Ledipasvir-sofosbuvir and sofosbuvir plus ribavirin in patients with chronic hepatitis C and bleeding disorders

INTRODUCTION

Chronic hepatitis C virus (HCV) infection is prevalent among patients with inherited bleeding disorders and is a leading cause of mortality in those with haemophilia.

AIM

We evaluated the efficacy and safety of ledipasvir-sofosbuvir and sofosbuvir plus ribavirin in patients with chronic HCV genotype 1-4 infection and an inherited bleeding disorder.

METHODS

Ledipasvir-sofosbuvir was administered for 12 weeks to patients with genotype 1 or 4 infection and for 12 or 24 weeks to treatment-experienced cirrhotic patients with genotype 1 infection. Patients with genotype 2 and 3 infection received sofosbuvir plus ribavirin for 12 and 24 weeks respectively.

RESULTS

The majority of the 120 treated patients had a severe bleeding disorder (55%); overall, 65% of patients had haemophilia A and 26% of patients had haemophilia B; 22% were HIV coinfected. Sustained virologic response at 12 weeks posttreatment was 99% (98/99) in patients with genotype 1 or 4 infection; 100% (5/5) in treatment-experienced cirrhotic patients with genotype 1 infection; 100% (10/10) in patients with genotype 2 infection; and 83% (5/6) in patients with genotype 3 infection. There were no treatment discontinuations due to adverse events (AEs). The most frequent non-bleeding AEs were fatigue, headache, diarrhoea, nausea and insomnia. Bleeding AEs occurred in 22 patients, of which all but one were considered unrelated to treatment.

CONCLUSION

Treatment with ledipasvir-sofosbuvir for patients with HCV genotype 1 or 4 infection or sofosbuvir plus ribavirin for patients with genotype 2 or 3 infection was highly effective and well tolerated among those with inherited bleeding disorders.

Evolution of the HCV viral population from a patient with S282T detected at relapse after sofosbuvir monotherapy

Clinical phase II/III studies of the nucleotide analogue HCV NS5B inhibitor sofosbuvir (SOF) have demonstrated high efficacy in HCV-infected patients in combination therapy. To date, resistance to SOF (S282T in NS5B) has rarely been detected in patients. In this study, we investigated the evolution of S282T viral variants detected in one HCV genotype 2b-infected patient who relapsed following 12 weeks of SOF monotherapy. Deep sequencing of the NS5B gene was performed on longitudinal plasma samples at baseline, days 2 and 3 on SOF, and longitudinal samples post-SOF treatment through week 48. Intrapatient HCV evolution was analysed by maximum-likelihood phylogenetic analysis. Deep sequencing analysis revealed a low level pre-existence of S282T at 0.05% of viral sequences (4/7755 reads) at baseline and 0.03% (6/23 415 reads) at day 2 on SOF. Viral relapse was detected at week 4 post-treatment where 99.8% of the viral population harboured S282T. Follow-up analysis determined that S282T levels diminished post-treatment reaching undetectable levels 24-48 weeks post-SOF. Phylogenetic analysis together with the persistence of unique post-treatment mutations in all post-SOF samples suggested that growth of wild type resulted from reversion of the S282T mutant to a wild type and not outgrowth of the baseline wild-type population. Our data suggest that a very low level of pre-existing S282T at baseline in this patient was enriched and transiently detected following SOF monotherapy. Despite relapse with drug resistance to SOF, this patient was successfully retreated with SOF plus ribavirin for 12 weeks and is now cured from HCV infection.

Once daily ledipasvir/sofosbuvir fixed-dose combination with ribavirin in patients with inherited bleeding disorders and hepatitis C genotype 1 infection

AIM

People with inherited bleeding disorders have been disproportionally affected by HCV. We assessed the fixed-dose combination of the NS5A inhibitor ledipasvir (LDV) with the NS5B polymerase inhibitor sofosbuvir (SOF) with ribavirin (RBV) in patients with genotype 1 HCV and inherited bleeding disorders.

METHODS

To be eligible, patients had to be over 18 years of age and have an inherited bleeding disorder. HCV treatment-naïve and -experienced patients could enrol. All patients received LDV 90 mg per SOF 400 mg once daily and weight-based RBV in a divided dose for 12 weeks. The primary efficacy endpoint was sustained virologic response (SVR), defined as HCV RNA below the limit of detection (15 IU mL^-1 ) 12 weeks after the end of treatment (SVR12).

RESULTS

Of the 14 patients enrolled, 8 (57%) had haemophilia A, 3 (21%) had haemophilia B and 2 (14%) had von Willebrand disease, and 1 (7%) had factor XIII deficiency. All 14 patients (100%, 95% CI: 77-100%) achieved SVR12. Treatment was well tolerated: all patients completed therapy, with mostly mild adverse events. No specific safety concerns associated with the patient's underlying bleeding disorders were noted.

CONCLUSION

These results appear to suggest that people with HCV and inherited bleeding disorders can be safely and effectively treated with 12 weeks of LDV/SOF plus RBV.

