Poor antibody response to pneumococcal polysaccharide vaccination suggests increased susceptibility to pneumococcal infection in splenectomized patients with hematological diseases

Updated Recommendations on the Prevention and Treatment of Infections in Children With Asplenia/Hyposplenism

Children with congenital or acquired asplenia or hyposplenism have an increased risk for severe and even life-threatening infections mainly due to encapsulated bacteria. Current practice focuses on preventing severe infections with timely administration of vaccinations, antibacterial prophylaxis when indicated, and urgent evaluation and treatment of febrile events. As new vaccines are now available for both children and adults with asplenia/hyposplenism, we present an up-to-date recommendation on the prevention and management of acute infections in children with asplenia/hyposplenism.

Prevention and treatment of infection in patients with an absent or hypofunctional spleen: A British Society for Haematology guideline

Guidelines for the prevention and treatment of infection in patients with an absent or dysfunctional spleen were published by the British Committee for Standards in Haematology in 1996 and updated in 2002 and 2011. With advances in vaccinations and changes in patterns of infection, the guidelines required updating. Key aspects included in this guideline are the identification of patients at risk of infection, patient education and information and immunisation schedules. This guideline does not address the non-infective complications of splenectomy or functional hyposplenism (FH). This replaces previous guidelines and significantly revises the recommendations related to immunisation. Patients at risk include those who have undergone surgical removal of the spleen, including partial splenectomy and splenic embolisation, and those with medical conditions that predispose to FH. Immunisations should include those against Streptococcus pneumoniae (pneumococcus), Neisseria meningitidis (meningococcus) and influenza. Haemophilus influenzae type b (Hib) is part of the infant immunisation schedule and is no longer required for older hyposplenic patients. Treatment of suspected or proven infections should be based on local protocols and consider relevant anti-microbial resistance patterns. The education of patients and their medical practitioners is essential, particularly in relation to the risk of serious infection and its prevention. Further research is required to establish the effectiveness of vaccinations in hyposplenic patients; infective episodes should be regularly audited. There is no single group ideally placed to conduct audits into complications arising from hyposplenism, highlighting a need for a national registry, as has proved very successful in Australia or alternatively, the establishment of appropriate multidisciplinary networks.

Efficacy, immunogenicity, and evidence for best-timing of pneumococcal vaccination in splenectomized adults: a systematic review

INTRODUCTION

: Streptococcus pneumoniae is the most frequent cause of overwhelming post-splenectomy infections. Pneumococcal vaccination is generally recommended for splenectomized individuals. However, most of our knowledge comes from a few observational studies or small randomized clinical trials. We conducted this systematic review to assess the evidence of efficacy, antibody response, and the best timing for pneumococcal vaccination in splenectomized individuals.

AREAS COVERED

: The systematic review was conducted according to the PRISMA guidelines. We screened 489 articles, included 21 articles, and assessed the risk of bias using Cochrane RoB 2 and ROBINS-I. We summarized the findings narratively due to the heterogeneity of the studies.

EXPERT OPINION

Splenectomized individuals seem to have adequate antibody responses to pneumococcal vaccines. No differences in antibody responses were observed compared to healthy controls, except in one study. The studies were heterogeneous, and the majority had moderate to high degree of bias. There is a lack of clinical evidence for efficacy and best timing of pneumococcal vaccination in splenectomized individuals. Randomized clinical trials addressing these issues are needed.

Perioperative Immunization for Splenectomy and the Surgeon's Responsibility: A Review

Importance

Patients who have had splenectomy have a lifelong risk of overwhelming postsplenectomy infection (OPSI), a condition associated with high mortality rates. Surgeons must be aware of the rationale of vaccination in the case of splenectomy, to provide appropriate immunization in the perioperative time.

Observations

English-language articles published from January 1, 1990, to December 31, 2019, were retrieved from MEDLINE/PubMed, Cochrane Library, and ClinicalTrials.gov databases. Randomized clinical trials as well as systematic reviews and observational studies were considered. Asplenia yields an impairment of both innate and adaptive immunity, thus increasing the risk of severe encapsulated bacterial infections. Current epidemiology of OPSI ranges from 0.1% to 8.5% but is hard to ascertain because of ongoing shifts in patients' baseline conditions and vaccine penetration. Despite the lack of randomized clinical trials, immunization appears to be effective in reducing OPSI incidence. Unfortunately, vaccination coverage is still suboptimal, with a great variability in vaccination rates being reported across institutions and time frames. Notably, current guidelines do not advocate any particular health care qualification responsible for vaccine prescription or administration. Given the dearth of high-level basic science or clinical evidence, the optimal vaccination timing and the need for booster doses are not yet well established. Although almost all guidelines indicate to not administer vaccines within 14 days before and after surgery, most data suggest that immunization might be effective even in the immediate perioperative time, thus placing the surgeon in a primary position for vaccine delivery. Furthermore, revaccination schedules are the target of ongoing debates, since a vaccine-driven hyporesponsiveness has been postulated.

