Extremely high peritoneal cancer index in colorectal peritoneal metastases demonstrates safety and overall survival benefit in selected patients undergoing cytoreductive surgery and heated intraperitoneal chemotherapy.

BACKGROUND: Colorectal peritoneal metastases are a devastating consequence of colorectal cancer (CRC) with extremely poor prognosis. Patients that can undergo complete cytoreduction by cytoreductive surgery and heated intraperitoneal chemotherapy (CRS/HIPEC) have a markedly improved overall survival. Traditionally, patients with extremely high peritoneal cancer index (PCI), PCI >20, are not offered CRS/HIPEC. METHODS: We performed a retrospective analysis of our prospectively maintained CRS/HIPEC database and evaluated all patients with CRC peritoneal metastases between 2012 and 2022. We divided the cohorts between those with low operative PCI (PCI<20) and high operative PCI (PCI =>20). We examined demographic, clinicopathologic data, perioperative, and oncological outcomes between the cohorts. RESULTS: Of the 691 patients who underwent CRS/HIPEC, 289 were evaluable with CRC metastases, 234 with PCI <20 and 43 with PCI => 20. Median radiologic preoperative and operative PCI was 4 and 10 versus 7 and 24.5 in the low and high PCI cohorts, respectively. Operative time was longer (6 vs. 4 h) and blood loss higher (500 vs. 400 mL) in the high PCI cohort. All other demographic, clinicopathological, and operative characteristics were similar. Median disease free survival (DFS) was longer in the low PCI cohort (11.5 vs. 7 months) but overall survival (OS) showed benefit (41.3 vs. 31.8 months), (p = 0.001 and p = 0.189, respectively), comparatively with an only chemotherapy strategy. CONCLUSIONS: Appropriately selected patients with CRC metastases and extremely high PCI demonstrate similar perioperative safety outcomes in experienced tertiary referral centers. Despite a shorter median DFS, these carefully selected patients demonstrated similar median OS.

Predictors of advanced liver fibrosis and the performance of fibrosis scores: lean compared to non-lean metabolic dysfunction-associated steatotic liver disease (MASLD) patients.

BACKGROUND: Non-alcoholic fatty liver disease (NAFLD) in lean patients differs from that of NAFLD in non-lean patients. However, current data regarding predictors of advanced fibrosis and the performance of fibrosis-4 index (FIB-4) and NAFLD fibrosis score (NFS) in lean compared to non-lean metabolic dysfunction-associated steatotic liver disease (MASLD) patients is insufficient. METHODS: This was a cross-sectional study. Lean was defined as Body Mass Index <25 kg/m2. Advanced fibrosis (F3-F4) was detected by liver biopsy or two-dimension shear wave elastography (2D-SWE). Predictors of advanced fibrosis were identified using logistic regression and area under ROC curves (AUROC) were derived for FIB-4 and NFS. RESULTS: Lean patients (N.=153) comprised 19.2% of the MASLD cohort. Advanced fibrosis was associated with the number of cardiometabolic risk factors (CMRF) in lean (OR=2.06, P=0.011) and non-lean (OR=1.58, P<0.001) patients, however, hypertension and diabetes or impaired fasting glucose were significant only among non-lean. Age was associated with advanced fibrosis in both subgroups with age ≥65 showing higher odds in lean compared to non-lean patients (P=0.016). Non-lean patients had higher odds for advanced fibrosis relative to lean patients (OR=4.8, P=0.048). FIB-4 and NFS predicted advanced fibrosis among lean (AUROC=0.79 and AUROC=0.85, respectively) and non-lean (AUROC=0.79 and AUROC=0.76, respectively) patients. NFS ≥-1.445 showed higher specificity among lean compared to non-lean (P<0.001) and compared to that of FIB-4 ≥1.3 in lean patients (P<0.001). CONCLUSIONS: The number of CMRF was predictive of advanced fibrosis in both subgroups while age ≥65 showed higher odds among lean patients. NFS ≥-1.445 is more specific than FIB-4 ≥1.3 for advanced fibrosis prediction in lean patients. These findings may help identify high-risk lean MASLD patients for further liver fibrosis stage assessment.

Time to Publication for Randomized Clinical Trials Presented as Abstracts at Three Gastroenterology and Hepatology Conferences in 2017.

