Debra D. Poutsiaka

Production of interleukin-1-receptor antagonist during experimental endotoxaemia

Interleukin-1 (IL-1) has been implicated in the pathogenesis of sepsis. IL-1-receptor antagonist (IL-1ra) is a naturally occurring inhibitor of IL-1 activity that competes with IL-1 for occupancy of cell-surface receptors but possesses no agonist activity. We induced endotoxaemia in 9 healthy human volunteers by injection of Escherichia coli endotoxin, and measured plasma concentrations of IL-1 and IL-1ra by radioimmunoassay during the next 24 h. Peak plasma concentrations of IL-1ra were about a hundred-fold greater than those of IL-1 beta. No IL-1 or IL-1ra were detectable in the plasma of 4 volunteers injected with saline. Our results suggest that the predominant natural response to endotoxin in man is the production of antagonist rather than agonist.

Interleukin-1 (IL-1) receptor blockade reduces endotoxin and Borrelia burgdorferi-stimulated IL-8 synthesis in human mononuclear cells.

Interleukin‐1 (IL‐1) is a potent stimulator of IL‐8 production by fibroblasts and monocytes. In the present study, we asked how much of endotoxin (LPS)‐induced IL‐8 production by human peripheral blood mononuclear cells was due to IL‐1 induced by LPS. Cells were stimulated with either IL‐1β, LPS, or Borrelia burgdorferi, and total IL‐8 was determined by a specific radioimmunoassay. The addition of saturating concentrations of IL‐1 receptor antagonist protein (IRAP) reduced the IL‐1β‐, LPS‐, and B. burgdorferi‐induced IL‐8 synthesis by 85, 50, and 40%, respectively. Increasing the concentration of LPS did not affect the reduction in IL‐8 synthesis observed in the presence of IRAP. Significant inhibition of the IL‐1β‐induced IL‐8 synthesis was observed when IRAP was added 60 or 90 min after IL‐1β; similarly, IL‐8 synthesis after LPS was also reduced by delayed addition of IRAP. These data suggest that the ameliorative effects of IL‐1 receptor blockade in models of inflammation and infection may be due, in part, to suppression of IL‐1‐induced IL‐8.—Porat, R.; Poutsiaka, D. D.; Miller, L. C.; Granowitz, E. V.; Dinarello, C. A. Interleukin‐1 (IL‐1) receptor blockade reduces endotoxin and Borrelia burgdorferi‐stimulated IL‐8 synthesis in human mononuclear cells. FASEB J. 6: 2482‐2486; 1992.

Late and Atypical Cytomegalovirus Disease in Solid-Organ Transplant Recipients

Posttransplantation cytomegalovirus (CMV) disease typically occurs 1-4 months after solid-organ transplantation. The case definition invariably includes unexplained fever for > or =3 days, often with leukopenia. Late and atypical presentation of CMV disease has been rarely reported. Five cases of late and atypical CMV disease in heart (n = 1), liver (n = 1), and kidney (n = 3) transplant recipients occurred within a 4-month period in early 1999. These patients presented at a median of 25 months after organ transplantation (range, 6 months to 22 years). Atypical findings included absence of fever in 3 patients, elevated white blood cell counts in 4 patients, and normal platelet counts in 4 patients. Four patients were at risk for primary CMV infection, and 3 received ganciclovir prophylaxis for 3 months. One patients was treated for rejection, and 2 patients had induction muromonab-CD3 (Orthclone; Orthobiotech). Two of the patients had pulmonary CMV disease, but neither of these patients had hypoxia. Two patients had enterocolitis, one of whom had chronic colitis for a year. These cases may represent a changing epidemiology and clinical presentation of CMV disease in solid-organ transplant recipients in an era of changing immunosuppression and improved CMV disease prevention in the early posttransplantation period.

Blood stream infection (BSI) and acute GVHD after hematopoietic SCT (HSCT) are associated

