Donor-Specific Antibody Detection by Single-Antigen Bead Assay for Renal Transplantation: A 2-Year Experience from South India.

Introduction: Recipient sensitization against donor human leukocyte antigens (HLA) plays a key role in transplant rejection, and this risk is best minimized by efficient pre transplant antibody detection. Determination of antibody specificity with the highest sensitivity and degree of resolution to the allelic antigen level is achieved by using single-antigen bead (SAB) assay. Methods: This study evaluated the correlation of Luminex cross match (LXM) with SAB assay for detection of donor-specific antibodies (DSA). A total of 2075 renal transplant patients were screened for the presence of DSA by LXM, complement-dependent cytotoxicity (CDC) cross match, and 125 patients for SAB from January 2018 to December 2019. Results: There was a male preponderance among recipients (P < 0.0001), and the most affected age group was 21-40 years. HLA typing was done in 550/2075 by DNA PCR-reverse sequence-specific oligonucleotide probes (SSOP) method. HLA DSA by LXM was detected in 16.3% of recipients (338/2075). Majority 180/338 (53.2%) of the patients were class II DSA positive, (P < 0.0001). Among the class II DSA positive patients, 20/180 (11.1%) samples gave false-positive results by LXM. SAB for class I and class II HLA IgG antibodies was done in 125/338 renal transplant recipients, which included 20 recipients with false-positive class II Luminex DSA, to check whether the DSA detected were really donor specific or not. The results showed that although 20/125 patients had some antibodies detected in their serum, they were not against the donor HLA antigens, as per the HLA typing reports of the donors. When compared to SAB assay, LXM showed more discrepant results, particularly to class II DSA. Conclusion: In conclusion, LXM, if used in combination with SAB assay and HLA typing of donors if necessary for virtual cross match, will help in avoiding unnecessary exclusion of donors for renal transplant recipients and also for post transplant monitoring of recipients, especially in cadaveric donor transplants.

Identification of the novel HLA-C allele HLA-C*12:02:02:22, in two individuals from Central India.

One nucleotide change (G > C) in intron 1 of HLA-C*12:02:02:01 results in novel HLA allele HLA-C*12:02:02:22.

Identification of the novel allele, HLA-B*44:256, in an individual from West Bengal in Eastern India.

Next generation sequencing based HLA typing has led to the identification of a novel allele HLA-B*44:256. The novel allele HLA-B*44:256 differs from B*44:02:01:01 by eight nucleotides in exon 3.

Clinicomicrobiological spectrum of infective endocarditis - from a tertiary care centre in south India.

BACKGROUND AND OBJECTIVES: Infective endocarditis (IE) is a microbial infection of the endothelial surface of the cardiac-valves. Rapid diagnosis, effective treatment and prompt recognition of complications are essential, in order to improve the outcome. We retrospectively reviewed and determined the clinical characteristics, microbiological profile and management strategies of IE cases, changing microbial spectrum of pathogens and outcome in Native Valve Endocarditis (NVE) and Prosthetic Valve Endocarditis (PVE) cases. MATERIALS AND METHODS: We retrospectively reviewed the medical records of 191 patients, clinically diagnosed with IE, based on modified Dukes criteria, from January 2011 to December 2016. Blood cultures received from all these patients were processed, using BacT/Alert system (bioMerieux, Marcy l'Etoile, France). RESULTS: Sixty eight (68/191) cases were positive for bacterial pathogens. Twenty four (24/191) cases had PVE and 167/191 had NVE. Nineteen cases (19/24, 79.1%) were PVE positive and forty nine (49/167, 29.3%) were NVE positive. Culture negative endocarditis cases were 123/191 (64.39%). The most common pathogen isolated from NVE cases, in our study was Streptococcus mitis, followed by methicillin-resistant coagulase negative staphylococcus (MRCONS) in PVE. The NVE were treated intravenously with a combination of a ß-lactam or glycopeptide with an aminoglycoside, for prolonged period of 4-6 weeks, with a successful outcome. The PVE cases were treated with the appropriate antibiotics as per the antibiotic susceptibility report. CONCLUSION: The high morbidity and mortality rates are associated with IE and hence accurate identification of aetiological agents and appropriate antimicrobial therapy is required.

