Management of infectious disease syndromes in thoracic organ transplants and mechanical circulatory device recipients: a Delphi panel.

PURPOSE: Antimicrobial misuse contributes to antimicrobial resistance in thoracic transplant (TTx) and mechanical circulatory support (MCS) recipients. This study uses a modified Delphi method to define the expected appropriate antimicrobial prescribing for the common clinical scenarios encountered in TTx and MCS recipients. METHODS: An online questionnaire on managing 10 common infectious disease syndromes was submitted to a multidisciplinary Delphi panel of 25 experts from various disciplines. Consensus was predefined as 80% agreement for each question. Questions where consensus was not achieved were discussed during live virtual live sessions adapted by an independent process expert. RESULTS: An online survey of 62 questions related to 10 infectious disease syndromes was submitted to the Delphi panel. In the first round of the online questionnaire, consensus on antimicrobial management was reached by 6.5% (4/62). In Round 2 online live discussion, the remaining 58 questions were discussed among the Delphi Panel members using a virtual meeting platform. Consensus was reached among 62% (36/58) of questions. Agreement was not reached regarding the antimicrobial management of the following six clinical syndromes: (1) Burkholderia cepacia pneumonia (duration of therapy); (2) Mycobacterium abscessus (intra-operative antimicrobials); (3) invasive aspergillosis (treatment of culture-negative but positive BAL galactomannan) (duration of therapy); (4) respiratory syncytial virus (duration of antiviral therapy); (5) left ventricular assist device deep infection (initial empirical antimicrobial coverage) and (6) CMV (duration of secondary prophylaxis). CONCLUSION: This Delphi panel developed consensus-based recommendations for 10 infectious clinical syndromes seen in TTx and MCS recipients.

Stability of distinct symptom experiences in patients with chronic obstructive pulmonary disease (COPD).

PURPOSE: This study aimed to examine reclassification rates among classes of chronic obstructive pulmonary disease (COPD) patients based on their distinct symptom experiences and to assess how these subgroups differed in symptom scores and health-related quality of life (HRQoL) outcomes over one year. Moreover, we wished to assess how these subgroups differed in demographic and clinical characteristics at 12 months. PATIENTS AND METHODS: This is a follow-up study of 267 patients with moderate, severe, and very severe COPD. Based on their distinct symptom experiences using the Memorial Symptom Assessment Scale (MSAS), three subgroups (i.e., "high", "intermediate", and "low") were identified at baseline. In the present study, transitions between the subgroups at three, six, nine, and 12 months were investigated and calculated as reclassification rates. Differences among the subgroups in symptom scores and HRQoL at each time point and demographic and clinical characteristics at 12 months were evaluated using analysis of variance with post hoc comparisons. RESULTS: Almost 65% were still in the "high" class after 12 months. At 12 months, pairwise comparisons for respiratory function measurements were not significantly different. Compared to the "intermediate" and "low" class, patients in the "high" class were more likely to be women and had significantly more comorbidities, reported a significantly higher number of symptoms at all time points, and worse HRQoL scores. CONCLUSION: Our findings suggest that the pattern of a high symptom burden in COPD is consistent over time. The patients' individual symptom experiences should be the primary focus of treatment.

Consensus document for the selection of lung transplant candidates: An update from the International Society for Heart and Lung Transplantation.

Tens of thousands of patients with advanced lung diseases may be eligible to be considered as potential candidates for lung transplant around the world each year. The timing of referral, evaluation, determination of candidacy, and listing of candidates continues to pose challenges and even ethical dilemmas. To address these challenges, the International Society for Heart and Lung Transplantation appointed an international group of members to review the literature, to consider recent advances in the management of advanced lung diseases, and to update prior consensus documents on the selection of lung transplant candidates. The purpose of this updated consensus document is to assist providers throughout the world who are caring for patients with pulmonary disease to identify potential candidates for lung transplant, to optimize the timing of the referral of these patients to lung transplant centers, and to provide transplant centers with a framework for evaluating and selecting candidates. In addition to addressing general considerations and providing disease specific recommendations for referral and listing, this updated consensus document includes an ethical framework, a recognition of the variability in acceptance of risk between transplant centers, and establishes a system to account for how a combination of risk factors may be taken into consideration in candidate selection for lung transplantation.