Blood stream infection (BSI) and acute GVHD (aGVHD) are serious complications of hematopoietic SCT (HSCT). We hypothesized that the two events were not independent of one another. We studied (1) associations between BSI and aGVHD; and (2) the impact of BSI and/or aGVHD on death within 100 days after HSCT, using a retrospective cohort analysis. Risk factor analysis was carried out using multivariable Cox proportional hazards analyses. Of 211 patients who underwent allogeneic HSCT from January 2000 to December 2005 (58% of whom underwent reduced intensity transplantation), 82 (39%) developed BSI. In 49 patients (23%), grade (gr) 2–4 aGVHD occurred. Early BSI was independently associated with an increased occurrence of subsequent aGVHD gr 2–4. CMV seropositivity was independently associated with decreased occurrence of aGVHD. aGVHD gr 2–4 independently predicted subsequent first BSI. Both BSI and aGVHD gr 2–4 were significant independent predictors of death within 100 days after HSCT. There is a strong, independent association between BSI and aGVHD. Potential explanations include the elaboration of cytokines during BSI favoring the development of aGVHD and/or the immunosuppressive treatment of aGVHD favoring the development of BSI. Future studies should be directed at the mechanistic investigations of this association.BSI and acute GVHD (aGVHD) are serious complications of HSCT. We hypothesized that the two events were not independent of one another. We studied (1) associations between BSI and aGVHD; (2) the impact of BSI and/or aGVHD on death within 100 days after HSCT, employing a retrospective cohort analysis. Risk factor analysis was performed using multivariable Cox proportional hazards analyses. Of 211 subjects undergoing allogeneic HSCT from 1/00–12/05 (58% of whom underwent reduced intensity transplantation), 82 (39%) developed BSI. In 49 patients (23%), grades (gr) 2–4 aGVHD occurred. Early BSI was independently associated with an increased occurrence of subsequent aGVHD gr 2–4. Cytomegalovirus seropositivity was independently associated with decreased occurrence of aGVHD. Acute GVHD gr 2–4 independently predicted subsequent first BSI. Both BSI and aGVHD gr 2–4 were significant independent predictors of death within 100 days after HSCT. There is a strong, independent association between BSI and aGVHD. Potential explanations include the elaboration of cytokines during BSI favoring the development of aGVHD and/or the immunosuppressive treatment of aGVHD favoring the development of BSI. Future studies should be directed at mechanistic investigations of this association.

The Clinical Impact of Ganciclovir Prophylaxis on the Occurrence of Bacteremia in Orthotopic Liver Transplant Recipients

BACKGROUND Cytomegalovirus (CMV) infection or receipt of a CMV-seropositive donor liver has been shown to be an independent predictor of bacteremia in orthotopic liver transplant (OLT) recipients. However, prevention of CMV infection through use of intense CMV prophylaxis has not been examined to assess the impact on bacteremia in liver transplant recipients. METHODS We analyzed the impact of CMV prophylaxis on rates of bacteremia by examining 192 consecutive OLT recipients during a 2-year follow-up period. RESULTS There were 29 episodes of bacteremia. Univariate analysis of risk factors for bacteremia showed that invasive fungal disease, initial anti-lymphocyte immunosuppression, treatment for rejection, and use of solumedrol were significantly associated with increased risk. Receipt of >or=14 days of ganciclovir prophylaxis (hazard ratio [HR], 0.40; 95% CI [confidence interval], 0.18-0.87; P=.02), end-to-end biliary anastomosis, and receipt of <10 units of red blood cells (RBCs) were significantly associated with a decreased risk. Three-variable analysis controlling for end-to-end anastomosis and use of <10 units of RBCs, showed that use of >or=14 days of ganciclovir was still associated with a reduced risk of bacteremia (HR, 0.44; 95% CI, 0.20-0.98; P=.0437). CONCLUSIONS Among factors associated with bacteremia, use of prophylactic ganciclovir is independently associated with a significant reduction of bacteremia in OLT recipients.

Risk factors for death after sepsis in patients immunosuppressed before the onset of sepsis.

Few studies have focused on sepsis in patients with pre-existing immunosuppression. Since the numbers and the incidence of sepsis are increasing, sepsis in immunosuppressed patients will increase in importance. We studied the epidemiology of sepsis and risk factors for 28-d mortality in patients immunosuppressed prior to the onset of sepsis using data from the Academic Medical Center Consortiums (AMCC) prospective observational cohort study of sepsis. We compared characteristics of immunosuppressed (n =412) and immunocompetent (n =754) patients. Immunosuppressed patients were younger and more likely to have underlying liver or lung disease, and nosocomial infection or bloodstream infection of unknown source when presenting with sepsis. They were also more likely to die within 28 d compared to immunocompetent patients (adjusted relative risk 1.62, 95% CI 1.38 – 1.91). Septic shock, hypothermia, cancer and invasive fungal infections were associated with increased mortality in immunosuppressed patients. Black race and the presence of rigors were independent predictors of survival in immunosuppressed patients. We conclude that sepsis among patients immunosuppressed prior to the onset of sepsis was associated with higher mortality than in immunocompetent patients. As the numbers of immunosuppressed patients continue to grow, more studies on the epidemiology of sepsis in this group will become increasingly important.

