Long-Term Follow-Up of Abatacept, Post-Transplantation Cyclophosphamide, and Sirolimus-Based Haploidentical Transplantation in Younger Patients with Nonmalignant Diseases

Haploidentical (haplo) hematopoietic cell transplantation (HCT) for nonmalignant disease (NMD) carries inherent challenges of both alloreactivity and graft failure. Building on promising results from pilot studies in which abatacept was combined with post-transplantation cyclophosphamide (PTCy) and sirolimus (AbaCyS) in younger NMD patients undergoing haplo-HCT, we present the long-term outcomes of this protocol. On the back of uniform disease-specific conditioning regimens containing antithymocyte globulin 4.5 mg/kg from day -9 to day -7, GVHD prophylaxis with AbaCyS consisted of abatacept administered on days 0, +5, +20, +35, and monthly until 180 days with PTCy and sirolimus. The patients were followed up with longitudinal assessment of immune reconstitution, growth, and reproductive development and quality of life (QoL) analyses. Among 40 patients (aplastic anemia, n = 24; hemoglobinopathies, n = 14; and primary immunodeficiencies, n = 2) with a median age of 10 years (range, 2 to 25 years), 95% achieved sustained engraftment. Post-transplantation hemophagocytic syndrome was detected in 3 patients, leading to graft failure in 2 cases. The incidence of acute graft-versus-host disease (GVHD) was 2.6%, and that of chronic GVHD (cGVHD) was 14.3%. Cytomegalovirus, adenovirus, and Epstein-Barr virus infections were observed in 45%, 5%, and 0% respectively. Rates of nonrelapse mortality, overall survival, event-free survival, and GVHD-free, event-free survival were 5%, 95%, 90%, and 82%, respectively, at a median follow-up of 4.6 years. Absence of cGVHD correlated with younger patient age and early sustained recovery of regulatory T cells and mature natural killer cells, which in turn was associated with improved QoL and lack of late infections. The AbaCyS protocol was associated with excellent long-term survival, with attenuation of both early and late alloreactivity in >80% of younger patients undergoing haplo-HCT for NMD. This study sheds light on predispositions to cGVHD and its impact on QoL, warranting further optimization of this approach.

Augmenting Vaccine Efficacy against Delta Variant with 'Mycobacterium-w'-Mediated Modulation of NK-ADCC and TLR-MYD88 Pathways

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.

Impact of an Immune Modulator Mycobacterium-w on Adaptive Natural Killer Cells and Protection Against COVID-19

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<0.0001). This translated to a significant reduction in the incidence and severity of COVID-19 in the Mw group (incidence risk ratio-0.15, p=0.0004). RNA-seq analysis at 6 months showed an upregulation of the ANK pathway genes and an enhanced ANK-mediated antibody-dependent cellular cytotoxicity (ADCC) signature. Thus, Mw was observed to have a salutary impact on the ANK cell profile and a long-term upregulation of ANK-ADCC pathways, which could have provided protection against COVID-19 in a non-immune high-risk population.

Impact of adaptive natural killer cells, KLRC2 genotype and cytomegalovirus reactivation on late mortality in patients with severe COVID-19 lung disease

Objective

SARS-CoV-2 infection results in severe lung disease in up to 50% of hospitalised patients. The aetiopathogenesis in a subset of such patients, who continue to have progressive pulmonary disease following virus clearance, remains unexplored.

Methods

We investigated the role of NKG2C⁺/NKG2A^- adaptive natural killer (ANK) cells, KLRC2 genotype and cytomegalovirus (CMV) reactivation in 22 such patients.

Results

The median duration of virus positivity was 23 days, and the median duration of hospitalisation was 48 days. The overall survival at 60 days in this group was 50%. Older age and comorbidities impacted survival negatively. CMV viraemia was documented in 11 patients, with a survival of 25% vs 80% in those without viraemia with viral load correlating with mortality. Both NK and T cells were markedly depressed in all patients at day 15. However, only persistently low ANK cells at 30 days along with an inversely high NKG2C^-/NKG2A⁺ inhibitory NK cells significantly correlated with high CMV viraemia and mortality, irrespective of KLRC2 genotype. However, day 30 ANK cells were significantly lower in the KLRC2 deletion group. The release of IFN-γ and perforin was severely compromised in all patients at day +15, with significant improvement in the survivors at day +30, but not in those with adverse outcome.

Conclusion

Patients with progressive lung disease even after negative SARS-CoV-2 status, with persistently reduced and functionally compromised ANK cells, are more likely to have CMV reactivation and an adverse outcome, independent of KLRC2 genotype.

