Predictors of infection in chronic lymphocytic leukaemia (CLL)

Reduced risk of infections with the intravenous immunoglobulin, IgPro10, in patients at risk of secondary immunodeficiency-related infections

Aim: Patients with secondary immunodeficiency (SID) are at increased risk of infections and may be treated with immunoglobulin replacement therapy (IgRT). Despite growing efficacy evidence for IgRT in infection prevention in SID, treatment guidelines are not aligned. Materials & methods: A retrospective database analysis was conducted to assess treatment patterns and infection rates in patients at risk of SID-related infections, with or without IgRT (IgPro10) exposure, to evaluate real-world effectiveness of IgRT in infection prevention. Results: Of 11,448 patients included, 222 received IgPro10. B-cell malignancies and solid organ transplants were the predominant underlying conditions. Despite being sicker at baseline, the IgPro10 cohort demonstrated fewer infections post-index than the non-IgRT cohort. Conclusion: IgPro10 may be an effective option for infection prevention in SID.

Combined Immune Defect in B-Cell Lymphoproliferative Disorders Is Associated with Severe Infection and Cancer Progression

B cell chronic lymphoproliferative diseases (B-CLPD) are associated with secondary antibody deficiency and other innate and adaptive immune defects, whose impact on infectious risk has not been systematically addressed. We performed an immunological analysis of a cohort of 83 B-CLPD patients with recurrent and/or severe infections to ascertain the clinical relevance of the immune deficiency expression. B-cell defects were present in all patients. Patients with combined immune defect had a 3.69-fold higher risk for severe infection (p = 0.001) than those with predominantly antibody defect. Interestingly, by Kaplan–Meier analysis, combined immune defect showed an earlier progression of cancer with a hazard ratio of 3.21, than predominantly antibody defect (p = 0.005). When B-CLPD were classified in low-degree, high-degree, and plasma cell dyscrasias, risk of severe disease and cancer progression significantly diverged in combined immune defect, compared with predominantly antibody defect (p = 0.001). Remarkably, an underlying primary immunodeficiency (PID) was suspected in 12 patients (14%), due to prior history of infections, autoimmune and granulomatous conditions, atypical or variegated course and compatible biological data. This first proposed SID classification might have relevant clinical implications, in terms of predicting severe infections and cancer progression, and might be applied to different B-CLPD entities.

Association between PCV13 pneumococcal vaccination and risk of hospital admissions due to pneumonia or sepsis among patients with haematological malignancies: a single-centre retrospective cohort study in Israel

OBJECTIVES

Patients with haematological malignancies receiving immunosuppressive therapy are at highest risk of invasive pneumococcal disease. Our goal was to investigate whether vaccination of haematological patients with pneumococcal 13-valent conjugated vaccine (PCV13) prior to therapy initiation is associated with decreased hospital admissions due to pneumonia or sepsis within 12 months.

DESIGN AND SETTING

A longitudinal retrospective cohort study was conducted at the haematology unit of Carmel Medical Center, Israel.

PARTICIPANTS

Information on adult patients (>18 years) who were diagnosed between 1 January 2009 and 30 December 2019 with haematological malignancies and received immunosuppressive therapy was retrieved from the electronic health records. Patients with haematological malignancies who received the PCV13 vaccination during or after initiation of the immunosuppressive therapy were excluded from the study.

OUTCOME MEASURES

A multivariate logistic regression model was performed to determine whether PCV13 vaccination is associated with fewer hospital admissions due to pneumonia or sepsis.

RESULTS

The cohort included 616 patients, of which 418 (67%) patients were not vaccinated and 198 (33%) were vaccinated. Within 12 months, 15.1% (n=63) of non-vaccinated patients compared with only 7.1% (n=14) of the vaccinated patients were hospitalised due to pneumonia or sepsis. The logistic regression analysis demonstrated that receiving PCV13 vaccination is associated with 45% (OR=0.45, 95% CI: 0.246 to 0.839, p=0.012) reduced odds of being hospitalised due to pneumonia or sepsis in patients with haematological malignancies receiving immunosuppressive therapy.

CONCLUSION

This is the first observational study to demonstrate the association between PCV13 vaccination and hospital admissions in patients with haematological malignancies receiving immunosuppressive therapy. Patients receiving PCV13 vaccination before immunosuppressive therapy initiation had significantly reduced odds of hospitalisation due to pneumonia or sepsis compared with non-PCV13-vaccinated patients.

Secondary Hypogammaglobulinemia in Patients with Chronic Lymphocytic Leukemia Receiving Ibrutinib Therapy

Secondary hypogammaglobulinemia (SHG) is characterized by a decrease in total serum immunoglobulin (Ig) levels and can lead to immunodeficiency associated with recurrent and severe infections and is a common complication of chronic lymphocytic leukaemia (CLL). SHG also increases with the treatment of CLL. Ibrutinib is one of these treatments and acts by inhibiting bruton tyrosine kinase. Twenty-seven patients with relapsed/refractory (R/R) CLL who received ibrutinib monotherapy were included. IgG levels, stage, bulky disease, previous treatments, genetics and laboratory features, overall survival (OS) and progression free survival (PFS) were compared with and without SHG. Nine patients (33.3%) had SHG and 18 patients (66.6%) didn't have SHG. The mean IgG levels after ibrutinib treatment first, third, 6th and 12th months were 684, 531.3, 452 and 360 mg/dL respectively in SHG arm (p < 0.001) and 1156, 1058.2, 1012.8 and 886.9 mg/dL respectively in without SHG arm (p < 0.001). All patients with SHG had ibrutinib related other adverse effects(AEs) but 2 (11.1%) patients without SHG had AEs (p < 0.001). In SHG arm 7 (77.7%) had complete and partial remission but in other arm only 6 (33.3%) had (p: 0.029). There was no significant difference in OS and PFS (p values 0.95 and 0.64, respectively). IgG levels at the beginning of ibrutinib treatment is the best predicted value for SHG development in our study (p = 0.001). As a result, we reported a significant decrease in IgG values after ibrutinib monotherapy in R/R CLL patients. This decrease occurs every month after ibrutinib use, but after a maximum of 1 year.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s12288-021-01466-1.

Subcutaneous immunoglobulin replacement for treatment of humoral immune dysfunction in patients with chronic lymphocytic leukemia

Background

Patients with chronic lymphocytic leukemia (CLL) experience hypogammaglobinemia and non-neutropenic infections. In this exploratory proof of concept study, our objective was to determine the prevalence of humoral immunodeficiency in patients with CLL and serum IgG ≥ 400 mg/dL, and to evaluate the efficacy of subcutaneous immunoglobulin (SCIG) in this population.

Patients and methods

Patients with CLL with serum IgG ≥ 400 mg/dL were evaluated for serum IgG, IgM, IgA, along with pre/post vaccine IgG titers to diphtheria, tetanus, and Streptococcus pneumoniae. Patients with evidence of humoral dysfunction were treated with SCIG with Hizentra every 7±2 days for 24 weeks.