Background & Aims: Results of randomized clinical trials are often first presented as conference abstracts, but these abstracts may be difficult to find, and trial results included in the abstract may not be followed by subsequent journal publications. In a review of abstracts submitted to eight major medical and surgical conferences in 2017, we identified 237 abstracts reporting primary results of randomized clinical trials accepted for presentation at three major gastroenterology and hepatology conferences. The aims of this new analysis were to determine the publication rate for these abstracts and the proportion of publications that included trial registration numbers in the publication abstract. Methods: Clinical trial registries, PubMed, Europe PMC, and Google Scholar were searched through November 1, 2021, for publications reporting trial results for the selected abstracts. Publications were reviewed to determine if they included a trial registration number and if the registration number was in the abstract. Results: Publications were found for 157 abstracts (66%) within four years of the conference. Publications were found more frequently for the 194 abstracts reporting results of registered trials (144, 74%) than for the 43 abstracts reporting unregistered trials (13, 30%), but only 67% of these 144 publications included the registration number in the publication abstract. Ten unpublished trials had summary results posted on ClinicalTrials.gov. Conclusions: Clinical trial results could be more accessible if all trials were registered, authors included registration numbers in both conference and journal abstracts, and journal editors required the inclusion of registration numbers in publication abstracts for registered clinical trials.

Research trends analysis of chronic hepatitis C versus nonalcoholic fatty liver disease: A literature review text-mining analysis of publications.

Background: Hepatits C virus (HCV) rates have lowered due to direct-acting antiviral treatment. Nonalcoholic steatohepatitis (NASH)/nonalcoholic fatty liver disease (NAFLD) is rising with no available therapy. We employed text-mining to analyze trends in HCV and NAFLD research from the past two decades. Materials and Methods: We queried PubMed for all HCV and NASH/NAFLD entries published between 2000 and 2020. We compared the total number of publications on both etiologies. We performed subanalyses for different terms of interest and for geographic origin. Results: Overall, 75,934 HCV-related entries and 24,987 NASH/NAFLD-related entries were published during the study period. Up to 2015, there was a linear upward slope in the number of annual HCV publications (154.9 publications/year, p < 0.001). In 2015, the yearly number of HCV publications started showing a downward slope (-242.2 publications/year, p < 0.001). The number of NASH/NAFLD publications showed a continuous upward slope during the study period. The NASH/NAFLD field lacks publications on screening and treatment methods. Conclusion: Trends in publications varied between both etiologies. They reflect the success of antiviral treatment for HCV. The growing rates of NAFLD/NASH and the lack of a targeted cure explain the rise in related publications.

A third dose of the BNT162b2 mRNA vaccine significantly improves immune responses among liver transplant recipients.

BACKGROUND & AIMS: Immune responses of solid organ transplant recipients to 2 doses of the BNT162b2 mRNA anti-SARS-CoV-2 vaccine are impaired. The immunogenicity and safety of a third dose among liver transplant (LT) recipients are unknown. This work aimed to evaluate the immune response of LT recipients to a third dose of the BNT162b2 mRNA vaccine. METHODS: Consecutive LT recipients (n = 61) in follow-up at Sheba Medical Center were included. Receptor binding domain (RBD) IgG, neutralizing antibody (NA) titers, and T-cell levels before and 21-28 days after a third vaccine dose were determined. Adverse effects after the third dose were monitored. RESULTS: The median age of LT recipients was 65 years and 57.4% were male. The humoral immune response rate improved significantly, with 56% of patients showing a response before the third vaccine dose compared to 98% after the third dose. The cellular response in 12 evaluated patients improved significantly (p = 0.008). The geometric mean of anti-RBD IgG levels, NA levels, and T-cell count also increased significantly after the third dose. NA titers after the third dose negatively correlated with age (p = 0.03), mycophenolate mofetil treatment (p = 0.005), and combined immunosuppression as opposed to calcineurin inhibitor monotherapy (p = 0.001). After the third dose, adverse effects were reported by 37% of recipients and were mostly mild (local pain and fatigue). CONCLUSION: After a third BNT162b2 mRNA vaccine, the immune response improved significantly among LT recipients, without serious adverse effects. Further studies are needed to evaluate immune response durability and to determine the optimal number and schedule of booster vaccine doses. LAY SUMMARY: The Pfizer-Biotech BNT162b2SARS-CoV-2 vaccine induced significant immunity among liver transplant recipients after a third dose. The majority of the patients developed sufficient levels of both humoral and cellular immune responses. Factors that predict non-response were older age and immunosuppressive medications.

