Immune reconstitution inflammatory syndrome and solid organ transplant recipients: are children protected?

The IRIS was initially described in HIV-positive patients as a sudden clinical deterioration after the introduction of highly active retroviral therapy. It is believed that IRIS is caused by a restored and exaggerated inflammatory immune response to different infectious or non-infectious triggers. This abnormal response is the consequence of an imbalance between pro-inflammatory and anti-inflammatory states. Recently, IRIS has also been reported in adult SOT recipients, causing local and systemic manifestations, and compromising long-term graft function and patient survival. However, IRIS has to date not been reported in pediatric SOT recipients. Here we review what is known and speculated about the pathogenesis of IRIS and propose that children may be relatively protected from IRIS.

Immunization and transplantation--what is new and what is coming?

Infections represent an important risk for pediatric transplant recipients. Many infections are preventable through immunization, and ongoing studies are working on increasing the number of available vaccines for these children either before or after transplantation. We examine new immunization schedules (such as pertussis vaccines in teenagers) and newly available vaccines (such as human papillomavirus vaccine), and suggest how to deliver them in pediatric transplant candidates or recipients. We also review less common vaccines (such as encephalitis vaccines), and possible vaccines of the future that could have an important clinical impact in these children, such as CMV or EBV vaccines.

Severe autoimmune hemolytic anemia in a liver transplanted child

AIHA can complicate solid organ and bone marrow transplantation early after transplant. We describe the first case report of a 16-month-old boy with mixed type warm-acting IgM and warm IgG autoantibodies AIHA, occurring eight months after liver transplantation. This case describes the complexity of this very rare form of AIHA. It also illustrates the efficacy of rituximab in this indication, as well as the transfusion support with extremely rare blood, along with the importance of international collaboration to provide it. In this report, the etiologies of HA occurring in post-transplant pediatric patients are reviewed and the different treatment strategies are discussed.

Recurrence of cardiorespiratory events following repeat DTaP-based combined immunization in very low birth weight premature infants

We evaluated the tolerance to immunization of 64 very low birth weight preterm infants. Thirty-three of the infants experienced a cardiorespiratory event after the first vaccination, and 6 of these 33 (18%) had a recurrence after the second vaccination, including 2 infants previously discharged to home. A cardiorespiratory event associated with the first vaccination was the sole risk factor for recurrence identified.

Bronchoalveolar cytology for diagnosing pulmonary GVHD after bone marrow transplant in children

BACKGROUND

Cytological composition of bronchoalveolar lavage (BAL) fluid in pediatric bone marrow transplant (BMT) recipients with pulmonary complications has not been comprehensively described and BAL specific markers of pulmonary GVHD are lacking. The aim of this retrospective study was to assess the role of BAL in the diagnosis of pulmonary GVHD by comparing BAL cytological findings between pediatric allogenic BMT patients with pulmonary complications and oncology children receiving chemotherapy alone.

METHODS

Retrospective analysis of BAL specimens for cytology, total and differential cell counts and presence of infections.

RESULTS

Seventeen BMT and 13 chemotherapy BAL were analyzed. BAL total cell count was increased but similar between groups (96.9 x 10(4) vs. 98.2 x 10(4), P = NS). BAL cellular composition differed considerably between groups with a significantly higher number of lymphocytes (18% vs. 6.25%, P = 0.03) and a significantly lower number of neutrophils (25.9% vs. 58%, P = 0.02) in BMT BAL specimens. Atypical epithelial cells were significantly more frequent (75% vs. 30.8%, P = 0.027), and significantly more severe (P = 0.01) in BMT patients. The presence and severity of atypia was not associated with infection or pneumotoxic drug exposure (P = NS).

CONCLUSION

BAL cytology differs significantly between BMT and chemotherapy patients. The presence BAL lymphocytosis and severe epithelial cell atypia concomitantly to respiratory symptoms and GVHD in other organs may suggest the diagnosis of pulmonary GHVD. Prospective studies assessing the reliability of this finding combined with markers such as epithelial cell apoptosis and increased cytokines are needed.

Influence of anesthesia on immune responses and its effect on vaccination in children: review of evidence

Anesthesia and surgery exert immunomodulatory effects and some authors argue that they may exert additive or synergistic influences on vaccine efficacy and safety. Alternatively, inflammatory responses and fever elicited by vaccines may interfere with the postoperative course. There is a lack of consensus approach among anesthesiologists to the theoretical risk of anesthesia and vaccination. Few studies have assessed the influence of anesthesia and surgery on pediatric vaccine responses. We have undertaken an extensive review of articles published in English between 1970 and 2006 meeting the criteria: measurement of immune parameters following general anesthesia in children. By searching the major medical databases (OVID Medline, PubMed, ISI Web of Science) and references cited in the articles themselves, among 277 articles obtained none examined directly the influence of anesthesia/surgery on vaccine responses. Only 16 original reports assessed the influence of several anesthetic agents on various markers of immunity including lymphocyte numbers and functions. These results are reinterpreted here in view of our current understanding of the immune mechanisms underlying vaccine efficacy and adverse events. We conclude that the immunomodulatory influence of anesthesia during elective surgery is both minor and transient (around 48 h) and that the current evidence does not provide any contraindication to the immunization of healthy children scheduled for elective surgery. However, respecting a minimal delay of 2 days (inactivated vaccines) or 14-21 days (live attenuated viral vaccines) between immunization and anesthesia may be useful to avoid the risk of misinterpretation of vaccine-driven adverse events as postoperative complications.