Results

Fifteen patients enrolled with median IgG = 782 mg/dL [IQR: 570 to 827], and 6/15 (40%) responded to vaccination with Td, while 5/15 (33%) responded to vaccination with PPV23. 14/15 (93.3%) demonstrated humoral immunodeficiency as evidenced by suboptimal vaccine responses, and were treated with SCIG. In patients treated with SCIG, serum IgG increased from 670 mg/dL [IQR: 565 to 819] to 1054 mg/dL [IQR: 1040 to 1166] after 24 weeks (95% CI: 271–540). For streptococcus pneumoniae, the median protective serotypes at baseline was 8 [IQR: 4 to 9] and increased to 17 [IQR: 17 to 19] after 24 weeks (95% CI: 6.93–13.72). Non-neutropenic infections (NNI) decreased from 14 to 5 during treatment with SCIG.

Conclusions

Patients with CLL demonstrate humoral immunodeficiency despite IgG > 400 mg/dL. For these patients, SCIG is well tolerated and efficacious in improving serum IgG, specific IgG to streptococcus pneumoniae, and may decrease reliance on antibiotics for the treatment of NNIs.

Clinical trials registration

NCT 03730129.

Can Immunocompetence Be Restored in Chronic Lymphocytic Leukemia?

Reversing or preventing immunodeficiency in patients with chronic lymphocytic leukemia (CLL) is of the highest priority. The past decade of research has met the challenge of treating CLL for most patients. Patients continue to struggle, however, with infections and second primary malignancies related to immunodeficiency. Strategies addressing this need currently are limited to vaccinations, with suboptimal efficacy, and immunoglobulin replacement. Correlative studies have provided insights into immunologic alterations on treatment. Understanding vulnerabilities in the immune system may help identify potential interventions to boost immunity. An emphasis on systematically testing such interventions is required to restore immunocompetence in patients with CLL.

The humoral immune response to high-dose influenza vaccine in persons with monoclonal B-cell lymphocytosis (MBL) and chronic lymphocytic leukemia (CLL)

BACKGROUND

Limited data are available regarding the immunogenicity of high-dose influenza vaccine among persons with chronic lymphocytic leukemia (CLL) and monoclonal B cell lymphocytosis (MBL).

METHODS

A prospective pilot study of humoral immune responses to 2013-2014 and 2014-2015 high-dose trivalent influenza vaccine (HD IIV; Fluzone® High-Dose; Sanofi Pasteur) was conducted among individuals with MBL and previously untreated CLL. Serum hemagglutination inhibition (HAI) antibody titers were measured at baseline and Day 28 after vaccination; seroprotection and seroconversion rates were determined. Memory B cell responses were assessed by B-cell enzyme-linked immune absorbent spotassays.

RESULTS

Thirty subjects (17 CLL and 13 MBL) were included. Median age was 69.5 years. Day 28 seroprotection rates for the cohort were 19/30 (63.3%) for A/H1N1; 21/23 (91.3%) for A/H3N2; and 13/30 (43.3%) for influenza B. Those with MBL achieved higher day 28 HAI geometric mean titers (54.1 [4.9, 600.1] vs. 12.1 [1.3, 110.1]; p = 0.01) and higher Day 28 seroprotection rates (76.9% vs. 17.6%; p = 0.002) against the influenza B-vaccine strain virus than those with CLL.

CONCLUSIONS

Immunogenicity of the HD IIV3 in patients with CLL and MBL is lower than reported in healthy adults. Immunogenicity to influenza B was greater in those with MBL than CLL.

AIDS-Related Kaposi Sarcoma, Version 2.2019, NCCN Clinical Practice Guidelines in Oncology

As treatment of HIV has improved, people living with HIV (PLWH) have experienced a decreased risk of AIDS and AIDS-defining cancers (non-Hodgkin's lymphoma, Kaposi sarcoma, and cervical cancer), but the risk of Kaposi sarcoma in PLWH is still elevated about 500-fold compared with the general population in the United States. The NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines) for AIDS-Related Kaposi Sarcoma provide diagnosis, treatment, and surveillance recommendations for PLWH who develop limited cutaneous Kaposi sarcoma and for those with advanced cutaneous, oral, visceral, or nodal disease.

Effectiveness and practical uses of 23-valent pneumococcal polysaccharide vaccine in healthy and special populations

Streptococcus pneumonia (S. pneumoniae) is responsible for significant morbidity and mortality throughout the world. The 23-valent pneumococcal polysaccharide vaccines (PPV23) have been widely used for many years, but challenges are remaining in some respects, especially for its effectiveness among high-risk populations and older adults. This review aims to summarize recent clinical trials and studies of PPV23 vaccination among healthy people ≥ 2 years of age and those with high-risk conditions such as pregnant women, individuals with immunocompromising diseases and other chronic conditions, and provide health officials in China and other developing countries a comprehensive understanding of the current vaccination strategies for PPV23 and for the combined use of PPV23 and pneumococcal conjugate vaccines (PCVs) in adults.

Antibodies against Pneumococcal Capsular Polysaccharides and Natural Anti-Galactosyl (Alpha-Gal) in Patients with Humoral Immunodeficiencies

Humoral deficiencies represent a broad group of disorders. The aim of the study was to compare the levels of antibodies against pneumococcal capsular polysaccharides (anti-PCP) and natural anti-galactosyl (anti-Gal) antibodies in (1) patients with chronic lymphocytic leukaemia (CLL), (2) patients with common variable immunodeficiency (CVID), and (3) a healthy population and to explore their diagnostic and prognostic potential. Serum immunoglobulin levels and levels of anti-Gal IgG, IgA, and IgM and anti-PCP IgG and IgG2 were determined in 59 CLL patients, 30 CVID patients, and 67 healthy controls. Levels of IgG, IgA, IgM, anti-Gal IgA, anti-Gal IgM, and anti-PCP IgA were lower in CLL and CVID patients than in healthy controls (p value for all parameters < 0.0001). Decrease in the levels of IgA, IgM, anti-Gal IgA, and anti-PCP IgA was less pronounced in the CLL group than in the CVID group. IgA decline, anti-Gal IgA, anti-PCP IgA, and anti-PCP IgG2 were negatively correlated with CLL stage. We devise the evaluation of anti-Gal antibodies to be a routine test in humoral immunodeficiency diagnostics, even in cases of immunoglobulin substitution therapy. Significant reductions, mainly in anti-Gal IgA, IgM, and anti-PCP IgA levels, may have prognostic importance in CLL patients.