Conclusions and Relevance

In patients who have undergone splenectomy, OPSI might be effectively prevented by proper immunization. Surgeons have the primary responsibility for achieving adequate, initial immunization in the setting of both planned and urgent splenectomy.

Outcome of autoimmune cytopenia after hematopoietic cell transplantation in primary immunodeficiency

BACKGROUND

Post hematopoietic cell transplantation (HCT) autoimmune cytopenia (AIC) is a potentially life-threatening complication, but studies focusing on large cohorts of patients transplanted for primary immunodeficiency are lacking.

OBJECTIVES

This study sought to determine the incidence, risk factors, and outcomes of post-HCT AIC and B-lymphocyte function following rituximab.

METHODS

We retrospectively studied 502 children with primary immunodeficiency who were transplanted at our center between 1987 and 2018.

RESULTS

Thirty-six patients (9%) developed post-HCT AIC, with a median onset of 6.5 months post-HCT. On univariate analysis, pre-HCT AIC, mismatched donor, alemtuzumab, anti-thymocyte antiglobulin, and acute and chronic graft versus host disease were significantly associated with post-HCT AIC. After multivariate analysis, alemtuzumab (subdistribution hazard ratio, 9.0; 95% CI, 1.50-54.0; P = .02) was independently associated with post-HCT AIC. Corticosteroid and high-dose intravenous immunoglobulin achieved remission in 50% (n = 18), additional rituximab led to remission in 25% (n = 9), and the remaining 25% were treated with a combination of various modalities including sirolimus (n = 5), bortezomib (n = 3), mycophenolate mofetil (n = 2), splenectomy (n = 2), and second HCT (n = 3). The mortality of post-HCT AIC reduced from 25% (4 of 16) prior to 2011 to 5% (1 of 20) after 2011. The median follow-up of 5.8 years (range, 0.4 to 29.1 years) showed that 26 of 30 survivors (87%) were in complete remission, and 4 were in remission with ongoing sirolimus and low-dose steroids. Of the 17 who received rituximab, 7 had B-lymphocyte recovery, 5 had persistent low B-lymphocyte count and remained on intravenous immunoglobulin replacement, 2 had second HCT, and 3 died.

CONCLUSIONS

The frequency of post HCT AIC in our cohort was 9%, and the most significant risk factors for its occurrence were the presence of graft versus host disease and the use of alemtuzumab.

Vaccination of patients with haematological malignancies who did not have transplantations: guidelines from the 2017 European Conference on Infections in Leukaemia (ECIL 7)

Patients with haematological malignancies are at high risk of infection because of various mechanisms of humoral and cell-mediated immune deficiencies, which mainly depend on underlying disease and specific therapies. Some of these infections are vaccine preventable. However, these malignancies are different from each other, and the treatment approaches are diverse and rapidly evolving, so it is difficult to have a common programme for vaccination in a haematology ward. Additionally, because of insufficient training about the topic, vaccination is an area often neglected by haematologists, and influenced by cultural differences, even among health-care workers, in compliance to vaccines. Several issues are encountered when addressing vaccination in haematology: the small size of the cohorts that makes it difficult to show the clinical benefits of vaccination, the subsequent need to rely on biological parameters, their clinical pertinence not being established in immunocompromised patients, scarcity of clarity on the optimal timing of vaccination in complex treatment schedules, and the scarcity of data on long-term protection in patients receiving treatments. Moreover, the risk of vaccine-induced disease with live-attenuated vaccines strongly limits their use. Here we summarise guidelines for patients without transplantations, and address the issue by the haematological group-myeloid and lymphoid-of diseases, with a special consideration for children with acute leukaemia.

Assessment of Postvaccine Immunity against Streptococcus pneumoniae in Patients with Asplenia, including an Analysis of Its Impact on Bacterial Flora of the Upper Respiratory Tract and Incidence of Infections

S. pneumoniae is a microorganism that may cause a serious threat in postsplenectomy patients due to a potentially invasive course of infection. In order to assess a protective activity after vaccination with the 23-valent vaccine, we made an analysis of the level of antibodies in patients with asplenia compared to a control group of healthy donors. Additionally, colonization by potentially pathogenic microorganisms of the upper respiratory tract was analyzed to determine the carrier state by strains with vaccine serotype. No such strains were found in the research, yet three non-vaccine-serotype strains were found. Colonization of the upper respiratory tract by potentially pathogenic microorganisms may be connected with increased susceptibility observed and incidence of infections in patients with asplenia. However, colonization by S. pneumoniae may not have an effect on the level of specific antibodies with the 23-valent vaccine against S. pneumoniae (PPV23) in postsplenectomy patients and healthy people. The response to vaccination against S. pneumoniae showed a lower level of specific antibodies in patients with splenectomy performed more than 2 years before the test than in patients with a recently removed spleen, i.e., from 1 month to 2 years before the test. Vaccination against pneumococci also has positive effects on incidence of other etiology infections, which is of high significance in the prophylaxis of infectious diseases in this group of patients.