International guidelines for the diagnosis and management of hereditary haemorrhagic telangiectasia

BACKGROUND

HHT is an autosomal dominant disease with an estimated prevalence of at least 1/5000 which can frequently be complicated by the presence of clinically significant arteriovenous malformations in the brain, lung, gastrointestinal tract and liver. HHT is under-diagnosed and families may be unaware of the available screening and treatment, leading to unnecessary stroke and life-threatening hemorrhage in children and adults.

OBJECTIVE

The goal of this international HHT guidelines process was to develop evidence-informed consensus guidelines regarding the diagnosis of HHT and the prevention of HHT-related complications and treatment of symptomatic disease.

METHODS

The overall guidelines process was developed using the AGREE framework, using a systematic search strategy and literature retrieval with incorporation of expert evidence in a structured consensus process where published literature was lacking. The Guidelines Working Group included experts (clinical and genetic) from eleven countries, in all aspects of HHT, guidelines methodologists, health care workers, health care administrators, HHT clinic staff, medical trainees, patient advocacy representatives and patients with HHT. The Working Group determined clinically relevant questions during the pre-conference process. The literature search was conducted using the OVID MEDLINE database, from 1966 to October 2006. The Working Group subsequently convened at the Guidelines Conference to partake in a structured consensus process using the evidence tables generated from the systematic searches.

RESULTS

The outcome of the conference was the generation of 33 recommendations for the diagnosis and management of HHT, with at least 80% agreement amongst the expert panel for 30 of the 33 recommendations.

Chimeras of the integrin beta subunit mid-region reveal regions required for heterodimer formation and for activation

A central region of the beta2 integrin subunit, RN (residues D300 to C459), was replaced by the equivalent sequences from beta1 and beta7 to give the chimeras beta2RN1 and beta2RN7. Whilst the former construct failed to form heterodimer at the cell surface with alphaL, the later of these could be expressed together with the alphaL subunit to form a variant LFA-1. Based on recent modelling work, the RN region consists of two parts, one is the C-terminal end of the putative A-domain (RB, residues D300 to A359), and the other the mid-region (BN, residues Y360 to C459). Chimeras exchanging the two component regions were made. Of the four resultant chimeras, only the beta2RB1 chimera failed to support LFA-1 expression. Thus the beta1 specific residues of this region affect the interaction with the alphaL subunit. Whereas the alphaL/beta2RB7 LFA-1 variant is wildtype like with respect to ICAM-1 adhesion, the alphaLbeta2BN1 and alphaLbeta2BN7, as well as the alphaLbeta2RN7, variants are more adhesive than the wildtype. These results suggest that an authentic beta2 mid-region is, in part, required for maintaining the LFA-1 in a resting state.

Contrast echocardiography for detection of pulmonary arteriovenous malformations

BACKGROUND

Pulmonary arteriovenous malformations (PAVMs) lead to stroke, brain abscess, and hemorrhage in hereditary hemorrhagic telangiectasia (HHT). The current screening approach for PAVMs in HHT patients with chest radiograph (CXR) and oxygen shunt study has not been validated and is thought to be insensitive. We hypothesized that agitated saline contrast echocardiography (ECHO) would be a useful screening test for PAVMs.

METHODS AND RESULTS

A total of 106 sequential HHT patients underwent screening for PAVMs with ECHO in a prospective study. If the test was positive, or if the CXR or shunt study suggested PAVMs, pulmonary angiography was performed. A positive ECHO was defined as appearance of bubbles in the left atrium after injection of agitated saline solution. A positive shunt study was defined as a partial pressure of oxygen in arterial blood <500 mm Hg while breathing 100% oxygen. The mean age was 41 years (range 15-80 years); 66% were female. Forty-four patients had positive ECHO. Forty-one of the 44 patients underwent angiography. Three patients declined further testing. Thirty-three of the 41 patients who underwent angiography were diagnosed with PAVMs. Of the 62 patients with a negative ECHO, 18 underwent angiography because of either a shunt study or CXR that was suggestive of PAVMs. Of these 18 patients, 2 had PAVMs. In the total population of 106 patients, 35 (33%) had PAVMs. ECHO was the only positive screening test in 11 of 35 (31%) patients. The diagnosis of PAVMs in these 11 patients would have otherwise been missed.

CONCLUSIONS

ECHO is a useful screening tool for PAVMs in HHT.

Transcatheter embolotherapy of maternal pulmonary arteriovenous malformations during pregnancy

STUDY OBJECTIVES

To determine if transcatheter embolotherapy is safe and effective for the treatment of pulmonary arteriovenous malformations during pregnancy.

DESIGN

Prospective study.

SETTING

Specialized hereditary hemorrhagic telangiectasia centers at Yale University School of Medicine and St. Michael's Hospital, University of Toronto.

PATIENTS

Seven pregnant women (age range, 24 to 34 years; gestational age range, 16 to 36 weeks) undergoing transcatheter embolotherapy.

INTERVENTIONS

Transcatheter embolotherapy in all patients.