No Evidence of Harms of Probiotic Lactobacillus rhamnosus GG ATCC 53103 in Healthy Elderly—A Phase I Open Label Study to Assess Safety, Tolerability and Cytokine Responses

Background Although Lactobacillus rhamnosus GG ATCC 53103 (LGG) has been consumed by 2 to 5 million people daily since the mid 1990s, there are few clinical trials describing potential harms of LGG, particularly in the elderly. Objectives The primary objective of this open label clinical trial is to assess the safety and tolerability of 1×1010 colony forming units (CFU) of LGG administered orally twice daily to elderly volunteers for 28 days. The secondary objectives were to evaluate the effects of LGG on the gastrointestinal microbiome, host immune response and plasma cytokines. Methods Fifteen elderly volunteers, aged 66–80 years received LGG capsules containing 1×1010 CFU, twice daily for 28 days and were followed through day 56. Volunteers completed a daily diary, a telephone call on study days 3, 7 and 14 and study visits in the Clinical Research Center at baseline, day 28 and day 56 to determine whether adverse events had occurred. Assessments included prompted and open-ended questions. Results There were no serious adverse events. The 15 volunteers had a total of 47 events (range 1–7 per volunteer), 39 (83%) of which were rated as mild and 40% of which were considered related to consuming LGG. Thirty-one (70%) of the events were expected, prompted symptoms while 16 were unexpected events. The most common adverse events were gastrointestinal (bloating, gas, and nausea), 27 rated as mild and 3 rated as moderate. In the exploratory analysis, the pro-inflammatory cytokine interleukin 8 decreased during LGG consumption, returning towards baseline one month after discontinuing LGG (p = 0.038) while there was no difference in other pro- or anti-inflammatory plasma cytokines. Conclusions Lactobacillus rhamnosus GG ATCC 53103 is safe and well tolerated in healthy adults aged 65 years and older. Trial Registration ClinicalTrials.gov NCT 01274598

Interleukin-1β (IL-1β), IL-1 receptor antagonist, and TNFα production in whole blood

The ability of an individual to mount defense responses to infection depend in part on the capacity to produce cytokines such as interleukin 1 (IL‐1) and tumor necrosis factor (TNF). The specialized equipment, labor intensity, and sterile practice required for the standard in vitro evaluation of cytokine production can make such evaluation impractical in some clinical situations. We report a method for stimulating whole blood to produce cytokines that can be implemented in laboratories without tissue culture facilities and requires minimal sample preparation. IL‐1β and TNFβ production in whole blood samples was stimulated with endotoxin and/or phyto‐ hemagglutinin in standard EDTA‐containing vacuum collection tubes. After incubation, plasma was removed and frozen for later assay. Comparison of this whole blood method with isolated mononuclear cell cultures indicated a significant correlation for IL‐1β production (r = 0.746, β = 0.005). This technique also produced the newly described cytokine, IL‐1 receptor antagonist. We conclude that the whole blood method is an acceptable alternative to isolated cell culture methods for measuring IL‐1β in situations that preclude the standard in vitro approach.

Pretransplant lymphopenia is a novel prognostic factor in cytomegalovirus and noncytomegalovirus invasive infections after liver transplantation.

Infection after liver transplantation (LT) remains a leading cause of morbidity and mortality. The risk of infection after LT is highest in those who are most immunosuppressed, but to date, no standard blood marker of ones degree of immunosuppression or risk index has been established. The purpose of this study was to determine whether pretransplant lymphopenia (absolute lymphocyte count < 500 cells/mm3 within 24 hours before LT) is a candidate marker of immunosuppression and could be useful in predicting the risk of cytomegalovirus (CMV) disease and non‐CMV invasive infections after LT. Data were extracted from medical records for all primary, solitary LT procedures performed at Tufts Medical Center from 1999 to 2009. Two hundred seventy‐six patients had sufficient data to be included in the analysis. Among these patients, 52% developed CMV or non‐CMV invasive infections within 5 years of LT. Within 2 years, 23 (8%) had CMV disease, and 103 (37%) at least 1 non‐CMV invasive infection. More lymphopenic patients than nonlymphopenic patients developed CMV (21% versus 4%, P < 0.001) and non‐CMV invasive infections (50% versus 33%, P = 0.02). In a multivariate survival analysis, pretransplant lymphopenia was the strongest independent predictor of CMV disease [hazard ratio (HR) = 5.52, 95% confidence interval (CI) = 2.31‐13.1, P = 0.001] after adjustments for known risk factors, including CMV serostatus (HR = 4.72, 95% CI = 2.01‐11.1, P < 0.001). Both pretransplant lymphopenia (HR = 1.64, 95% CI = 1.14‐2.53, P = 0.03) and CMV (HR = 2.93, 95% CI = 1.23‐6.92, P = 0.02) independently predicted non‐CMV infections. Our results suggest that pretransplant lymphopenia is a novel independent predictor of both CMV disease and non‐CMV invasive infections after LT and is a candidate marker of immunosuppression in LT recipients. Liver Transpl 20:1497‐1507, 2014.

Antimicrobial Resistance in the Chronically Critically Ill Patient

Infection caused by organisms resistant to conventional antimicrobial therapy is an emerging problem of global proportions. This article describes the epidemiology of infections caused by resistant organisms in chronically critically ill patients and explores factors and mechanisms that lead to the development of resistance. Specific organisms and strategies for the treatment and control of these resistance organisms are discussed.