Hypogammaglobulinemia following cardiac transplantation: a link between rejection and infection

The time-dependent changes in serum immunoglobulin after kidney transplantation and its association with infection

Introduction

Kidney transplant recipients often experience significant alterations in their immune system, which can lead to increased susceptibility to infections. This study aimed to analyze time-dependent changes in serum immunoglobulin and complement levels and determine the risk factors associated with infection.

Methods

A retrospective analysis of serum samples from 192 kidney transplant recipients who received transplantations between August 2016 and December 2019 was conducted. The serum samples were obtained at preoperative baseline (T0), postoperative 2 weeks (T1), 3 months (T2), and 1 year (T3). The levels of serum C3, C4, IgG, IgA, and IgM were measured to evaluate immune status over time.

Results

The analysis revealed significant decreases in IgG and IgA levels at T1. This period was associated with the highest occurrence of hypogammaglobulinemia (HGG) and hypocomplementemia (HCC), as well as an increased incidence of severe infection requiring hospitalization and graft-related viral infections. Using a time-dependent Cox proportional hazards model adjusted for time-varying confounders, HGG was significantly associated with an increased risk of infection requiring hospitalization (HR, 1.895; 95% CI: 1.871-1.920, P-value<0.001) and graft-related viral infection (HR, 1.152; 95% CI: 1.144-1.160, P-value<0.001).

Discussion

The findings suggest that monitoring serum immunoglobulin levels post-transplant provides valuable insights into the degree of immunosuppression. Hypogammaglobulinemia during the early post-transplant period emerges as a critical risk factor for infection, indicating that serum immunoglobulins could serve as feasible biomarkers for assessing infection risk in kidney transplant recipients.

Comparative Analysis of Clinical Outcomes for COVID-19 and Influenza among Cardiac Transplant Recipients in the United States

COVID-19 infections can lead to worse outcomes in an immunocompromised population with multiple comorbidities, e.g., heart transplant patients. We used the National Inpatient Sample database to compare heart transplant outcomes in patients with COVID-19 vs. influenza. A total of 2460 patients were included in this study: heart transplant with COVID-19 (n = 1155, 47.0%) and heart transplant with influenza (n = 1305, 53.0%) with the primary outcome of in-hospital mortality. In-hospital mortality (n = 120) was significantly higher for heart transplant patients infected with COVID-19 compared to those infected with influenza (9.5% vs. 0.8%, adjusted OR: 51.6 [95% CI 4.3-615.9], p = 0.002) along with significantly higher rates of mechanical ventilation, acute heart failure, ventricular arrhythmias, and higher mean total hospitalization cost compared to the influenza group. More studies are needed on the role of vaccination and treatment to improve outcomes in this vulnerable population.

Hypogammaglobulinemia in pediatric kidney transplant recipients

Infections remain the most common cause of hospitalization after kidney transplantation, contributing to significant post-transplant morbidity and mortality. There is a growing body of literature that suggests that immunoglobulins may have a significant protective role against post-transplant infections, although the literature remains sparse, inconsistent, and not well publicized among pediatric nephrologists. Of great concern are data indicating a high prevalence of immunoglobulin abnormalities following transplantation and a possible link between these abnormalities and poorer outcomes. Our educational review focuses on the epidemiology and risk factors for the development of immunoglobulin abnormalities after kidney transplantation, the outcomes in patients with low immunoglobulin levels, and studies evaluating possible interventions to correct these immunoglobulin abnormalities.

Supplementary Role of Immunological Indicators in the Diagnosis and Prognosis of Pneumocystis Pneumonia in Non-HIV Immunocompromised Patients

Background

Pneumocystis pneumonia (PCP) has a high mortality in HIV-negative immunocompromised patients. The occurrence and development of PCP are believed to be correlated with the level of lymphocytes and their subsets. The aim of this study was to determine if the levels of lymphocyte subpopulations and immunoglobulin are associated with PCP.

Methods

A total of 74 immunocompromised patients were enrolled in this single-center cohort study. Diagnosis of PCP was based on the relevant pulmonary symptoms and radiological imaging, and the detection of Pneumocystis jirovecii in BAL fluid or biopsy tissue by metagenomic next-generation sequencing (mNGS). All patients were divided into two groups (PCP group and non-PCP group) and the patients in PCP group were then divided into two groupsbased on the outcome of the disease during the hospitalization.

Results

We observed a significant lower level of IgG (p=0.000) and B lymphocyte counts (p=0.017) in the PCP group comparing to that in the non-PCP group. CD4+ T cell counts, as well as the ratio of CD4+/CD8+ T cells in circulation and BAL fluid were also lower in the PCP group comparing to those in the non-PCP group. Lactate dehydrogenase (LDH) in the PCP group was significantly higher than that in the non-PCP group (p=0.029). In the PCP group, a lower level of total lymphocytes (p=0.004), T cells (p=0.001), CD4+ cells (p=0.001), and CD8+ cells (p=0.007), as well as the proportion of lymphocytes in BAL fluid (p=0.000) were found in deceased patients comparing to those in the survived group.

Conclusion

Our study revealed an important role of humoral immunity in the infection of Pneumocystis jirovecii. The level of B cells and IgG could be used as a supplement to predict the occurrence of PCP. The level of CD4+ and CD8+ lymphocytes was significantly correlated with the outcome of PCP.

Practical guidance for the diagnosis and management of secondary hypogammaglobulinemia: A Work Group Report of the AAAAI Primary Immunodeficiency and Altered Immune Response Committees

Secondary hypogammaglobulinemia (SHG) is characterized by reduced immunoglobulin levels due to acquired causes of decreased antibody production or increased antibody loss. Clarification regarding whether the hypogammaglobulinemia is secondary or primary is important because this has implications for evaluation and management. Prior receipt of immunosuppressive medications and/or presence of conditions associated with SHG development, including protein loss syndromes, are histories that raise suspicion for SHG. In patients with these histories, a thorough investigation of potential etiologies of SHG reviewed in this report is needed to devise an effective treatment plan focused on removal of iatrogenic causes (eg, discontinuation of an offending drug) or treatment of the underlying condition (eg, management of nephrotic syndrome). When iatrogenic causes cannot be removed or underlying conditions cannot be reversed, therapeutic options are not clearly delineated but include heightened monitoring for clinical infections, supportive antimicrobials, and in some cases, immunoglobulin replacement therapy. This report serves to summarize the existing literature regarding immunosuppressive medications and populations (autoimmune, neurologic, hematologic/oncologic, pulmonary, posttransplant, protein-losing) associated with SHG and highlights key areas for future investigation.