Lung transplantation for sarcoidosis: outcome and prognostic factors.

STUDY QUESTION: In patients with sarcoidosis, past and ongoing immunosuppressive regimens, recurrent disease in the transplant and extrapulmonary involvement may affect outcomes of lung transplantation. We asked whether sarcoidosis lung phenotypes can be differentiated and, if so, how they relate to outcomes in patients with pulmonary sarcoidosis treated by lung transplantation. PATIENTS AND METHODS: We retrospectively reviewed data from 112 patients who met international diagnostic criteria for sarcoidosis and underwent lung or heart-lung transplantation between 2006 and 2019 at 16 European centres. RESULTS: Patient survival was the main outcome measure. At transplantation, median (interaquartile range (IQR)) age was 52 (46-59) years; 71 (64%) were male. Lung phenotypes were individualised as follows: 1) extended fibrosis only; 2) airflow obstruction; 3) severe pulmonary hypertension (sPH) and airflow obstruction; 4) sPH, airflow obstruction and fibrosis; 5) sPH and fibrosis; 6) airflow obstruction and fibrosis; 7) sPH; and 8) none of these criteria, in 17%, 16%, 17%, 14%, 11%, 9%, 5% and 11% of patients, respectively. Post-transplant survival rates after 1, 3, and 5 years were 86%, 76% and 69%, respectively. During follow-up (median (IQR) 46 (16-89) months), 31% of patients developed chronic lung allograft dysfunction. Age and extended lung fibrosis were associated with increased mortality. Pulmonary fibrosis predominating peripherally was associated with short-term complications. ANSWER TO THE STUDY QUESTION: Post-transplant survival in patients with pulmonary sarcoidosis was similar to that in patients with other indications for lung transplantation. The main factors associated with worse survival were older age and extensive pre-operative lung fibrosis.

Predictors of long intensive care need after lung transplantation.

BACKGROUND: While expected need for intensive care after lung transplantation (LTx) does not normally affect organ allocation, it would be useful to estimate whether intensive care capacity is limited. The aim of this study was to assess factors available before LTx to identify predictors of prolonged intensive care unit (ICU) length of stay (LOS) after LTx. METHODS: All bilateral LTx recipients excluding re-transplantation and multi-organ transplantation at Oslo University Hospital from 2000 to 2013 were included (n = 277). Predictive factors for ICU LOS were identified using pre- and perioperative variables. RESULTS: Univariate analyses showed that recipients with pulmonary arterial hypertension, young age, female gender, low body height, low pretransplant actual total lung capacity (aTLC), and recipients who received an oversized donor lung were at risk for long ICU LOS. Patients with emphysema had lower risk of long ICU LOS. In multivariate analyses, a lower aTLC (p < .001) and a higher mean pulmonary artery pressure (mPAP) (p = .004) predicted prolonged ICU LOS. CONCLUSIONS: We found that small recipient lung volume and high mPAP were predictors for prolonged ICU LOS. Our observations may be useful in planning use of resources in LTx, particularly in times of limited intensive care resources.

Changes in and predictors of pain and mortality in patients with chronic obstructive pulmonary disease.

