Immunogenicity and safety of a 23-valent pneumococcal polysaccharide vaccine in healthy children and in children at increased risk of pneumococcal infection

Vaccines and nephrotic syndrome: efficacy and safety

Vaccines represent the most important medical evolution in the last two centuries allowing prevention and formally eradication of a wide number of infectious diseases. Safety and effectiveness are main issues that still require an open discussion. A few clinical reports described a critical temporal relationship between vaccination and acute nephrotic syndrome, indirectly suggesting an association. For this review, the literature was reviewed to identify articles reporting associations of nephrotic syndrome with vaccines against a vast array of infectious diseases (including bacteria, virus and Sars-Cov-2). As specific aims, we evaluated effectiveness and safety in terms of occurrence of either "de novo" nephrotic syndrome in health subjects or "relapse" in those already affected by the disease. In total, 377 articles were found; 166 duplicates and 71 non-full text, animal studies or non-English language were removed. After excluding another 50 articles not containing relevant data on generic side effects or on relapses or new onset nephrotic syndrome, 90 articles met the search criteria. Overall, studies reported the effect of vaccines in 1015 patients, plus 4 nationwide epidemiologic investigations. Limited experience on vaccination of NS patients with measles, mumps, and rubella live attenuated vaccines does not allow any definitive conclusion on their safeness. VZV has been administered more frequently without side effects. Vaccines utilizing virus inactivated, recombinant, and toxoid can be utilized without risks in NS. Vaccines for influenza reduce the risk of infections during the pandemic and are associated with reduced risk of relapse of NS typically induced by the infection. Vaccines for SARS-CoV-2 (all kinds) offer a concrete approach to reduce the pandemic. "De novo" NS or recurrence are very rare and respond to common therapies.

Association between asthma and invasive pneumococcal disease risk: a systematic review and meta-analysis

Purpose

Asthma has been shown to be related to an increased risk of invasive pneumococcal disease (IPD), although the results remain inconclusive. Therefore, we performed a meta-analysis to determine whether asthma increases the risk of IPD. This meta-analysis was performed to validate and strengthen the association between asthma and IPD.

Methods

PubMed, EMBASE, Web of Science, and the reference lists of all relevant articles and books were screened until May 2019. Two authors independently assessed eligibility and study quality and extracted data. A common odds ratio was estimated using a random-effects meta-analysis model of aggregated published data.

Results

A total of eight studies with 8877 IPD cases and 78,366 controls were included. Our meta-analysis showed that asthma was significantly associated with the increased risk of IPD (OR 2.44 [95% CI, 2.02–2.96]). The children with asthma (0–17 years old) (OR 2.86 [95% CI 1.80–4.55]) had a higher risk of IPD susceptibility compared with the adult patients (≥ 18 years old) (OR 2.45 [95% CI 1.98–3.03]).

Conclusions

Results of this meta-analysis indicated that the patients with asthma had a higher risk of IPD susceptibility, especially among the children with asthma.

Why are people with asthma susceptible to pneumonia? A review of factors related to upper airway bacteria

Asthma and pneumonia are common respiratory conditions globally, affecting individuals of all ages. Streptococcus pneumoniae is the predominant bacterial cause of pneumonia, with nasopharyngeal carriage an important step towards invasive and pulmonary disease. Vaccines provide individual protection, and also prevent nasopharyngeal carriage, providing herd immunity. Asthma is associated with an increased risk of pneumonia, but there is limited information on the underlying mechanism of this predisposition. Both asthma and its treatment may conceivably alter propensity to, and density of, carriage through an altered epithelial microenvironment driven by disease-related inflammation or treatment-related immunomodulation, for example with inhaled corticosteroids. The relative importance of these factors could impact the efficacy of vaccines in this vulnerable patient population. In this review, we summarize the evidence for an increased risk of pneumonia in asthma, and discuss factors affecting nasopharyngeal carriage in the context of current guidelines for pneumococcal vaccination.

Relationship between asthma status and antibody response pattern to 23-valent pneumococcal vaccination

Objective: Asthma poses an increased risk for serious pneumococcal disease, but little is known about the influence of asthma status on the 23-valent serotype-specific pneumococcal antibody response. We examined differences in antibody titers between pre- and post-vaccination with 23-valent pneumococcal polysaccharide vaccine (PPSV-23) in relation to asthma status. Methods: Asthma status was retrospectively ascertained by the Predetermined Asthma Criteria in an existing vaccine cohort through comprehensive medical record review. Twenty-three serotype-specific pneumococcal antibody titers measured at baseline and 4-6 weeks post-vaccination were analyzed. Vaccine responses to PPSV-23 were calculated from pre- to post-vaccine titers for each of the serotypes. Results: Of the 64 eligible and enrolled subjects, 18 (28%) had asthma. Controls (i.e., subjects without asthma) demonstrated a statistically significant fold change response compared to their baseline for all serotypes, while those with asthma did not mount a significant response to serotypes 7F, 22F, and 23F. The overall vaccine response as measured by fold change over baseline was lower in subjects with asthma than controls. Conclusions: Poorer humoral immune responses to PPSV-23 as measured by fold change were more likely to be observed in subjects with asthma compared to controls. We recommend the consideration of asthma status when interpreting vaccine response for immune competence workup through larger studies. Further studies are warranted to replicate these findings.

Safety and Efficacy of Pneumococcal Vaccination in Pediatric Nephrotic Syndrome

Nephrotic syndrome affects both children and adults. Idiopathic nephrotic syndrome is reported to be one of the most frequent renal pathologies in childhood. Nephrotic children are at high risk for severe pneumococcal infections as one of the life-threatening complications of nephrotic syndrome due to involvement of the immunosuppressive regimen and the acquired immune deficiency induced by nephrotic syndrome including decreased plasma IgG and low complement system components. Aiming to prevent pneumococcal infection is of paramount importance especially in this era of ever-increasing pneumococcal resistance to penicillins and cephalosporins. The pneumococcal vaccines currently available are inactivated vaccines-the two main forms in use are polysaccharide vaccines and conjugated vaccines. However, the data supporting the use of these vaccines and to guide the timing and dosage recommendations is still limited for nephrotic children. Thus, this review discusses the evidences of immunogenicity and safety profile of both vaccinations on nephrotic patients as well as the effect of nephrotic syndrome treatment on vaccine seroresponses.

Asthma, other atopic conditions and risk of infections in 105 519 general population never and ever smokers

BACKGROUND

Individuals with atopic conditions may have increased susceptibility to infections outside the organs directly affected by their atopic condition.

OBJECTIVE

We tested the hypothesis that atopic conditions overall, and stratified by smoking history, are associated with increased risk of hospitalization for infections.

METHODS

We collected information on smoking history and self-reported atopic conditions from 105 519 individuals from the general population and followed them for up to 23 years for infectious disease hospitalizations and deaths. For asthma, we focused on never smokers with asthma diagnosed before age 50 (early asthma) to minimize confounding by chronic obstructive pulmonary disease.

RESULTS

During follow-up, 11 160 individuals had infections. Never smokers with early asthma versus no atopic conditions had significantly increased risks of any infection (hazard ratio 1.65; 95% confidence interval 1.40-1.94), pneumonia (2.44; 1.92-3.11) and any non-respiratory tract infection (1.36; 1.11-1.67); results were similar in ever smokers. Never smokers with any asthma had significantly increased risks of any infection (1.44; 1.24-1.66) and pneumonia (1.99; 1.62-2.44). Neither atopic dermatitis (1.00; 0.91-1.10) nor hay fever (1.00; 0.93-1.07) was associated with risk of any infection. In never smokers, risk estimates for any infection were comparable between asthma and diabetes, as were the population attributable fractions of 2.2% for any asthma and 2.9% for diabetes.