Infective endocarditis due to Granulicatella adiacens: a case report and review.

Infective endocarditis (IE) caused by nutritionally variant Streptococci (NVS) is associated with high bacteriologic and treatment failure and mortality rates compared to endocarditis caused by other Streptococci. With automated blood culture systems, the rates of NVS-associated IE accounts for 5%-6% cases. We report a case of IE caused by NVS in an elderly female patient with no risk factors. The patient was successfully treated with combination antimicrobial therapy.

The clinical, serological and molecular diagnosis of emerging dengue infection at a tertiary care institute in southern, India.

INTRODUCTION: Dengue is an acute viral infection which presents as uneventful pyrexia to a fatal complication. This infection is increasingly being recognized as the world's major emerging tropical disease and an important public health problem. This article highlights the clinical manifestations of Dengue virus infection and the various molecular tests that were used for its laboratory diagnosis. METHODS: Serum samples from 713 suspected cases of Dengue were collected between August and December 2007. The clinical profiles of 123 hospitalized patients were analyzed. Serology, RT- PCR, virus isolation and sequencing were done. RESULTS: The most common clinical symptoms were fever, thrombocytopenia, rash and elevated liver enzymes. The demonstration of the Dengue RNA in 5.16% samples, the detection of Dengue specific IgM antibodies in 18% samples and the isolation of the DENV-4 and the DENV-3 viruses from the clinical samples confirmed this Dengue outbreak. A co -infection with Chikungunya was observed in 2.06% of the cases. The phylogenetic analysis revealed that the Indian Dengue-4 isolates from this outbreak belonged to the genotype I. This study clearly indicated the sudden dominance of DENV-4 in an Indian Dengue outbreak. CONCLUSION: The surveillance of the Dengue viruses needs to be closely monitored for the emergence of newer serotype(s) in hitherto unknown areas.

Development and evaluation of a 1-step duplex reverse transcription polymerase chain reaction for differential diagnosis of chikungunya and dengue infection.

Dengue (DEN) and chikungunya (CHIK) have emerged as the 2 most important arboviral infections of global significance. The similarities in clinical presentations, their circulation in the same geographic area, and the transmission through the same vector necessitate an urgent need for the differential diagnosis of these 2 infections. So far, no single assay is reported for differential diagnosis of these 2 infections. In this study, we report the development and evaluation of a 1-step single-tube duplex reverse transcription polymerase chain reaction (D-RT-PCR) assay by targeting E1 gene of CHIK and C-prM gene junction of DEN virus (DENV), respectively. The sensitivity of this assay was found to be better than conventional virus isolation and could detect as low as 100 copies of genomic RNA, which is equivalent to respective virus-specific RT-PCR. The evaluation was carried out with 360 clinical samples from recent CHIK and DEN outbreaks in India. This assay could also be able to detect dual infection of CHIK and DEN in 3 patients. The phylogenetic analysis based on the nucleotide sequencing of D-RT-PCR amplicon could precisely identify the genotypes of all the serotypes of DENV and CHIK viruses (CHIKV). These findings demonstrate the potential clinical and epidemiologic application of D-RT-PCR for rapid sensitive detection, differentiation, and genotyping of DENV and CHIKV in clinical samples.

Clinical features and molecular diagnosis of Chikungunya fever from South India.

An epidemic of Chikungunya fever of unprecedented magnitude occurred in many parts of India in early 2006 after an interval of 33 years, and there has been a resurgence in some parts of South India since June 2007. The article highlights clinical manifestations of infection and various molecular tests that were used for diagnoses of Chikungunya virus infection. Of particular interest is the real-time loop-mediated isothermal amplification (RT LAMP) assay, which is rapid and cost-effective and can be adopted at ill-equipped laboratories. Clinical symptoms were characterized by a triad of fever, rash, and severe rheumatic manifestations. RT LAMP identified 20 additional Chikungunya virus-positive cases, compared with reverse-transcriptase polymerase chain reaction. Chikungunya virus was isolated from 20 randomly selected samples. Genotyping of the virus isolates revealed that the East Central South African genotype of Chikungunya virus was the etiologic agent of this epidemic. Molecular diagnosis is an important tool to identify such new vectorborne viral illnesses.