Tip of the iceberg: A comprehensive review of liver disease in Inborn errors of immunity.

Inborn errors of immunity (IEIs) consist of numerous rare, inherited defects of the immune system that affect about 500,000 people in the United States. As advancements in diagnosis through genetic testing and treatment with targeted immunotherapy and bone marrow transplant emerge, increasing numbers of patients survive into adulthood posing fresh clinical challenges. A large spectrum of hepatobiliary diseases now present in those with immunodeficiency diseases, leading to morbidity and mortality in this population. Awareness of these hepatobiliary diseases has lagged the improved management of the underlying disorders, leading to missed opportunities to improve clinical outcomes. This review article provides a detailed description of specific liver diseases occurring in various inborn errors of immunity. A generalized approach to diagnosis and management of hepatic complications is provided, and collaboration with hepatologists, immunologists, and pathologists is emphasized as a requirement for optimizing management and outcomes.

HBV-RNA, Quantitative HBsAg, Levels of HBV in Peripheral Lymphocytes and HBV Mutation Profiles in Chronic Hepatitis B.

A comprehensive characterization of chronic HBV (CHB) patients is required to guide therapeutic decisions. The cumulative impact of classical and novel biomarkers on the clinical categorization of these patients has not been rigorously assessed. We determined plasma HBV-RNA and HBsAg levels, HBV in peripheral lymphocytes (PBMCs) and HBV mutation profiles in CHB patients. Patient demographics (n = 139) and classical HBV biomarkers were determined during a clinical routine. HBV-RNA in plasma and HBV-DNA in PBMCs were determined by RT-PCR. HBsAg levels were determined using Architect. In samples with HBV-DNA viral load >1000 IU/mL, genotype mutations in precore (PC), basal core promoter (BCP), HBsAg and Pol regions were determined by sequencing. Most patients (n = 126) were HBeAg-negative (HBeAgNeg) with significantly lower levels of HBV-RNA, HBV-DNA and HBsAg compared to HBeAg-positive (HBeAgPos) patients (p < 0.05). HBV genotype D prevailed (61/68), and >95% had BCP/PC mutations. Escape mutations were identified in 22.6% (13/63). HBeAgNeg patients with low levels of HBsAg (log IU ≤ 3) were older and were characterized by undetectable plasma HBV-DNA and undetectable HBV-RNA but not undetectable HBV-DNA in PBMCs compared to those with high HBsAg levels. In >50% of the studied HBeAgNeg patients (66/126), the quantitation of HBsAg and HBV-RNA may impact clinical decisions. In conclusion, the combined assessment of classical and novel serum biomarkers, especially in HBeAgNeg patients, which is the largest group of CHB patients in many regions, may assist in clinical decisions. Prospective studies are required to determine the real-time additive clinical advantage of these biomarkers.

Postprandial Plasma Lipidomics Reveal Specific Alteration of Hepatic-derived Diacylglycerols in Nonalcoholic Fatty Liver Disease.

BACKGROUND & AIMS: Hepatic energy metabolism is a dynamic process modulated by multiple stimuli. In nonalcoholic fatty liver disease (NAFLD), human studies typically focus on the static fasting state. We hypothesized that unique postprandial alterations in hepatic lipid metabolism are present in NAFLD. METHODS: In a prospective clinical study, 37 patients with NAFLD and 10 healthy control subjects ingested a standardized liquid meal with pre- and postprandial blood sampling. Postprandial plasma lipid kinetics were characterized at the molecular lipid species level by untargeted lipidomics, cluster analysis, and lipid particle isolation, then confirmed in a mouse model. RESULTS: There was a specific increase of multiple plasma diacylglycerol (DAG) species at 4 hours postprandially in patients with NAFLD but not in controls. This was replicated in a nonalcoholic steatohepatitis mouse model, where postprandial DAGs increased in plasma and concomitantly decreased in the liver. The increase in plasma DAGs appears early in the disease course, is dissociated from NAFLD severity and obesity, and correlates with postprandial insulin levels. Immunocapture isolation of very low density lipoprotein in human samples and stable isotope tracer studies in mice revealed that elevated postprandial plasma DAGs reflect hepatic secretion of endogenous, rather than meal-derived lipids. CONCLUSIONS: We identified a selective insulin-related increase in hepatic secretion of endogenously derived DAGs after a mixed meal as a unique feature of NAFLD. DAGs are known to be lipotoxic and associated with atherosclerosis. Although it is still unknown whether the increased exposure to hepatic DAGs contributes to extrahepatic manifestations and cardiovascular risk in NAFLD, our study highlights the importance of extending NAFLD research beyond the fasting state.

