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Introduction: Diffuse Large B-cell Lymphoma (DLBCL) is the most common type of Non-Hodgkin Lymphoma (NHL) and is categorised into the Germinal Centre B-cell (GCB) and Activated B-cell (ABC/Non GCB) subtypes as per the Cell Of Origin (COO) model with the help of gene expression profiling/immunohistochemistry. The non GCB subtype has been found to associate with the Double Expressor (DE) phenotype (i.e., co-expression of BCL-2 and c-myc by IHC and this association was substantiated and proven to be statistically significant in the present study. Aim: To categorise all DLBCL cases into GCB and Non GCB and further into DE and Non-DE by using Hans and Choi IHC alogrithm. Materials and Methods: A retrospective study of 50 patients was carried out with the help of archival material filed in the Department of Anatomic Pathology at Dharamshila Narayana Superspeciality Hospital, New Delhi, India from 1st January 2019 to 30th June 2020. The study was approved by Instituitional Ethics Committee (IEC). The study cohort was divided into two groups- group A with nodal presentation and group B with extranodal presentation. By using the Hans and Choi IHC algorithms, the cases were categorised into the GCB and non GCB subtypes in both the groups. Chi-square test and Yates correction were used for statistical analysis. Results: The median age at presentation was 49 years (20-81 years) with a male to female ratio of 2.3:1 (35 males and 15 females). Group A with nodal disease included 28 patients and group B with extranodal disease included 22 patients. The DE phenotype was determined in each case by the co-expression of c-myc (>40%) and BCL-2 (>50%) by IHC. By using the statistical chi-square test analysis and Yates correction, the association of DE was found to be statistically significant with non GCB type lymphomas and non DE with GCB lymphomas with p-value being 0.0005 and 0.00168, respectively. Conclusion: Due to the heterogeneity inherent in DLBCL, prediction of the DE phenotype and the COO by IHC is a sensitive tool and helps in the prognostication and therapeutic triage of patients. Hence, in all the cases diagnosed as DLBCL, a detailed morphological and IHC work up is mandatory to determine prognosis and possibly tailor therapy according to COO and DE phenotype.

The kinetics of NKG2C+ adaptive natural killer (ANK) cells and NKG2A+inhibitory NK (iNK) cells with respect to the incidence of SARS-CoV-2 infection were studied for 6 months in a cohort of healthcare workers following the administration of the heat-killed Mycobacterium w (Mw group) in comparison to a control group. In both groups, corona virus disease 2019 (COVID-19) correlated with lower NKG2C+ANK cells at baseline. There was a significant upregulation of NKG2C expression and IFN-γ release in the Mw group (p=0.0009), particularly in those with a lower baseline NKG2C expression, along with the downregulation of iNK cells (p

Mycobacterium-w (Mw) was shown to boost adaptive natural killer (ANK) cells and protect against COVID-19 during the first wave of the pandemic. As a follow-up of the trial, 50 healthcare workers (HCW) who had received Mw in September 2020 and subsequently received at least one dose of ChAdOx1 nCoV-19 vaccine (Mw + ChAdOx1 group) were monitored for symptomatic COVID-19 during a major outbreak with the delta variant of SARS-CoV-2 (April–June 2021), along with 201 HCW receiving both doses of the vaccine without Mw (ChAdOx1 group). Despite 48% having received just a single dose of the vaccine in the Mw + ChAdOx1 group, only two had mild COVID-19, compared to 36 infections in the ChAdOx1 group (HR-0.46, p = 0.009). Transcriptomic studies revealed an enhanced adaptive NK cell-dependent ADCC in the Mw + ChAdOx1 group, along with downregulation of the TLR2-MYD88 pathway and concomitant attenuation of downstream inflammatory pathways. This might have resulted in robust protection during the pandemic with the delta variant.