This longitudinal study of patients with chronic obstructive pulmonary disease (COPD) aimed to investigate changes in pain characteristics (i.e., occurrence, intensity, and interference) and covariates associated with pain from study enrollment to 12 months, and to investigate if the different pain characteristics were associated with 5-year mortality. In total, 267 patients with COPD completed questionnaires five times over 1 year. The mean age of the patients was 63 years (standard deviation: 9.0), 53% were women, and 46% had very severe COPD. Median number of comorbidities was 2.0 (range: 0-11) and 47% of patients reported back/neck pain. Mixed models and Cox regression models were used for analyses. In total, 60% of the patients reported pain at baseline, and 61% at 12 months. The mixed model analyses revealed that those with better forced expiratory volume in 1 s (% predicted), more comorbidities, only primary school education, and more respiratory symptoms reported significantly higher average pain intensity. Moreover, those with more comorbidities, more respiratory symptoms, and more depression reported higher pain interference with function. At the 5-year follow-up, 64 patients (24%) were deceased, and the cumulative 5-year mortality rate was 22% (95% confidence interval [19-25]). Older age, lower forced expiratory volume in 1 s (% predicted), and higher pain interference at enrollment were all independently and significantly associated with higher 5-year mortality. Our findings show that many patients with COPD have persistent pain, and awareness regarding comorbidities and how pain interferes with their lives is needed.

Ethical considerations regarding heart and lung transplantation and mechanical circulatory support during the COVID-19 pandemic: an ISHLT COVID-19 Task Force statement.

To understand the challenges for thoracic transplantation and mechanical circulatory support during the current coronavirus disease 2019 pandemic, we propose separating the effects of the pandemic into 5 distinct stages from a healthcare system perspective. We discuss how the classical ethical principles of utility, justice, and efficiency may need to be adapted, and we give specific recommendations for thoracic transplantation and mechanical circulatory support centers to balance their clinical decisions and strategies for advanced heart and lung disease during the current pandemic.

Hypogammaglobulinemia and Risk of Exacerbation and Mortality in Patients with COPD.

Introduction: Chronic obstructive pulmonary disease (COPD) may, in some patients, be characterized by recurring acute exacerbations. Often these exacerbations are associated with airway infections. As immunoglobulins (Ig) are important parts of the immune defence against airway infections, the aim of this study was to relate the levels of circulating immunoglobulins to clinical features in unselected patients with COPD included in a Norwegian multicenter study. Methods: Clinical and biological data, including circulating levels of immunoglobulins, were assessed in 262 prospectively included patients with COPD GOLD stage II-IV at five hospitals in south-eastern Norway. A revisit was done after one year, and survival was assessed after five years. Clinical features and survival of those with immunoglobulin levels below reference values were compared to those with normal levels. Results: In total, 11.5% of all COPD patients and 18.5% of those with GOLD stage IV had IgG concentrations below reference values. These patients were more likely to use inhaled or oral steroids, had lower BMI, and lower FEV1%. Moreover, they had significantly more COPD-related hospital admissions (2.8 vs 0.6), number of prednisolone courses (3.9 vs 1.2), and antibiotic treatments (3.7 vs 1.5) in the preceding year. Importantly, hypogammaglobulinemia was significantly associated with reduced survival in a log-rank analysis. In multivariate regression analysis, we found that the higher risk for acute exacerbations in these patients was independent of other risk factors and was associated with impaired survival. Conclusion: In conclusion, our study suggests that hypogammaglobulinemia may be involved in poor outcome in COPD and may thus be a feasible therapeutic target for interventional studies in COPD.

Utilization of hepatitis C virus-infected organ donors in cardiothoracic transplantation: An ISHLT expert consensus statement.

The advent of therapies for successful treatment of hepatitis C virus has allowed the heart and lung transplant community to re-explore the use of hepatitis C virus-positive donors for organ transplantation, with a benefit for many terminally ill patients. The consensus statements provided herein represent the current state of knowledge and expertise in this area, which we expect will continue to rapidly evolve over the next few years.

Eight novel variants in the SLC34A2 gene in pulmonary alveolar microlithiasis.

