Pruritus in cutaneous graft-versus-host disease: A systematic review.

Pruritus is a common symptom of cutaneous graft-versus-host disease (GVHD) following haematopoietic stem cell transplantation (HSCT). However, little is known about its prevalence, pathophysiology, perceptual characteristics, impact on quality of life and response to antipruritic therapies. The aim of this review was to determine the current knowledge on pruritus in cutaneous GVHD. The review was conducted according to the Preferred Reporting Items for Systematic Review and Meta-Analyses statement. Of the 338 studies screened, 13 were included. The prevalence of pruritus in cutaneous GVHD was reported in three studies, ranging from 37.0% to 63.8%. Only four trials used pruritus assessment tools. There was little or no information on the intensity of pruritus, its qualitative perception, the location of pruritus and the impact of pruritus on quality of life. Antipruritic treatments for GVHD-associated pruritus were mentioned in five studies (38.5%), including topical ointments (steroids, tacrolimus and calcipotriene), broadband UVB, systemic antihistamines and oral ursodeoxycholic acid. In conclusion, pruritus in cutaneous GVHD appears to be common, but very little is known about the pathophysiology, impact on quality of life and effective treatment options. Basic research and controlled clinical trials are warranted to improve knowledge and management of this important issue.

Busulfan-cyclophosphamide versus cyclophosphamide-busulfan as conditioning regimen before allogeneic hematopoietic cell transplantation: a prospective randomized trial.

Busulfan and cyclophosphamide (BuCy) is a frequently used myeloablative conditioning regimen for allogeneic hematopoietic cell transplantation (allo-HCT). Theoretical considerations and pharmacological data indicate that application of busulfan prior to subsequent cyclophosphamide (BuCy) may trigger liver toxicity. Reversing the order of application to cyclophosphamide-busulfan (CyBu) might be preferable, a hypothesis supported by animal data and retrospective studies. We performed a prospective randomized trial to determine impact of order of application of Bu and Cy before allo-HCT in 70 patients with hematological malignancy, 33 patients received BuCy and 37 CyBu for conditioning. In the short term, there were minimal differences in liver toxicity favoring CyBu over BuCy, significant only for alanine amino transferase at day 30 (p = 0.03). With longer follow-up at 4 years, non-relapse mortality (6% versus 27%, p = 0.05) was lower and survival (63% versus 43%, p = 0.06) was higher with CyBu compared to BuCy. Other outcomes, such as engraftment (p = 0.21), acute and chronic graft-versus-host disease (p = 0.40; 0.36), and relapse (p = 0.79), were similar in both groups. We prospectively show evidence that the order of application of Cy and Bu in myeloablative conditioning in allo-HCT patients has impact on outcome.

Very long-term follow-up of aplastic anemia treated with immunosuppressive therapy or allogeneic hematopoietic cell transplantation.

INTRODUCTION: Since the 1970s outcome of aplastic anemia (AA) patients has improved significantly due to the introduction of immunosuppressive therapy (IST) and allogeneic hematopoietic transplantation (HCT). However, patients may suffer from persistent disease, relapse, clonal evolution, graft-versus-host disease and other late effects. Here, we analyse very long-term outcome of all AA patients at our institution comparing not only survival, but also response status and complications. METHODS: Patient charts of all 302 AA patients treated between 1973 and 2017 at the University Hospital Basel, Switzerland, were retrospectively analysed. RESULTS: First line treatment was IST in 226 (75%) and HCT in 76 (25%) patients. Overall survival at 30 years was similar in patients treated initially by HCT and IST (44% (±14%), and 40% (± 9%) respectively, with better results in more recent years. Partial and no response occurred more frequently after IST, relapse incidence after IST was 24 %, whereas non-engraftment and graft failure was documented in 15 patients (19 %) after HCT. Clonal evolution to myelodysplastic syndrome / acute myeloid leukemia was 16 % at 25 years in IST patients, 1.3 % in HCT patients, iron overload (18 versus 4 %, p = 0.002) and cardiovascular events (11 versus 1 %, p=0.011) occured significantly more often in IST than HCT treated patients. The majority of long-term survivors, 96% of those alive at 25 years, were in complete remission at last follow up, irrespective of the initial treatment modality. CONCLUSION: Very long term survivors after AA are those with stable hematopoietic recovery.

Microbiologically documented infections after adult allogeneic hematopoietic cell transplantation: A 5-year analysis within the Swiss Transplant Cohort study.