Invasive pneumococcal infections in pediatric liver-small bowel-pancreas transplant recipients

Children undergoing LSBPTx are at increased risk of IPI due to splenectomy. We aimed to describe the clinical features and outcomes of IPI in pediatric LSBPTx recipients. Between 2008 and 2016, 122 LSBPTx children at our center were retrospectively reviewed. Nine patients had 12 episodes of IPI; the median age at first infection was 3.5 years (range: 1.5-7.1 years). The median time from transplant to first infection was 3 years (range: 0.8-5.8 years). Clinical presentation included as follows: pneumonia (n = 1), bacteremia/sepsis (n = 7), pneumonia with sepsis (n = 1), meningitis with sepsis (n = 2), pneumonia and meningitis with sepsis (n = 1). The overall risk for IPI was 7.4% or 0.9% per year. The mortality rate was 22%. Seven (78%) children had received at least one dose of PCV13, four (44%) patients had received 23-valent pneumococcal polysaccharide vaccine prior to IPI. All patients were on oral penicillin prophylaxis. In conclusion, despite partial or complete pneumococcal immunization and reported antimicrobial prophylaxis, IPI in LSBPTx children can have a fatal outcome. Routine monitoring of pneumococcal serotype antibodies to determine the timing for revaccination might be warranted to ensure protective immunity in these transplant recipients.

Infectious diseases and immunological markers associated with patients with non-Hodgkin lymphoma treated with rituximab

BACKGROUND

The use of rituximab (RTX) is increasing, even in developing countries. It has become the first-line therapy or adjuvant to chemotherapy (CHOP; cyclophosphamide, hydroxydaunorubicin, oncovin and prednisone) for various diseases, including B cell lymphoma and autoimmune diseases.

AIM

We describe the infectious diseases and immunological markers associated with RTX treatment of patients with non-Hodgkin lymphoma (NHL).

METHODS

Serum immunoglobulins were determined before and after intravenous immunoglobulin (IVIg) administration. Pneumo-23IgG-specific anti-pneumococcal antibodies were evaluated before and after vaccination. Immunophenotyping and lymphocyte proliferation were determined in the course of the treatment.

RESULTS

Seven patients were followed and median age was 56.0 ± 5.0 years (range, 41.9-71.6 years). At baseline, the mean level of IgG was 333.7 ± 40.8 and IgM 40.9 ± 11.3 mg/dL, respectively; immunoglobulin A and E (IgA and IgE) were under the limit of detection. Two patients had reduced or absent B cells and T cell subsets were at normal levels in five patients. All patients failed to mount an efficient post-vaccination immune response against hepatitis B virus, tetanus, diphtheria and against the 23-valent pneumococcal polysaccharide vaccine. During RTX/CHOP treatment, human-IgG-immunoglobulin (IVIg) therapy was introduced in six patients after recurrent infections, including community-acquired pneumonia (85.7%), chronic sinusitis (85.7%) and gastroenteritis (42.9%).

CONCLUSION

Poor response against pneumococcal vaccines increases the susceptibility of respiratory diseases in these patients. In patients with NHL treated with RTX, the benefits achieved with IVIg replacement for the control of recurrent infectious diseases is of paramount importance. Clinicians dealing with monoclonal antibodies against cancer therapy, especially RTX, should be aware of the increasing risks for symptomatic induced hypogammaglobulinemia and respiratory infections.

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.

[Long-term infectious risks after splenectomy: A retrospective cohort study with up to 10 years follow-up]

INTRODUCTION

Although most infections occur within the first 2 years after splenectomy, the relatively short follow-up reported in many studies may underestimate the frequency of infections. The objective of the study was to determine the incidence of infective outcomes and factors associated with infection after splenectomy by studying a group of patients who underwent splenectomy over a 10-year period.

METHODS

A retrospective and monocentric study of patients who underwent splenectomy between January 1st, 1997 and December 31st, 2004 in a French university hospital. Age, sex, indication for splenectomy, infectious events, death, vaccination and antibiotic prophylaxis were collected in January 2015.

RESULTS

One hundred and sixty-five patients were included. The most common reasons for splenectomy were therapeutic hematological indications (37.5%). Ninety-seven per cent received pneumococcal vaccine. Prophylactic antibiotics were prescribed in 78% of patients. Thirty-seven patients had 42 severe infections with a median incidence rate of 4 years after splenectomy (2 days-12 years). The rate of infection after splenectomy declined over time but 57% occurred after 2 years and 14.3% after 10 years. Respiratory infections were the most common sites of infections. The incidence of infection differed according to age was highest among the elderly (HR=6.2; 95%CI: 1.4-27.1; after 65 years old) and underlying reason for splenectomy (P=0.02). There is no difference with or without prophylactic antibiotics.

CONCLUSION

After splenectomy, the incidence of severe infection declined over time but can occur after 10 years. The onset of infection is linked to age and reason for splenectomy.

Influenza and Pneumococcal Vaccination in Hematological Malignancies: a Systematic Review of Efficacy, Effectiveness, and Safety

Background

The risk of getting influenza and pneumococcal disease is higher in cancer patients, and serum antibody levels tend to be lower in patients with hematological malignancy.