BACKGROUND: Pulmonary alveolar microlithiasis (PAM) is caused by genetic variants in the SLC34A2 gene, which encodes the sodium-dependent phosphate transport protein 2B (NaPi-2b). PAM is characterised by deposition of calcium phosphate concretions (microliths) in the alveoli leading to pulmonary dysfunction. The variant spectrum of SLC34A2 has not been well investigated and it is not yet known whether a genotype-phenotype correlation exists. METHODS: We collected DNA from 14 patients with PAM and four relatives, and analysed the coding regions of SLC34A2 by direct DNA sequencing. To determine the phenotype characteristics, clinical data were collected and a severity score was created for each variant, based on type and localisation within the protein. RESULTS: We identified eight novel allelic variants of SLC34A2 in 14 patients with PAM. Four of these were nonsense variants, three were missense and one was a splice site variant. One patient was heterozygous for two different variants and all other patients were homozygous. Four patients were asymptomatic and 10 patients were symptomatic. The severity of the disease was associated with the variant severity. CONCLUSIONS: Our findings support a significant role for SLC34A2 in PAM and expand the variant spectrum of the disease. Thus, SLC34A2 variants were detected in all patients and eight novel allelic variants were discovered. An association between disease severity and the severity of the variants was found; however, this needs to be investigated in larger patient populations.

Lung transplantation for scleroderma lung disease: An international, multicenter, observational cohort study.

BACKGROUND: Due to its multisystemic nature, scleroderma is considered a relative contraindication to lung transplantation at many centers. However, recent studies suggest similar post-transplant outcomes in patients with scleroderma compared to those with other causes of interstitial lung disease (ILD). Furthermore, it remains unknown whether scleroderma-associated pulmonary arterial hypertension (PAH) influences post-transplant outcomes. Our objective in this study was to assess the indications, survival, and prognostic factors of lung or heart-lung transplantation for scleroderma lung disease. METHODS: We retrospectively reviewed the data of 90 patients with scleroderma who underwent lung or heart-lung transplantation between 1993 and 2016 at 14 European centers. International criteria were used to diagnose scleroderma. Pulmonary hypertension (PH) was diagnosed during right heart catheterization based on international guidelines. RESULTS: Survival rates after 1, 3, and 5 years were 81%, 68%, and 61%, respectively. By univariate analysis, borderline-significant associations with poorer survival were found for female gender (hazard ratio 2.11; 95% confidence interval [CI] 0.99 to 4.50; p = 0.05) and PAH as the reason for transplantation (hazard ratio 1.90; 95% CI 0.96 to 3.92; p = 0.06). When both these factors were present in combination, the risk of death was 3-fold that in males without PAH. The clinical and histologic presentation resembled veno-occlusive disease in 75% of patients with PAH. CONCLUSIONS: Post-transplant survival rates and freedom from chronic lung allograft dysfunction in patients with scleroderma were similar to those in patients with other reasons for lung transplantation. Female sex and PAH in combination was associated with lower survival.

Distinct pain profiles in patients with chronic obstructive pulmonary disease.

Background: Few studies have examined changes in the pain experience of patients with COPD and predictors of pain in these patients. Objectives: The objectives of the study were to examine whether distinct groups of COPD patients could be identified based on changes in the occurrence and severity of pain over 12 months and to evaluate whether these groups differed on demographic, clinical, and pain characteristics, and health-related quality of life (HRQoL). Patients and methods: A longitudinal study of 267 COPD patients with very severe COPD was conducted. Their mean age was 63 years, and 53% were females. The patients completed questionnaires including demographic and clinical variables, the Brief Pain Inventory, and the St Georges Respiratory Questionnaire at enrollment, and 3, 6, 9, and 12 months follow-up. In addition, spirometry and the 6 Minute Walk Test were performed. Latent class analysis was used to identify subgroups of patients with distinct pain profiles based on pain occurrence and worst pain severity. Results: Most of the patients (77%) reported pain occurrence over 12 months. Of these, 48% were in the "high probability of pain" group, while 29% were in the "moderate probability of pain" group. For the worst pain severity, 37% were in the "moderate pain" and 39% were in the "mild pain" groups. Females and those with higher body mass index, higher number of comorbidities, and less education were in the pain groups. Patients in the higher pain groups reported higher pain interference scores, higher number of pain locations, and more respiratory symptoms. Few differences in HRQoL were found between the groups except for the symptom subscale. Conclusion: Patients with COPD warrant comprehensive pain management. Clinicians may use this information to identify those who are at higher risk for persistent pain.