CONCLUSION

Early asthma was associated with significantly increased risks of any infection, pneumonia and any non-respiratory tract infection in never and ever smokers. In never smokers, risk estimates as well as population attributable fractions for any infection were comparable between asthma and diabetes, suggesting that asthma may be a substantial risk factor for infections in the general population.

A case series evaluating the serological response of adult asthma patients to the 23-valent pneumococcal polysaccharide vaccine

BACKGROUND

Asthma is an independent risk factor for invasive pneumococcal disease; however, the immune response of adult asthma patients to pneumococcal vaccination is unknown. We explore the serologic response of patients with moderate to severe asthma to the 23-valent pneumococcal polysaccharide vaccine (PPSV23).

METHODS

Seventeen moderate to severe adult asthma patients that had not been vaccinated against pneumococcus over the 5 previous years were prospectively recruited from a tertiary care asthma clinic. Serum was analyzed for the presence of antibodies to five capsular polysaccharide (CP) antigens (6B, 9V, 19A, 19F, 23F) before and 4 weeks after PPSV23 vaccination.

RESULTS

There was a wide variability in baseline anti-CP antibody concentrations. Other than for serotype 19A, our patients frequently have baseline anti-CP antibody concentrations below 1 µg/mL (35% for serotype 19F, 41% for serotypes 9V and 23F, and 59% for serotype 6B). All post-vaccination geometric mean antibody concentrations were significantly higher than baseline. In the 31 tests where the baseline antibody concentration was <1 µg/mL, 77.4% had at least a twofold increase post-vaccination. Despite this, a large proportion of post-vaccination anti-CP antibody concentrations remained <1 µg/mL (51.6% of tests). Nine patients had at least one anti-CP antibody concentration <1 µg/mL post-vaccination. There was no difference between these patients and the remaining eight patients in demographic or clinical variables.

CONCLUSIONS

Patients with moderate to severe asthma have variable baseline and low post-vaccination antibody concentrations to common CP antigens included in the PPSV23 vaccine. The clinical relevance of these observations remains to be determined since the threshold concentration in adults required for clinical protection from invasive pneumococcal disease is uncertain.

Cost-effectiveness and Health Benefits of Pediatric 23-valent Pneumococcal Polysaccharide Vaccine, 7-valent Pneumococcal Conjugate Vaccine and Forecasting 13-valent Pneumococcal Conjugate Vaccine in China

BACKGROUND

Each year in China, approximately 700,000 children under 5 years old are diagnosed with pneumonia, and 30,000 die of the disease. Although 7-valent pneumococcal conjugate vaccine (PCV-7) and 23-valent pneumococcal polysaccharide vaccine (PPV-23) are available in China, the costs are borne by the consumer, resulting in low coverage for PCV-7. We aimed to conduct a simulation study to assess the cost-effectiveness and health benefits of PCV-7, 13-valent pneumococcal conjugate vaccine (PCV-13) and PPV-23 to prevent childhood pneumonia and other vaccine-preventive diseases in China.

METHODS

An economic evaluation was performed using a Markov simulation model. Parameters including demographic, epidemiological data, costs and efficacy of vaccines were obtained from previous studies. A hypothetical cohort of 100,000 newborns (focusing on pneumococcal diseases ≤7 years old) was followed up until death or 100 years of age. The model incorporated the impact of vaccination on reduction of incidence of pneumococcal diseases and mortality of children ≤7 years. Outcomes are presented in terms of disease cases averted, quality-adjusted life years (QALYs) and incremental cost-effectiveness ratio.

RESULTS

Under baseline assumptions, PPV-23 is currently the only cost-effective option, whereas PCV-13 showed the greatest impact on pneumococcal disease burden, reducing invasive pneumococcal diseases by 31.3%, pneumonia by 15.3% and gaining 73.8 QALYs (10,000 individuals at discount rate of 3%). Incremental cost-effectiveness ratios of PCV-13 and PCV-7 are US$29,460/QALY and US$104,094/QALY, respectively, showing no cost-effectiveness based on the World Health Organization recommended willingness-to-pay threshold. On the other hand, the incremental cost-effectiveness ratios of PCVs were most sensitive to vaccination costs; if it reduces 4.7% and 32.2% for PCV-7 and PCV-13, respectively, the vaccination will be cost-effective.

CONCLUSIONS

To scale up current vaccination strategies and achieve potential health benefits, the replacement of PCV-7 with PCV-13 should be considered. As well, PCV's costs need to be reduced by increasing public subsidies and providing financial support to poor families.

Optimizing seroprotection against pneumococcus in children with nephrotic syndrome using the 13-valent pneumococcal conjugate vaccine

BACKGROUND

Infections are among the main life-threatening complications in patients with nephrotic syndrome (NS), in particular with Streptococcus pneumoniae, the first cause of bacterial peritonitis and sepsis in these patients. This study aims to evaluate the baseline seroprotection of NS patients against S. pneumoniae, and immunize them with the 13-valent pneumococcal conjugate vaccine (PCV13) regardless of disease activity and previous immunization history, in order to evaluate the immunogenicity, safety profile, and effect of NS treatment on vaccine responses.

METHODS

This multicentre prospective interventional study enrolled 42 children with NS at disease onset or during a regular follow-up appointment. PCV13 was administered at inclusion. Serotype-specific S. pneumoniae IgG titer were assessed at baseline, after immunization, and at 1year follow-up. Vaccine safety was evaluated clinically and by urinary tests.

RESULTS

PCV13 induced high serotype-specific IgG titers that were maintained at high levels one year after vaccination, even in children previously immunized. No serious adverse event occurred and relapse frequency was unchanged.

CONCLUSION

Given that high IgG titers were achieved and maintained after PCV13 vaccination, and considering the high morbidity related to S. pneumoniae, we propose PCV13 (re-)vaccination for all NS patients, irrespective of their previous immunization history, treatment and disease activity.

Influence of HLA-DR polymorphism and allergic sensitization on humoral immune responses to intact pneumococcus in a transgenic mouse model

Asthma is independently associated with HLA-DR3 and increased risks of pneumococcal diseases. We aimed to determine whether HLA-DR polymorphism (HLA-DRB1*03), sensitization to house dust mite (HDM), or their interaction affects humoral immune responses to pneumococcal polysaccharide and protein antigens of intact pneumococci. Induction of serum titers of anti-pneumococcal polysaccharide and anti-surface protein IgM and IgG in response to immunization with intact pneumococci (Pn) serotype 14 was determined using humanized HLA-DR3 and DR2 transgenic mice. Transgenic mice were sensitized by injecting HDM and challenged with intranasal HDM. Mice were subsequently immunized with heat-killed Pn14 at day 24. Serum titers of anti-phosphorylcholine (PC) IgM and IgG, anti-pneumococcal polysaccharide, capsular type 14 (PPS14) IgM and IgG, and anti-pneumococcal surface protein A (PspA) IgG were measured. We included a total of 44 mice (22 DR3 and 22 DR2 mice) and half of mice in each group were sensitized with HDM (i.e. 22 HDM-sensitized and 22 control mice). HDM-sensitized mice, irrespective of HLA-DR polymorphism, had significantly lower humoral immune responses. HLA-DR3 mice, irrespective of HDM sensitization, elicited a significantly lower anti-PC IgG response. In contrast, the anti-PspA IgG response was higher in DR3 relative to DR2 mice. The effect of HDM sensitization on lowering humoral immune responses to Pn14 was observed in DR3 mice regardless of the nature of the antigen, whereas such decreases were observed only for the anti-PPS14 IgG and anti-PC IgM responses in DR2 mice. HDM sensitization lowered humoral immune responses to intact pneumococcus and this effect was significantly modified by the HLA-DR polymorphism.