Vaccine-induced immunity in children after orthotopic liver transplantation: a 12-yr review of the Swiss national reference center

Infections represent a significant threat in solid-organ recipients. However, a certain number of infections can be prevented by immunizing patients before their transplantation. The aim of this study is to determine the level of immunity of children undergoing liver transplantation and to assess their capacity to maintain protective levels after surgery. Charts of 44 children transplanted with deceased donation livers between 1990 and 2002 at the Children's Hospital of Geneva were reviewed. Vaccine antibody responses were established pre- and post-transplantation. Only 43% of patients were up to date for diphtheria, tetanus, acellular pertussis, and polio vaccines at the pretransplantation visit, while 44% of children older than 12 months had received their required measles-mumps-rubella vaccines. Six of 44 children had received at least one dose of hepatitis B vaccine, while only two patients had received at least one dose of hepatitis A vaccine. After immunization, and one yr after transplantation, only 14 of 44 patients had detectable anti-HBs antibodies and seven of 18 had anti-HAV antibodies. Varicella antibodies were undetectable in 15 of 19 patients immunized prior to transplantation. This study highlights the need to enforce vaccination before transplantation, follow-up on vaccine- induced immunity, and adapt vaccination schedules after liver transplantation in children, especially for non-live vaccines, which are universally recommended in this population.

Increased incidence of apparently life-threatening events due to supine position

Gastro-oesophageal reflux (GOR) has a high prevalence in infancy. The supine position is among numerous aggravating factors. The exact relationship between GOR and apparently life-threatening events (ALTE) is not clear, although it has been repeatedly investigated. In 1992 the worldwide Back to Sleep campaign was implemented, which had a dramatic effect on the incidence of sudden infant death syndrome (SIDS) with a drop of 50%. Although the vast majority of children now sleep on their back, the effect of this position on ALTE has not been studied. In this retrospective study, we aim to define the potential association between GOR and ALTE. We hypothesise that the incidence of ALTE has increased since the 1992 recommendation. No bias in the population's selection was introduced, as our centre is the only one for paediatric emergencies in the county. A total of 107 children presenting with ALTE were identified during the study period (1987-99). A pH study was performed in the 75 patients presenting with ALTE in the last 6 years of the study (1994-99). Neither morbidity nor mortality was noted in a long-term 4-year follow-up. Our present results show that the frequency of ALTE increased sevenfold (P < 0.005) between 1992 and 1999. The ALTE episodes took place significantly more often in the post-prandial period. The prevalence of GOR was much higher in patients presenting with ALTE (nearly 75%) when compared with the general population. Furthermore, on medical treatment for GOR, very few patients presented with a second episode of ALTE. Consequently it is thought that GOR and ALTE are linked and that ALTE patients would benefit from GOR treatment. The worldwide marked decrease in SIDS since the implementation of the supine position possibly masks the negative effect of an increase in ALTE.

How do physicians immunize their own children? Differences among pediatricians and nonpediatricians

CONTEXT

Immunization has an essential impact on public health worldwide. Numerous studies have shown the efficacy of different vaccines to protect individuals from various diseases. However, some parents choose not to vaccinate their children for reasons such as, among others, doubts regarding their usefulness, concerns over safety or efficacy, etc. Physicians are known to exert a direct influence on immunization rates by answering questions and clarifying misconceptions. Yet, it is unknown how they immunize their own children.

OBJECTIVE

We sought to assess how physicians interested in vaccination issues immunized, or would immunize, their own children.

DESIGN, SETTING, AND PARTICIPANTS

An 11-question, Web-based survey with a total of 102 discrete answers was sent to 2070 Swiss physicians in October 2004. All physicians were subscribers to a nonprofit, Web-based expert network (InfoVac, www.infovac.ch) that distributes monthly newsletters and answers question within 2 days on immunization issues. The InfoVac network reaches > 95% of pediatricians in Switzerland but < 20% of general practitioners. All responses were anonymous, and no identifier could be used to trace the participants of the survey. Questions were divided into 2 parts: (1) physicians who were parents were asked which vaccines they gave to their own children and at what age, and (2) all physicians were asked which vaccines they would give to their own child and at what age if they had a newborn child in 2004. Vaccines available in Switzerland at the time of the survey were offered as possible replies, and recommended vaccines were considered as those noted in the Swiss federal immunization schedule issued yearly. One question compared their immunization practice between their own children and their patients. Sociodemographics, qualifying year, membership in different professional groups, and their type of practice were also requested. Statistics. Standard descriptive statistics were used for sociodemographic characteristics. Univariate statistical analyses were performed for each variable to determine its relationship to the dependent variable, being a pediatrician or nonpediatrician. Logistic-regression analysis was used to calculate the adjusted odds ratios (ORs) and 95% confidence intervals (CIs), controlling for any statistically significant demographic variables that might function as confounders (gender, parenthood, workplace, year of diploma, and type of practice). For all statistical tests, differences were considered significant at P < .05.