Objective

To assess flu and pneumococcal vaccinations efficacy, effectiveness, and safety in onco-hematological patients.

Methods

Two systematic reviews and possible meta-analysis were conducted to summarize the results of all primary study in the scientific literature about the flu and pneumococcal vaccine in onco-hematological patients. Literature searches were performed using Pub-Med and Scopus databases. StatsDirect 2.8.0 was used for the analysis.

Results

22 and 26 studies were collected respectively for flu and pneumococcal vaccinations. Protection rate of booster dose was 30% (95% CI=6–62%) for H1N1. Pooled prevalence protection rate of H3N2 and B was available for meta-analysis only for first dose, 42.6% (95% CI=23.2 – 63.3 %) and 39.6 % (95% CI=26%–54.1%) for H3N2 and B, respectively. Response rate of booster dose resulted 35% (95% CI=19.7–51.2%) for H1N1, 23% (95% CI=16.6–31.5%) for H3N2, 29% (95% CI=21.3–37%) for B.

Conclusion

Despite the low rate of response, flu, and pneumococcal vaccines are worthwhile for patients with hematological malignancies. Patients undergoing chemotherapy in particular rituximab, splenectomy, transplant recipient had lower and impaired response. No serious adverse events were reported for both vaccines.

Prophylactic immunoglobulin therapy in secondary immune deficiency - an expert opinion

INTRODUCTION

In primary immunodeficiency (PID), immunoglobulin replacement therapy (IgRT) for infection prevention is well-established and supported by a wealth of clinical data. On the contrary, very little evidence-based data is available on the challenges surrounding the use of IgRT in secondary immune deficiencies (SID), and most published guidelines are mere extrapolations from the experience in PID.

AREAS COVERED

In this article, four European experts provide their consolidated opinion on open questions surrounding the prophylactic use of IgRT in SID, based on their clinical experience. The main topics are IgRT initiation, route of administration, dose optimization, and therapy discontinuation. The authors hope this discussion will be of assistance to practicing physicians in their daily decision-making. Expert commentary: Although growing experience indicates that IgRT could play an important role in the management of SID, very little robust evidence is available to guide clinical practice. The authors stress the urgent need for new studies in the field and discuss points they find of importance to design them adequately.

Overwhelming Postsplenectomy Infection: A Prospective Multicenter Cohort Study

BACKGROUND

Recent population-based cohort studies have questioned the role of pneumococci as the most frequent pathogen causing severe infection in patients after splenectomy. The aim of the study was to define the causative pathogens and clinical presentation of patients with overwhelming postsplenectomy infection (OPSI).

METHODS

In a prospective cohort study in 173 German intensive care units, we searched for patients with and without asplenia and community-acquired severe sepsis/septic shock. Clinical and laboratory variables and survival of patients were assessed.

RESULTS

Fifty-two patients with severe sepsis or septic shock with asplenia and 52 without asplenia were included. OPSI patients more often had a history of malignancy (38% vs 17%; P = .016) and had a lower body mass index (24 kg/m(2) vs 28 kg/m(2); P = .004). Streptococcus pneumoniae was detected more frequently in OPSI patients (42% vs 12% without asplenia; P < .001) and more frequently manifested as bloodstream infection (31% vs 6%; P = .002). Gram-negative infection was similar in both groups (12% vs 19%; P = .157). Pneumococcal vaccine coverage of OPSI patients was low overall (42% vs 8% among patients without asplenia; P < .001). Purpura fulminans was a frequent complication, developing in 19% of OPSI patients vs 5% of patients without asplenia (P = .038). The interval between splenectomy and OPSI was 6 years (range, 1 month-50 years). On multivariable Poisson regression, asplenia was the only predictive variable independently associated with pneumococcal sepsis (adjusted relative risk, 2.53 [95% confidence interval, 1.06-6.08]).

CONCLUSIONS

Pneumococcal infections remain the most important cause of severe sepsis and septic shock following splenectomy.

Vaccinations in patients with hematological malignancies

Patients with hematological malignancies are at risk for a number of infections that are potentially preventable by vaccinations such as pneumococcal infections and influenza. Treatment, especially with anti-B-cell antibodies and hematopoietic stem cell transplantation (HSCT), negatively impacts the response to vaccination for several months. It is therefore recommended that patients be vaccinated before initiating immunosuppressive therapy if possible. The risk of side-effects with inactivated vaccines is low, but care has to be taken with live vaccines, such as varicella-zoster virus vaccine, since severe and fatal complications have been reported. HSCT patients require repeated doses of most vaccines to achieve long-lasting immune responses. New therapeutic options for patients with hematological malignancies that are rapidly being introduced into clinical practice will require additional research regarding the efficacy of vaccinations. New vaccines are also in development that will require well-designed studies to ascertain efficacy and safety.