BACKGROUND: Infections are an important complication after allogeneic hematopoietic cell transplantation (allo-HCT). The present study aimed at determining the landscape of infections occurring in a large cohort of allo-HCT patients, as well as associated risk factors for infections and for one-year non-relapse mortality. METHODS: This is a retrospective cohort study using STCS and EBMT databases to assess the one-year incidence rate of infection, as well as risk factors for infections and for one-year non-relapse mortality among adult allo-HCT patients transplanted between 2010 and 2014 in Switzerland. Univariable and multivariable quasi-Poisson and multivariable Cox regression models were used. RESULTS: Of 553 patients included, 486 had an infection with a global incidence rate of 3.66 infections per patient-year. Among a total of 1534 infections analyzed, viral infections were predominant (n = 1138, 74.2%), followed by bacterial (n = 343, 22.4%) and fungal (n = 53, 3.5%) infections. At one year, the cumulative incidence of relapse and non-relapse mortality was 26% and 16%, respectively. 195 (35.3%) of patients had at least one episode of severe graft-versus-host-disease (GvHD). A center effect was observed, and underlying disease, donor type, cytomegalovirus serological constellation, and GvHD were also associated with the incidence rate of infections. There was an increased risk for one-year non-relapse mortality associated with all pathogens, specifically within two months of infection, and this remained true beyond 2 months of a fungal infection. CONCLUSION: Despite advances to limit infections in this population, they still occur in most allo-HCT patients with a major impact on survival at 1 year.

Extracorporeal Photopheresis in Graft-versus-Host Disease.

BACKGROUND AND SUMMARY: Extracorporeal photopheresis (ECP) is a leukapheresis-based procedure used in the therapy of acute and chronic graft-versus-host disease (aGvHD, cGvHD) and other diseases. Based on the substantial efficacy and the excellent safety profile in the absence of immunosuppression ECP has established itself as a major treatment form for steroid-refractory GvHD. Here we review the current literature on ECP as a treatment option for patients with aGvHD as well as cGvHD. KEY MESSAGES: ECP is a well-established second-line therapy for cGvHD. Its role in the treatment of aGvHD is less clear but also points towards an effective second-line therapy option. In the future ECP could play a role in the prevention of GvHD. More experimental and randomized controlled trials are needed to define the best patient selection criteria, settings, and therapy regimens for GvHD.

Donor Experiences of Second Marrow or Peripheral Blood Stem Cell Collection Mirror the First, but CD34+ Yields Are Less.

Little is known about the experiences of individuals donating peripheral blood stem cells (PBSCs) or marrow for a second time. To study this, unrelated donors making a second donation through the National Marrow Donor Program between 2004 and 2013 were evaluated. Experiences of second-time donors giving marrow (n = 118: first donation was PBSC in 76 and marrow in 42) were compared with those making only 1 marrow donation (n = 5829). Experiences of second-time donors giving PBSCs (n = 602) (first donation was PBSCs in 362; marrow in 240) were compared to first-time PBSC donors (n = 16,095). For donors giving a second PBSC or marrow donation there were no significant differences in maximum skeletal pain, maximum symptoms measured by an established modified toxicity criteria, and recovery time compared with those who donated only once. Notably, the yield of marrow nucleated cells and PBSC CD34+ cells with second donations was less. As previously noted with single first-time donations, female (PBSCs and marrow) and obese donors (PBSCs) had higher skeletal pain and/or toxicity with a second donation. PBSC donors who experienced high levels of pain or toxicity with the first donation also experienced high levels of these symptoms with their second donation and slower recovery times. In conclusion, for most donors second donation experiences were similar to first donation experiences, but CD34+ yields were less. Knowledge of the donor's first experience and stem cell yields may help centers decide whether second donations are appropriate and institute measures to improve donor experiences.

Diagnosis of invasive mold diseases in patients with hematological malignancies using Aspergillus, Mucorales, and panfungal PCR in BAL.