MAIN OUTCOME MEASURE

We performed a comparison of past and projected immunization rates in the children of pediatricians and nonpediatricians.

RESULTS

One thousand seventeen valid questionnaires were received (response rate: 49.1%; pediatricians: 53.3%). Nine hundred fifteen physicians (90%) had > or = 1 child. All physicians reported immunizing children in their practice. Pediatricians were more likely to be women and to work in private practice than nonpediatricians but less likely to belong to a self-reported alternative medicine association. Among the nonpediatricians, 317 were general practitioners, 144 were internists, and 95 were other specialists. Ninety-two percent of pediatricians followed the official immunization recommendations for their own children. In contrast, after controlling for gender, workplace, type of practice, and year of diploma, nonpediatricians were more likely not to have immunized their children against measles, mumps, hepatitis B, or Haemophilus influenzae type b. They more frequently postponed diphtheria-tetanus-pertussis (DTP) (OR: 4.5; 95% CI: 2.0-10.19) and measles-mumps-rubella (MMR) vaccination. Although projected immunization rates were higher than effective rates, 10% of nonpediatricians would still not follow the official immunization recommendations in 2004. They would more frequently refrain from using combination vaccines and postpone DTP and MMR immunization to later in life. Several comparisons confirmed the weaker use of the more recently licensed vaccines by nonpediatricians. In addition to vaccines currently recommended in Switzerland, both groups of physicians added hepatitis A, influenza, and varicella vaccines to the vaccination schedule of their own children. Pediatricians were more likely to give pneumococcal (OR: 2.26; 95% CI: 1.004-4.68) and meningococcal C (OR: 2.26; 95% CI: 1.62-3.17) vaccines to their own children. In contrast, they were less likely to give tick-borne encephalitis virus vaccine (OR: 0.65; 95% CI: 0.44-0.95).

CONCLUSIONS

Ninety-three percent of the surveyed physicians agree with the current official vaccination recommendations and would apply them to their own children. However, the observation that 5% of nonpediatricians would not use Haemophilus influenzae type b vaccine if they had a child born in 2004 is unexpected and concerning. In contrast, both groups gave additional vaccines than those recommended to their own children. Among physicians in Switzerland interested in immunization, a significant proportion of nonpediatricians decline or delay the immunization of their own children with the recommended MMR- or DTP-based combination vaccines, which indicates that clarification of misconceptions such as fear of "immune overload" has not yet reached important targets among health care providers who thus are unlikely to answer parental concerns adequately.

Spectrum of clinical manifestations of West Nile virus infection in children

Reports of clinical manifestations of West Nile virus (WNV) infections in children have been relatively rare. Four cases of WNV infection in children are described: the first report of prolonged encephalitis and fulminant hepatitis caused by WNV, and 3 other presentations of WNV, including the first report of ocular involvement in a child.

Pneumococcal vaccines: do they prevent infection and how?

PURPOSE OF REVIEW

The purpose of this review is to update and summarize information concerning the epidemiology of infections due to Streptococcus pneumoniae and the early results of effectiveness studies of the heptavalent pneumococcal conjugate vaccine. This vaccine was licensed in the US in 2000, and has been used increasingly since that time.

RECENT FINDINGS

Several studies have documented a dramatic decline in the rate of invasive infections due to S. pneumoniae in children under 5 years of age. There has been a simultaneous decrease in serious infections in persons over 20 years of age, presumably because of a decrease in transmission of S. pneumoniae to unvaccinated individuals. Three different studies have shown a modest reduction in the overall number of cases of acute otitis media in children who have received the vaccine. Although the overall number of cases has decreased there has been an increase in the number of cases of acute otitis media caused by serotypes of S. pneumoniae not contained in the vaccine. Worldwide, many studies have appeared that examine the prevalence of different pneumococcal serotypes/serogroups as a cause of invasive and respiratory disease, to assess the likelihood that the vaccine will be effective in particular geographic areas.

SUMMARY

Use of the heptavalent pneumococcal conjugate vaccine has led to a major decline in the prevalence of invasive pneumococcal disease (bacteremia, meningitis) and a more modest decrease in respiratory tract infections (acute otitis media, pneumonia). Continued surveillance is essential to document future trends in the occurrence of pneumococcal infections and the enduring protectiveness of the heptavalent pneumococcal conjugate vaccine.