Bacterial Infections Following Splenectomy for Malignant and Nonmalignant Hematologic Diseases

Splenectomy, while often necessary in otherwise healthy patients after major trauma, finds its primary indication for patients with underlying malignant or nonmalignant hematologic diseases. Indications of splenectomy for hematologic diseases have been reducing in the last few years, due to improved diagnostic and therapeutic tools. In high-income countries, there is a clear decrease over calendar time in the incidence of all indication splenectomy except nonmalignant hematologic diseases. However, splenectomy, even if with different modalities including laparoscopic splenectomy and partial splenectomy, continue to be a current surgical practice both in nonmalignant hematologic diseases, such as Immune Thrombocytopenic Purpura (ITP), Autoimmune Hemolytic Anemia (AIHA), Congenital Hemolytic Anemia such as Spherocytosis, Sickle Cell Anemia and Thalassemia and Malignant Hematological Disease, such as lymphoma. Today millions of people in the world are splenectomized. Splenectomy, independently of its cause, induces an early and late increase in the incidence of venous thromboembolism and infections. Infections remain the most dangerous complication of splenectomy. After splenectomy, the levels of antibody are preserved but there is a loss of memory B cells against pneumococcus and tetanus, and the loss of marginal zone monocytes deputed to immunological defense from capsulated bacteria. Commonly, the infections strictly correlated to the absence of the spleen or a decreased or absent splenic function are due to encapsulated bacteria that are the most virulent pathogens in this set of patients. Vaccination with polysaccharide and conjugate vaccines again Streptococcus pneumoniae, Haemophilus influenzae, and Neisseria meningitidis should be performed before the splenectomy. This practice reduces but does not eliminate the occurrence of overwhelming infections due to capsulated bacteria. At present, most of infections found in splenectomized patients are due to Gram-negative (G-) bacteria. The underlying disease is the most important factor in determining the frequency and severity of infections. So, splenectomy for malignant diseases has the major risk of infections.

Nationwide survey in Japan regarding splenectomy/partial splenic embolization for interferon treatment targeting hepatitis C virus-related chronic liver disease in patients with low platelet count

AIM

In chronic liver disease associated with hepatitis C virus (HCV), a low platelet count is a major obstacle in carrying out interferon (IFN) treatment. We used a questionnaire to clarify the extent to which splenectomy/partial splenic embolization (PSE) is performed before IFN treatment, as well as the efficacy and complications thereof.

METHODS

Two questionnaires were distributed to 413 medical institutes in Japan specializing in the treatment of liver diseases, and responses were obtained from 204 institutes. Furthermore, a more detailed questionnaire was completed by 10 institutes that experienced cases of death.

RESULTS

In patients with HCV genotype 1b and a high viral load (HCV1b/High), the sustained viral response (SVR) rate was 28% for the splenectomy group and 22% for the PSE group, with no significant difference between these groups. In patients that were not HCV1b/High, the SVR rate was higher in those that underwent splenectomy (71%) compared to the PSE group (56%; P = 0.025). There were cases of death in seven of 799 splenectomy cases (0.89%) and four of 474 PSE cases (0.84%). Infectious diseases were involved in nine of 11 cases of death, with a peculiar patient background of Child-Pugh B (6/10) and an age of 60 years or greater (7/11).

CONCLUSION

The application of splenectomy/PSE before IFN treatment should be avoided in patients with poor residual hepatic function and/or elderly patients. In HCV1b/High patients, splenectomy/PSE should be performed only after selecting those in which IFN treatment should be highly effective.

[Overwhelming postsplenectomy infection syndrome]

The overwhelming postsplenectomy infection syndrome (OPSI) is a fulminant sepsis that is mainly caused by Streptococcus pneumoniae and is characterized by a particular high mortality. Patients whose spleen was removed due to a hematological disease are at special risk. Even after the recommended immunization against Streptococcus pneumoniae 20-30 % of these patients do not develop an adequate level of antibody response. Therefore, this particular group of patients must be trained how to behave in case of fever and need to obtain immediate specific sepsis therapy with antibiotic prophylaxis.

Pneumococcal immunization in immunocompromised hosts: where do we stand?

Immunocompromised patients are all at risk of invasive pneumococcal disease, of different degrees and timings. However, considerable progress in pneumococcal immunization over the last 30 years should benefit these patients. The 23-valent polysaccharide vaccine has been widely evaluated in these populations, but due to its low immunogenicity, its efficacy is sub-optimal, or even low. The principle of the conjugate vaccine is that, through the protein conjugation with the polysaccharide, the vaccine becomes more immunogenic, T-cell dependent, and thus providing a better early response and a boost effect. The 7-valent conjugate vaccine has been the first one to be evaluated in different immunocompromised populations. We review here the efficacy and safety of the different antipneumococcal vaccines in cancer, transplant and HIV-positive patients and propose a critical appraisal of the current guidelines.

2013 IDSA clinical practice guideline for vaccination of the immunocompromised host

An international panel of experts prepared an evidenced-based guideline for vaccination of immunocompromised adults and children. These guidelines are intended for use by primary care and subspecialty providers who care for immunocompromised patients. Evidence was often limited. Areas that warrant future investigation are highlighted.