Immunogenicity and Adverse Effects of the 2-Dose BNT162b2 Messenger RNA Vaccine Among Liver Transplantation Recipients.

The BNT162b2 messenger RNA (mRNA) vaccine against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been shown to be safe and effective in immunocompetent patients. The safety and efficacy of this vaccine in liver transplantation (LT) recipients is still under evaluation. The objective of this study was to assess the safety and efficacy of the BNT162b2 vaccine among transplant recipients. The immune responses of 76 LT recipients receiving 2 doses of the vaccine were compared with those of 174 age-matched immunocompetent controls. Postvaccination immunoglobulin G (IgG) antibodies against the receptor-binding domain (RBD) of SARS-CoV-2 and neutralizing antibodies (NA) to the BNT162b2 mRNA vaccine were determined at least 14 days after the second dose of the vaccine. IgG antibody titers ≥1.1 were defined as positive antibodies. Adverse effects were monitored during the study period. Following administration of the second dose, transplant recipients showed reduced immune responses compared with controls (72% versus 94.2%; P < 0.001). At a median time of 38 days after the second vaccination, the geometric mean of RBD IgG and NA titers were 2.1 (95% confidence interval [CI], 1.6-2.6) and 150 (95% CI, 96-234) among transplant recipients and 4.6 (95% CI, 4.1-5.1) and 429 (95% CI, 350-528) in the control group, respectively (P < 0.001). Antibody responses were lower in transplant recipients who were receiving combined immunosuppression therapy and in those with impaired renal function. Among the LT recipients with negative antibody responses, 1 became infected with SARS-CoV-2, but no recipients with positive antibody responses became infected. Overall, most (n = 39 [51%]) adverse effects self-reported by transplant recipients were mild and occurred more often in women than in men. Compared with patients who were immunocompetent, LT recipients had lower immune responses. The durability of immune responses to the BNT162b2 vaccine among LT recipients requires further investigation.

XCR1+ type 1 conventional dendritic cells drive liver pathology in non-alcoholic steatohepatitis.

Non-alcoholic fatty liver disease (NAFLD) and non-alcoholic steatohepatitis (NASH) are prevalent liver conditions that underlie the development of life-threatening cirrhosis, liver failure and liver cancer. Chronic necro-inflammation is a critical factor in development of NASH, yet the cellular and molecular mechanisms of immune dysregulation in this disease are poorly understood. Here, using single-cell transcriptomic analysis, we comprehensively profiled the immune composition of the mouse liver during NASH. We identified a significant pathology-associated increase in hepatic conventional dendritic cells (cDCs) and further defined their source as NASH-induced boost in cycling of cDC progenitors in the bone marrow. Analysis of blood and liver from patients on the NAFLD/NASH spectrum showed that type 1 cDCs (cDC1) were more abundant and activated in disease. Sequencing of physically interacting cDC-T cell pairs from liver-draining lymph nodes revealed that cDCs in NASH promote inflammatory T cell reprogramming, previously associated with NASH worsening. Finally, depletion of cDC1 in XCR1DTA mice or using anti-XCL1-blocking antibody attenuated liver pathology in NASH mouse models. Overall, our study provides a comprehensive characterization of cDC biology in NASH and identifies XCR1+ cDC1 as an important driver of liver pathology.

Lipoprotein Insulin Resistance Index Reflects Liver Fat Content in Patients With Nonalcoholic Fatty Liver Disease.

