Early blood stream infection following allogeneic hematopoietic stem cell transplantation is a risk factor for acute grade III-IV GVHD in children and adolescents

BACKGROUND

Graft-versus-host disease (GVHD) remains a major cause of mortality and morbidity in allogeneic hematopoietic stem cell transplantation (HSCT). In adults, early blood stream infection (BSI) and acute GVHD (AGVHD) have been reported to be related. The impact of BSI on risk for AGVHD, however, has not been assessed in pediatric patients.

PROCEDURE

We conducted a retrospective analysis to test the hypothesis that early BSI (before day +30) predisposes allogeneic pediatric transplant patients to severe AGVHD. We analyzed 293 allogeneic HSCT performed at Children's Healthcare of Atlanta between 2005 and 2014 that met eligibility criteria.

RESULTS

The cumulative incidence of acute grade III-IV GVHD at 100 days after HSCT was 17.1%. In multivariate analysis, risk for acute grade III-IV GVHD was associated with HLA-mismatched donor (hazard ratio [HR] = 4.870, P < 0.001), and BSI between day 0 and +30 prior to AGVHD (HR = 3.010, P = 0.001).

CONCLUSIONS

These results indicate that early BSI appears to be a risk factor for acute grade III-IV GVHD. Further research is needed to determine if the link is causal.

Respiratory Decompensation and Immunization of Preterm Infants

BACKGROUND

Concern for respiratory decompensation after immunization in premature infants, particularly those with bronchopulmonary dysplasia (BPD), may lead to delayed and altered immunization schedules.

METHODS

A retrospective cohort of premature infants at <32 weeks' gestational age cared for in a tertiary level 4 NICU and immunized during their hospital stay were evaluated for respiratory decompensation within 72 hours of immunization. Respiratory measurements including change in respiratory support, mean fraction of inspired oxygen, and apnea, bradycardia, and desaturation events were compared between those infants with BPD and those without. The primary outcome was the difference in respiratory decompensation defined as a composite of increased respiratory support or increased fraction of inspired oxygen ≥10% within 72 hours of immunization.

RESULTS

Of 403 infants admitted to the NICU and immunized, 240 met the study criteria. Of those infants, 172 had a diagnosis of BPD. There was no difference in the primary outcome of respiratory decompensation after immunization between groups (P = .65). There was also no significant difference in apnea, bradycardia, and desaturation events between groups (P = .51).

CONCLUSIONS

In this cohort, respiratory decompensation requiring clinical intervention after immunization of preterm infants both with and without BPD was uncommon and not significantly different between groups. Consideration for immunization of this vulnerable population should not be delayed out of concern for clinical deterioration.

Instinctive Clinical Teaching: Erasing the Mental Boundary Between Clinical Education and Patient Care to Promote Natural Learning

Effective clinical teaching is essential in physician education, yet faculty members rarely receive formal training in clinical teaching. Formal models for training clinical educators are often tedious and require significant time and effort. Instinctive clinical teaching allows clinicians to seamlessly integrate and promote effective teaching into their clinical practice. The approach is guided by similarities between the components of Kolb's experiential learning cycle-concrete experience, reflective observation, abstract conceptualization, and active experimentation-and the elements of the patient care process-history and physical, initial assessment, differential, hypothesis, final diagnosis, management, and follow-up. Externalization of these clinical thought processes allows for inclusion of learners and promotes effective clinical teaching.

Rifaximin for preventing acute graft-versus-host disease: impact on plasma markers of inflammation and T-cell activation

In murine allogeneic hematopoietic cell transplantation models, inhibiting bacterial translocation stemming from conditioning-induced damage to the gut mucosa abrogates inflammatory stimulation of donor T cells, preventing acute graft-versus-host disease (AGVHD). We conducted a phase I trial to begin testing the hypothesis that rifaximin, a broadly acting oral antibiotic, would reduce systemic inflammation and T-cell activation. We administered rifaximin to 20 adolescents and younger adults (day -10 through day +30) receiving intensive conditioning. We measured the plasma level of interleukin-6, as a marker of conditioning-induced inflammation, and the levels of soluble tumor necrosis factor receptor-1 and soluble interleukin-2 receptor, as surrogate markers of AGVHD. We formed a historical control group (n=24), from a previous study of biomarkers in AGVHD. The increase in the treatment group's mean interleukin-6 level from baseline to day 0 was 73% less than that in the control group (P=0.006). The increase from baseline to day 15 in the treatment group's mean soluble tumor necrosis factor-1 and soluble interleukin-2 receptor levels was similar to the control group. Incidences of grade 2 to 4 AGVHD also did not differ. This suggests that rifaximin may abrogate bacterial translocation and resultant inflammation, but in alternative donor transplants this does not prevent downstream activation of donor T cells.