Microbiological Evaluation of Patients Admitted with Acute Respiratory Illness during First Wave of COVID-19 Pandemic in New Delhi, India

Introduction: The Coronavirus Disease 2019 (COVID-19) is associated with damage of cells of both innate and adaptive immunity, which results in immune system’s impairment leading to secondary infections. Microbiological evaluation helps in diagnostic as well as antimicrobial stewardship leading to accurate treatment of COVID-19 infected patients. Aim: To evaluate superadded bacterial and fungal infections in COVID-19 infected patients and to evaluate bacterial and fungal infections in COVID-19 non infected patients admitted with Acute Respiratory Illness (ARI). Materials and Methods: This retrospective study was carried out in a tertiary care hospital in Delhi, India, over a period of eight months (May to December, 2020). Respiratory samples, received from indoor patients with history of ARI, were processed for COVID-19 (TrueNat Real Time Polymerase chain reaction) as well as for bacterial and fungal cultures following Standard Operating Procedures (SOP). Identification and susceptibility pattern was evaluated by Vitek2 compact system (bioMérieux, Inc. Durham, North Carolina/USA). Quality control strains used were American Type Culture Collection (ATCC) Staphylococcus aureus 29213, Escherichia coli 25922 and Candida parapsilosis ATCC 22019. Minimum Inhibitory Concentration (MIC) levels were standardised as per Clinical and Laboratory Standards Institute (CLSI) guideline, 2020. All statistical analysis was done by Chi-square test using Software Statistical Package for the Social Sciences (SPSS) version 22.0. Results: Total patients admitted with the history of ARI were 542; COVID-19 Positive Group (CPG) included 115 (21.22%) while COVID-19 Negative Group (CNG) included 427 (78.78%). Growth in bacterial and fungal cultures in CPG was 59.13% (68/115) while in CNG; it was 47.78% (204/427). Among the bacterial isolates, most common isolate was Klebsiella pneumoniae {CPG: 41.93% (26/62); CNG: 36.72% (76/207)}, followed by Pseudomonas aeruginosa {CPG: 33.87% (21/62); CNG: 31.88% (66/207)}. Fungal isolates in CPG was 19.48% (15/77) (p-value 0.0445). On comparing Antimicrobial Susceptibility (AST) pattern of Enterobacterales in both CPG (n=36) and CNG (n=102), no statistically significant difference was observed. Co-morbid conditions were found mostly in CNG 89% (140/158) with ARI while only 11% (18/158) was found in CPG. Conclusion: Secondary respiratory infections are quite common amongst COVID-19 positive patients. However, growth in culture, type of isolates, Antimicrobial Resistance (AMR) was almost similar with COVID-19 non infected patients admitted with ARI. Co-morbidity had the similar impact as COVID-19 infection with respect to co-infections.

Bacteremia by Chryseobacterium indologenes in a Patient with Lung Cancer: A Clinical and Microbiological Investigation

We present a case of bacteremia by an unsual, instrinsically multidrug resistant organism, Chryseobacterium indologenes in a 59 year old gentleman with squamous cell carcinoma of lung with multiple metastasis. Despite of treating as per sensitivity report after isolatingChryseobacterium indologenes, patient could not be survived. The pathogenicity and predictability of the organism towards antibiotics, bothin vivo and in vitro needs further research.

How to cite this article

Bhagawati G, Bhardwaj A et al. Bacteremia by Chryseobacterium Indologenes in a Patient with Lung Cancer: A Clinical and Microbiological Investigation. Indian J Crit Care Med 2019;23(3):157-159.

Get aware of hand hygiene: Implement it in your attitude

BACKGROUND

Although there is advancement in the health-care system, the rates of hospital-acquired infections (HAIs) are still high. Poor hand hygiene (HH) among healthcare workers (HCWs) is identified as one of the major causes of HAIs.

AIMS

The aim and objective of this study is to assess the awareness and attitude regarding hand hygiene (HH) among HCWs in a superspecialty hospital in Ghaziabad, Uttar Pradesh, India.

SETTINGS AND DESIGN

A cross-sectional, semi-structured, questionnaire-based study was carried out in a superspecialty hospital, Uttar Pradesh, India. Questionnaires were distributed on the training session of HH organized in the eve of World HH Day on May 5^th, 2016.

SUBJECTS AND METHODS

A total 104 questionnaires were distributed among various HCWs. Each questionnaire was composed of 14 questions to test the awareness and attitude regarding HH. Awareness regarding HH among HCWs was graded as excellent (>80% correct response), satisfactory (80%-50%), and unsatisfactory (<50%). Attitude was graded on the basis of their response: excellent (strongly agree), satisfactory (agree), and unsatisfactory (other response).

RESULTS

Awareness was found to be unsatisfactory regarding the most frequent source of germs in hospital setting (39.42%) and effective time of proper hand rub (42.30%). Lack of awareness regarding adequate time of hand wash among doctors (85.71%) was an important issue.