The recently developed lipoprotein insulin resistance index (LP-IR) incorporates lipoprotein particle numbers and sizes and is considered to reflect both hepatic and peripheral IR. As tissue IR is a strong component of nonalcoholic fatty liver disease (NAFLD) pathogenesis, we aimed to assess the degree by which LP-IR associates with hepatic fat content. This was a single-center retrospective analysis of patients with NAFLD. LP-IR, the homeostasis model assessment of insulin resistance (HOMA-IR), and adipose tissue IR (Adipo-IR) were measured simultaneously. Liver fat content was estimated by FibroScan controlled attenuated parameter. Associations were assessed using Spearman's correlation and multivariate linear regression. The study included 61 patients. LP-IR was correlated with HOMA-IR (ρ = 0.30; P = 0.02), typically thought to reflect hepatic IR, but not with Adipo-IR (ρ = 0.15; P = 0.25). Liver fat content was significantly associated with Adipo-IR (ρ = 0.48; P < 0.001), LP-IR (ρ = 0.35; P = 0.005), and to a lesser degree with HOMA-IR (ρ = 0.25; P = 0.051). The association of liver fat with LP-IR was limited to patients without diabetes (ρ = 0.60; P < 0.0001), whereas no association was seen in those with diabetes. In a multivariate model, Adipo-IR, LP-IR, and diabetes were independently associated with liver fat and together explained 35% of the variability in liver fat. Conclusion: LP-IR is a reasonable measure of IR in non-diabetic patients with NAFLD and is associated with hepatic fat content. Although adipose tissue is the major contributor to liver fat, the additional contribution of nonadipose tissues can be easily estimated using LP-IR.

The liver in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection.

BACKGROUND: The ongoing outbreak of COVID-19 is associated with higher levels of morbidity and mortality among patients with comorbidities, including the metabolic syndrome. Liver impairment has been reported in up to 54% of hospitalized patients with COVID-19. The impact of COVID-19 on a preexisting chronic liver disease is an actively studied area of research. The contribution of our study is towards determining the predictors of severity and the outcome of liver injury among hospitalized patients with COVID-19 infection, including patients with a preexisting liver disease and COVID-19. METHODS: This single center retrospective cohort study included all patients ≥18 years, admitted in Sheba Medical Center with confirmed COVID-19 infection. Demographic, clinical and laboratory data were obtained using the MDClone platform and rechecked after data decryption using electronic health records. RESULTS: Of 382 patients with COVID-19, 66.4% had increased liver biochemistry. Mild increase was observed in 76.7%. The higher level of fibrosis-4 (FIB-4) at admission was independently associated with higher mortality rate. Preexisting liver disease was detected in 15.4% patients. Most common etiology was nonalcoholic fatty liver disease (78.7%). The mortality of hospitalized patients with preexisting liver disease was 16.7% compared to 6.8% in patients without preexisting liver disease (RR = 2.792, P = 0.01). In multivariate analysis, liver disease adjusted to age and BMI was associated with mortality with high statistical significance. CONCLUSIONS: Patients with preexisting chronic liver disease were at a higher risk of mortality. The FIB-4 level at admission was associated with worse prognosis. These findings should be reevaluated in a larger cohort of patients.

The Spectrum of the Deficiency of Adenosine Deaminase 2: An Observational Analysis of a 60 Patient Cohort.

The deficiency of adenosine deaminase 2 (DADA2) is an autosomal recessively inherited disease that has undergone extensive phenotypic expansion since being first described in patients with fevers, recurrent strokes, livedo racemosa, and polyarteritis nodosa in 2014. It is now recognized that patients may develop multisystem disease that spans multiple medical subspecialties. Here, we describe the findings from a large single center longitudinal cohort of 60 patients, the broad phenotypic presentation, as well as highlight the cohort's experience with hematopoietic cell transplantation and COVID-19. Disease manifestations could be separated into three major phenotypes: inflammatory/vascular, immune dysregulatory, and hematologic, however, most patients presented with significant overlap between these three phenotype groups. The cardinal features of the inflammatory/vascular group included cutaneous manifestations and stroke. Evidence of immune dysregulation was commonly observed, including hypogammaglobulinemia, absent to low class-switched memory B cells, and inadequate response to vaccination. Despite these findings, infectious complications were exceedingly rare in this cohort. Hematologic findings including pure red cell aplasia (PRCA), immune-mediated neutropenia, and pancytopenia were observed in half of patients. We significantly extended our experience using anti-TNF agents, with no strokes observed in 2026 patient months on TNF inhibitors. Meanwhile, hematologic and immune features had a more varied response to anti-TNF therapy. Six patients received a total of 10 allogeneic hematopoietic cell transplant (HCT) procedures, with secondary graft failure necessitating repeat HCTs in three patients, as well as unplanned donor cell infusions to avoid graft rejection. All transplanted patients had been on anti-TNF agents prior to HCT and received varying degrees of reduced-intensity or non-myeloablative conditioning. All transplanted patients are still alive and have discontinued anti-TNF therapy. The long-term follow up afforded by this large single-center study underscores the clinical heterogeneity of DADA2 and the potential for phenotypes to evolve in any individual patient.