Cutaneous Adverse Events of Targeted Therapies for Hematolymphoid Malignancies

The identification of oncogenic drivers of liquid tumors has led to the rapid development of targeted agents with distinct cutaneous adverse event (AE) profiles. The diagnosis and management of these skin toxicities has motivated a novel partnership between dermatologists and oncologists in developing supportive oncodermatology clinics. In this article we review the current state of knowledge of clinical presentation, mechanisms, and management of the most common and significant cutaneous AEs observed during treatment with targeted therapies for hematologic and lymphoid malignancies. We systematically review according to drug-targeting pathway the cutaneous AE profiles of these drugs, and offer insight when possible into whether pharmacologic target versus immunologic modulation primarily underlie presentation. We include discussion of tyrosine kinase inhibitors (imatinib, dasatinib, nilotinib, bosutinib, ponatinib), blinatumomab, ibrutinib, idelalisib, anti-B cell antibodies (rituximab, ibritumomab, obinutuzumab, ofatumumab, tositumomab), immune checkpoint inhibitors (nivolumab, pembrolizumab), alemtuzumab, brentuximab, and proteasome inhibitors (bortezomib, carfilzomib, ixazomib). We highlight skin reactions seen with antiliquid but not solid tumor agents, draw attention to serious cutaneous AEs that might require therapy modification or cessation, and offer management strategies to permit treatment tolerability. We emphasize the importance of early diagnosis and treatment to minimize disruptions to care, optimize prognosis and quality of life, and promptly address life-threatening skin or infectious events. This evolving partnership between oncologists and dermatologists in the iterative characterization and management of skin toxicities will contribute to a better understanding of these drugs' cutaneous targets and improved patient care.

Challenges in the Role of Gammaglobulin Replacement Therapy and Vaccination Strategies for Hematological Malignancy

Patients with chronic lymphocytic leukemia (CLL) and multiple myeloma (MM) are prone to present with antibody production deficits associated with recurrent or severe bacterial infections that might benefit from human immunoglobulin (Ig) (IVIg/SCIg) replacement therapy. However, the original IVIg trial data were done before modern therapies were available, and the current indications do not take into account the shift in the immune situation of current treatment combinations and changes in the spectrum of infections. Besides, patients affected by other B cell malignancies present with similar immunodeficiency and manifestations while they are not covered by the current IVIg indications. A potential beneficial strategy could be to vaccinate patients at monoclonal B lymphocytosis and monoclonal gammopathy of undetermined significance stages (for CLL and MM, respectively) or at B-cell malignancy diagnosis, when better antibody responses are attained. We have to re-emphasize the need for assessing and monitoring specific antibody responses; these are warranted to select adequately those patients for whom early intervention with prophylactic anti-infective therapy and/or IVIg is preferred. This review provides an overview of the current scenario, with a focus on prevention of infection in patients with hematological malignancies and the role of Ig replacement therapy.

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.

Secondary immunodeficiency in lymphoproliferative malignancies

Secondary immunodeficiencies occur as a consequence of various diseases, including hematological malignancies, and the use of pharmacological therapies, such as immunosuppressive, anti-inflammatory, and biological drugs. Infections are the main cause of morbidity and mortality in multiple myeloma (MM) and chronic lymphocytic leukemia (CLL) patients. Recent advances in treatment have prolonged the duration of remission and the time between relapse phases in MM and CLL patients. However, managing multiple relapses and the use of salvage therapies can lead to cumulative immunosuppression and a higher risk of infections. The pathogenesis of immune deficiency secondary to lymphoproliferative malignancy is multifactorial including disease- and treatment-related factors. Supportive treatment, including early vaccination, anti-infective prophylaxis, and replacement immunoglobulin, plays a key role in preventing infections in MM and CLL. This article provides an overview of the basic immunology necessary to understand the pathogenesis of secondary immunodeficiency and the infectious complications in MM and CLL. We also discuss the evidence supporting the role of prophylactic replacement immunoglobulin treatment in patients with antibody failure secondary to MM and CLL and the indications for its use. Copyright © 2016 John Wiley & Sons, Ltd.

Partial reconstitution of humoral immunity and fewer infections in patients with chronic lymphocytic leukemia treated with ibrutinib

Chronic lymphocytic leukemia (CLL) is characterized by immune dysregulation, often including hypogammaglobulinemia, which contributes to a high rate of infections and morbidity. Ibrutinib, a covalent inhibitor of Bruton tyrosine kinase (BTK), inhibits B-cell receptor signaling and is an effective, US Food and Drug Administration (FDA)-approved treatment of CLL. Inactivating germline mutations in BTK cause a severe B-cell defect and agammaglobulinemia. Therefore, we assessed the impact of ibrutinib on immunoglobulin levels, normal B cells, and infection rate in patients with CLL treated with single-agent ibrutinib on a phase 2 investigator-initiated trial. Consistent with previous reports, immunoglobulin G (IgG) levels remained stable during the first 6 months on treatment, but decreased thereafter. In contrast, there were a transient increase in IgM and a sustained increase in IgA (median increase 45% at 12 months, P < .0001). To distinguish the effects on clonal B cells from normal B cells, we measured serum free light chains (FLCs). In κ-clonal CLL cases, clonal (κ) FLCs were elevated at baseline and normalized by 6 months. Nonclonal (λ) FLCs, which were often depressed at baseline, increased, suggesting the recovery of normal B cells. Consistently, we observed normal B-cell precursors in the bone marrow and an increase in normal B-cell numbers in the peripheral blood. Patients with superior immune reconstitution, as defined by an increase in serum IgA of ≥50% from baseline to 12 months, had a significantly lower rate of infections (P = .03). These data indicate that ibrutinib allows for a clinically meaningful recovery of humoral immune function in patients with CLL. This trial was registered at www.clinicaltrials.gov as #NCT015007330.

Antibody and plasmablast response to 13-valent pneumococcal conjugate vaccine in chronic lymphocytic leukemia patients--preliminary report

BACKGROUND

Chronic lymphocytic leukemia (CLL) leads to significant immune system dysfunction. The predominant clinical presentation in 50% of patients involves recurrent, often severe, infections. Infections are also the most common (60-80%) cause of deaths in CLL patients. The scope of infections varies with the clinical stage of the disease. Treatment-naive patients typically present with respiratory tract infections caused by encapsulated bacteria Streptococcus pneumoniae and Haemophilus influenzae. Since 2012, the 13-valent pneumococcal conjugate vaccine (PCV13) has been recommended in the United States and some EU countries for pneumococcal infection prevention in patients with CLL (besides the long-standing standard, 23-valent pneumococcal polysaccharide vaccine, PPV23). The aim of this study was to compare the immune response to PCV13 in 24 previously untreated CLL patients and healthy subjects.

METHODS

Both groups were evaluated for: the levels of specific pneumococcal antibodies, the levels of IgG and IgG subclasses and selected peripheral blood lymphocyte subpopulations including the frequency of plasmablasts before and after immunization.