BACKGROUND: Accurate diagnosis of invasive mold diseases (IMD) remains challenging. Here, the performance of panfungal PCR, Aspergillus and MucoralesPCR in bronchoalveolar lavage (BAL) was evaluated. METHODS: We conducted a single-center study including 167 hematologic patients at risk for IMD with BAL performed 2011-2014. Diagnostic performance of single tests (Aspergillus-, Mucorales-, and panfungal PCR, galactomannan (GM)≥0.5 and ≥1, culture/cytology) or in combination was calculated for predicting IMD comparing proven/probable or proven/probable/possible IMD vs no IMD, respectively. RESULTS: IMD was classified as proven (n = 6), probable (n = 31), possible (n = 29) and no IMD (n = 101) according to EORTC/MSG criteria. GM ≥ 0.5 in BAL showed the highest sensitivity with 81% for diagnosing IMD whereas the other tests only 5%-35%. By contrast, specificity was highest for panfungal PCR with 99% and GM ≥ 1, Mucorales and AspergillusPCR reached specificity ≥91%. When combining the tests, GM ≥ 0.5 and panfungal PCR show a sensitivity and specificity of 87% and 78% for IMD or with AspergillusPCR a sensitivity and specificity of 88% and 72% for invasive pulmonary aspergillosis, respectively. Including possible IMD patients did not improve the sensitivity of PCRs. In probable/proven IMD patients, the addition of panfungal PCR resulted further in detection of Fusarium species and Alternaria species, and the MucoralesPCR was positive in 2 probable IMD cases. CONCLUSION: This study illustrates that the diagnosis of IMD is still very problematic and lacks objectivity. Together with GM in BAL, the PCRs may prove an addition to the current available diagnostic armamentarium in IMD because of their ability to identify molds on a species level.

European Group for Blood and Marrow Transplantation Centers with FACT-JACIE Accreditation Have Significantly Better Compliance with Related Donor Care Standards.

Previous studies have identified healthcare practices that may place undue pressure on related donors (RDs) of hematopoietic cell products and an increase in serious adverse events associated with morbidities in this population. As a result, specific requirements to safeguard RD health have been introduced to Foundation for the Accreditation of Cellular Therapy/The Joint Accreditation Committee ISCT and EBMT (FACT-JACIE) Standards, but the impact of accreditation on RD care has not previously been evaluated. A survey of transplant program directors of European Group for Blood and Marrow Transplantation member centers was conducted by the Donor Health and Safety Working Committee of the Center for International Blood and Marrow Transplant Research to test the hypothesis that RD care in FACT-JACIE accredited centers is more closely aligned with international consensus donor care recommendations than RD care delivered in centers without accreditation. Responses were received from 39% of 304 centers. Our results show that practice in accredited centers was much closer to recommended standards as compared with nonaccredited centers. Specifically, a higher percentage of accredited centers use eligibility criteria to assess RDs (93% versus 78%; P = .02), and a lower percentage have a single physician simultaneously responsible for an RD and their recipient (14% versus 35%; P = .008). In contrast, where regulatory standards do not exist, both accredited and nonaccredited centers fell short of accepted best practice. These results raise concerns that despite improvements in care, current practice can place undue pressure on donors and may increase the risk of donation-associated adverse events. We recommend measures to address these issues through enhancement of regulatory standards as well as national initiatives to standardize RD care.

Determination of Eligibility in Related Pediatric Hematopoietic Cell Donors: Ethical and Clinical Considerations. Recommendations from a Working Group of the Worldwide Network for Blood and Marrow Transplantation Association.

Related donors for hematopoietic cell (HC) transplantation are a growing population in recent years because of expanding indications for allogeneic transplantation. The safety and welfare of the donor are major concerns for the transplantation community, especially for related sibling donors of young recipients who are children and, thus, not able to fully consent. Because donation of HC does not improve the donor's own physical health and carries a risk of side effects, careful assessment of medical risks specific to the individual donor, as well as consideration of ethical and legal aspects associated with donation from a child, must be considered. In addition, donor centers must balance the needs of both the donor and the recipient, understanding the inherent conflict parents may have as they can be overly focused on the very sick child receiving a transplant, rather than on the relatively less significant health or emotional problems that a sibling donor may have, which could impact risk with donation. Likewise, consideration must be made regarding the nature of the relationship of the sibling donor to the recipient and also aspects of performing research on pediatric HC donors. In this article, as members of the Donor Issues Committee of the Worldwide Network for Blood and Marrow Transplantation, we review key ethical concerns associated with pediatric donation and then give recommendations for screening potential child donors with underlying health conditions. These recommendations are aimed at protecting the physical and emotional well-being of childhood donors and arise out of the Third International Conference on Health and Safety of Donors sponsored by the Worldwide Network for Blood and Marrow Transplantation.

Significant Improvements in the Practice Patterns of Adult Related Donor Care in US Transplantation Centers.