Pneumocystis pneumonia with hypogammaglobulinemia in a pediatric patient who underwent heart transplantation

A 23-month-old Caucasian female who had heart transplantation (HT) at 11 days of age was diagnosed with Pneumocystis pneumonia (PCP) in the setting of secondary hypogammaglobulinemia (HGG). She was diagnosed with HGG at 5 months of age and had been receiving monthly intravenous immunoglobulin infusion. This is the first case report describing the clinical course of PCP in a pediatric patient with HGG. She developed PCP 23 months after HT even when she was off steroids and was receiving timely IVIG. The case posed some clinical questions regarding PCP prophylaxis and HGG management.

Hypogammaglobulinemia following heart transplantation: Prevalence, predictors, and clinical importance

Hypogammaglobulinemia (HGG) can occur following solid organ transplantation. However, there are limited data describing the prevalence, risk factors, and clinical outcomes associated with HGG following heart transplantation. We retrospectively reviewed data of 132 patients who had undergone heart transplantation at our institution between April 2014 and December 2018. We classified patients into three groups based on the lowest serum IgG level post-transplant: normal (≥700 mg/dL), mild HGG (≥450 and <700 mg/dL), and severe HGG (<450 mg/dL). We compared clinical outcomes from the date of the lowest IgG level. Mean age was 57 (47, 64) years, and 94 (71%) patients were male. Prevalence of severe HGG was the highest (27%) at 3-6 months following heart transplantation and then decreased to 5% after 1 year. Multivariate analysis showed that older age and Caucasian race were independent risk factors for HGG. Overall survival was comparable between the groups; however, survival free of infection was 73%, 60%, and 45% at 1 year in the normal, mild HGG, and severe HGG groups, respectively (P = .013). In conclusion, there is a high prevalence of HGG in the early post-heart transplant period that decreases over time. HGG is associated with an increased incidence of infection.

Acquired hypogammaglobulinemia and pathogen-specific antibody depletion after solid organ transplantation in human immunodeficiency virus infection: A brief report

Hypogammaglobulinemia (HGG) frequently occurs in recipients after types of (SOT). The incidence and significance of HGG in HIV+ recipients of SOT are just being explored. We reported that 12% of the recipients in the SOT in multi-center HIV-TR (HIV-TR) Study developed moderate or severe HGG at 1 year. In LT recipients, this was associated with serious infections and death. We have now further characterized the decreased antibodies in HIV+ SOT recipients who developed HGG. We measured the levels of pathogen-specific antibodies and poly-specific self-reactive antibodies (PSA) in relation to total IgG levels from serial serum samples for 20 HIV+ SOT recipients who developed moderate to severe HGG following SOT. Serum antibody levels to measles, tetanus toxoid, and HIV-1 were determined by EIA. Levels of PSAs were determined by incubating control lymphocytes with patient serum, staining with anti-human IgG Fab-FITC, and analysis by flow cytometry. Levels of PSA were higher compared to healthy, HIV-uninfected controls at pre-transplant baseline and increased by weeks 12 and 26, but the changes were not significant. Likewise, anti-HIV antibody levels remained unchanged over time. In contrast, antibody levels against measles and tetanus were significantly reduced from baseline by week 12, and did not return to baseline, even after 2 years. For HIV patients who develop moderate to severe HGG after transplant, the reduction in IgG levels is associated with a significant decrease in pathogen-specific antibody titers, while PSA levels and anti-HIV antibodies are unchanged. This may contribute to infectious complications and other clinical endpoints.

Clinical outcomes of polyvalent immunoglobulin use in solid organ transplant recipients: A systematic review and meta-analysis - Part II: Non-kidney transplant

Immunoglobulin (IG) is commonly used to desensitize and treat antibody-mediated rejection in solid organ transplant (SOT) recipients. The impact of IG on other outcomes such as infection, all-cause mortality, graft rejection, and graft loss is not clear. We conducted a similar systematic review and meta-analysis to our previously reported Part I excluding kidney transplant. A comprehensive literature review found 16 studies involving the following organ types: heart (6), lung (4), liver (4), and multiple organs (2). Meta-analysis could only be performed on mortality outcome in heart and lung studies due to inadequate data on other outcomes. There was a significant reduction in mortality (OR 0.34 [0.17-0.69]; 4 studies, n = 455) in heart transplant with hypogammaglobulinemia receiving IVIG vs no IVIG. Mortality in lung transplant recipients with hypogammaglobulinemia receiving IVIG was comparable to those of no hypogammaglobulinemia (OR 1.05 [0.49, 2.26]; 2 studies, n = 887). In summary, IVIG targeted prophylaxis may decrease mortality in heart transplant recipients as compared to those with hypogammaglobulinemia not receiving IVIG, or improve mortality to the equivalent level with those without hypogammaglobulinemia in lung transplant recipients, but there is a lack of data to support physicians in making decisions around using immunoglobulins in all SOT recipients for infection prophylaxis.

Enteroviruses and Parechoviruses

Infections with enteroviruses and human parechoviruses are highly prevalent, particularly in neonates, where they may cause substantial morbidity and mortality. Individuals with B-cell-related immunodeficiencies are at risk for severe enteroviral infections, usually a chronic and fatal meningoencephalitis. In transplant recipients and patients with malignancy, enterovirus infections typically involve the respiratory tract, but cases of severe, disseminated infection have been described. The mainstay of diagnosis for enterovirus and human parechovirus infections involves the use of molecular diagnostic techniques. However, routine nucleic acid-detection methods for enteroviruses will not detect human parechoviruses. Laboratory diagnosis of these viral infections is important in determining a patient's prognosis and guiding clinical management.

Evaluation of humoral immunity profiles to identify heart recipients at risk for development of severe infections: A multicenter prospective study

BACKGROUND

New biomarkers are necessary to improve detection of the risk of infection in heart transplantation. We performed a multicenter study to evaluate humoral immunity profiles that could better enable us to identify heart recipients at risk of severe infections.

METHODS

We prospectively analyzed 170 adult heart recipients at 8 centers in Spain. Study points were before transplantation and 7 and 30 days after transplantation. Immune parameters included IgG, IgM, IgA and complement factors C3 and C4, and titers of specific antibody to pneumococcal polysaccharide antigens (anti-PPS) and to cytomegalovirus (CMV). To evaluate potential immunologic mechanisms leading to IgG hypogammaglobulinemia, before heart transplantation we assessed serum B-cell activating factor (BAFF) levels using enzyme-linked immunoassay. The clinical follow-up period lasted 6 months. Clinical outcome was need for intravenous anti-microbials for therapy of infection.