Asthma and risk of breakthrough varicella infection in children

BACKGROUND

We recently reported a more rapid waning of vaccine-induced humoral immunity (measles vaccine) in children with asthma. It is unknown if asthma affects susceptibility to vaccine-preventable diseases.

OBJECTIVE

To determine whether asthma is associated with an increased risk of vaccine-preventable disease, e.g., breakthrough varicella infection.

METHODS

This was a retrospective population-based case-control study that examined cases of breakthrough varicella among children between 2005 and 2011. Children with a diagnosis of breakthrough varicella infection in Olmsted County, Minnesota (infection of >42 days after vaccination) between 2005 and 2011 and two age- and sex-matched controls were enrolled for each case. Asthma status was determined by using predetermined criteria. Conditional logistic regression models were used to calculate matched odds ratios (OR) and their corresponding 95% confidence intervals (CI).

RESULTS

Of the 165 cases and their 330 matched controls, 48% were boys and the mean (standard deviation) age at the index date was 6.6 ± 3.5 years for both cases and controls. Of the 330 controls, 80 (24%) had two doses of the varicella vaccine compared with only 23 (14%) of the 165 cases (OR 0.29 [95% CI, 0.14-0.61]; p = 0.001). Children with a history of asthma ever had a higher risk of developing breakthrough varicella compared with those without a history of asthma (adjusted OR 1.63 [95% CI, 1.04-2.55]; p = 0.032) when adjusting for elapsed time since the first varicella vaccination and the number of varicella vaccine doses.

CONCLUSIONS

A history of asthma might be an unrecognized risk factor for breakthrough varicella infection. Children with asthma should follow the two-dose varicella vaccine policy.

Safety and immunogenicity of 23-valent pneumococcal polysaccharide vaccine in 2 to 70 year old healthy people in China: A phase III double blind, randomized clinical trial

To evaluate the safety and immunogenicity of 23-valent pneumococcal polysaccharide vaccine (PPV23), a randomized, double-blind and parallel controlled clinical trial was conducted in Yancheng, Jiangsu Province of China. There were 1200 subjects randomized into 2 groups with a 1:1 allocation. Subjects received 0.5 mL of tested PPV23 or control PPV23 by intramuscular injection in the deltoid, respectively. Results showed that seroconversion rates of all 23 types except type 3 were not significantly different between the 2 groups. The seroconversion rate of the Group T for type 3 (P = 0.0009) was significantly higher than the Group C. The post-vaccination GMCs of the Group T for types 1 (P = 0.0340), 3 (P = 0.0003), 9V (P = 0.0016), 11A (P = 0.0222) and 33F (P = 0.0344) were significantly higher than the Group C. The frequencies of local and general reactions were not significantly different and acceptable in both groups. In conclusion, The PPV23 showed a good immunogenicity and tolerability in 2 to 70 y old healthy people.

The FACT score in predicting pneumococcal antibody levels in asthmatics

BACKGROUND

There is no measure currently available to identify asthmatics with potential immune incompetence.

OBJECTIVE

We propose use of a novel scoring system called the FACT score, which is formulated based on four parameters: (1) Family history of asthma, (2) Atopic conditions, (3) Bacterial colonization and (4) Th1 versus Th2 immune profile.

METHODS

This was a cross-sectional study involving 16 asthmatics and 14 non-asthmatics. The first two parameters of the FACT score were obtained via a chart review and interview. For the third parameter, nasopharyngeal swab samples were cultured. The ratio of interleukin-5 to interferon-gamma for each patient was measured by peripheral blood mononuclear cells cultured with house dust mite. Antibodies to 23 pneumococcal antigens were used for humoral immunity.

RESULTS

The FACT scores for asthmatics (mean ± SD: 5.2 ± 1.87) were higher than those for non-asthmatics (mean ± SD: 3.3 ± 1.5) (p = 0.008). Of the 16 asthmatics, 7 (44%) had 12 or more positive serotype-specific polysaccharide antibodies, whereas 12 of 14 (86%) of non-asthmatics subjects had 12 or more positive serotype-specific polysaccharide antibodies (p = 0.014). Overall, the FACT score was inversely correlated with the number of positive serotype-specific antibody levels [rho (ρ) = -0.38, p = 0.04]. The proportions of subjects with 12 or more positive serotype-specific antibodies among non-asthmatics and asthmatics below and above the median of the FACT scores were 86, 50 and 38%, respectively (p = 0.052).

CONCLUSIONS

The FACT score may help us identify a subset of asthmatics with immune incompetence. Study findings need to be replicated in a larger study.

Asthma status and waning of measles antibody concentrations after measles immunization

BACKGROUND

Asthmatics have increased risks of common and serious microbial infections including vaccine preventable diseases. Little is known about whether asthma influences waning of humoral immunity. We assessed whether asthma status influences waning of anti-measles virus antibody concentrations over time.

METHODS

The study used a cross-sectional study cohort of healthy children who had been immunized with 1 dose of MMR-II at age approximately 15 months. Between 5 and 12 years of age, measles vaccine virus-specific antibody (IgG) values were measured by enzyme immunoassay and considered seropositive if the enzyme immunoassay index unit was ≥ 1. The medical records were reviewed to determine asthma status during the first 18 years of life by applying predetermined criteria for asthma. A least squares regression model was used to evaluate the effect of asthma status on the relationship between measles antibody titer and time elapsed between the initial measles vaccination and measurement of measles antibody concentrations.

RESULTS

Of the 838 eligible children, 281 (34%) met criteria for asthma. Measles antibody waned over time (r = -0.19, P < 0.001), specifically more rapidly in asthmatics (r = -0.30, P < 0.001, a decrease of -0.114 unit per year) than non-asthmatics (r = -0.13, P = 0.002, a decrease of -0.046 unit per year; P value for interaction = 0.010). This differential waning rate resulted in a lower mean (SD) measles antibody concentration [1.42 (0.67) vs. 1.67 (0.69), P = 0.008] and lower seropositivity rate (73% vs. 84%, P = 0.038) in asthmatics than non-asthmatics starting around 9.3 years after the initial measles vaccination.

CONCLUSION

Asthma status is associated with waning kinetics of measles antibody among children.

Programming of the lung by early-life infection

Many important human diseases, such as asthma, have their developmental origins in early life. Respiratory infections in particular may alter the course of asthma and may either protect against or promote the development of this disease. It is likely that the nature of the effects depends on the type and age of infection and is determined by the impact of infection on the immune and respiratory systems. Immunity in early life is plastic and can be moulded by antigen encounter, which may enhance or reinforce the asthmatic phenotype of early life, or induce protective responses. Chlamydial respiratory infections have specific effects and may increase asthma severity in early life by promoting systemic interleukin 13 responses and causing permanent changes in lung structure. Respiratory viral infections, such as those of respiratory syncytial virus and rhinovirus, promote pro-asthmatic responses in early life that contribute to the induction of asthma. By contrast, probiotics or infection or exposure to certain bacteria, such as Streptococcus pneumoniae, may have protective effects in asthma by increasing the numbers and activity of regulatory T cells. Here, we review the impact of infections on the developmental origins of asthma. Understanding these effects may lead to new therapeutic approaches for asthma that either target deleterious infections or utilize beneficial ones.