Recent investigations have found a higher incidence of adverse events associated with hematopoietic cell donation in related donors (RDs) who have morbidities that if present in an unrelated donor (UD) would preclude donation. In the UD setting, regulatory standards ensure independent assessment of donors, one of several crucial measures to safeguard donor health and safety. A survey conducted by the Center for International Blood and Marrow Transplant Research (CIBMTR) Donor Health and Safety Working Committee in 2007 reported a potential conflict of interest in >70% of US centers, where physicians had simultaneous responsibility for RDs and their recipients. Consequently, several international organizations have endeavored to improve practice through regulations and consensus recommendations. We hypothesized that the changes in the 2012 Foundation for the Accreditation of Cellular Therapy and the Joint Accreditation Committee-International Society for Cellular Therapy and European Society for Blood and Marrow Transplantation standards resulting from the CIBMTR study would have significantly impacted practice. Accordingly, we conducted a follow-up survey of US transplantation centers to assess practice changes since 2007, and to investigate additional areas where RD care was predicted to differ from UD care. A total of 73 centers (53%), performing 79% of RD transplantations in the United States, responded. Significant improvements were observed since the earlier survey; 62% centers now ensure separation of RD and recipient care (P < .0001). This study identifies several areas where RD management does not meet international donor care standards, however. Particular concerns include counseling and assessment of donors before HLA typing, with 61% centers first disclosing donor HLA results to an individual other than the donor, the use of unlicensed mobilization agents, and the absence of long-term donor follow-up. Recommendations for improvement are made.

Allogeneic haematopoietic stem cell transplantation for mitochondrial neurogastrointestinal encephalomyopathy.

Haematopoietic stem cell transplantation has been proposed as treatment for mitochondrial neurogastrointestinal encephalomyopathy, a rare fatal autosomal recessive disease due to TYMP mutations that result in thymidine phosphorylase deficiency. We conducted a retrospective analysis of all known patients suffering from mitochondrial neurogastrointestinal encephalomyopathy who underwent allogeneic haematopoietic stem cell transplantation between 2005 and 2011. Twenty-four patients, 11 males and 13 females, median age 25 years (range 10-41 years) treated with haematopoietic stem cell transplantation from related (n = 9) or unrelated donors (n = 15) in 15 institutions worldwide were analysed for outcome and its associated factors. Overall, 9 of 24 patients (37.5%) were alive at last follow-up with a median follow-up of these surviving patients of 1430 days. Deaths were attributed to transplant in nine (including two after a second transplant due to graft failure), and to mitochondrial neurogastrointestinal encephalomyopathy in six patients. Thymidine phosphorylase activity rose from undetectable to normal levels (median 697 nmol/h/mg protein, range 262-1285) in all survivors. Seven patients (29%) who were engrafted and living more than 2 years after transplantation, showed improvement of body mass index, gastrointestinal manifestations, and peripheral neuropathy. Univariate statistical analysis demonstrated that survival was associated with two defined pre-transplant characteristics: human leukocyte antigen match (10/10 versus <10/10) and disease characteristics (liver disease, history of gastrointestinal pseudo-obstruction or both). Allogeneic haematopoietic stem cell transplantation can restore thymidine phosphorylase enzyme function in patients with mitochondrial neurogastrointestinal encephalomyopathy and improve clinical manifestations of mitochondrial neurogastrointestinal encephalomyopathy in the long term. Allogeneic haematopoietic stem cell transplantation should be considered for selected patients with an optimal donor.

Immune Reconstitution After Allogeneic Hematopoietic Stem Cell Transplantation and Association With Occurrence and Outcome of Invasive Aspergillosis.

BACKGROUND: Invasive aspergillosis (IA) remains a leading cause of morbidity and mortality in patients receiving allogeneic hematopoietic stem cell transplantation (HSCT). To date, no reliable immunological biomarkers for management and outcome of IA exist. Here, we investigated reconstitution of antifungal immunity in patients during the first 12 months after HSCT and correlated it with IA. METHODS: Fifty-one patients were included, 9 with probable/proven IA. We determined quantitative and qualitative reconstitution of polymorphonuclear (PMN), CD4, CD8, and natural killer (NK) cells against Aspergillus fumigatus over 5 time points and compared the values to healthy donors. RESULTS: Absolute CD4 and CD8 cell counts, antigen-specific T-cell responses, and killing capacity of PMN against A. fumigatus were significantly decreased in all patients over 12 months. In patients with probable/proven IA, reactive oxygen species (ROS) production tended to be lower compared to patients without IA, and absolute NK-cell counts remained below 200 cells/µL. Patients with well-controlled IA showed significantly higher ROS production and NK-cell counts compared to patients with poor outcome. CONCLUSIONS: This study highlights the importance of functional PMN, T-cell, and NK-cell immunity for the outcome of IA. Larger multicenter studies should address the potential use of NK-cell counts for the management of antifungal therapy.