Bartonella henselae-mediated disease in solid organ transplant recipients: two pediatric cases and a literature review

Bartonella henselae, the etiologic agent of cat-scratch disease, causes a well-defined, self-limited syndrome of fever and regional lymphadenopathy in immunocompetent hosts. In immunocompromised hosts, however, B. henselae can cause severe disseminated disease and pathologic vasoproliferation known as bacillary angiomatosis (BA) or bacillary peliosis. BA was first recognized in patients infected with human immunodeficiency virus. It has become more frequently recognized in solid organ transplant (SOT) recipients, but reports of pediatric cases remain rare. Our review of the literature revealed only one previously reported case of BA in a pediatric SOT recipient. We herein present 2 pediatric cases, one of which is the first reported case of BA in a pediatric cardiac transplant recipient, to our knowledge. In addition, we review and summarize the literature pertaining to all cases of B. henselae-mediated disease in SOT recipients.

Sixteen-Year-Old Boy From Nigeria With a Rash

DATE: Thursday, October 20, 2011.

SESSION TITLE

Pediatric Fellows' Day Workshop Hosting Organization: Infectious Diseases Society of America.

HOSTING EVENT

49th Annual Meeting of the Infectious Diseases Society of America.

LOCATION

Boston, Massachusetts.

Mycobacterium tuberculosis Infection of the placenta: a study of the early (innate) inflammatory response in two cases

Infections with Mycobacterium tuberculosis (MTb) are globally prevalent in many countries, yet descriptions of placental pathology in tuberculous patients are scanty. The usual necrotizing granulomatous response associated with tuberculous infections requires an activation of the adaptive immune system. However, before this system is turned on, the 1st encounter with the tubercle bacillus is mediated by the innate immune system. This pathway utilizes innate surface receptors in neutrophils and histiocytes predominantly and does not produce a granulomatous pattern of inflammation. In this report we describe 2 cases of placental involvement with MTb in which an acute abscess-like inflammatory response with Myeloperoxidase and CD68-positive neutrophils and histiocytes causing acute villitis and intervillitis, with abundant acid-fast mycobacteria, were identified. Other cellular markers consistent with adaptive immunity were negative. These nongranulomatous lesions are seen in primary tuberculous infections occurring in a naïve woman and, obviously, a naïve fetus. These cases with early response inflammation in the placenta are frequently missed precisely because the mother is not known to be infected or has been recently diagnosed and because the symptoms in the newborn may not develop for several weeks, by which time the placenta may have been discarded. This report also shows that the differential diagnosis of acute villitis and intervillitis in the placenta should include tuberculosis aside from the more common bacterial infections such as listeriosis.

Risk factors for lower respiratory tract infection death among infants in the United States, 1999-2004

OBJECTIVE

To describe maternal and birth-related risk factors associated with lower respiratory tract infection (LRTI) deaths among infants.

METHODS

Records for infants with LRTI as a cause of death were examined by using the linked birth/infant death database for 1999-2004. Singleton infants dying with LRTI and a random sample of surviving singleton infants were compared for selected characteristics.

RESULTS

A total of 5420 LRTI-associated infant deaths were documented in the United States during 1999-2004, for an LRTI-associated infant mortality rate of 22.3 per 100,000 live births. Rates varied according to race; the rate for American Indian/Alaska Native (AI/AN) infants was highest (53.2), followed by black (44.1), white (18.7), and Asian/Pacific Islander infants (12.3). Singleton infants with low birth weight (<2500 g) were at increased risk of dying with LRTI after controlling for other characteristics, especially black infants. Both AI/AN and black infants born with a birth weight of > or =2500 g were more likely to have died with LRTI than other infants of the same birth weight. Other risk factors associated with LRTI infant death included male gender, the third or more live birth, an Apgar score of <8, unmarried mother, mother with <12 years of education, mother <25 years of age, and mother using tobacco during pregnancy.

CONCLUSIONS

Low birth weight was associated with markedly increased risk for LRTI-associated death among all of the racial groups. Among infants with a birth weight of > or =2500 g, AI/AN and black infants were at higher risk of LRTI-associated death, even after controlling for maternal and birth-related factors. Additional studies and strategies should focus on the prevention of maternal and birth-related risk factors for postneonatal LRTI and on identifying additional risk factors that contribute to elevated mortality among AI/AN and black infants.