[Post-splenectomy complications in primary immune thrombocytopenia. Literature review and preventive measures]

Management of primary immune thrombocytopenia (ITP) has changed, and clinical practice broadens the use of thrombopoietin receptor agonists and anti-CD20 antibody as options for second-line therapy, as alternative to splenectomy. Splenectomy remains a successful, definitive curative treatment. The purpose of this review about the complications of the splenectomy, in the context of ITP, is to increase the awareness of clinicians towards the preventive measures, which are often not correctly applied.

Long-term risks after splenectomy among 8,149 cancer-free American veterans: a cohort study with up to 27 years follow-up

Although preservation of the spleen following abdominal trauma and spleen-preserving surgical procedures have become gold standards, about 22,000 splenectomies are still conducted annually in the USA. Infections, mostly by encapsulated organisms, are the most well-known complications following splenectomy. Recently, thrombosis and cancer have become recognized as potential adverse outcomes post-splenectomy. Among more than 4 million hospitalized USA veterans, we assessed incidence and mortality due to infections, thromboembolism, and cancer including 8,149 cancer-free veterans who underwent splenectomy with a follow-up of up to 27 years. Relative risk estimates and 95% confidence intervals were calculated using time-dependent Poisson regression methods for cohort data. Splenectomized patients had an increased risk of being hospitalized for pneumonia, meningitis, and septicemia (rate ratios=1.9-3.4); deep venous thrombosis and pulmonary embolism (rate ratios=2.2); certain solid tumors: buccal, esophagus, liver, colon, pancreas, lung, and prostate (rate ratios =1.3-1.9); and hematologic malignancies: non-Hodgkin lymphoma, Hodgkin lymphoma, multiple myeloma, acute myeloid leukemia, chronic lymphocytic leukemia, chronic myeloid leukemia, and any leukemia (rate ratios =1.8-6.0). They also had an increased risk of death due to pneumonia and septicemia (rate ratios =1.6-3.0); pulmonary embolism and coronary artery disease (rate ratios =1.4-4.5); any cancer: liver, pancreas, and lung cancer, non-Hodgkin lymphoma, Hodgkin lymphoma, and any leukemia (rate ratios =1.3-4.7). Many of the observed risks were increased more than 10 years after splenectomy. Our results underscore the importance of vaccination, surveillance, and thromboprophylaxis after splenectomy.

Preserved antibody levels and loss of memory B cells against pneumococcus and tetanus after splenectomy: tailoring better vaccination strategies

Splenectomized patients are exposed to an increased risk of septicemia caused by encapsulated bacteria. Defense against infection is ensured by preformed serum antibodies produced by long-lived plasma cells and by memory B cells that secrete immunoglobulin in response to specific antigenic stimuli. Studying a group of asplenic individuals (57 adults and 21 children) without additional immunologic defects, we found that spleen removal does not alter serum anti-pneumococcal polysaccharide (PnPS) IgG concentration, but reduces the number of PnPS-specific memory B cells, of both IgM and IgG isotypes. The number of specific memory B cells was low in splenectomized adults and children that had received the PnPS vaccine either before or after splenectomy. Seven children were given the 13-valent pneumococcal conjugated vaccine after splenectomy. In this group, the number of PnPS-specific IgG memory B cells was similar to that of eusplenic children, suggesting that pneumococcal conjugated vaccine administered after splenectomy is able to restore the pool of anti-PnPS IgG memory B cells. Our data further elucidate the crucial role of the spleen in the immunological response to infections caused by encapsulated bacteria and suggest that glycoconjugated vaccines may be the most suitable choice to generate IgG-mediated protection in these patients.

Vaccination of immunocompromised patients

Vaccination of immunocompromised patients is challenging both regarding efficacy and safety. True efficacy data are lacking so existing recommendations are based on immune responses and safety data. Inactivated vaccines can generally be used without risk but the patients who are most at risk for infectious morbidity and mortality as a result of their severely immunosuppressed state are also those least likely to respond to vaccination. However, vaccination against pneumococci, Haemophilus influenzae and influenza are generally recommended. Live vaccines must be used with care because the risk for vaccine-associated disease exists.

Effectiveness and immunogenicity of pneumococcal vaccination in splenectomized and functionally asplenic patients

The aim of the present study was to evaluate the effectiveness and immunogenicity of pneumococcal vaccination in 145 splenectomized and 2 functionally asplenic patients receiving the 23-valent pneumococcal polysaccharide vaccine and/or the 7-valent pneumococcal conjugate vaccine (PCV7) during the period 1996-2009. Progression of underlying malignant disease was the main cause of death in 68% of the 53 deceased patients, followed by septic shock in 13.2%. Twelve of 94 living patients developed post-vaccine complications: pneumonia in 9 patients, otitis media in 2, pneumococcal sepsis in 4. Compared with a non-splenectomized non-vaccinated control group (n=34), splenectomized patients vaccinated in the previous five years (n=15) had significantly higher GMCs (P<0.05) against serotypes 4, 6B, 9V, 14, 18C, 19F and 23F. Our data demonstrated strong serological responses in splenectomized patients within the first 5 years after pneumococcal vaccination by PCV7. Nevertheless, post-vaccine pneumococcal sepsis was still diagnosed in 3.3% of splenectomized survivors.