RESULTS

Adequate response to vaccination, defined as an at least two-fold increase in specific pneumococcal antibody titers versus pre-vaccination baseline titers, was found in 58.3% of CLL patients and 100% of healthy subjects. Both the CLL group and the control group demonstrated a statistically significant increase in the IgG2 subclass levels following vaccination (P = 0.0301). After vaccination, the frequency of plasmablasts was significantly lower (P<0.0001) in CLL patients in comparison to that in controls. Patients who responded to vaccination had lower clinical stage of CLL as well as higher total IgG, and IgG2 subclass levels. No significant vaccine-related side effects were observed.

CONCLUSIONS

PCV13 vaccination in CLL patients is safe and induces an effective immune response in a considerable proportion of patients. To achieve an optimal vaccination response, the administration of PCV13 is recommended as soon as possible following CLL diagnosis.

Primary vs. secondary antibody deficiency: clinical features and infection outcomes of immunoglobulin replacement

Secondary antibody deficiency can occur as a result of haematological malignancies or certain medications, but not much is known about the clinical and immunological features of this group of patients as a whole. Here we describe a cohort of 167 patients with primary or secondary antibody deficiencies on immunoglobulin (Ig)-replacement treatment. The demographics, causes of immunodeficiency, diagnostic delay, clinical and laboratory features, and infection frequency were analysed retrospectively. Chemotherapy for B cell lymphoma and the use of Rituximab, corticosteroids or immunosuppressive medications were the most common causes of secondary antibody deficiency in this cohort. There was no difference in diagnostic delay or bronchiectasis between primary and secondary antibody deficiency patients, and both groups experienced disorders associated with immune dysregulation. Secondary antibody deficiency patients had similar baseline levels of serum IgG, but higher IgM and IgA, and a higher frequency of switched memory B cells than primary antibody deficiency patients. Serious and non-serious infections before and after Ig-replacement were also compared in both groups. Although secondary antibody deficiency patients had more serious infections before initiation of Ig-replacement, treatment resulted in a significant reduction of serious and non-serious infections in both primary and secondary antibody deficiency patients. Patients with secondary antibody deficiency experience similar delays in diagnosis as primary antibody deficiency patients and can also benefit from immunoglobulin-replacement treatment.

Secondary antibody deficiency

Secondary antibody deficiencies are defined by a quantitative or qualitative decrease in antibodies that occur most commonly as a consequence of renal or gastrointestinal immunoglobulin loss, hematological malignancies and corticosteroid, immunosuppressive or anticonvulsant medications. Patients with hematological malignancies or requiring immunosuppressive medications are known to be at increased risk of infection, but few studies directly address this relationship in the context of antibody deficiency. Immunoglobulin replacement therapy has been shown to be effective in reducing infections in primary and some secondary antibody deficiencies. The commonly encountered causes of secondary antibody deficiencies and their association with infection-related morbidity and mortality are discussed. Recommendations are made for screening and clinical management of those at risk.

Antibody deficiency secondary to chronic lymphocytic leukemia: Should patients be treated with prophylactic replacement immunoglobulin?

Hypogammaglobulinemia is a common finding in chronic lymphocytic leukemia (CLL). Its incidence increases with disease duration and stage such that it is present in up to 85 % of patients at some point in their disease course. It is therefore important to monitor patients for the development of an antibody deficiency. However, not all patients with antibody deficiency secondary to CLL are symptomatic with bacterial infections. In addition patients are susceptible to viral, fungal and opportunistic infections as a result of iatrogenic immunosuppression and through a variety of disease-related mechanisms, which affect cellular immunity and phagocytes. Published guidelines suggest that patients with a history of recurrent bacterial infections and a documented failure of antibody production should be treated with antibiotic prophylaxis in the first instance, with replacement immunoglobulin reserved for those who continue to suffer with significant bacterial infections. Here we present a review of the existing literature in order to provide a practical approach, based on best available evidence, to the investigation, monitoring and treatment of patients with antibody failure secondary to CLL; and we highlight areas in which further studies are needed.

Serum immunoglobulins and risk of infection: how low can you go?

OBJECTIVES

To determine the relationship between the levels of serum immunoglobulin (Ig) levels and risk of infection. The following 2 main questions are addressed: (1) At what level do reduced serum concentrations of the different Ig species (focusing on IgA, IgG, and IgM) significantly increase the risk of infection above background and (2) For how long can Ig depletion be tolerated before an increased risk of infection becomes apparent.

METHODS

Information was gathered from a search of PubMed and relevant congress abstracts up to and including November 2007.

RESULTS

Sustained, very low levels of IgA, IgG, or IgM, as occur in primary immunodeficiency syndromes, are associated with significantly increased risks of infections, primarily respiratory tract infections of bacterial origin. Patients with IgG levels <100 mg/dL or IgM levels <20 mg/dL for prolonged periods have an increased risk of recurrent and sometimes life-threatening infectious episodes. Generally, IgA deficiency appears better tolerated. Replenishment of IgG in patients with hypogammaglobulinemia reduces the infection risk to background if IgG levels are maintained at approximately 500 mg/dL, although higher levels may be necessary in the presence of certain comorbidities. Transient depletion of IgG and/or IgM (or, less commonly, IgA) can occur in some patients following the administration of certain drugs, including anticonvulsants, corticosteroids, and rituximab. Available evidence suggests that such changes are not generally associated with an increased risk of infections.

CONCLUSIONS

While prolonged, very low levels of IgG and/or IgM are associated with a heightened risk of infections, transient or less severe immunodeficiency appears to be tolerated in most subjects.

The effect of ranitidine on antibody responses to polysaccharide vaccines in patients with B-cell chronic lymphocytic leukaemia

OBJECTIVES

To analyse the effects of ranitidine treatment on vaccination induced antibody responses in patients with chronic lymphocytic leukaemia (CLL).

METHODS

Fifty CLL patients were vaccinated with tetanus conjugated Hib vaccine and a 23-valent pneumococcal polysaccharide vaccine with (n = 25) or without (n = 25) ranitidine treatment in a matched case--control setting. Anti tetanus toxoid (TT), anti-Hib and anti-pneumococcal antibody levels were determined before and after vaccination. Additionally, cytokine levels were assessed in patients treated with ranitidine.

RESULTS

Vaccination-induced increases in anti-Hib and anti-TT antibody levels were higher in the ranitidine group compared with the control group. Anti-pneumococcal antibody responses were not improved by administration of ranitidine. Higher levels of IL-18 were found in patients treated with ranitidine compared with healthy controls. Levels of IL-6, IL-8, IL-18, RANTES, IP-10, sVCAM-1 and sICAM-1 were within normal ranges and did not change during ranitidine treatment.

CONCLUSION

Ranitidine treatment improves vaccination-induced T-cell dependent antibody responses in patients with CLL but has no beneficial effect on the response to vaccination with unconjugated polysaccharide antigens.