Roadmap to resuming care for liver diseases after coronavirus disease-2019.

The global pandemic of coronavirus disease-2019 (COVID-19) has led to significant disruptions in healthcare delivery. Patients with chronic liver diseases require a high level of care and are therefore particularly vulnerable to disruptions in medical services during COVID-19. Recent data have also identified chronic liver disease as an independent risk factor for COVID-19 related hospital mortality. In response to the pandemic, national and international societies have recommended interim changes to the management of patients with liver diseases. These modifications included the implementation of telehealth, postponement or cancelation of elective procedures, and other non-urgent patient care-related activities. There is concern that reduced access to diagnosis and treatment can also lead to increased morbidity in patients with liver diseases and we may witness a delayed surge of hospitalizations related to decompensated liver disease after the COVID-19 pandemic has receded. Therefore, it is paramount that liver practices craft a comprehensive plan for safe resumption of clinical operations while minimizing the risk of exposure to patients and health-care professionals. Here, we provide a broad roadmap for how to safely resume care for patients with chronic liver disease according to various phases of the pandemic with particular emphasis on outpatient care, liver transplantation, liver cancer care, and endoscopy.

Incidence rates and clinical characteristics of primary gastrointestinal non-Hodgkin lymphoma: a population study.

BACKGROUND & AIMS: After the rise of lymphoma incidence in the 1990's, there is a paucity of epidemiologic studies describing the characteristics of primary gastrointestinal non-Hodgkin's lymphoma (PGIL). This epidemiologic survey aims to identify recent trends in PGIL. METHODS: A retrospective, population-based study describing adult patients with PGIL in the Israeli Negev region between 1998 and 2013. RESULTS: 131 patients were diagnosed with PGIL, representing an annual incidence rate of 22.42/100,000, compared to 35.87/100,000 in the overall Israeli population. Both incidence rates did not significantly change during the study period. The median age was 66 years, and the most common presentation was in the stomach (49.6%) and oral cavity (18.3%). Histologically, diffuse large B cell lymphoma (DLBCL) was predominant (55.0%). Most patients (66.4%) had early stage disease. Only T-cell lymphoma showed a male predominance (14.7% versus 5.4%, P=0.008). Fifty patients (44.2%) had H. pylori testing, and 35 (70.0%) were positive. Of these, 91.4% received eradication treatment, and 57.1% were negative thereafter.Most patients received CHOP or RCHOP protocols (16.0% and 48.1%, respectively). Complete response was achieved in 53.4%. Median follow-up was 48 months, and 62 patients (47.3%) died during the study period. Liver involvement had a worse prognosis, (33.0% 5-year survival) compared to upper and lower GI disease(70.5% and 46.8% respectively, P=0.003 for the comparison between liver and other locations). T-cell lymphoma had worse survival (11 months vs. not reached, P=0.003). CONCLUSIONS: This study demonstrates the incidence, and clinical characteristics of PGIL in the Negev region. It is important to identify disease characteristics, thus facilitating better disease detection and prognostication.

Stimulating More Than Just the Granulocytes: Drug-Induced Liver Injury From Filgrastim.

Granulocyte-colony-stimulating factors such as filgrastim are currently used for multiple indications, one of which is administration to healthy donors for allogeneic stem cell collection. So far, filgrastim has not been described as a cause of drug-induced liver injury. We report a case of drug-induced liver injury secondary to filgrastim use in a 54-year-old healthy donor. The patient presented with an upsurge of liver enzymes a week from the drug administration with a rapid downtrend over the next few weeks. We wish to highlight the possibility of a similar idiosyncratic adverse drug reaction in other healthy individuals.