RESULTS

During follow-up, 53 patients (31.2%) developed at least 1 severe infection. We confirmed that IgG hypogammaglobulinemia at Day 7 (defined as IgG <600 mg/dl) is a risk factor for infection in general, bacterial infections in particular, and CMV disease. At Day 7 after transplantation, the combination of IgG <600 mg/dl + C3 <80 mg/dl was more strongly associated with the outcome (adjusted odds ratio 7.40; 95% confidence interval 1.48 to 37.03; p = 0.014). We found that quantification of anti-CMV antibody titers and lower anti-PPS antibody concentrations were independent predictors of CMV disease and bacterial infections, respectively. Higher pre-transplant BAFF levels were a risk factor of acute cellular rejection.

CONCLUSION

Early immunologic monitoring of humoral immunity profiles proved useful for the identification of heart recipients who are at risk of severe infection.

Evaluation of an immunological score to assess the risk of severe infection in heart recipients

BACKGROUND

We previously reported how specific humoral and cellular immunological markers that are readily available in clinical practice can be used to identify heart transplant recipients (HTR) at risk of developing severe infections. In this study, we perform an extended analysis to identify immunological profiles that could prove to be superior to individual markers in assessing the risk of infection early after heart transplantation.

METHODS

In a prospective follow-up study, we evaluated 100 HTR at 1 week after transplantation. Laboratory tests included determination of immunoglobulin (Ig) levels (IgG, IgA, IgM), complement factors (C3 and C4), and lymphocyte subsets (CD3+, CD4+, CD8+ T cells, B cells, and natural killer [NK] cells). The prevalence of infection during the first 3 months was registered at scheduled visits after transplantation. Severe infections were defined as all infections requiring hospitalization and intravenous antimicrobial therapy.

RESULTS

During follow-up, 33 patients (33%) developed severe infections. The individual risk factors of severe infection, according to the Cox regression analysis, were as follows: IgG <600 mg/dL (hazard ratio [HR], 2.41; 95% confidence interval [CI], 1.21-4.78; P = 0.012), C3 <80 mg/dL (HR, 4.65; 95% CI, 2.31-9.38; P < 0.0001), C4 <18 mg/dL (HR 2.30, 95% CI, 1.15-4.59; P = 0.018), NK count <30 cells/μL (HR 4.07, 95% CI, 1.76-9.38; P = 0.001), and CD4 count <350 cells/μL (HR, 3.04; 95% CI, 1.47-6.28; P = 0.0027). An immunological score was created. HRs were used to determine the number of points assigned to each of the 5 previously mentioned individual risk factors. The score was obtained from the sum of these factors. In the multivariate Cox regression analysis, the immunological score was useful for identifying patients at risk of infection and was the only variable that maintained a significant association with the development of infection, after adjustment for the 5 individual factors.

CONCLUSION

Patients with an immunological score ≥13 were at the highest risk of severe infections (HR, 9.29; 95% CI, 4.57-18.90; P < 0.0001). This score remained significantly associated with the risk of severe infection after adjustment for clinical risk factors of infection. An immunological score was useful for identifying HTR at risk of developing severe infections. If this score is validated in multicenter studies, it could be easily introduced into clinical practice.

Intravenous immunoglobulin for hypogammaglobulinemia after lung transplantation: a randomized crossover trial

Background

We aimed to determine the effects of treatment with intravenous immunoglobulin on bacterial infections in patients with hypogammaglobulinemia (HGG) after lung transplantation.

Methods

We performed a randomized, double-blind, placebo-controlled two-period crossover trial of immune globulin intravenous (IVIG), 10% Purified (Gamunex, Bayer, Elkhart, IN) monthly in eleven adults who had undergone lung transplantation more than three months previously. We randomized study participants to three doses of IVIG (or 0.1% albumin solution (placebo)) given four weeks apart followed by a twelve week washout and then three doses of placebo (or IVIG). The primary outcome was the number of bacterial infections within each treatment period.

Results

IVIG had no effect on the number of bacterial infections during the treatment period (3 during IVIG and 1 during placebo; odds ratio 3.5, 95% confidence interval 0.4 to 27.6, p = 0.24). There were no effects on other infections, use of antibiotics, or lung function. IVIG significantly increased trough IgG levels at all time points (least square means, 765.3 mg/dl during IVIG and 486.3 mg/dl during placebo, p<0.001). Four serious adverse events (resulting in hospitalization) occurred during the treatment periods (3 during active treatment and 1 during the placebo period, p = 0.37). Chills, flushing, and nausea occurred during one infusion of IVIG.

Conclusions

Treatment with IVIG did not reduce the short-term risk of bacterial infection in patients with HGG after lung transplantation. The clinical efficacy of immunoglobulin supplementation in HGG related to lung transplantation over the long term or with recurrent infections is unknown.

Trial Registration

Clinicaltrials.gov NCT00115778

Clinical immune-monitoring strategies for predicting infection risk in solid organ transplantation

Infectious complications remain a leading cause of morbidity and mortality after solid organ transplantation (SOT), and largely depend on the net state of immunosuppression achieved with current regimens. Cytomegalovirus (CMV) is a major opportunistic viral pathogen in this setting. The application of strategies of immunological monitoring in SOT recipients would allow tailoring of immunosuppression and prophylaxis practices according to the individual's actual risk of infection. Immune monitoring may be pathogen-specific or nonspecific. Nonspecific immune monitoring may rely on either the quantification of peripheral blood biomarkers that reflect the status of a given arm of the immune response (serum immunoglobulins and complement factors, lymphocyte sub-populations, soluble form of CD30), or on the functional assessment of T-cell responsiveness (release of intracellular adenosine triphosphate following a mitogenic stimulus). In addition, various methods are currently available for monitoring pathogen-specific responses, such as CMV-specific T-cell-mediated immune response, based on interferon-γ release assays, intracellular cytokine staining or main histocompatibility complex-tetramer technology. This review summarizes the clinical evidence to date supporting the use of these approaches to the post-transplant immune status, as well as their potential limitations. Intervention studies based on validated strategies for immune monitoring still need to be performed.

Adenovirus infections in heart transplantation

Adenovirus infections have been associated with significant morbidity and mortality in immunocompromised hosts. The clinical significance of adenovirus disease in heart transplantation is not well-defined; in particular, the significance of adenovirus identification in myocardium remains unclear. Although severe adenovirus disease has been described in heart transplant recipients, adenovirus infections seem to be more frequently associated with increased risk of adverse cardiac events, such as rejection, ventricular dysfunction, coronary vasculopathy, need for retransplantation, and graft loss because of death. Cidofovir is currently considered the standard of treatment for adenovirus disease not responding to reduction of immunosuppression.