Targets and strategies for T-cell based vaccines in patients with B-cell chronic lymphocytic leukemia

T-cell based immunotherapies might be a novel option for the treatment of B-cell chronic lymphocytic leukemia (B-CLL), a disease characterized by a prolonged natural course. Different strategies of active immunotherapy have been tested in vitro to enhance a specific T-cell response against tumor cells and an anti-leukemic effect has been observed in B-CLL patients after allogenic stem cell transplantation. Several antigens have been characterized as tumor/leukemia associated antigens (T/LAAs) in B-CLL with the potential to elicit specific anti-tumor response encompassing idiotype immunoglobulin, oncofetal antigen-immature laminin receptor protein (OFAiLRP), survivin, as well as fibromodulin, the receptor for hyaluronic acid mediated motility (RHAMM/CD168) and the murine double-minute 2 oncoprotein (MDM2). This study presents an overview of possible targets and genetherapeutical maneuvers for future immunotherapies of B-CLL patients and summarizes recent clinical vaccination trials with dendritic cells (DCs) for B-CLL.

Due to low infection rates no routine anti-infective prophylaxis is required in younger patients with chronic lymphocytic leukaemia during fludarabine-based first line therapy

The impact of the combination therapy fludarabine plus cyclophosphamide (FC) in comparison with fludarabine alone regarding the incidence and severity of infections among previously untreated patients with chronic lymphocytic leukaemia (CLL) was evaluated within a multicentre phase III study. A total of 375 patients, up to 65 years old, were randomised between fludarabine or FC for first line therapy. No routine anti-infective prophylaxis was provided. A total of 196 infectious episodes, including 33 severe infections, were documented. In the fludarabine arm, 32.9% of the patients developed an infectious complication compared with 39.9% in the FC arm (P = 0.2). No difference was observed in the rate of severe infections (Common Toxicity Criteria grades III and IV) between both treatment arms. Dose reductions were performed more frequently in FC-treated patients. Granulocyte colony-stimulating factor (G-CSF) was administered due to leucopenia in 5% of all patients. A multivariate regression model identified only elevated thymidine kinase, but not the treatment arm, as a statistically independent risk factor for infections. In summary, FC was not associated with a higher rate of infections compared with fludarabine alone. No routine antibiotic or virostatic prophylaxis, or preemptive treatment with G-CSF, is necessary in first line therapy with fludarabine-based regimens in younger patients with CLL, if adequate dose reduction is performed. The combination therapy FC is not associated with a higher rate of infections compared with fludarabine alone. No routine antibiotic or virostatic prophylaxis as well as preemptive treatment with G-CSF is necessary in first line therapy with fludarabine-based regimen in younger patients with CLL, if adequate dose reductions due to cytopenia or previous infections are performed.

Humoral immune responses and CD27+ B cells in children with DiGeorge syndrome (22q11.2 deletion syndrome)

The spectrum of T-cell abnormalities in 22q11.2 syndrome is quite broad, ranging from profound and life threatening to non-existent defects. Humoral abnormalities have been described in some of these patients, although no data are currently available on their phenotypical and functional B cell subsets. The purpose of this study was to investigate humoral immune function in a cohort of 13 children with DiGeorge syndrome by immunophenotyping B and by analysing their functionality in vivo. Humoral immunity was assessed by serum immunoglobulin evaluation, IgG subclasses determination, and testing of specific antibody titers to recall antigens. B cells were analyzed by flow cytometry and the relevant percentage of membrane surface expression of CD27, IgM, IgD was evaluated. In our cohort, one of 13 children (7.7%) had a complete IgA deficiency, four of 13 (30.7%) had minor immunoglobulin abnormalities, and five (38%) had an impaired production of specific antibodies. Five of 13 children (38%) had recurrent infections. Interestingly, peripheral CD27+ B cells were reduced in our patients as compared with age-matched healthy controls, and this decrement was statistically significant for IgM+ IgD+ CD27+ B cells. Immunoglobulin abnormalities were associated with the occurrence of recurrent infections. We conclude that a significant proportion of patients with DiGeorge syndrome have defective humoral immunity, which may represent an additional pathogenic mechanism underlying the increased susceptibility to infections. Whether the decreased CD27+ B-cell subset might be one of the defects that contribute to impaired humoral immunity, and to susceptibility to infection remains to be elucidated.

Use of intravenous immunoglobulin G (IVIG)

Intravenous immunoglobulin G (IVIG) has become increasingly important both as replacement therapy in primary and acquired humoral immunodeficiency and as an immunomodulatory therapy in autoimmune disease and transplantation. Multiple potential mechanisms for the effects of IVIG have now been recognized but the contribution of each mechanism in different diseases is uncertain. IVIG is generally well tolerated but serious side effects can occur and need to be addressed. IVIG has Food and Drug Administration (FDA) approval for a half dozen indications but these account for only about half the use of IVIG. This chapter reviews the development of IVIG for primary immunodeficiency, the evidence for efficacy of IVIG in autoimmune and inflammatory conditions, the risks associated with administration of IVIG, and steps that can be taken to minimize adverse events.

Immune defects in patients with chronic lymphocytic leukemia

Over the past decade, the introduction of nucleoside analogs and monoclonal antibodies into the treatment of patients with chronic lymphocytic leukemia (CLL) has resulted in higher rates and longer duration of response. This is a significant step towards achieving the ultimate goal of disease-eradication and improved survival. A continuing problem, however, is the susceptibility of these patients to infections. Profound dysregulation of the host immune system in patients with CLL and its impact on the clinical course of the disease are well established. A number of investigators have sought to identify the mechanisms underlying this innate immune dysfunction, which is further exacerbated by the actions of the potent therapeutic agents. The early recognition of infections as well as prophylactic administration of appropriate antibiotics has been the mainstay of managing infections in patients with CLL. Hopefully, increasing understanding of the molecular events underlying the neoplastic change in CLL will lead to more targeted and less immunosuppressive therapeutic modalities. Furthermore, the understanding of the mechanisms of immune dysfunction in CLL is of pivotal importance in the novel immune-based therapeutic strategies currently under development.

The Outcomes of Lung Transplantation in Patients With Bronchiectasis and Antibody Deficiency

BACKGROUND

Lung transplantation is an established treatment for end-stage bronchiectasis. A proportion of patients with bronchiectasis have an associated antibody deficiency. This group benefits from immunoglobulin replacement therapy, but the outcome of lung transplantation is not known.

METHODS

We conducted a retrospective observational study of all who received a transplant for bronchiectasis at our unit. We compared the survival after transplant, number of infective and rejection episodes, and the change in forced expiratory volume in 1 second (FEV1).