Pneumococcal polysaccharide 23-valent vaccine: long-term persistence of circulating antibody and immunogenicity and safety after revaccination in adults

Since publication of a 1997 review of the immunogenicity and safety data for pneumococcal polysaccharide vaccines (PPSVs), dozens of additional studies have been published, involving larger cohorts, longer observation periods, and more specific assays. Additionally, a 13-valent pneumococcal conjugate vaccine (PCV) has been licensed for adults. This paper reviews adult studies assessing antibody persistence for ≥ 3 years after pneumococcal vaccination, and adult studies of immunogenicity and safety after revaccination. This review emphasizes the currently registered PPSV23 formulations containing 25-μg polysaccharide per serotype, for which far more long-term data are available. Broadly, IgG and functional antibody levels after PPSV23 in adults persist above concentrations in unvaccinated adults for at least 5-10 years in most studies. The few exceptions involve populations of non-ambulatory adults or those with confounding host-factor issues. Revaccination with PPSV23 5-10 years after a previous dose consistently and substantially increases both IgG and functional antibody levels. There is an inverse association between circulating antibody level just before primary or revaccination and subsequent antibody increase. Although injection-site reactions (e.g., pain, swelling, redness) were reported more commonly after PPSV23 revaccination than after primary vaccination in most studies, these reactions typically resolved within 5 days. We interpret the contemporary literature as supporting pneumococcal revaccination as a means to sustain anti-pneumococcal antibodies at levels greater than among unvaccinated adults. PPSV23 is a broad-spectrum public-health tool to help prevent serious pneumococcal diseases across the adult lifespan.

Review of guidelines for the prevention and treatment of infection in patients with an absent or dysfunctional spleen: prepared on behalf of the British Committee for Standards in Haematology by a working party of the Haemato-Oncology task force

Guidelines for the prevention and treatment of infection in patients with an absent or dysfunctional spleen were first published by the British Committee for Standards in Haematology (BCSH) in 1996 and formally reviewed in 2002. Although the guidelines originated from discussion within the BCSH, the intended readership is wide given the multidisciplinary nature of the management of hyposplenism.

Can the response to 23-valent pneumococcal vaccine in splenectomised patients be predicted?

The 23-valent pneumococcal vaccine has unequal effectiveness in splenectomised patients. We performed a longitudinal study (2005-2008) whose main objective was to characterize the profile of non-responders among splenectomised patients treated at our institution and identify potential predictive indicators of the response to the vaccine. The immune response was evaluated in 96 subjects. The proportion of responders was 70% (95% CI: 60-78%). Immunosuppression (OR=3.19, 95% CI 1.04-9.73) and the reason for splenectomy (hematologic neoplasia versus non-malignant hematologic diseases, OR=7.37, 95% CI 1.71-31.7) were independent predictors of non-response to vaccination. However, the positive predictive value of the model and the likelihood ratio for a positive result were low (PPV=76.6%, 95% CI 66.2-84.4%, LR(+)=1.41, 95% CI 1.08-1.86). We recommend determining the response to pneumococcal vaccine in these patients when possible.

Partial splenectomy for hereditary spherocytosis: a multi-institutional review

BACKGROUND/PURPOSE

Partial splenectomy has emerged as a surgical option for selected children with hereditary spherocytosis, with the goal of reducing anemia while preserving splenic function. This multi-institutional study is the largest series to date examining outcomes data for partial splenectomy in patients with hereditary spherocytosis.

METHODS

Data were collected retrospectively from 5 North American pediatric hospitals. Sixty-two children underwent partial splenectomy for hereditary spherocytosis between 1990 and 2008.

RESULTS

At 1 year following partial splenectomy, mean hemoglobin significantly increased by 3.0 ± 1.4 g/dL (n = 52), reticulocyte count decreased by 6.6% ± 6.6% (n = 41), and bilirubin level decreased by 1.3 ± 0.9 mg/dL (n = 25). Patients with poor or transient hematologic response were found to have significantly more splenic regeneration postoperatively compared with patients with a durable clinical response (maximal spleen dimension, 9.0 ± 3.4 vs 6.3 ± 2.2 cm). Clinically significant recurrence of anemia or abdominal pain led to completion splenectomy in 4.84% of patients. No patients developed postsplenectomy sepsis.

CONCLUSIONS

Our multi-institutional review indicates that partial splenectomy for hereditary spherocytosis leads to sustained and clinically significant improvement in hematologic profiles and clinical symptoms in most patients. Our data support partial splenectomy as an alternative for selected children with hereditary spherocytosis.