Lung transplantation after allogeneic stem cell transplantation: a pan-European experience.

Late-onset noninfectious pulmonary complications (LONIPCs) affect 6% of allogeneic stem cell transplantation (SCT) recipients within 5 years, conferring subsequent 5-year survival of 50%. Lung transplantation is rarely performed in this setting due to concomitant extrapulmonary morbidity, excessive immunosuppression and concerns about recurring malignancy being considered contraindications. This study assesses survival in highly selected patients undergoing lung transplantation for LONIPCs after SCT.SCT patients undergoing lung transplantation at 20 European centres between 1996 and 2014 were included. Clinical data pre- and post-lung transplantation were reviewed. Propensity score-matched controls were generated from the Eurotransplant and Scandiatransplant registries. Kaplan-Meier survival analysis and Cox proportional hazard regression models evaluating predictors of graft loss were performed.Graft survival at 1, 3 and 5 years of 84%, 72% and 67%, respectively, among the 105 SCT patients proved comparable to controls (p=0.75). Sepsis accounted for 15 out of 37 deaths (41%), with prior mechanical ventilation (HR 6.9, 95% CI 1.0-46.7; p<0.001) the leading risk factor. No SCT-specific risk factors were identified. Recurring malignancy occurred in four patients (4%). Lung transplantation <2 years post-SCT increased all-cause 1-year mortality (HR 7.5, 95% CI 2.3-23.8; p=0.001).Lung transplantation outcomes following SCT were comparable to other end-stage diseases. Lung transplantation should be considered feasible in selected candidates. No SCT-specific factors influencing outcome were identified within this carefully selected patient cohort.

Distinct symptom experiences in subgroups of patients with COPD.

BACKGROUND: In addition to their respiratory symptoms, patients with COPD experience multiple, co-occurring symptoms. OBJECTIVES: The aims of this study were to identify subgroups of COPD patients based on their distinct experiences with 14 symptoms and to determine how these subgroups differed in demographic and clinical characteristics and disease-specific quality of life. PATIENTS AND METHODS: Patients with moderate, severe, and very severe COPD (n=267) completed a number of self-report questionnaires. Latent class analysis was used to identify subgroups of patients with distinct symptom experiences based on the occurrence of self-reported symptoms using the Memorial Symptom Assessment Scale. RESULTS: Based on the probability of occurrence of a number of physical and psychological symptoms, three subgroups of patients (ie, latent classes) were identified and named "high", "intermediate", and "low". Across the three latent classes, the pairwise comparisons for the classification of airflow limitation in COPD were not significantly different, which suggests that measurements of respiratory function are not associated with COPD patients' symptom burden and their specific needs for symptom management. While patients in both the "high" and "intermediate" classes had high occurrence rates for respiratory symptoms, patients in the "high" class had the highest occurrence rates for psychological symptoms. Compared with the "intermediate" class, patients in the "high" class were younger, more likely to be women, had significantly more acute exacerbations in the past year, and reported significantly worse disease-specific quality of life scores. CONCLUSION: These findings suggest that subgroups of COPD patients with distinct symptom experiences can be identified. Patients with a higher symptom burden warrant more detailed assessments and may have therapeutic needs that would not be identified using current classifications based only on respiratory function.

Long-term persistence of human donor alveolar macrophages in lung transplant recipients.