Risks for infection in patients with asthma (or other atopic conditions): is asthma more than a chronic airway disease?

Most of the research effort regarding asthma has been devoted to its causes, therapy, and prognosis. There is also evidence that the presence of asthma can influence patients' susceptibility to infections, yet research in this aspect of asthma has been limited. There is additional debate in this field, with current literature tending to view the increased risk of infection among atopic patients as caused by opportunistic infections secondary to airway inflammation, especially in patients with severe atopic diseases. However, other evidence suggests that such risk and its underlying immune dysfunction might be a phenotypic or clinical feature of atopic conditions. This review argues (1) that improved understanding of the effects of asthma or other atopic conditions on the risk of microbial infections will bring important and new perspectives to clinical practice, research, and public health concerning atopic conditions and (2) that research efforts into the causes and effects of asthma must be juxtaposed because they are likely to guide each other.

What does tympanostomy tube placement in children teach us about the association between atopic conditions and otitis media?

Otitis media is the most common infection second only to viral upper respiratory infection in the outpatient setting. Tympanostomy tube insertion (TTI) is the most common ambulatory surgical procedure in the USA. While many risk factors for otitis media have been identified, atopic conditions have been underrecognized as risk factors for recurrent and persistent otitis media. Given that asthma and other atopic conditions are the most common chronic conditions during childhood, it is worth examining the association between atopic conditions and risk of otitis media, which can provide insight into how atopic conditions influence the risk of microbial infections. This paper focuses its discussion on otitis media; however, it is important that the association between atopic conditions and risk of otitis media be interpreted in the context of the association of atopic conditions with increased risks of various microbial infections.

Impact of Asthma on the Severity of Serious Pneumococcal Disease

We recently reported an increased risk of serious pneumococcal disease (SPD) in asthmatics. Little is known about the impact of asthma status on the severity of SPD. We compared the severity of serious pneumococcal disease (SPD) between patients with asthma and those without asthma. The study subjects were Rochester, Minnesota residents who developed SPD between 1964 and 1983. SPD and asthma status were ascertained by using explicit predetermined criteria Severity of SPD was assessed using intensive care unit (ICU) admission rate and total days of ICU stay and hospitalization associated with treatment for SPD. We found that there were no significant differences in severity outcomes between asthmatics (n=11) and non-asthmatics (n=163). Asthma status may increase the risk of SPD but not influence its severity. However, given a small sample size of our study, a larger study needs to be considered to clarify the relationship between asthma and severity of SPD.

Serum 25-hydroxyvitamin D concentrations and waning pneumococcal antibody titers among individuals with atopy

Serum 25-hydroxyvitamin D (25[OH]D) concentrations are positively associated with pneumococcal antibody titers (PATs) in subjects with atopy or asthma. Little is known about the association of serum 25(OH)D concentrations and the waning of PATs over time in subjects with or without atopy. This study was designed to determine whether serum 25(OH)D concentrations are associated with waning of PATs and if such relationship is modified by atopic conditions. The study was designed as a prospective cohort study, which followed 20 asthmatic patients and 19 individuals without asthma for an average of 12 months. We measured PATs and serum 25(OH)D concentrations at baseline and at a subsequent follow-up visit. Asthma was ascertained by predetermined criteria. The association between serum 25(OH)D concentrations and PATs was determined by Pearson's correlation coefficient and a least square model. Of the 39 children and adults, 21(53%) were male subjects, all were white, and 6 (15%) were children. There was an overall negative correlation between serum 25(OH)D concentrations and the decrease of PATs during follow-up (r = -0.47; p = 0.004), suggesting that higher 25(OH)D concentrations were associated with a reduction in waning of PATs over time. Controlling for follow-up duration and pneumococcal colonization, these trends were significant among asthmatic patients but not in individuals without asthma. Similar trends were observed for individuals with or without other atopic conditions. Serum 25(OH)D concentrations are inversely associated with the waning of PATs over time, especially individuals with asthma and other atopy conditions. These study findings deserve further investigation.

Asthma and antibodies to pneumococcal virulence proteins

PURPOSE

We previously reported that asthmatics had lower anti-serotype-specific pneumococcal polysaccharide antibody levels than non-asthmatics, and the T-helper 2 (Th2) immune profile was associated with suboptimal pneumococcal polysaccharide antibody. Our objective was to determine the influence of asthma status on anti-pneumococcal protein antigen antibody levels.

METHODS

We conducted a cross-sectional study, which enrolled 16 children and adults with asthma and 14 subjects without asthma. Asthma was ascertained by predetermined criteria. Serum IgG antibody levels to pneumococcal surface protein A (PspA), pneumococcal surface protein C (PspC), pneumococcal choline-binding protein A (PcpA), and pneumolysin (PLY) were measured by enzyme-linked immunosorbent assays (ELISA). These antibody levels were compared between asthmatics and non-asthmatics. The Th2 immune profile was determined by IL-5 secretion from PBMCs cultured with house dust mite (HDM) and staphylococcal enterotoxin B (SEB) at day 7. The correlation between the anti-pneumococcal antibody levels and the Th2-HDM and SEB-responsive immune profile was assessed.

RESULTS

Of the 30 subjects, 16 (53%) were male and the median age was 26 years. There were no significant differences in anti-PspA, anti-PspC, anti-PcpA, and anti-PLY antibody levels between asthmatics and non-asthmatics. The Th2 immune profile was inversely correlated with the anti-PspC antibody levels (r = -0.53, p = 0.003). This correlation was significantly modified by asthma status (r = -0.74, p = 0.001 for asthmatics vs. r = -0.06, p = 0.83 for non-asthmatics). Other pneumococcal protein antibodies were not correlated with the Th2 immune profile.

CONCLUSION

No significant differences in the anti-pneumococcal protein antigen antibody levels between asthmatics and non-asthmatics were found. Asthma status is an important effect modifier determining the negative influence of the Th2 immune profile on anti-PspC antibody levels.

Influence of asthma epidemiology on the risk for other diseases

Asthma is a multifactorial chronic disease affecting a significant proportion of people in the United States and worldwide. Numerous laboratory and epidemiological studies have attempted to understand the etiology and underlying mechanisms of asthma and to identify effective therapies. However, the impact of asthma on the risk for other diseases has drawn little attention. This paper discusses the potential effects of asthma as a risk factor for other diseases, explores the potential mechanisms, and reviews the implications of the findings to clinical practice, public health, and research.