Acquired hypogammaglobulinemia in HIV-positive subjects after liver transplantation

INTRODUCTION

As more solid organ transplantations are performed in patients infected with human immunodeficiency virus (HIV), post-transplant complications in this population are becoming better defined.

METHODS

Using serum samples from the Solid Organ Transplantation in HIV: Multi-Site Study, we studied the epidemiology of acquired hypogammaglobulinemia (HGG) after liver transplantation (LT) in 79 HIV-infected individuals with a median CD4 count at enrollment of 288 (interquartile range 200-423) cells/μL. Quantitative immunoglobulin G (IgG) levels before and after LT were measured, with moderate and severe HGG defined as IgG 350-500 mg/dL and <350 mg/dL, respectively. Incidence, risk factors, and associated outcomes of moderate or worse HGG were evaluated using Kaplan-Meier estimator and proportional hazards (PH) models.

RESULTS

The 1-year cumulative incidence of moderate or worse HGG was 12% (95% confidence interval [CI]: 6-22%); no new cases were observed between years 1 and 2. In a multivariate PH model, higher pre-transplant model for end-stage liver disease score (P = 0.04) and treated acute rejection (P = 0.04) were both identified as significant predictors of moderate or worse HGG. There was a strong association of IgG levels <500 mg/dL with non-opportunistic serious infection (hazard ratio [95% CI]: 3.5 [1.1-10.6]; P = 0.03) and mortality (3.2 [1.1-9.4]; P = 0.04). These associations held after adjustment for important determinants of infection and survival among the entire cohort.

CONCLUSION

These results suggest that a proportion of HIV-positive LT recipients will develop clinically significant HGG after transplantation.

Incidence, timing, and significance of early hypogammaglobulinemia after intestinal transplantation

BACKGROUND

Despite recent advances in intestinal transplantation (ITx), infection (INF) and acute cellular rejection (ACR) remain major causes of patient and graft loss. Studies in other solid-organ transplantations indicate that low levels of serum immunoglobulin G (IgG) negatively impact outcomes. To date, there have been no studies on IgG after ITx.

METHODS

A retrospective review of an IgG measurement protocol in primary ITx recipients between 2007 and 2011 was undertaken. IgG levels were measured at the time of evaluation, transplantation, and at weekly intervals for 2 months. Hypogammaglobulinemia (HGG) was defined as IgG levels below the lower limit of the 95% confidence interval for age. Associations between HGG, INF, and ACR were tested, and the incidence and timing of INF and ACR were compared.

RESULTS

Thirty-four patients were transplanted at a mean (SD) age of 12.4 (17.2) years. Most were Latino children with gastroschisis who received multivisceral grafts. Relative to pre-ITx levels, a statistically significant decrease in IgG levels was observed after ITx (P<0.05). Twenty patients (59%) developed HGG during the post-ITx period at a mean (SD) of 9.8 days. No significant associations were identified between HGG and INF or ACR.

CONCLUSIONS

This is the first study to describe serum IgG levels after ITx. A marked decrease in serum IgG levels was observed early on, in most patients. The etiology is potentially related to immunotherapy. HGG was not associated with INF or ACR, possibly related to the sample size and our practice of exogenous intravenous immunoglobulin replacement.

Effect of hypogammaglobulinemia on the incidence of community-acquired respiratory viral infections after lung transplantation

BACKGROUND

Hypogammaglobulinemia (HGG) has been associated with an increased risk of infectious complications in lung transplant recipients, but its effect specifically on community-acquired respiratory viruses (CARVs) remains unknown. This study aimed to determine if lung transplant recipients with HGG are at an increased risk of developing CARV infection. Secondary endpoints included the effect of HGG on lung function, incidence of rejection, and mortality.

METHODS

A retrospective review of all lung transplant recipients from 2008 to 2011 was performed. Patients were stratified as either having HGG after transplantation or having normal IgG titers according to their nadir IgG level. HGG was defined a serum IgG level of <700 mg/dL. CARVs included human metapneumovirus, influenza A/B, respiratory syncytial virus A/B, parainfluenza 1/2/3, rhinovirus, and adenovirus isolated from bronchoalveolar lavage/wash, sputum, or nasal swab.

RESULTS

The cohort consisted of 263 patients with a mean follow-up time of 612 ± 356 days. The incidence of CARV infection was 27% in patients with normal IgG titers and 23.4% in patients with HGG (P = .62). No difference in rejection, mortality, or lung function was found between the groups. As expected, patients who ever had a CARV infection had a significantly lower 1-second forced expiratory volume % reference on their most recent spirometry than those who had not had a CARV infection (81.6% vs 86.9%; P = .027).

CONCLUSIONS

Although CARV infection has been shown to affect lung graft function, these data suggests that HGG is not associated with the incidence of CARV infection.

Comprehensive immune monitoring reveals profound immunological changes in pancreas after kidney (PAK) transplant recipients

Pancreas transplantation is a therapeutic option for the management of complicated Type 1 diabetes mellitus. While standard protocols include use of induction therapy followed by maintenance immunosuppression, the amount, frequency and duration of induction treatment has not been clearly defined. While the effect of various induction regimens on lymphocytes has been demonstrated, a prospective immune monitoring approach is not widely used to determine "immunological titration" of immunosuppression. In this study, we analyzed a patient cohort with pancreas after kidney transplantation and measured a wide range of quantitative and functional T and B cell parameters to identify those that would provide greatest value in personalized prospective immune assessment and design of immunosuppression. While there were significant quantitative differences observed in the 2 groups of PAK patients for various lymphocyte subsets, the notable observation was that lymphocyte subset quantitation was uninformative with regard to T cell function. Patients with normal lymphocyte counts had impaired T cell functional responses and vice versa. The use of immune monitoring to determine optimal IS regimens needs to be studied further to facilitate personalized management of immunosuppression with reduced risk of allograft rejection in PAK, and limited morbidity and mortality related to infection and malignancy.