BACKGROUND: Alveolar macrophages (AMFs) are critical regulators of lung function, and may participate in graft rejection following lung transplantation. Recent studies in experimental animals suggest that most AMFs are self-maintaining cells of embryonic origin, but knowledge about the ontogeny and life span of human AMFs is scarce. METHODS: To follow the origin and longevity of AMFs in patients with lung transplantation for more than 100 weeks, we obtained transbronchial biopsies from 10 gender-mismatched patients with lung transplantation. These were subjected to combined in situ hybridisation for X/Y chromosomes and immunofluorescence staining for macrophage markers. Moreover, development of AMFs in humanised mice reconstituted with CD34+ umbilical cord-derived cells was assessed. RESULTS: The number of donor-derived AMFs was unchanged during the 2 year post-transplantation period. A fraction of the AMFs proliferated locally, demonstrating that at least a subset of human AMFs have the capacity to self-renew. Lungs of humanised mice were found to abundantly contain populations of human AMFs expressing markers compatible with a monocyte origin. Moreover, in patients with lung transplantation we found that recipient monocytes seeded the alveoli early after transplantation, and showed subsequent phenotypical changes consistent with differentiation into proliferating mature AMFs. This resulted in a stable mixed chimerism between donor and recipient AMFs throughout the 2-year period. CONCLUSIONS: The finding that human AMFs are maintained in the lung parenchyma for several years indicates that pulmonary macrophage transplantation can be a feasible therapeutic option for patients with diseases caused by dysfunctional AMFs. Moreover, in a lung transplantation setting, long-term persistence of donor AMFs may be important for the development of chronic graft rejection.

A unique set of 6 circulating microRNAs for early detection of non-small cell lung cancer.

INTRODUCTION: Circulating microRNAs are promising biomarkers for diagnosis, predication and prognostication of diseases. Lung cancer is the cancer disease accountable for most cancer deaths, largely due to being diagnosed at late stages. Therefore, diagnosing lung cancer patients at an early stage is crucial for improving the outcome. The purpose of this study was to identify circulating microRNAs for detection of early stage lung cancer, capable of discriminating lung cancer patients from those with chronic obstructive pulmonary disease (COPD) and healthy volunteers. RESULTS: We identified 7 microRNAs separating lung cancer patients from controls. By using RT-qPCR, we validated 6 microRNAs (miR-429, miR-205, miR-200b, miR-203, miR-125b and miR-34b) with a significantly higher abundance in serum from NSCLC patients. Furthermore, the 6 miRNAs were validated in a different dataset, revealing an area under the receiver operating characteristic curve of 0.89 for stage I-IV and 0.88 for stage I/II. MATERIALS AND METHODS: We profiled the expression of 754 unique microRNAs by TaqMan Low Density Arrays, and analyzed serum from 38 patients with NSCLC, 16 patients suffering from COPD and 16 healthy volunteers from Norway, to explore their potential as diagnostic biomarkers. For validation, we analyzed serum collected from high-risk individuals enrolled in the Valencia branch of the International Early Lung Cancer Action Program screening trial (n=107) in addition to 51 lung cancer patients. CONCLUSIONS: Considering the accessibility and stability of circulating miRNAs, these 6 microRNAs are promising biomarkers as a supplement in future screening studies.

Lung disease, T-cells and inflammation in common variable immunodeficiency disorders.