RESULTS

Five of the 37 patients identified with bronchiectasis had an antibody deficiency that required immunoglobulin replacement therapy. Actuarial survival was similar in the 2 groups, being 81% at 12 months in the Bronchiectasis Group and 80% in the Antibody Deficiency Group. The FEV1 at 12 months after transplantation was similar in each group, with a predicted mean +/- SD FEV1 of 83.7% +/- 24.2% in those with bronchiectasis and 83.0% +/- 30.4% in those with antibody deficiency as well. The infection and rejection rates in the first year after transplantation were lower in the Antibody Deficiency Group. Infection episodes per 100 patient-days for bronchiectasis alone were 0.90 vs 0.53 and rejection episodes per 100 patient-days were 0.59 vs 0.24.

CONCLUSIONS

There was no evidence that transplant recipients with bronchiectasis and antibody deficiency have a worse prognosis than those with bronchiectasis alone.

Developing practice guidelines for the administration of intravenous immunoglobulin

As the use of intravenous immunoglobulin (IGIV) continues to expand, infusion nurses have a greater need for a comprehensive understanding of the product, patient risk factors, and comorbidities when developing guidelines for administering IGIV. Because immunoglobulin therapy is a blood derivative product, many nurses may not have as much experience administering this type of infusion. This article provides an in-depth overview of immunoglobulin therapy and helps to define the infusion nurse's major role in coordinating, assessing, and ensuring patient safety during IGIV administration.

Infections associated with purine analogs and monoclonal antibodies

Nucleoside analogs and monoclonal antibodies are commonly used to treat lymphoproliferative disorders and have become established as the treatment of choice in chronic lymphocytic leukemia, hairy cell leukemia, and follicular lymphomas, as well as a number of other malignant lymphoid neoplasms. When used in standard doses, these agents have a low incidence of extramedullary side effects resulting in their inclusion in a number of combination regimens. The most important complications associated with these drugs are myelosuppression, immunosuppression and infections. This is further accentuated when they are used in combination with other drugs such as alkylating agents. Several investigators have attempted to delineate the risk factors predicting the risk of infections associated with these agents. Furthermore, risk-based strategies to decrease the incidence of these infectious complications have been proposed.

Nationwide study of recurrent invasive pneumococcal infections in a population with a low prevalence of human immunodeficiency virus infection

Recurrent invasive infections caused by Streptococcus pneumoniae are rare, and often considered to be indicative of serious underlying illness. However, the prevalence of this problem, and the relevance of specific predisposing conditions, can be hard to assess, since many of the studies are based on specific risk groups. A population-based study of recurrent invasive pneumococcal disease in Iceland during the 30-year period 1975-2004 was performed. Clinical information, including mortality and vaccine use, was analysed retrospectively. Invasive pneumococcal isolates were serotyped and susceptibility testing was performed. During this period, 36 (4.4%) of 819 patients who survived an initial infection experienced recurrence, with a median time between episodes of 9.7 months. Pneumonia with bacteraemia was the most common clinical diagnosis (48% of cases), followed by bacteraemia without a clear focus (21%) and meningitis (13%). Most (94%) of the patients had identifiable predisposing conditions, most commonly, multiple myeloma in adults, and antibody deficiencies in children. Compared with children, adults were more likely to present with pneumonia (65% vs. 18%; p 0.0001). No significant change in the 30-day mortality rate was observed during the three decades of the study. Only 26% of eligible patients received pneumococcal vaccination. Patients with recurrent invasive pneumococcal disease should be investigated thoroughly for underlying diseases. Greater use of pneumococcal vaccines should be encouraged among high-risk patients. More effective preventive and therapeutic measures are needed to improve outcomes.

The role of stem cell transplantation in chronic lymphocytic leukemia

Chronic lymphocytic leukemia (CLL) generally follows an indolent clinical course and usually occurs in the elderly. However, the disease is heterogeneous with some patients having a more aggressive clinical course and short survival. Although the role of fludarabine in combination with other chemotherapy drugs and/or monoclonal antibody therapy appears promising, to date chemotherapy has not been curative in this disease. At present, the only potential cure for CLL appears to be stem cell transplantation (SCT), but its role in the management of CLL has not been established. In particular, patient selection for consideration of SCT, timing of SCT in the clinical course of CLL, selection of autologous versus allogeneic SCT, use of nonmyeloablative regimens, and exploitation of the graft-versus-leukemia (GVL) effect are currently under investigation.

Immunologic monitoring in chronic lymphocytic leukemia

Chronic lymphocytic leukemia (CLL) is characterized by progressive defects in humoral- and cell-mediated immunity. These defects are manifested as a propensity to develop infections with encapsulated bacteria, and less frequently, with gram-negative enterics. In addition, reactivation of viruses such as herpesvirus is not uncommon. Treatment of the disease further exacerbates immunosuppression by depleting immune effectors and broadening the spectrum of potentially offending pathogens. Risk of infection can potentially be reduced by administration of intravenous immunoglobulin and use of prophylactic antibiotics for individuals who are at high risk. Current work focuses on development of cellular and cytokine therapy to facilitate immune reconstitution in patients with CLL, thereby reducing morbidity and mortality and potentially improving survival.

Measurement and interpretation of pneumococcal IgG levels for clinical management

The detection of pneumococcal IgG antibodies is helpful for the evaluation of response to pneumococcal vaccination and need for revaccination. Results generated by the clinical assay which is currently used, in which the 23 valent polysaccharide vaccine is the antigen, were compared to those obtained by a capsular polysaccharide serotype-specific assay that measures IgG antibodies to 9 common serotypes causing invasive disease. Discrepancies in 21/47 (45%) of the results were observed in a direct comparison between the two assays. In each case a positive titre was obtained on the clinical assay but IgG levels on the serotype-specific assay were below the putative protective level of 0.2 micro g/ml for at least one of the 9 serotypes assayed. The generation of false positives by the current clinical assay is due to its lack of specificity. Antibodies to C-polysaccharide and all of the 23 serotypes included in the pneumococcal polysaccharide vaccine are incorporated into the final titre whereas the serotype-specific assay adsorbs out noncapsular polysaccharide antibodies. The discrepancies between the two assays highlight the importance of standardized assays that measure putative correlates of protection and demonstrate the need to re-evaluate the current clinical assay. A tool that allows the interpretation of the results of the serotype-specific assay is provided and its potential for assessing individual susceptibility levels to vaccine preventable pneumococcal infection is discussed.