Better leukemia-free and overall survival in AML in first remission following cyclophosphamide in combination with busulfan compared with TBI.

Cyclophosphamide combined with total body irradiation (Cy/TBI) or busulfan (BuCy) are the most widely used myeloablative conditioning regimens for allotransplants. Recent data regarding their comparative effectiveness are lacking. We analyzed data from the Center for International Blood and Marrow Transplant Research for 1230 subjects receiving a first hematopoietic cell transplant from a human leukocyte antigen-matched sibling or from an unrelated donor during the years 2000 to 2006 for acute myeloid leukemia (AML) in first complete remission (CR) after conditioning with Cy/TBI or oral or intravenous (IV) BuCy. Multivariate analysis showed significantly less nonrelapse mortality (relative risk [RR] = 0.58; 95% confidence interval [CI]: 0.39-0.86; P = .007), and relapse after, but not before, 1 year posttransplant (RR = 0.23; 95% CI: 0.08-0.65; P = .006), and better leukemia-free survival (RR = 0.70; 95% CI: 0.55-0.88; P = .003) and survival (RR = 0.68; 95% CI: 0.52-0.88; P = .003) in persons receiving IV, but not oral, Bu compared with TBI. In combination with Cy, IV Bu is associated with superior outcomes compared with TBI in patients with AML in first CR.

Second solid cancers after allogeneic hematopoietic cell transplantation using reduced-intensity conditioning.

We examined risk of second solid cancers after allogeneic hematopoietic cell transplantation (AHCT) using reduced-intensity/nonmyeloablative conditioning (RIC/NMC). RIC/NMC recipients with leukemia/myelodysplastic syndrome (MDS) (n = 2833) and lymphoma (n = 1436) between 1995 and 2006 were included. In addition, RIC/NMC recipients 40 to 60 years of age (n = 2138) were compared with patients of the same age receiving myeloablative conditioning (MAC, n = 6428). The cumulative incidence of solid cancers was 3.35% at 10 years. There was no increase in overall cancer risk compared with the general population (leukemia/MDS: standardized incidence ratio [SIR] .99, P = 1.00; lymphoma: SIR .92, P = .75). However, risks were significantly increased in leukemia/MDS patients for cancers of lip (SIR 14.28), tonsil (SIR 8.66), oropharynx (SIR 46.70), bone (SIR 23.53), soft tissue (SIR 12.92), and vulva (SIR 18.55) and skin melanoma (SIR 3.04). Lymphoma patients had significantly higher risks of oropharyngeal cancer (SIR 67.35) and skin melanoma (SIR 3.52). Among RIC/NMC recipients, age >50 years was the only independent risk factor for solid cancers (hazard ratio [HR] 3.02, P < .001). Among patients ages 40 to 60 years, when adjusted for other factors, there was no difference in cancer risks between RIC/NMC and MAC in leukemia/MDS patients (HR .98, P = .905). In lymphoma patients, risks were lower after RIC/NMC (HR .51, P = .047). In conclusion, the overall risks of second solid cancers in RIC/NMC recipients are similar to the general population, although there is an increased risk of cancer at some sites. Studies with longer follow-up are needed to realize the complete risks of solid cancers after RIC/NMC AHCT.

Pharmacokinetic Modeling and Simulation with Pharmacogenetic Insights Support the Relevance of Therapeutic Drug Monitoring for Myeloablative Busulfan Dosing in Adult HSCT.