Serum 25-hydroxyvitamin D is associated with enhanced pneumococcal antibody levels in individuals with asthma

Recent studies suggest that vitamin D modulates innate immunity and reduces the risk of microbial infections. Little is known about the role of vitamin D in antipneumococcal immunity in individuals with asthma. We determined the correlation between serum 25-hydroxyvitamin D (25[OH]D) levels and pneumococcal antibody levels in individuals with asthma, atopic dermatitis, or allergic rhinitis, and atopic sensitization status. A cross-sectional study was conducted for 21 subjects with asthma and 23 subjects without asthma. Pearson's correlation coefficient between serum 25(OH)D concentrations and the number of positive serotype-specific antibody levels was calculated among individuals with and without asthma, atopic dermatitis, and/or allergic rhinitis and atopic sensitization status. The overall correlation between serum 25(OH)D concentrations and positive pneumococcal antibody levels in all subjects regardless of asthma was not significant (r = -0.14; p = 0.38). Stratified analysis results showed that there was a positive correlation between serum 25(OH)D concentrations and positive pneumococcal antibody levels in asthmatic patients (r = 0.45; p < 0.05) and an inverse correlation was observed in nonasthmatic patients (r = -0.53; p < 0.05). These trends were similar for subjects with and without atopic dermatitis and/or allergic rhinitis (r = 0.58 and p = 0.008 versus r = -0.63 and p = 0.001). Despite similar trends in the correlation between serum 25(OH)D and pneumococcal antibody concentrations among those with and without atopic sensitization status (r = 0.27 and p = 0.19 versus r = -0.41 and p = 0.08), they did not reach statistical significance. The 25(OH)D may enhance humoral immunity against Streptococcus pneumonia in subjects with atopic conditions but not without atopic conditions. Atopic conditions may have an important effect modifier in the relationship between serum 25(OH)D concentrations and immune function.

Influence of asthma status on serotype-specific pneumococcal antibody levels

BACKGROUND

Asthma has been reported to be associated with an increased risk of invasive pneumococcal disease (IPD).

OBJECTIVE

We compared serotype-specific antibody responses with pneumococcal polysaccharide antigens of individuals with and without asthma.

METHODS

A cross-sectional study was conducted for 16 subjects with asthma and 14 subjects without asthma from the community of Rochester, MN. Asthma was determined by predetermined criteria based on comprehensive medical record reviews. Serotype-specific antibody to 23 pneumococcal polysaccharide antigens was measured by enzyme-linked immunosorbent assay, and seropositivity was considered ≥ 1.3 μg/mL. Interferon-γ (IFN-γ) and interleukin-5 (IL-5) were measured from peripheral blood mononuclear cells cultured with house dust mites and staphylococcal enterotoxin B.

RESULTS

Of the 30 subjects, 16 (53%) were male, 21 (70%) were white, and the median age was 26 years. The median numbers of positive serotype-specific antibodies for asthmatics and nonasthmatics were 8.5 and 15.5, respectively (P = 0.034). There was an inverse relationship between the ratio of log-transformed IL-5/IFN-γ and the number of positive serotype-specific antibodies (r = -0.36; P = 0.052). As potential covariates and confounders, a history of pneumococcal vaccination (P = 0.84), having a high-risk condition for IPD (P = 0.68), and taking asthma medications, including inhaled/systemic corticosteroids (P = 0.79), were not associated with the number of positive serotype-specific antibodies.

CONCLUSION

Asthmatics had significantly lower serotype-specific pneumococcal antibody levels than nonasthmatics. House dust mite-induced T-helper 2 (Th2) cytokine immune profile may be related to the association. This may account for an increased risk of IPD in asthmatics and deserves further investigation.

Increased risk of serious pneumococcal disease in patients with asthma

BACKGROUND

Individuals with asthma have been reported to be at increased risk of invasive pneumococcal disease (IPD). These findings need to be confirmed in a different population-based study setting.

OBJECTIVE

We assessed whether serious pneumococcal disease (SPD), defined as an IPD, pneumococcal pneumonia, or both, was associated with asthma status.

METHODS

This is a retrospective case-control study using criteria-based methods for ascertaining SPD, as well as asthma. Subjects were residents of Rochester, Minnesota, who had SPD between 1964 and 1983 (the primarily pre-pneumococcal vaccine era) and their age- and sex-matched control subjects using 1:2 matching. Potential cases and control subjects were identified by using the Rochester Epidemiology project database and confirmed by medical record reviews. All cases and control subjects were merged with the database comprising the entire pool of Rochester residents with and without asthma between 1964 and 1983.

RESULTS

A total of 3941 records of potential patients with SPD were reviewed, and we identified 174 cases of SPD (51% male subjects and 94% white subjects). SPD was associated with a history of asthma among all ages (odds ratio, 2.4; 95% CI, 0.9-6.6; P = .09) and among adults (odds ratio, 6.7; 95% CI, 1.6-27.3; P = .01), controlling for high-risk conditions for IPD and smoking exposure. The population-attributable risk percentage was 17% in the adult population.

CONCLUSION

Adults with asthma might be at increased risk of SPD.

Inhibition of allergic airways disease by immunomodulatory therapy with whole killed Streptococcus pneumoniae

Asthma is a common inflammatory disease of the airways. Current therapies alleviate symptoms but do not treat the disease. We aim to develop effective immunomodulatory therapies (IMTs) for asthma that target the underlying causes of disease based on Streptococcus pneumoniae (Spn). The effect of Spn IMT on the development of asthma [allergic airways disease (AAD)] was determined in mice. Killed Spn was administered before, during or after ovalbumin sensitization, and the subsequent development of AAD was assessed. IMT attenuated T cell cytokine production, goblet cell hyperplasia, airways hyperresponsiveness (AHR), and eosinophil numbers in the blood, bronchoalveolar lavage fluid and peribronchial tissue. This indicates the potential of Spn as an IMT for asthma.

Randomised revaccination with pneumococcal polysaccharide or conjugate vaccine in asplenic children previously vaccinated with polysaccharide vaccine

OBJECTIVE

Asplenic children are at high risk of invasive pneumococcal infection. In this group, the American Academy of Pediatrics recommends a single revaccination with the 23-valent polysaccharide vaccine (PSV23) 3-5 years after a previous PSV23 dose. Despite potential advantages, there are few data available regarding the safety and immunogenicity of the heptavalent pneumococcal conjugate vaccine (PCV7) in this population. The aim of the study was to prospectively determine and to compare, in asplenic children, the vaccine specific antibody titres against the seven serotypes included in the PCV7 after administration of one dose of PCV7 or of PSV23, 3 years or more after an initial vaccination with PSV23.

PATIENTS AND METHODS

In this randomised, single-centre study, antibody titres were monitored at baseline, at 1 and 6 months after revaccination in 21 children with anatomic or functional asplenia. Response was considered as positive when there was a four-fold increase in antibody titres from baseline.

RESULTS

The most frequently reported adverse events were local reactions in 7/11 of PCV7 subjects and in 5/8 of PSV23 subjects, and general reactions (loss of appetite, sleepiness) in 5/11 of PCV7 subjects and in 1/8 of PSV23 subjects; without any serious adverse events. One child in the PCV7 group had increased temperature (38.4 degrees C). At least half of the PCV7 children responded to four or five serotypes, while more than half of the PSV23 subjects responded to less than 3 serotypes (p=0.285). After 1 month, the immune response for serotype 23F was significantly greater after PCV7 vaccination than after PSV23 vaccination (p=0.036).

CONCLUSIONS

PCV7 revaccination is safe and immunogenic in asplenic children previously vaccinated with PSV23, and could provide appropriate booster response in this high-risk population. The clinical repercussion on invasive pneumococcal diseases remains to be demonstrated.