INTRODUCTION: Besides hypogammaglobulinemia and recurrent infections, abnormalities of T-cells might contribute to lung damage in common variable immunodeficiency disorders (CVID). MATERIALS AND METHODS: In 16 adult patients, the majority of whom had pulmonary abnormalities, we studied T-cell subsets and markers of inflammation in bronchoalveolar lavage fluid (BALF) and blood and their relations with pulmonary function and high resolution computed tomography (HRCT). RESULTS: We demonstrated that some of the lymphocyte abnormalities previously demonstrated in peripheral blood from CVID patients, such as low CD4/CD8 T-cell ratio, were also present in BALF. Moreover, low BALF CD4/CD8 ratio (≤ 1), found in seven patients, was significantly associated with higher blood CD8⁺ cell count and to lower values of the lung function variables; forced expiratory volume (FVC), total lung capacity (TLC), vital capacity (VC) and residual volume (RV) in % of predicted. The expression of the inflammatory markers HLA-DR and CCR5 on T-cells was significantly higher, and the expression of CCR7 significantly lower, in BALF compared to blood, possibly reflecting an inflammatory/cytotoxic T-cell phenotype within pulmonary tissue in CVID. Furthermore, patients with bronchiectasis had higher concentrations of the pro-inflammatory cytokine TNFα in plasma, compared to those without. CONCLUSION: Our findings suggest that inflammation and T-cell activation may be involved in the immunopathogenesis of pulmonary complications in CVID.

Multiorgan procurement increases systemic inflammation in brain dead donors.

Organs available for solid organ transplantation are mainly procured from brain dead donors. The inflammation associated with brain death may reduce organ quality and increase organ immunogenicity, thus leading to inferior recipient outcome. We hypothesized that the extensive surgical procedure performed during multiorgan procurement enhances the levels of systemic inflammatory biomarkers. We measured the levels of 27 cytokines and the terminal complement complex (TCC) in plasma samples from brain dead organ donors (n = 34) drawn before and at three specific time points during procurement surgery. Baseline levels of G-CSF, interferon-γ, IL-1ra, IL-4, IL-6, IL-7, IL-8, IL-10, IP-10, MCP-1, macrophage inflammatory protein (MIP)-1ß, platelet derived growth factor (PDGF), regulated upon activation T cell expressed and secreted, and tumor necrosis factor-α were significantly elevated in brain dead donors compared with normal individuals (n = 14), but they were not associated with time on ventilator or any other registered clinical variable. Notably, the secretion of G-CSF, IL1-ra, IL-6, IL-8, IL-10, IP-10, MCP-1, MIP-1ß, PDGF, and TCC, the latter reflecting ongoing complement activation, increased significantly during surgery. None of the biomarker increases were correlated with operation duration. Multiorgan procurement surgery significantly adds to the inflammatory response revealed by both pro- and anti-inflammatory biomarkers associated with brain death. Future studies should determine whether this is associated with inferior recipient outcome.

Relevance of biallelic versus monoallelic TNFRSF13B mutations in distinguishing disease-causing from risk-increasing TNFRSF13B variants in antibody deficiency syndromes.

TNFRSF13B encodes transmembrane activator and calcium modulator and cyclophilin ligand interactor (TACI), a B cell- specific tumor necrosis factor (TNF) receptor superfamily member. Both biallelic and monoallelic TNFRSF13B mutations were identified in patients with common variable immunodeficiency disorders. The genetic complexity and variable clinical presentation of TACI deficiency prompted us to evaluate the genetic, immunologic, and clinical condition in 50 individuals with TNFRSF13B alterations, following screening of 564 unrelated patients with hypogammaglobulinemia. We identified 13 new sequence variants. The most frequent TNFRSF13B variants (C104R and A181E; n=39; 6.9%) were also present in a heterozygous state in 2% of 675 controls. All patients with biallelic mutations had hypogammaglobulinemia and nearly all showed impaired binding to a proliferation-inducing ligand (APRIL). However, the majority (n=41; 82%) of the pa-tients carried monoallelic changes in TNFRSF13B. Presence of a heterozygous mutation was associated with antibody deficiency (P< .001, relative risk 3.6). Heterozygosity for the most common mutation, C104R, was associated with disease (P< .001, relative risk 4.2). Furthermore, heterozygosity for C104R was associated with low numbers of IgD(-)CD27(+) B cells (P= .019), benign lymphoproliferation (P< .001), and autoimmune complications (P= .001). These associations indicate that C104R heterozygosity increases the risk for common variable immunodeficiency disorders and influences clinical presentation.