Monitoring of immunoglobulin levels identifies kidney transplant recipients at high risk of infection

We aimed to analyze the incidence, risk factors and impact of hypogammaglobulinemia (HGG) in 226 kidney transplant (KT) recipients in which serum immunoglobulin (Ig) levels were prospectively assessed at baseline, month 1 (T(1) ), and month 6 (T(6) ). The prevalence of IgG HGG increased from 6.6% (baseline) to 52.0% (T(1) ) and subsequently decreased to 31.4% (T(6) ) (p < 0.001). The presence of IgG HGG at baseline (odds ratio [OR] 26.9; p = 0.012) and a positive anti-HCV status (OR 0.17; p = 0.023) emerged as risk factors for the occurrence of posttransplant IgG HGG. Patients with HGG of any class at T(1) had higher incidences of overall (p = 0.018) and bacterial infection (p = 0.004), bacteremia (p = 0.054) and acute pyelonephritis (p = 0.003) in the intermediate period (months 1-6). Patients with HGG at T(6) had higher incidences of overall (p = 0.004) and bacterial infection (p < 0.001) in the late period (>6 month). A complementary log-log model identified posttransplant HGG as an independent risk factor for overall (hazard ratio [HR] 2.03; p < 0.001) and bacterial infection (HR 2.68; p < 0.0001). Monitoring of humoral immunity identifies KT recipients at high risk of infection, offering the opportunity for preemptive immunoglobulin replacement therapy.

[Risk factors for cytomegalovirus in solid organ transplant recipients]

Cytomegalovirus (CMV) is the most important opportunistic pathogen in patients undergoing solid organ transplantation and increases mortality due to both direct and indirect effects. The most important risk factor for the development of CMV disease is discordant donor-recipient CMV serology (positive donor and negative recipient), which confers more than 50% risk of developing CMV disease if no prophylaxis is given. The use of highly potent antiviral agents for CMV prophylaxis in high-risk patients has changed the characteristics of CMV disease in this population. Other classical risk factors for CMV disease include acute graft rejection, the type of organ transplanted, coinfection with other herpesviruses and the type of immunosuppressive agents employed. New risk factors for this complication have recently been described, including variations in the CMV genotype between donor and recipient and genetic alterations in the recipient's innate immunity. The present review discusses classical risk factors and the latest findings reported on the development of CMV in organ transplant recipients.

Immunological risk factors for infection after immunosuppressive and biologic therapies

Immunosuppressive and biologic therapies are costly and can involve a considerable risk of infection. Noninvasive diagnostic tools for early prediction of infection before and after administration of these therapies are of major interest. Serial longitudinal immune monitoring would provide data on immunocompetence and complement clinical follow-up protocols. Biomarkers of immune response may be useful to identify patients at risk of developing infection and who could be candidates for immunosuppressant dose reduction. This article focuses on the potential use of biomarkers of immune response to predict development of infection after immunosuppressive and biologic therapies in selected settings of autoimmune disease (rituximab for treatment of rheumatoid arthritis) and solid organ transplantation.

Hypogammaglobulinemia: Incidence, risk factors, and outcomes following pediatric lung transplantation

Infection is the leading cause of morbidity and mortality in the first year following lung transplantation. HG after adult lung transplantation has been associated with increased infections and hospitalization as well as decreased survival. The purpose of this study is to define the incidence, risk factors, and outcomes of HG in the first year following pediatric lung transplantation. A retrospective review of all lung transplant recipients at a single pediatric center over a four-yr period was performed. All serum Ig levels drawn within one yr of transplantation were recorded. An association between HG during the first year after transplantation and age, race, gender, diagnosis leading to transplantation and clinical outcomes including hospitalization, infections requiring hospitalization, viremia, fungal recovery from BAL lavage, and mortality was sought. HG was defined using age-based norms. Fifty-one charts were reviewed. Mean (+/-s.d.) post-transplantation levels for IgG, IgA, and IgM were 439.9 +/- 201.3, 82.3 +/- 50.2, and 75.2 +/- 41.4 mg/dL, respectively. HG was present in 48.8%, 12.2%, and 17.1% of patients for IgG, IgA, and IgM, respectively. Patients with HG for IgG were older (14.3 +/- 3.8 vs. 9.2 +/- 5.4 yr; p < 0.01). IgA and IgM HG were associated with invasive aspergillosis (p < 0.01 and p = 0.05, respectively). IgG and IgM levels inversely correlated with bacterial infections and hospital days, respectively (p < 0.01, p < 0.05). HG is a frequent complication following pediatric lung transplantation. Low Ig levels are associated with increased infections and hospital stay.

Hypogammaglobulinemia and infection risk in solid organ transplant recipients

PURPOSE OF REVIEW

Hypogammaglobulinemia may develop as a result of a number of immune deficiency syndromes that can be devastating. This review article explores the risk of infection associated with hypogammaglobulinemia in solid organ transplantation and discusses therapeutic strategies to alleviate such a risk.

RECENT FINDINGS

Hypogammaglobulinemia is associated with increased risk of opportunistic infections, particularly during the 6-month posttransplant period when viral infections are most prevalent. The preemptive use of immunoglobulin replacement results in a significant reduction of opportunistic infections in patients with moderate and severe hypogammaglobulinemia.

SUMMARY

Monitoring immunoglobulin G levels may aid in clinical management of solid organ transplant recipients. The preemptive use of immunoglobulin replacement may serve as a new strategy for managing solid organ transplant recipients with hypogammaglobulinemia.

Immune monitoring of anti cytomegalovirus antibodies and risk of cytomegalovirus disease in heart transplantation

We sought to determine whether quantitative assessment of anti-cytomegalovirus (CMV) antibodies could be useful to identify patients at risk of cytomegalovirus (CMV) disease after heart transplantation (HT). 75 patients who underwent HT at a single health care center were prospectively studied. Induction therapy included 2 doses of daclizumab and maintenance tacrolimus (n=42) or cyclosporine (n=29), mycophenolate mofetil and prednisone. All patients received prophylaxis with gancyclovir or valganciclovir. Anti-CMV intravenous immunoglobulin (CMV-IG) was added in high risk patients (CMV D+/R- serostatus). Serial determinations of anti-CMV antibodies, immunoglobulins (IgG, IgA, IgM) and IgG-subclasses were analysed. CMV infection was based on detection of the virus by antigenemia. CMV disease consisted of detection of signs or symptoms attributable to this microorganism. Ten patients (13.3%) developed CMV disease. Mean time of development of CMV disease was 3.4+/-1.6 months. In Cox regression analysis, patients with low baseline anti-CMV titers (<4.26 natural logarithm of titer, RH: 8.1, 95%CI: 1.93-34.1, p=0.004) and recipients with 1-month post-HT IgG hypogammaglobulinemia (IgG<500 mg/dl, RH: 4.49, 95%CI: 1.26-15.94, p=0.02) were at higher risk of having CMV disease. Despite use of prophylactic CMV-IG, D+/R- patients showed significantly lower titers of anti-CMV antibodies at 7 d, 30 d and 90 d post HT as compared with HT recipients without infections. Four out of 6 of these patients developed late CMV disease. Monitoring of specific anti-CMV antibodies on the bedside warrants further evaluation as a potential tool to identify heart transplant recipients at higher risk of CMV disease.