Immunoglobulins and immunogenicity of pneumococcal vaccination in preschool asthma

Pneumococcal vaccination is advocated for asthmatics. Although routinely performed, data supplying evidence for this recommendation are limited. We examined the immunological background of 215 asthmatic children (2-5 year old) at a university children's hospital and compared the immunogenicity of the recommended pneumococcal vaccines. Testing encompassed serum immunoglobulins, immunoglobulin G (IgG)-subclasses, and pneumococcal antibodies against serotypes 4, 6B, 9V, 14, 18C, 19F and 23F. An infection-prone subgroup received one dose of 23-valent pneumococcal polysaccharide vaccine (PPV-23; n = 38, median age 45 months) or of 7-valent conjugate vaccine (PCV-7; n = 23; median age 35 months). Pneumococcal antibodies were determined again after 4 weeks. Low immunoglobulin- and/or IgG-subclass levels were found in 27 subjects (14 infection-prone). Prevaccination pneumococcal antibody levels ranged from 0.36 to 1.06 microg/ml, depending on the serotype. The percentage of subjects with putative protective antibody levels > or =1.0 microg/ml ranged only from 19.9% to 54.1%, over all. Postvaccination, antibody geometric mean concentrations increased significantly higher in PCV-7 vaccinees for serotype 14 (p < 0.01) and 23F (p < 0.05). Now the percentage of putatively protected subjects ranged from 40.9% (serotype 6B) to 90.9% (serotype 19F) following PCV-7 compared with 31.6% (serotype 6B and 23F) to 81.6% (serotype 19F) in PPV-23 vaccinees. Our data give further evidence for pneumococcal vaccination of asthmatic children. PCV-7 is at least as immunogenic as PPV-23. Moreover, for children suffering from persistent asthma, PCV immunisation should be considered.

Recent advances in pneumococcal vaccination of children

Pneumococcal disease is a major cause of childhood morbidity and mortality worldwide. However, there is a lack of epidemiological data to describe the vaccine-preventable burden of disease. New pneumococcal conjugate vaccines offer hope of preventing infant pneumococcal disease. The efficacy of the 7- and 9-valent pneumococcal conjugate vaccine (PCV) against invasive vaccine-type pneumococcal disease in young children is between 77 and 97%. The PCV vaccine efficacy against radiological pneumonia in HIV-negative infants for the 7- or 9-valent PCV is 23-30%. The vaccine efficacy in HIV-positive infants is lower--65% against invasive vaccine-type pneumococcal disease and no significant efficacy against radiological pneumonia. The 7-valent PCV showed modest efficacy against acute otitis media (7%) but seems to be more effective in preventing recurrent or severe disease. The high cost of these new vaccines is a barrier to their widespread introduction. The development of other pneumococcal vaccine candidates with wider serotype coverage should be encouraged. These vaccines should be affordable for all countries, particularly those with the highest burden of disease. In addition, other vaccination strategies such as maternal and neonatal immunisation and combinations of fewer doses of the PCV combined with an early dose of the cheaper pneumococcal polysaccharide vaccine need to be assessed further.

Advances in Pneumococcal Vaccines

The introduction of Haemophilus influenzae type b (Hib) vaccine into the universal immunisation schedules of many industrialised countries and the subsequent remarkable decline in the incidence of invasive Hib disease has further highlighted the impact of invasive pneumococcal diseases. Streptococcus pneumoniae is now the leading cause of bacterial meningitis in children in many settings and a leading cause of vaccine-preventable bacterial disease in children worldwide. The currently marketed 23-valent pneumococcal polysaccharide vaccine provides large serotype coverage at a relatively low cost. However, it is not efficacious in young children. Pneumococcal conjugate vaccines (PCVs) are highly effective in preventing invasive disease in infants and young children, with favourable safety and immunogenicity profiles. These vaccines have also shown efficacy in reducing cases of non-invasive disease (i.e. otitis media), nasopharyngeal acquisition of vaccine-specific serotypes of S. pneumoniae, and protection against pneumococcal disease caused by resistant strains. However, PCV contains a limited number of pneumococcal serotypes and, given adequate ecological pressure, replacement disease by non-vaccine serotypes remains a threat, particularly in areas with very high disease burden. Furthermore, although capsular-specific antibodies have been shown to be highly protective, it remains unclear what concentration of these serotype-specific antibodies protect against disease and, more recently, it has become clear that opsonic activity and avidity of these antibodies are more critical determinants of protection than concentration. Therefore, monitoring disease burden and defining immune correlates of protection after widespread use of conjugate vaccines are crucial for the evaluation of these new generation vaccines. Furthermore, a need exists to develop pneumococcal vaccines with lower cost and larger serotype coverage. Development of one or more protein vaccines that might be easier and, thus, less expensive to manufacture, and which might provide protection against multiple serotypes, is in progress. This article reviews the current state of pneumococcal disease and pneumococcal vaccines in clinical use.

Pneumococcal conjugate vaccines for preventing vaccine-type invasive pneumococcal disease and pneumonia with consolidation on x-ray in children under two years of age

BACKGROUND

Pneumonia, most commonly caused by Streptococcus pneumoniae (Pnc), is a major cause of morbidity and mortality among young children especially in developing countries. Recently, the prevalence of antibiotic-resistant Pnc has increased worldwide such that the effectiveness of preventive strategies, like the new pneumococcal conjugate vaccines (PCV) on rates of invasive pneumococcal disease (IPD) and pneumonia, needs to be evaluated.

OBJECTIVES

To determine the efficacy of PCV in reducing the incidence of IPD due to vaccine serotypes (VT) and x-ray confirmed pneumonia with consolidation of unspecified etiology in children who received PCV before 12 months of age.

SEARCH STRATEGY

We searched the following databases: the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library, Issue 1 2004), MEDLINE (1990 to March 2004) and EMBASE (1990 to December 2003). Reference list of articles, and books of abstracts of relevant symposia, were hand searched. Researchers in the field were also contacted.

SELECTION CRITERIA

Randomised controlled trials (RCTs) comparing PCV with placebo, or another vaccine, among children below two years with IPD and clinical/radiographic pneumonia as outcomes.

DATA COLLECTION AND ANALYSIS

Two reviewers independently identified eligible studies, assessed trial quality, and extracted data. Differences were resolved by discussion. The inverse variance method was used to pool effect sizes.

MAIN RESULTS

We identified four trials assessing the efficacy of PCV in reducing the incidence of IPD, two on x-ray confirmed pneumonia as outcome, and one on clinical pneumonia, with or without x-ray confirmation. Results from pooling HIV-1 negative children from the South African study with the other studies were as follows: the pooled vaccine efficacy (VE) for vaccine-type IPD was 88% (95% confidence interval (CI) 73% to 94%; fixed effect and random effects models), the effect measure was statistically significant (p <0.00001) and there was no heterogeneity (p = 0.77I2 0%); the pooled VE for all-serotype IPD was 66% (95% CI 46% to 79%; fixed effect model), the effect measure was statistically significant (p <0.00001) and there was no statistical heterogeneity (p = 0.09, I2 51%); the pooled VE for x-ray confirmed pneumonia was 22% (95% CI 11% to 31%; both fixed effect and random effects models) and there was no statistical heterogeneity (p = 0.80, I2 0%). Analyses that included all the children in the South African study (HIV-1 negative and HIV-1 positive children) and pooled with data from the other studies gave very similar results.

REVIEWERS' CONCLUSIONS

PCV is effective in reducing the incidence of IPD from all serotypes but exerts a greater effect in reducing VT IPD. Although PCV is also effective in reducing the incidence of x-ray confirmed pneumonia, there are still uncertainties about the definition of this outcome. Additional randomised controlled trials are currently in progress.