Polysaccharide antibody responses are impaired post bone marrow transplantation for severe combined immunodeficiency, but not other primary immunodeficiencies

Established treatment of severe combined immunodeficiencies (SCID) and other primary immunodeficiencies (PID) is bone marrow transplantation (BMT). Normal lymphocyte numbers and protein antigen responses are present within 2 years of BMT, polysaccharide antibody responses appear last. Streptococcus pneumoniae infection causes significant morbidity and mortality post-BMT. Previous studies have shown good protein antigen responses post-BMT for SCID and PID, but had not examined the polysaccharide responses. We retrospectively analysed pneumococcal polysaccharide (PPS) responses in our patient series. In total, 22 SCID and 12 non-SCID PID were evaluated, all >2 years post BMT: 17 SCID, 12 PID received chemotherapy conditioning; 17 SCID, three PID had T-cell depleted (TCD) BMT, others had nonconditioned whole marrow BMT. All had normal Haemophilus influenza B and tetanus antibody responses. Of 22 SCID, 13 vs 11/12 PID responded to PPS vaccine (P=0.05). There was no association with donor age, GvHD, B-cell chimerism, or IgG2 level. Fewer TCD marrow recipients responded to PPS (P=0.04). Analysis of the SCID group showed no association of PPS response with type of marrow received. This is the first study to specifically examine PPS antibody responses following SCID and PID BMT. Pneumococcal conjugate vaccine antibody responses should be examined in these children.

Infections in Patients with Hematological Cancer: Recent Developments

One of the most common complications involved in treating patients with hematologic cancer is infection. In many cases there are multiple factors that predispose these patients to infections such as neutropenia induced by therapy or bone marrow involvement, hypogammaglobulinemia, T-cell dysfunction, and mucosal damage. In addition, newer therapies have changed the spectrum of infection that is seen in these patients.

In Section I, Dr. Blijlevens discusses mucosal damage as a major risk factor for complications of cytotoxic chemotherapy. She focuses on mucosal barrier injury (MBI) as manifest in the GI tract and will describe a pathological model to explain MBI, evaluate risk factors for development of this syndrome, explain the relationship between MBI and infection, and discuss treatment and prevention of this injury.

Invasive fungal infections continue to represent a significant problem in patients with hematologic cancer. In Section II, Drs. Anaissie and Mahfouz review the latest developments in the diagnosis, prevention, and management of invasive fungal infections with a focus on a risk-adjusted approach to this problem.

Finally, in Section III, Dr. O’Brien reviews infections associated with newer therapeutic regimens in hematologic cancers. The spectrum of infections has changed with the use of purine analogs and the advent of monoclonal antibodies. The profound T-cell suppression associated with these therapies has led to the emergence of previously rare infections such as cytomegalovirus. An approach to both prophylaxis and management of these infections is discussed.

Antibody deficiency and autoimmunity in 22q11.2 deletion syndrome

BACKGROUND

Although severe T cell immunodeficiency in DiGeorge anomaly is rare, previous studies of humoral function in these patients have found no antibody abnormalities but have not examined the response to polysaccharide antigens. Isolated cases of autoimmunity have been reported. Several patients with 22q11.2 deletion attending our immunology clinic suffered recurrent sinopulmonary infection or autoimmune phenomena.

AIMS

To investigate humoral immunodeficiency, particularly pneumococcal polysaccharide antibody deficiency, and autoimmune phenomena in a cohort of patients with 22q11.2 deletion.

METHODS

A history of severe or recurrent infection and autoimmune symptoms were noted. Lymphocyte subsets, immunoglobulins, IgG subclasses, specific vaccine antibodies, and autoantibodies were measured. Subjects were vaccinated with appropriate antigens as indicated.

RESULTS

Of 32 patients identified, 26 (81%) had severe or recurrent infection, of which 13 (50%) had abnormal serum immunoglobulin measurements and 11/20 >/=4 years old (55%) had an abnormal response to pneumococcal polysaccharide. Ten of 30 patients (33%) had autoimmune phenomena; six (20%) were symptomatic.

CONCLUSIONS

Humoral immunodeficiency is more common than previously recognised in patients with 22q11.2 deletion. Normal T cell function and immunoglobulin levels do not exclude poor specific antibody responses. Patients should be referred for formal immunological assessment of cellular and humoral immune function.

Intravenous immunoglobulins: clinical experience and viral safety

OBJECTIVES

To discuss the current procedures and processes by which viral safety is ensured for intravenous immunoglobulins (IVIGs), to place in context the current increase in clinical indications for IVIGs, and to describe the safety issues that have led to product shortages.

DATA SOURCES

Articles on viral safety retrieved from MEDLINE using the search terms gamma globulin, intravenous, adverse reaction, and infection and information from the manufacturers' literature and Food and Drug Administration package inserts.

STUDY SELECTION AND DATA EXTRACTION

Studies that specifically addressed the areas of major concern or advancement in viral safety of IVIGs, including donor selection, plasma screening, and other quality control procedures to ensure safety of source plasma; detection of viruses that may have escaped antibody screening tests through the use of polymerase chain reaction-based assays, which are capable of detecting small amounts of viral genomic material (e.g., hepatitis C virus, hepatitis B virus, and human immunodeficiency virus [HIV]) in small plasma pools; and industrial-scale, validated viral inactivation methods, such as pasteurization and solvent/detergent treatment, that have been incorporated into the manufacturing processes of immunoglobulins to further minimize the risk of viral transmission.

DATA SYNTHESIS

In addition to the treatment of primary immunodeficiency disorders, the clinical uses of IVIGs have expanded to include treatment of Kawasaki's syndrome, idiopathic thrombocytopenic purpura, infection following bone marrow transplantation, secondary immunologic disorders (e.g., pediatric HIV infection), hematologic disorders (e.g., chronic lymphocytic leukemia), and neurologic indications (e.g., Guillain-Barré syndrome). Although IVIG preparations are derived from human plasma, they have a long safety record and a low risk for transmitting viral infections.

CONCLUSION

Viral validation studies demonstrated that the processes discussed herein differ in their capabilities to inactivate lipid-enveloped and nonlipid-enveloped viruses.

Antibody responses to pneumococcal and haemophilus vaccinations in patients with B-cell chronic lymphocytic leukaemia

Although vaccination against Streptococcus pneumoniae (S. pneumoniae) and Haemophilus influenzae type b (Hib) is recommended for immunocompromised patients, such as patients with B-cell chronic lymphocytic leukaemia (B-CLL), its protective effect is questionable. We studied antibody responses to pneumococcal polysaccharide vaccine (Pneumovax-23) and to conjugated H. influenzae type b-vaccine (Act-Hib) in 25 patients with B-CLL. After vaccination, the number of patients with antibody levels in the protective range against pneumococcal serotypes and H. influenzae b increased from 9 (38%) to 12 (50%) of 24 patients and from 8 (35%) to 11 (48%) of 23 patients, respectively. The patients with adequate antibody response to Pneumovax-23 and Act-Hib had significantly less advanced stages of B-CLL, higher gammaglobulin levels, total IgG-levels and IgG-subclasses 2 and 4 levels, and lower levels of soluble CD23. Consequently, vaccination with these vaccines should be given as soon as the diagnosis of B-CLL is made, early in the course of the disease with determination of post-vaccination antibody levels.