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.

Hypogammaglobulinemia in a pediatric tertiary care setting

Hypogammaglobulinemia has been described as a secondary consequence of many disorders. It is also the seminal finding in many primary immune deficiencies. There are few studies examining the global etiologies of hypogammaglobulinemia. This study undertook a database discovery of all cases of laboratory-defined hypogammaglobulinemia identified in a large tertiary care pediatric hospital setting between August of 1990 until June of 2006. Eight thousand three hundred and four IgG levels were sent during that time frame. One thousand two hundred and ninety-five specimens from 680 individual patients exhibited hypogammaglobulinemia and these patients represent the study population. The majority of cases in whom an identifiable cause was found had pre-existing conditions and the IgG level was sent as part of a monitoring process. Of the 366 patients who had an IgG level obtained for diagnostic purposes, nearly half were found to have an immune deficiency. One hundred and seventy-two patients with an immune deficiency were identified. Seven percent of these had severe combined immune deficiency. Seventy-four percent of the immune deficient patients identified required active intervention with IVIG, bone marrow transplantation or other management (not including prophylactic antibiotics). Evaluating all patients with IgG levels less than half of the lower limit for age revealed 122 patients of whom 33% had a primary immune deficiency. This study provides a framework for considering causes of hypogammaglobulinemia. At the study institution, hypogammaglobulinemia was found most often as a secondary immune deficiency due to chemotherapy or from complex cardiac anomalies. The magnitude of the secondary hypogammaglobulinemia in a tertiary care setting requires public health consideration as these patients have an unknown risk of infection and an unknown risk of prolonged viral shedding; issues which could be important in epidemic settings.

Evolution of immunoglobulin and mannose binding protein levels after renal transplantation: association with infectious complications

Hypogammaglobulinemia (hypo-Ig) and low mannose binding protein (MBP) levels might be involved in the infectious risk in renal transplantation. In 152 kidney transplant recipients treated with calcineurin inhibitors (CNI) and mycophenolate mofetil (MMF), during the first year, we prospectively recorded the incidence of hypogammaglobulinemia, and low MBP levels. Their influence on infectious complications was evaluated in 92 patients at 3 and 12 months (T3 and T12). The proportion of deficiency increased significantly: hypo-IgG: 6% (T0), 45% (T3), and 30% (T12) (P < 0.001); hypo-MBP: 5%, 11%, and 12% (P = 0.035). Hypo-IgG at T3 was not associated with an increased incidence of first-year infections. A significantly higher proportion of patients with combined hypogammaglobulinemia [IgG+ (IgA and/or IgM)] at T3 and with isolated hypo-IgG at T0 developed infections until T3 compared with patients free of these deficits (P < 0.05). Low MBP levels at T3 were associated with more sepsis and viral infections. Hypogammaglobulinemia is frequent during the first year after renal transplantation in patients treated with a CNI and MMF. Hypo-IgG at T0 and combined Igs deficts at T3 were associated with more infections. MBP deficiency might emerge as an important determinant of the post-transplant infectious risk.

Clostridium difficile–associated Diarrhea in Heart Transplant Recipients: Is Hypogammaglobulinemia the Answer?

BACKGROUND

Information regarding Clostridium difficile-associated diarrhea (CDAD) after solid-organ transplantation (SOT) is scarce, particularly after heart transplantation (HT). Although host immune response to C. difficile plays a substantial role in the outcome of this infection, the responsibility of hypogammaglobulinemia (HGG) as a predisposing condition for CDAD has not been studied in SOT. We analyzed the incidence, clinical presentation, outcome and risk factors, including HGG, of CDAD after HT.

METHODS

Two hundred thirty-five patients who underwent HT (1993 to 2005) were included. Transplantation procedure and immunosuppression were standard. From January 1999 HGG was systematically searched and corrected when IgG levels were <400 mg/dl or severe infection was present. Toxin-producing C. difficile was detected by means of cytotoxin assay and culture of stool samples. Patients with and without CDAD were compared for identification of risk factors.

RESULTS

CDAD was detected in 35 patients (14.9%). Incidence decreased significantly since HGG was sought and treated: 29 (20.6%) in the first period, and 6 (6.4%) in the second (p = 0.003). CDAD appeared a mean of 32 days (range 5 to 3,300 days) after HT. No related death or episode of fulminant colitis was detected. At least one episode of recurrence was noted in 28.6% of patients. Severe HGG was found to be the only independent risk factor for CDAD after HT (RR 5.8; 95% CI: 1.05 to 32.1; p = 0.04).

CONCLUSIONS

C. difficile is a significant cause of diarrhea in HT recipients and post-transplant HGG is independently associated with an increased risk. The potential role of immunoglobulin administration in this population requires further study.

The Potential Impact of Substitutive Therapy With Intravenous Immunoglobulin on the Outcome of Heart Transplant Recipients With Infections

Hypogammaglobulinemia has been proposed to be a risk factor for infection after heart transplantation (OHT). Infection is a leading cause of morbility and mortality among these patients. In a retrospective study we analyzed the impact of substitutive therapy with nonspecific intravenous immunoglobulin (IVIG) on the outcomes of heart transplant patients with infections. We analyzed the outcome of 123 consecutive heart transplant recipients in our center from June 1996 to November 2005. Their mean age was 53 years (range = 22 to 69 years), and the mean follow-up = 51 months, (range = 1 to 124 months). Twenty-nine patients with hypogammaglobulinemia (mean serum immunoglobulin G levels = 480 mg/dL) experienced severe infections due to cytomegalovirus (CMV) disease, n = 4; CMV disease + another infection, n = 6; CMV infection, n = 4; CMV infection + other infection, n = 3; pulmonary nocardiosis, n = 2; recurrent pneumonia, n = 2; clostridium-difficile-associated diarrhea, n = 2; pulmonary tuberculosis, n = 1; bacterial infections, n = 5. They were treated with IVIG (400 mg/kg every 21 days) with the goal to reach normal serum immunoglobulin G levels (>700 mg/dL). Overall (n = 123), a logistic regression analysis showed IVIG therapy to be associated with a decreased risk of death [odds ratio (OR) = 0.204, 95% confidence interval (CI) = 0.04 to 0.92, P = .03]. Among patients who developed infections during follow-up (n = 70), IVIG therapy was also associated with a lower risk of death (OR = 0.104, CI = 0.02 to 0.50, P = .0047). When we stratified patients with CMV disease (n = 24) according to the presence (n = 10) or absence (n = 14) of IVIG therapy, the mortality rate of IVIG-treated patients was 20% versus 71% for non-IVIG treated patients [OR = 0.06, CI = 0.0060 to 0.63, P = .01]. The use of nonspecific IVIG in OHT with hypogammaglobulinemia and infections might reduce the risk of death. Randomized studies in a larger cohort of patients are necessary to confirm these results.

