerase chain reaction analyses of the same samples.

Identification of the novel allele, HLA-A*01:01:01:92, in an individual from North India.

HLA-A*01:01:01:92 differs from HLA-A*01:01:01:01 by a single nucleotide G->C change at gDNA-56 position.

Correlation of sample-to-cut-off ratio of anti-SARS-CoV-2 IgG antibody chemiluminescent assay with neutralization activity: a prospective multi-centric study in India.

Background and Objectives: There are limited published data on association of results from commercial serological anti-SARS-CoV-2 IgG antibody CLIA (chemiluminescent immunoassay) assays with neutralizing antibodies. This study was undertaken with an objective to correlate sample-to-cut-off (S/Co) ratio of CLIA antibody tests with inhibition activity, which may then serve as a valuable guide for labelling plasma as COVID convalescent plasma (CCP) for therapy and assessing vaccine efficacy. Materials and Methods: A total of 139 donor serum samples who were previously RT-PCR positive and had recovered completely from COVID-19 at least 28 days prior to collection of samples were recruited at three sites. The samples were analysed for S/Co ratio and per cent inhibition activity with VITROS SARS-CoV-2 IgG chemiluminescent assay and GenScript cPass SARS-CoV-2 Surrogate Virus Neutralization Test (sVNT) kit, respectively. Linear regression equation and receiver operating characteristic (ROC) curve were used to check the proposed model of comparing S/Co with per cent inhibition. Results: The results indicate very good correlation between the S/Co ratio of the chemiluminescent IgG assay and the neutralization activity depicted by per cent inhibition on sVNT assay. S/Co ratio of 4·04 (low-titre) and 8·19 (high-titre) correlated with 30% and 68% inhibition, respectively. Conclusion: Chemiluminescent SARS-CoV-2 IgG assay can be used as a semi-quantitative test, with a cut-off of >8·19S/Co ratio for selecting donors for convalescent plasma therapy and assessing efficacy of vaccination.

The correlation of spurious eosinophilia in automated hematological analyzer Sysmex XS-800i with Plasmodium infection diagnosis.

CONTEXT: Automated analyzers based on flow cytometry have evolved as an effective adjuvant diagnostic tool in malaria diagnosis. AIM: To find out the correlation of interpretive (IP) message from automated hematology analyzer XS-800i and Plasmodium infection diagnosed in peripheral smear. SETTINGS AND DESIGN: Prospective study carried over a period of 2 years (July 2010 to June 2012). MATERIALS AND METHODS: All cases with IP message of eosinophilia in Sysmex XS-800i analyzer were screened for microscopic correlation of eosinophilia and other peripheral smear findings. RESULTS: In 24 out of 5012 patients with eosinophilia, microscopic eosinophil counts were normal. In these 24 cases, IP message in hematology analyzers was that the eosinophilia and WBC scattergram showed narrowed space between the eosinophil and neutrophil population. On careful examination of the peripheral smears of all 5012 cases, 39 cases revealed different stages of Plasmodium vivax (trophozoites, schizonts or gametocytes) in erythrocytes. CONCLUSION: Peripheral smears of the cases having inconsistent eosinophilia result with that of Sysmex XS-800i analyzer should be examined carefully for the presence of malaria parasites in the red blood cells. Sysmex XS-800i analyzers have moderate range of sensitivity and high degree of specificity in diagnosing malaria as spurious eosinophilia.