Prevention of life-threatening infections due to encapsulated bacteria in children with hyposplenia or asplenia: a brief review of current recommendations for practical purposes

The aim of the present work was to summarise in a single paper all the options for prevention of life-threatening infections due to encapsulated bacteria in patients with hyposplenism or asplenia. Prevention of these infections should be obtained in all patients with 1) patient and family education, 2) prophylaxis by means of vaccination against Haemophilus influenzae and Streptococcus pneumoniae, 3) antibiotic prophylaxis, based primarily on penicillin, 4) delay of elective splenectomy or use methods of tissue salvage in splenic trauma. Vaccination is not effective against all serotypes of S. pneumoniae and Neisseria meningitidis causing life-threatening infections in hypo/asplenic patients. Moreover, antibacterial prophylaxis could select antibacterial-resistant pathogens and is highly conditioned by patient's compliance. Therefore, empirical antibacterial therapy of fever and/or suspected infection should be recommended to all splenectomised patients independently from time elapsing from splenectomy, vaccinal status and assumption of antibacterial prophylaxis.

Epidemiology, antibiotic susceptibility, and serotype distribution of Streptococcus pneumoniae associated with invasive pneumococcal disease in British Columbia - A call to strengthen public health pneumococcal immunization programs

BACKGROUND

This study examined the epidemiology, antibiotic susceptibility and serotype distribution of Streptococcus pneumoniae associated with invasive pneumococcal disease (IPD) in British Columbia.

METHODS

Six hospitals and one private laboratory network participated in a prospective, sentinel laboratory based surveillance study of IPD, between October 1999 and October 2000. At each site, S pneumoniae isolates were collected and epidemiological data were gathered using a structured questionnaire, for all cases of IPD meeting the study case definition. Isolates were serotyped and tested for antimicrobial susceptibility. Bivariate associations were analyzed and multivariate logistic regression was used to identify independent risk factors associated with hospitalization or death.

RESULTS

One hundred three reports and isolates were collected. Seventy-nine per cent of cases were community-acquired, 64% required hospitalization and 5% died. Cases with one or more assessed risk factor for IPD and of female sex were independent variables associated with hospitalization or death. One-third of isolates had reduced penicillin susceptibility and 96% of these represented serotypes contained in the 23-valent pneumococcal polysaccharide vaccine (PPV-23). Overall, 89% of serotypes identified are included in the PPV-23 vaccine and 88% of isolates from children under five years of age are found in the 7-valent pneumococcal conjugate vaccine (PCV-7). Forty-one per cent of cases qualified for publicly funded pneumococcal vaccine and 34% of eligible persons were vaccinated.

CONCLUSIONS

Overall, pneumococcal serotypes associated with IPD in this study closely matched serotypes included in PPV-23 products currently licensed in Canada. Most serotypes associated with IPD in children under five years of age are included in a recently licenced PCV-7. One third of isolates demonstrated reduced penicillin susceptibility, most involving serotypes included in PPV-23. Effective delivery of current public health immunization programs using PPV-23 and extending protection to infants and young children using the PCV-7 will prevent many cases of IPD.

A retrospective cohort study of the association of varicella vaccine failure with asthma, steroid use, age at vaccination, and measles-mumps-rubella vaccination

OBJECTIVE

Varicella breakthrough, the occurrence of varicella disease >42 days after vaccination, is indicative of vaccination failure. A sevenfold increased risk of breakthrough among vaccinated children with asthma was observed in a 1996 varicella outbreak in a child care center. More recent outbreak investigations have also identified age at vaccination as a potential risk factor for breakthrough. We assessed the association of varicella breakthrough with asthma, steroids, age at varicella vaccination, and timing of measles-mumps-rubella (MMR) vaccination.

METHODS

We performed a retrospective cohort study among children born after 1993 and followed up through 1999 at 2 health maintenance organizations ([HMOs] A and B) in the United States. Information was obtained from automated vaccination, clinic, hospital discharge, and pharmacy records.

RESULTS

We identified 268 and 97 breakthrough cases among 80 584 and 8181 children vaccinated against varicella at HMOs A and B, respectively. Varicella breakthrough was not associated with asthma, inhaled steroids prescribed at any time, and oral steroids prescribed before vaccination. An increased risk of varicella breakthrough was found in the 3 months immediately after prescription for oral steroids at HMO A (adjusted relative risk [aRR]: 2.4; 95% confidence interval [CI]: 1.3-4.4) and HMO B (aRR: 2.8; 95% CI: 1.0-7.8), when varicella vaccine was given before 15 months of age at HMO A (aRR: 1.4; 95% CI: 1.1-1.9), and when varicella vaccination followed MMR vaccine within 28 days at HMO A (aRR: 3.1; 95% CI: 1.5-6.4).

CONCLUSIONS

Varicella vaccine failure in children was not associated with asthma or the use of inhaled steroids, but with the use of oral steroids. Administration of varicella vaccine before the age of 15 months may be associated with a slightly increased risk of breakthrough disease. As currently recommended, varicella vaccination should not be administered for 28 days after MMR vaccination.

Current state of pneumococcal vaccines

Streptococcus pneumoniae is a leading cause of bacterial pneumonia, meningitis, and acute otitis media in children and adults worldwide. According to World Health Organization estimates, at least 1 million children under 5 years of age die each year from pneumococcal pneumonia. The emergence of resistant strains necessitates the development of an effective vaccine with a large serotype coverage. The 11 most common serotypes cause 72-83% of all serious pneumococcal diseases worldwide. Currently marketed 23-valent pneumococcal polysaccharide vaccine provides large serotype coverage and offers a less expensive option. However, it is efficacious only in adults but not in infants. Conjugate vaccines offer a solution by generating immunological memory already at early age. A recently licensed 7-valent conjugate vaccine is immunogenic and efficacious in infants. Its serotype coverage might be sufficient in Europe and North America, but not in Africa, Asia and Oceania. A need exists to develop pneumococcal vaccines with lower cost and larger serotype coverage. Several 11-valent pneumococcal conjugate vaccines are being evaluated in phase I-III trials. This study reviews the current state of pneumococcal problem and pneumococcal vaccines in clinical use.

Laparoscopic splenectomy for hematological diseases

BACKGROUND

We reviewed retrospectively the records of all patients who underwent laparoscopic splenectomy (LS) at our institution for a wide range of hematological disorders. We compared our experience to those reported in the literature and analyzed various aspects of the treatment that are still under discussion and in need of confirmation, such as the treatment of malignant blood diseases, the indication in case of splenomegaly, and the adequacy of the detection of accessory spleens.

METHODS

Between June 1997 and June 2001, we performed 43 LS. The patients were classified into three groups according to clinical diagnosis: idiopathic thrombocytopenic purpura (ITP) (n = 23), hemolytic anemia (HA) (n = 5), and hematological malignancy (HM) (n = 15). Statistical analyses were done to compare the three groups.

RESULTS

LS was completed in 41 patients, with a conversion rate of 5%. Splenomegaly was present in 37% of all patients (73% of HM). Mean operative time was 128 min. The incidence of accessory spleens was 20%. A concomitant laparoscopic procedure was done in three cases (cholecystectomy). Postoperative complications occurred in eight patients (18%). Duration of surgery, length of hospital stay, transfusions rate, and some demographics features, such as age and spleen weight and length, were significantly different in each group. No deaths were attributed to the procedure.

CONCLUSIONS

The statistical analysis of our series shows that, the laparoscopic approach reliable even in the management of malignant and nonmalignant blood diseases.