The Impact of Hypogammaglobulinemia on Infection Outcome in Patients Undergoing Ventricular Assist Device Implantation

BACKGROUND

Infection is a major comorbidity after ventricular assist device (VAD) placement. Defects in cellular immunity have been reported after VAD placement. However, to our knowledge, quantitative immunoglobulin G (IgG) level determination and the impact of hypogammaglobulinemia (HGG) on infections after VAD implantation have not been evaluated before.

METHODS

A total of 76 patients (mean age, 53 years) underwent VAD implantation as a bridge to transplantation and had IgG levels determined as a baseline before transplantation. Patients were divided into 2 groups according to IgG level: Control Group (n = 56, IgG > or = 700 mg/dl) and HGG Group (n = 20, IgG < 700 mg/dl). Infection outcome during the VAD course and after transplantation was analyzed in relation to the IgG level.

RESULTS

Baseline characteristics were similar in both groups. The incidence of bacteremia (14/20 [70%] vs 18/56 [32%], p = 0.0032) and major infection (19/20 [95%] vs 31/56 [56%], p = 0.0009) were significantly increased in the HGG Group compared with the Control Group. After transplantation, the episodes of rejection were similar in both groups and survival was similar. The HGG Group experienced more cytomegalovirus infections compared with the Control Group (9/20 [45%] vs 9/56 [16%], p = 0.009).

CONCLUSIONS

VAD patients with HGG are at increased risk of infections. After transplantation, these patients also experience increased cytomegalovirus infections. A randomized preemptive IgG replacement trial may be warranted in the future to determine if this intervention will alleviate the risk of infection.

Immunoglobulin G levels before and after lung transplantation

RATIONALE

The determinants of immunoglobulin G (IgG) level and the risk of hypogammaglobulinemia (HGG) in patients with severe lung disease before and after lung transplantation are unknown.

OBJECTIVES

We aimed to identify predictors of low IgG levels before and after lung transplantation.

METHODS

We performed a retrospective cohort study of 40 consecutive lung transplant recipients at our center. Total IgG levels were measured before and serially after transplantation. Mild HGG was defined as IgG levels from 400-699 mg/dl; severe HGG was defined as IgG levels<400 mg/dl.

MEASUREMENTS AND MAIN RESULTS

Before transplantation, six (15%) patients had mild HGG, and none had severe HGG. Patients with chronic obstructive pulmonary disease had lower IgG levels compared with patients with other diseases (independent of corticosteroid use and age; p=0.001) and an increased risk of mild HGG (p=0.005). The cumulative incidences of mild and severe HGG significantly increased after transplantation (58 and 15%, respectively, both p<0.04 compared with pretransplant prevalences). Lower pretransplant IgG level and treatment with mycophenolate mofetil were associated with lower IgG levels after transplantation (both p<0.05). Only lower pretransplant IgG levels were significantly associated with an increased risk of severe HGG after transplantation (p=0.02).

CONCLUSIONS

Mild HGG is common in patients with severe chronic obstructive pulmonary disease, and the incidences of mild and severe HGG increase significantly early after lung transplantation. Baseline IgG levels and treatment with mycophenolate mofetil affect post-transplant IgG levels.

Hypogammaglobulinemia in Liver Transplant Recipients: Incidence, Timing, Risk Factors, and Outcomes

BACKGROUND

Recent studies suggest a substantial incidence of posttransplant hypogammaglobulinemia and an association with infection.

METHODS

We conducted a retrospective analysis of immunoglobulin (Ig) G levels from blood prospectively collected during a randomized double-blind placebo-controlled trial of cytomegalovirus (CMV) immune globulin that included 146 patients who underwent liver transplantation between December 1987 and June 1990. Serum samples collected at baseline and approximately weeks 4, 8, 12, 16, 24, and 32 posttransplant were analyzed. Hypogammaglobulinemia was defined as having at least one IgG level below 560 mg/dl. A variety of variables were analyzed as potential risk factors and outcomes of hypogammaglobulinemia.

RESULTS

A total of 613 samples from 112 patients were analyzed. Twenty-nine (26%) patients had posttransplant hypogammaglobulinemia. Fourteen (12.5%) had hypogammaglobulinemia at the time of their baseline measurement. There was a strong association between hypogammaglobulinemia and both one-year (P=0.0490) and five-year mortality (P=0.0187), even when adjusted for variables known to be associated with mortality (HR for one-year mortality 3.08, confidence interval 1.20, 7.91). Risk factors for hypogammaglobulinemia included only non A/non B hepatitis and "other diagnosis" (a category made up of rare causes of liver disease). None of the infectious outcomes examined, including CMV infection, CMV disease, bacteremia or invasive fungal disease, or rejection were significantly associated with hypogammaglobulinemia.

CONCLUSIONS

In orthotopic liver transplant recipients we found a 26% incidence of posttransplant hypogammaglobulinemia. Approximately half of these patients were hypogammaglobulinemic at baseline. A strong association between hypogammaglobulinemia and mortality was seen. Prospective studies are needed to further elucidate the risk factors and outcomes of posttransplant hypogammaglobulinemia.

IgG monitoring to identify the risk for development of infection in heart transplant recipients

Infectious complication represents a significant source of morbidity and mortality in heart transplant recipients. To assess humoral immunity markers that can predict the development of infection, 38 consecutive recipients of heart transplants performed at a single center were prospectively studied. Induction therapy included daclizumab. Immunoglobulin (IgG, IgA, IgM) and complement factors (C3, C4, and factor B) were performed by nephelometry in peripheral blood samples obtained before transplantation, and 7 days and 1 month after transplantation. During a mean follow-up of 16.9 months, 13 patients had at least one episode of infection (34.2%). Eight of these were cytomegalovirus (CMV) infections treated with intravenous ganciclovir, 2 were bacterial pneumonia, 1 patient had bacterial septicemia, 1 patient had urinary tract infection, and 1 patient had pulmonary nocardiosis. No significant association was found between infection and age, sex, immunosuppression, CMV serostatus of donor and recipient, or treated rejection episodes. Pre-transplant IgG (below median value=1140 mg/dL; relative risk [RR] 3.69; 95% confidence interval [CI] 1.01-13.54; P=0.04) and post-transplant IgG levels at day 7 (below median value=679 mg/dL; RR 11.21; CI 1.04-89.48; P=0.022) were associated with an increase in the risk for developing infections. Early monitoring of immunoglobulin levels might help to identify the risk for developing infection in heart transplantation.