Characterization of the impaired antipneumococcal polysacharide antibody production in immunosuppressed pediatric patients following cardiac transplantation

We previously have demonstrated impaired pneumococcal polysaccharide IgG antibody responses in children immunosuppressed following cardiac transplantation in early childhood. We have further characterized the antibody defect. To further investigate the production of antibody, antipneumococcal polysaccharide (PPS) specific IgM, IgG, IgG subclasses, and IgA were measured in postvaccination sera by enzyme-linked immunosorbent assay. Two groups were studied: posttransplant children who made pneumococcal antibody in vivo following natural exposure or PPS immunization (R) and those with an impaired response (NR). There was no difference in IgM or IgA levels between R and NR. IgG and IgG2 levels were higher in R than NR (P = 0.002), even after adsorption of nonspecific common cell wall antigen antibody. Differences in anti-pneumococcal antibody levels suggest that immunoglobulin isotype switching from IgM to IgG and particularly IgG2 is impaired in patients immunosuppressed at a young age. These findings confirm data regarding the effect of immunosuppressive agents derived from animal models in humans.

Infection and immunity in chronic lymphocytic leukemia

Patients having chronic lymphocytic leukemia (CLL) are at increased risk for infectious morbidity and mortality. The predisposition to infections in CLL patients has many components, including both immunodeficiency related to the leukemia itself (humoral and cellular immune dysfunction) and the results of cumulative immunosuppression related to CLL treatment. The risk of infectious complications increases with the duration of CLL, reflecting the natural history of the disease and the cumulative immunosuppression related to its treatment. Hence, in early, untreated CLL, the infectious risk is mainly related to hypogammaglobulinemia, and infections by encapsulated bacteria are common. However, in patients having advanced CLL, particularly those who receive the newer purine analogues, neutropenia and defects in cell-mediated immunity appear to be the major predisposing factors. An expanded spectrum of pathogens, including opportunistic fungi, Pneumocystis carinii, Listeria monocytogenes, mycobacteria, and herpesviruses, are seen in that setting. The changing spectrum of infections in this latter group of patients mandates a newer approach to prophylaxis and therapy.

Management of chronic lymphocytic leukaemia

Chronic lymphocytic leukaemia (CLL) is the most common form of adult leukaemia in Western countries. The diagnosis requires mature-appearing lymphocytes in the peripheral blood to >5 x 10(9)/L. The immunophenotype typically includes B cell antigens CD19, CD20 and CD23, low expression of surface immunoglobulin and CD5+, with other T cell antigens absent. Bone marrow biopsy, although not required for diagnosis, must show at least 30% lymphocytes. Cytogenetic abnormalities are frequent in patients with CLL, and may be associated with poor prognosis. Clinically, most patients are asymptomatic at presentation, with incidental lymphadenopathy and/or hepatosplenomegaly in the routine physical examination. Infections by opportunistic pathogens are the major cause of death. Aggressive transformation occurs in 10% of patients with CLL, most commonly prolymphocytic leukaemia (PLL) and Richter's syndrome. PLL de novo must be differentiated from PLL of an aggressive transformation. The incidences of autoimmune diseases and solid or haemopoietic secondary malignancies are increased in patients with CLL. Clinical stage is the strongest prognostic factor in CLL. There is no indication for early intervention. The current recommendation to start treatment includes disease-related symptoms, massive and/or progressive hepatosplenomegaly or lymphadenopathy, increasing bone marrow failure, autoimmune disease, and recurrent infections. Alkylating agents (e.g. chlorambucil) and nucleoside analogues (e.g. fludarabine) are the most active agents for CLL. Fludarabine induces higher response rates, but no improvement in overall survival has been observed. Fludarabine is the drug of choice for the majority of patients with CLL. Chlorambucil may be helpful for elderly patients with poor performance, and for patients who do not tolerate fludarabine. No drug combination is better than single agents. For patients refractory to initial treatment, referral to a clinical trial is the best choice. Other salvage therapy includes retreatment with the same initial agent (chlorambucil or fludarabine) if initial response was observed, or fludarabine for patients refractory to chlorambucil. Promising new approaches include cycle-active agents, nelarabine, biological therapy such as anti-CD52 monoclonal antibody, bone marrow transplantation, including the use of submyeloablative preparative regimens ('minitransplant') to induce graft-versus-leukaemia effect, and gene therapy. Prophylactic antibacterials and intravenous immunoglobulin should not be used routinely during supportive care. Epoetin may be helpful for patients who have anaemia without obvious cause. Assessment of response to therapy in CLL has been updated by the National Cancer Institute Working Group, and these guidelines are used worldwide for clinical trials.

Effect of immunosuppression after cardiac transplantation in early childhood on antibody response to polysaccharide antigen

BACKGROUND

Three children who had cardiac transplantation before age 4 years later presented with recurrent sinopulmonary infection caused by organisms including Streptococcus pneumoniae, in which capsular polysaccharide plays an important part, one developed bronchiectasis. We therefore studied responses to polysaccharide antigen after immunosuppression started in early childhood.

METHODS

Antibodies against pneumococcal and haemophilus polysaccharides, and total IgG, IgG1, IgG2, and IgA concentrations were measured in 33 cardiac-transplant recipients transplanted before the age 4 years (group 1) and after that age (group 2). Patients with low pneumococcal and haemophilus antibody concentrations were immunised with 23 polyvalent pneumococcal and tetanus-haemophilus conjugate vaccines and antibody responses were measured.

FINDINGS

Five patients from group 1 and seven from group 2 were transplanted for congenital heart disease and ten patients in each group had heart transplants because of cardiomyopathy; none were asplenic. Group 1 (16 patients) were aged 2-10 years when investigated, group 2 (17 patients), were 6-16 years. Four of 16 patients in group 1 responded to pneumococcal polysaccharide vaccine compared with 14 of 17 in group 2 (p=0.0016). This difference remained when those in group 1, aged less than 4 years at investigation, were excluded (p=0.0060). Response to haemophilus-conjugate vaccine was similar in both groups (14 of 16 vs 14 of 17, p=1.0). Significantly more patients who failed to respond to pneumococcal vaccine had low IgG2 concentrations (p=0.0269).

INTERPRETATION

Children who had a transplantation and immunosuppression in early childhood before they had developed antibody responses to pneumococcal polysaccharide, still failed to show a response when older-ie, when such responses are the norm. Ongoing immunosuppression prevents the maturation of antipolysaccharide responses leaving children susceptible to severe and recurrent damaging infection.

Use of intravenous immunoglobulin to prevent or treat infections in persons with immune deficiency

Intravenous immunoglobulin (IVIG) concentrates were originally developed as replacement therapy for individuals with primary deficiencies of the immune system. However, in various well-designed, controlled clinical trials, the ability of IVIG to prevent and possibly treat infections in patients with secondary immune deficiencies has also been considered. In this review, we briefly consider these different applications and suggest whether the data are sufficient to employ IVIG in these clinical settings.