Therapeutic drug monitoring (TDM) of busulfan (Bu) is well-established in pediatric hematopoietic stem cell transplantation (HSCT), but its use in adults is limited due to a lack of clear recommendations and scarcity of evidence regarding its utility. GSTA1 promoter variants are reported to affect Bu clearance in both adults and pediatric patients. This study aimed to evaluate the value of preemptive genotyping GSTA1 and body composition (obesity) in individualizing Bu dosing in adults, through pharmacokinetic (PK) modeling and simulations. A population pharmacokinetic (PopPK) model was developed and validated with data from 60 adults who underwent HSCT. Simulations assessed different dosing scenarios based on body size metrics and GSTA1 genotypes. Due to the limited number of obese patients in the cohort, the effect of obesity on Bu pharmacokinetics (PK) was evaluated in silico using a physiologically-based pharmacokinetic (PBPK) model and relevant virtual populations from Simcyp software. Patients with at least 1 GSTA1*B haplotype had 17% lower clearance on average. PopPK simulations indicated that adjusting doses based on genotype increased the probability of achieving the target exposure (3.7 to 5.5 mg.h/L) from 53% to 60 % in GSTA1*A homozygous patients, and from 50% to 61% in *B carriers. Still, Approximately 40% of patients would not achieve this therapeutic window without TDM. A 2-sample optimal design was validated for routine model-based Bu first dose AUC0-∞ estimation, and the model was implemented in the Tucuxi user-friendly TDM software. PBPK simulations confirmed body surface area-based doses of 29 to 31 mg/m2/6h as the most appropriate, regardless of obesity status. This study emphasizes the importance of individualized Bu dosing strategies in adults to achieve therapeutic targets. Preemptive genotyping alone may not have a significant clinical impact, and routine TDM may be necessary for optimal transplantation outcomes.

Genital chronic GVHD in men after hematopoietic stem cell transplantation: a single-center cross-sectional analysis of 155 patients.

We assessed the prevalence and clinical features of genital skin changes in men after allogeneic hematopoietic stem cell transplantation (HSCT) and evaluated the correlation between genital chronic graft-versus-host disease (cGVHD) and other manifestations of cGVHD as well as sexual issues. In a cross-sectional cohort study, 155 male recipients alive 1 year or more after HSCT were assessed during their annual follow-up evaluation. Correlation between genital skin changes and other cGVHD manifestations was evaluated, and post-transplantation sexual contentment and sexual functioning were assessed by 2 self-assessment questionnaires, including the 5-item version of the International Index of Erectile Function (IIEF-5) and the modified Brief Sexual Symptom Checklist (mBSSC). Median time between HSCT and genital examination was 5.9 years (range, 1 to 30.3 years). Thirty-one of 155 patients (20%) presented with genital skin changes. Twenty-one of those (13%) presented clinically inflammatory genital skin changes considered as genital cGVHD: 12 had inflammatory (noninfectious) balanoposthitis, 6 had lichen sclerosis-like lesions, 5 had phimosis, and 2 patients had more than 1 feature. Patients with inflammatory genital skin changes had a significantly higher coincidence of oral (P < .0001), ocular (P < .002), and/or cutaneous cGVHD (P < .026) when compared with patients without genital lesions. The rate of IIEF-5 questionnaire response was 59% (91 of 155). Among them, 67% reported erectile dysfunction. Erectile dysfunction was significantly more frequent in patients with genital cGVHD (P = .0075). Seventy-five of 155 patients (48%) answered the mBSSC questionnaire. Only 40% of them reported sexual contentment. Genital skin changes in male recipients after allogeneic HSCT are frequent and seem to be an under-reported relevant late effect. Inflammatory genital skin changes can be considered as a form of genital cGVHD often associated with manifestations of extragenital mucocutaneous cGVHD.

Lung histology predicts outcome of bronchiolitis obliterans syndrome after hematopoietic stem cell transplantation.

Bronchiolitis obliterans (BO) is a severe complication after allogeneic hematopoietic stem cell transplantation with an unfavorable prognosis. Lung biopsy remains the gold standard for diagnosis. In this retrospective single-center study, we describe 33 patients who underwent biopsy for suspected BO. Ten patients had constrictive BO (CBO); 9 had lymphocytic bronchiolitis (LB), characterized by lymphocytic infiltration of the bronchioles. Six additional patients (4, CBO; 2, LB) had concomitant infection; 8 had other pathological diagnoses. Seven patients with CBO and 3 with LB met the National Institutes of Health consensus BO syndrome definition criteria. An additional 7 patients with histologically confirmed CBO did not meet the consensus definition, 4 of them because of concomitant airway infection. At diagnosis, there were no significant differences between the CBO and LB groups in clinical presentation; pulmonary function tests (median forced expiratory volume in one second [FEV1] at baseline, 90.4% and 99% predicted, at time of video-assisted thoracoscopic surgery, 55.1% and 60.8% for CBO and LB groups, respectively); and chest scans. Treatment was similar in both groups but outcome was different depending on histological findings. FEV1 significantly improved in LB patients compared with CBO patients. Survivals at 1 and 3 years were 77% ± 12% and 60% ± 14% for patients with CBO and 91% ± 9% for patients with LB (P = .028). Lung biopsy in patients with suspected BO enables better characterization of the pattern of BO syndrome. In contrast to CBO, LB is associated with a good long-term prognosis.