[Prevention and follow-up care of sepsis. 1st revision of S2k guidelines of the German Sepsis Society (Deutsche Sepsis-Gesellschaft e.V., DSG) and the German Interdisciplinary Association of Intensive Care and Emergency Medicine (Deutsche Interdisziplinäre Vereinigung für Intensiv- und Notfallmedizin, DIVI)]

The 1st revision of the S2k guideline on the prevention and follow-up care of sepsis, provided by the German Sepsis Society in collaboration with 17 German medical scientific societies and one self-help group provides state-of-the-art information on the effective and appropriate medical care of critically ill patients with severe sepsis or septic shock. The guideline recommendations may not be applied under all circumstances. It rests with the clinician to decide whether a certain recommendation should be adopted or not, taking into consideration the unique set of clinical facts presented in connection with each individual patient as well as the available resources.

Pneumococcal and influenza immunization in asplenic persons: a retrospective population-based cohort study 1990-2002

Background

Splenectomy is associated with increased risk for bacteremia, due to impaired clearance of bloodborne agents and to altered phagocytosis and humoral immunity. We conducted a retrospective cohort study of patients at risk for splenectomy for a 13-year period to determine immunization coverage, and outcomes of those with and without splenectomy, and with or without receipt of influenza or pneumococcal vaccine.

Methods

Data were extracted from the provincial Medical Services Insurance database for insured services rendered by a physician for 1990-2002, and from the Vital Statistics Death database. The eligible cohort was selected based on diagnostic codes for hematologic conditions for which splenectomy might be considered, such as immune thrombocytopenia. Each patient was followed longitudinally from the date of first diagnosis until 31Dec2002, or death, or relocation out-of province. In addition, persons with splenectomy and no hematologic condition were identified and followed for 6 months post-surgery. Infectious illness rates per 100 person-years of observation and death rates were calculated with and without splenectomy. Death rates were determined using splenectomy status as a time-dependent covariate. The relationship between splenectomy and death according to immunization status was examined using Cox proportional hazard ratios.

Results

Of 38,812 persons in the cohort 427 subjects with a hematologic diagnosis had splenectomy and another 452 subjects without a hematologic diagnosis had this surgery. 72% were > 18 years of age. Pneumococcal immunization was recorded in 16.5% of asplenic patients overall, and was not associated with reduced risk of death in these persons (adjusted Hazard Ratio [HR] = 1.07, 95% CI 0.70 - 1.65). Influenza immunization was recorded in 53.1% of asplenic patients overall, and was associated with reduced risk of death (adjusted HR = 0.46, 0.33-0.62). No pneumococcal or influenza immunization was recorded in patients with a hematologic diagnosis without splenectomy. Infectious illness visits were higher among all patients who had a splenectomy than among those without a splenectomy (151 visits/100 person-years of observation in the post-splenectomy period vs. 120 visits/100 person-years; p < 0.0001).

Conclusions

In asplenic patients, influenza immunization is associated with a 54% reduced risk of death compared to unimmunized asplenic persons; no reduction in risk was demonstrated with (polysaccharide) pneumococcal vaccine. Vaccine coverage in the entire cohort was less than routinely recommended. Improved delivery of infection prevention programs to this population is warranted. Conjugate pneumococcal vaccines should be urgently studied in this immunocompromised population.

Prevention, diagnosis, therapy and follow-up care of sepsis: 1st revision of S-2k guidelines of the German Sepsis Society (Deutsche Sepsis-Gesellschaft e.V. (DSG)) and the German Interdisciplinary Association of Intensive Care and Emergency Medicine (Deutsche Interdisziplinäre Vereinigung für Intensiv- und Notfallmedizin (DIVI))

Practice guidelines are systematically developed statements and recommendations that assist the physicians and patients in making decisions about appropriate health care measures for specific clinical circumstances taking into account specific national health care structures. The 1^st revision of the S-2k guideline of the German Sepsis Society in collaboration with 17 German medical scientific societies and one self-help group provides state-of-the-art information (results of controlled clinical trials and expert knowledge) on the effective and appropriate medical care (prevention, diagnosis, therapy and follow-up care) of critically ill patients with severe sepsis or septic shock. The guideline had been developed according to the “German Instrument for Methodological Guideline Appraisal” of the Association of the Scientific Medical Societies (AWMF). In view of the inevitable advancements in scientific knowledge and technical expertise, revisions, updates and amendments must be periodically initiated. The guideline recommendations may not be applied under all circumstances. It rests with the clinician to decide whether a certain recommendation should be adopted or not, taking into consideration the unique set of clinical facts presented in connection with each individual patient as well as the available resources.

Vaccination of asplenic or hyposplenic adults

Background

Sepsis is a feared complication in patients with an absent or dysfunctioning spleen.

Methods

A literature search was undertaken to identify recommendations for vaccination in asplenic or hyposplenic adults, and published data regarding the effectiveness of the vaccines in reducing the incidence of infections, and vaccine failures.

Results

Various committees and organizations recommend that the pneumococcal, meningococcal and Haemophilus influenza vaccine, plus booster doses, should be administered to patients with an absent or dysfunctional spleen. However, adherence to such recommendations varies. Furthermore, vaccine failures still occur in a subset of properly immunized individuals. Immunocompromised individuals, in particular, have a greater risk of inadequate antibody response.

Conclusion

Immunization is partially responsible for the observed reduction in sepsis after splenectomy.