Pneumococcal vaccine for asthma

BACKGROUND

Infection with Streptococcus pneumoniae is an important cause of pneumonia and other serious illnesses, particularly amongst those with certain high-risk medical conditions such as asthma. Although pneumococcal vaccine is routinely advocated for people with asthma, there is uncertainty about the evidence base that underpins this recommendation.

OBJECTIVES

To determine the efficacy of pneumococcal vaccine in reducing mortality or morbidity from pneumococcal disease in asthmatics.

SEARCH STRATEGY

Randomised controlled trials were identified using the Cochrane Airways Group's register derived from MEDLINE, EMBASE, and CINAHL electronic databases and hand searched respiratory journals and meeting abstracts.

SELECTION CRITERIA

Randomised controlled trials, with or without blinding, in which pneumococcal vaccine has been compared with placebo or no treatment in people with clinician diagnosed asthma.

DATA COLLECTION AND ANALYSIS

Two reviewers independently reviewed all abstracts and full papers of all articles of potential relevance were retrieved. Methodological quality was rated using the Cochrane approach and the Jadad rating scale. Data extraction was performed by one reviewer and checked independently by a second. We planned to perform quantitative analyses of outcomes on an intention-to-treat basis, where possible.

MAIN RESULTS

Of the three papers retrieved, only one satisfied the inclusion criteria and the methodological quality of this study was low (unblinded and inadequate allocation concealment). None of the data could be aggregated in a meta-analysis. Comparisons in a sub-set of 30 asthmatic children prone to recurrent episodes of otitis media, showed that pneumococcal vaccination decreased the incidence of acute asthma exacerbations from 10 to 7 (per child per year).

REVIEWER'S CONCLUSIONS

This review found very limited evidence to support the routine use of pneumococcal vaccine in people with asthma. A randomised trial of vaccine efficacy in children and adults with asthma is needed.

B cell immunopoiesis: visualizing the impact of CD40 engagement on the course of T cell-independent immune responses in an Ig transgenic system

This study tracks the fate of antigen-reactive B cells through follicular and extrafollicular responses and addresses the function of CD40 in these processes. The unique feature of this system is the use of transgenic B cells in which the heavy chain locus has been altered by site-directed insertion of a rearranged V(H) DJ(H) exon such that they are able to clonally expand, isotype-switch and follow a normal course of differentiation upon immunization. These Ig transgenic B cells when adoptively transferred into non-transgenic (Tg) mice in measured amounts expanded and differentiated distinctively in response to T cell-independent (TI) or T cell-dependent (TD) antigens. The capacity of these Tg B cells to faithfully recapitulate the humoral immune response to TI and TD antigens provides the means to track clonal B cell behavior in vivo. Challenge with TI antigen in the presence of agonistic anti-CD40 mAb resulted in well-defined alterations of the TI response. In vivo triggering of Tg B cells with TI antigen and CD40 caused an increase in the levels IgG produced and a broadening of the Ig isotype profile, characteristics which partially mimic TD responses. Although some TD characteristics were induced by TI antigen and CD40 triggering, the Tg B cells failed to acquire a germinal center phenotype and failed to generate a memory response. Therefore, TD-like immunity can be only partially reconstituted with CD40 agonists and TI antigens, suggesting that there are additional signals required for germinal center formation and development of memory.

Ten-year review of invasive pneumococcal diseases in children and adults from Uruguay: clinical spectrum, serotypes, and antimicrobial resistance

OBJECTIVES

Since 1987, the Reference Laboratory of the Ministry of Health of Uruguay has been monitoring infections due to Streptococcus pneumoniae in patients under 5 years of age, in those between 5 to 14 years of age, and in adults. The purpose of the present study was to retrospectively analyze a 10-year collection of invasive S. pneumoniae isolates from children 5 to 14 years of age and adults.

METHODS

The Reference Children's Hospital, Pasteur Hospital, and two private hospitals in Montevideo as well as four hospitals located in other representative areas of the country participated in the pneumococcal surveillance program. Based on the information available at the Microbiology Department of the Central Public Health Laboratory (demographic data, date and site of isolate, and clinical diagnosis), all patients with an invasive pneumococcal disease were recorded. Pneumonia was clinically and radiologically diagnosed and etiology was assessed by isolation of S. pneumoniae from blood or pleural fluid. All specimens were collected at the Emergency Service. Capsular serotyping and antimicrobial susceptibilities were determined for each isolate.

RESULTS

During the 10-year period, 228 invasive S. pneumoniae were identified and included in the study (blood, n = 129; cerebrospinal fluid [CSF], n = 73; pleural fluid, n = 20; peritoneal fluid, n = 3; synovial fluid, n = 1; pericardic fluid, n = 1; abscess, n = 1). The most frequent clinical presentations were pneumonia (n = 71) and meningitis (n = 69). Thirty-five adults had an underlying condition including, four with malignancies, four with lupus, two with human immunodeficiency virus (HIV)-infected, and two patients in hemodialysis among others. Eighteen of the 228 patients died (7.9% fatality rate), but only four of these had an underlying condition. Eleven fatal cases were attributable to meningitis (2 children, 9 and 11 years old; 9 adults, mean age, 59 y). Four patients with pneumonia and three with sepsis died, including a splenectomized woman. Nine different capsular serotypes (1, 5, 7, 9, 12, 15, 19A, 20, and 23A) were identified among the 18 fatal cases. Resistance to penicillin, generally combined with trimethoprim-sulfamethoxazole, fluctuated annually, not surpassing 10%.

CONCLUSIONS

The study results indicated that 96% of the serotypes involved in severe pneumococcal diseases were included in the 23-valent vaccine and that S. pneumoniae resistance to penicillin was moderate.

[Recommended vaccines and immunoglobulins for immunocompromised patients]

A revision of the literature was made as to the recommendations given for the use of vaccines and immune globulins in persons who presented total or partial immunodeficiency, mainly related to the nineties. The analysis of 75 references led to the following principal conclusions: the vaccines containing living agents are generally inappropriate for persons who present conditions which determine serious immunodeficiency; the vaccines which contain dead agents or only antigenic fractions, despite their being less immunogenic and conferring lower rates of protection to severely immunocompromised persons as compared to normal persons, are safe and should be administered to them. Immunocompromised patients should receive immune globulins for the same indications and in the same doses as immunocompetent persons, with the exception of immune globulin to prevent measles, as recommended in a dosage of 0.5 mL/Kg for immunodeficients (15 mL, maximum).

Enhancement of T cell-independent immune responses in vivo by CD40 antibodies

In this report we describe a potentially powerful method for vaccinating infants against encapsulated bacterial pathogens such as Haemophilus influenzae, Streptococcus pneumoniae and Neisseria meningitidis. High levels of antibody directed against the polysaccharides of the bacterial capsule are normally protective. Unfortunately, the capsular polysaccharides are T cell-independent antigens (TI); lacking T-cell help, they induce only weak, predominantly IgM antibody responses, with infants responding especially poorly. T-cell help, given to B cells during responses to protein antigens, causes stronger antibody responses and isotype switching to the IgG isotypes. T-cell help is mainly mediated through ligation of the B-cell surface antigen, CD40, by its cognate T-cell ligand, CD154. Here we show that administering anti-CD40 monoclonal antibody to mice, along with pneumococcal polysaccharide, provides a substitute for T-cell help and results in the generation of strong, isotype-switched antibody responses, which are protective. The work points the way toward a possible effective and inexpensive means of protecting susceptible groups against important bacterial pathogens.