Gastrointestinal infections in immunocompromised hosts

PURPOSE OF REVIEW

Gastrointestinal infections in the immunocompromised host continue to have significant morbidity and mortality throughout the world. They all have similar exposures to viruses, bacteria and parasites and respond to these infections in a similar way. This review will summarize the latest reports on the epidemiology, diagnosis and treatment of known and emerging infections over the last 12 months.

RECENT FINDINGS

Highly active antiretroviral therapy has reduced esophageal opportunistic infections in HIV patients compared to patients who are not taking this therapy. Esophageal candidiasis responds to escalating doses of micafungin as effectively as fluconazole. HIV-infected patients with untreated Mycobacterium avium-complex diarrhea are associated with a wasting syndrome that disrupts the somatostatin axis. Polymerase chain reaction testing has improved diagnosis of microsporidial infections. Cytomegalovirus polymerase chain reaction of tissue may improve the diagnosis of cytomegalovirus disease of the gastrointestinal tract in organ-transplant recipients. The treatment of hypogammaglobulinemia in transplant recipients with recurrent cytomegalovirus gastrointestinal disease may resolve their symptoms. Community viruses are an emerging threat to transplant recipients and may affect drug levels. Lastly, anti-tumor necrosis factor alpha therapy in the treatment of inflammatory conditions may cause Listeria monocytogenes to disseminate.

SUMMARY

Immunocompromised hosts remain at risk for severe gastrointestinal and even disseminated infections. Management includes an early rapid diagnosis with rapid restoration of the immune system and appropriate anti-infective therapy. With the immunocompromised population rapidly increasing, prevention of these infections remains the greatest challenge.

High dose intravenous immunoglobulin treatment: mechanisms of action

Intravenous immunoglobulin (IVIg) treatment was introduced as replacement therapy for patients with antibody deficiencies, but evidence suggests that a wide range of immune-mediated conditions could benefit from IVIg. The immunoglobulins are precipitated from human plasma by fractionation methods. In conclusion, the differences in basic fractionation methods and the addition of various modifications for purification, stabilization, and virus inactivation result in products significantly different from each other.

The Impact of CytoGam on Cardiac Transplant Recipients With Moderate Hypogammaglobulinemia: A Randomized Single-Center Study

BACKGROUND

We have previously shown that the preemptive use of cytomegalovirus (CMV) immunoglobulin (Ig) replacement (CytoGam) decreases the incidence of opportunistic infections in cardiac transplant recipients with severe hypogammaglobulinemia. However, the impact of Ig replacement in moderately hypogammaglobulinemic patients is unknown.

METHODS

Periodic monitoring of the IgG levels was done in 300 heart transplant recipients. Moderate hypogammaglobulinemia (IgG, 350-500 mg/dl) developed in 56 patients (18.6%). Thirty-three patients declined randomization but agreed to have their IgG levels monitored. Twenty-three patients were randomized to placebo (n = 10) or CytoGam (n = 13) at 105 +/- 63 days after transplantation.

RESULTS

The baseline characteristics were similar. A significant reduction in CMV infection was noted in the CytoGam Group compared with the Placebo Group (15.4% [2/13] vs 60% [6/10], p = .039). Among patients who declined randomization, CMV infection developed in 13 (39.4%) of 33, and 6 (46.1%) of the 13 progressed to severe hypogammaglobulinemia. A trend for reduction in the average episodes of > or =grade 2 rejection during the 6-month period after randomization was noted in the CytoGam group (0.4 +/- 0.6 vs 1.4 +/- 1.3, p = 0.065).

CONCLUSIONS

The preemptive use of CytoGam decreases the incidence of CMV infection in patients with moderate hypogammaglobulinemia. A larger randomized study is needed to substantiate these results.

Decreased Levels of Serum Immunoglobulins as a Risk Factor for Infection After Heart Transplantation

OBJECTIVE

We aimed to assess humoral immunity markers that provide prognostic value for the development of infections in heart transplant recipients.

PATIENTS AND METHODS

Forty-one heart transplant recipients underwent humoral immunity studies, including Immunoglobulin (IgG, IgA, IgM) and IgG subclasses determined by nephelometry on serum samples obtained before transplantation and 1 month after transplantation. Potential clinical risk factors were evaluated: waiting time for transplantation, pretransplant cytomegalovirus (CMV) serologic status of donor and recipient; recipient age; gender; cardiac disease severity before transplantation; type of immunosuppression; and occurrence of rejection.

OUTCOME MEASURES

We measured infections requiring intravenous (IV) drug therapy during the first year. The association between variables and outcome was assessed using Cox proportional hazards modelling. Immunoglobulin levels were split into two groups using the median value observed as the cut-off.

RESULTS

Of 41 patients studied, 19 (46%) had at least one episode of infection, 16 of which were CMV infections treated with IV gancyclovir, 1 CMV disease + aspergillosis and 2 bacterial pneumonia. Pretransplant IgG (<1055 mg/dL; RR 5.32; 95% confidence interval [CI] 1.73 to 16.29; P = .0034); pretransplant IgG1 (<695 mg/dL; RR 4.80; CI 1.57 to 14.68; P = .006), and posttransplant IgG levels (<589 mg/dL; RR 3.38; CI 1.21 to 9.44, P = .019) were associated with an increased risk of developing infections. Both waiting time for transplantation (RR 0.95; CI 0.91 to 0.98, P = .007) and pretransplant cardiac disease severity (RR 1.94; CI 1.17 to 3.21, P = .009) were significant risk factors for infection. After adjustment for clinical predictive variables, decreased values of posttransplant IgG remained significant predictors.

CONCLUSIONS

The existence of decreased levels of IgG in the setting of heart transplantation was associated with an higher risk for infection. Monitoring of immunoglobulin levels, a rapid and well-standardized nephelometric determination, in heart transplantation, may identify a subset of patients at risk for development of infections.