MEASUREMENTS AND RESULTS

Thirteen pulmonary arteriovenous malformations in seven patients were embolized with detachable silicone balloons and/or stainless steel coils without incident. The estimated fetal radiation dose ranged from < 50 to 220 mrad. No complications of pulmonary arteriovenous malformations occurred in any of the patients after transcatheter embolotherapy. The mothers went on to deliver healthy babies in all cases.

CONCLUSIONS

Transcatheter embolotherapy of maternal pulmonary arteriovenous malformations performed by an experienced radiologist appears to be safe and effective after 16 weeks of gestational age.

Effect of integrin beta 2 subunit truncations on LFA-1 (CD11a/CD18) and Mac-1 (CD11b/CD18) assembly, surface expression, and function

LFA-1 (CD11a/CD18) and Mac-1 (CD11b/CD18) are members of the beta2 integrins involved in leukocyte function during immune and inflammatory responses. We aimed to determine a minimized beta2 subunit that forms functional LFA-1 and Mac-1. Using a series of truncated beta2 variants, we showed that the subregion Q23-D300 of the beta2 subunit is sufficient to combine with the alphaL and alphaM subunits intracellularly. However, only the beta2 variants terminating after Q444 promote cell surface expression of LFA-1 and Mac-1. Thus, the major cysteine-rich region and the three highly conserved cysteine residues at positions 445, 447, and 449 of the beta2 subunit are not required for LFA-1 and Mac-1 surface expression. The surface-expressed LFA-1 variants are constitutively active with respect to ICAM-1 adhesion and these variants express the activation reporter epitope of the mAb 24. In contrast, surface-expressed Mac-1, both the wild type and variants, require 0. 5 mM MnCl2 for adhesion to denatured BSA. These results suggest that the role of the beta2 subunit in LFA-1- and Mac-1-mediated adhesion may be different.

Summary of Canadian guidelines for the initial management of community-acquired pneumonia: an evidence-based update by the Canadian Infectious Disease Society and the Canadian Thoracic Society

Community-acquired pneumonia (CAP) is a serious illness with a significant impact on individual patients and society as a whole. Over the past several years, there have been significant advances in the knowledge and understanding of the etiology of the disease, and an appreciation of problems such as mixed infections and increasing antimicrobial resistance. The development of additional fluoroquinolone agents with enhanced activity against Streptococcus pneumoniae has been important as well.It was decided that the time had come to update and modify the previous CAP guidelines, which were published in 1993. The current guidelines represent a joint effort by the Canadian Infectious Diseases Society and the Canadian Thoracic Society, and they address the etiology, diagnosis and initial management of CAP. The diagnostic section is based on the site of care, and the treatment section is organized according to whether one is dealing with outpatients, inpatients or nursing home patients.

Summary of Canadian guidelines for the initial management of community-acquired pneumonia: an evidence-based update by the Canadian Infectious Disease Society and the Canadian Thoracic Society

Community-acquired pneumonia (CAP) is a serious illness with a significant impact on individual patients and society as a whole. Over the past several years, there have been significant advances in our knowledge and understanding of the etiology of the disease, and an appreciation of problems such as mixed infections and increasing antimicrobial resistance. The development of additional fluoroquinolone agents with enhanced activity against Streptococcus pneumoniae has been important as well. It was decided that the time had come to update and modify the previous CAP guidelines, which were published in 1993. The current guidelines represent a joint effort by the Canadian Infectious Disease Society and the Canadian Thoracic Society, and they address the etiology, diagnosis and initial management of CAP. The diagnostic section is based on the site of care, and the treatment section is organized according to whether one is dealing with outpatients, inpatients or nursing home patients.

Diagnostic criteria for hereditary hemorrhagic telangiectasia (Rendu-Osler-Weber syndrome)

Hereditary Hemorrhagic Telangiectasia (HHT) is easily recognized in individuals displaying the classical triad of epistaxis, telangiectasia, and a suitable family history, but the disease is more difficult to diagnosis in many patients. Serious consequences may result if visceral arteriovenous malformations, particularly in the pulmonary circulation, are unrecognized and left untreated. In spite of the identification of two of the disease-causing genes (endoglin and ALK-1), only a clinical diagnosis of HHT can be provided for the majority of individuals. On behalf of the Scientific Advisory Board of the HHT Foundation International, Inc., we present consensus clinical diagnostic criteria. The four criteria (epistaxes, telangiectasia, visceral lesions and an appropriate family history) are carefully delineated. The HHT diagnosis is definite if three criteria are present. A diagnosis of HHT cannot be established in patients with only two criteria, but should be recorded as possible or suspected to maintain a high index of clinical suspicion. If fewer than two criteria are present, HHT is unlikely, although children of affected individuals should be considered at risk in view of age-related penetration in this disorder. These criteria may be refined as molecular diagnostic tests become available in the next few years.

Diagnostic criteria for hereditary hemorrhagic telangiectasia (Rendu-Osler-Weber syndrome)

Hereditary Hemorrhagic Telangiectasia (HHT) is easily recognized in individuals displaying the classical triad of epistaxis, telangiectasia, and a suitable family history, but the disease is more difficult to diagnosis in many patients. Serious consequences may result if visceral arteriovenous malformations, particularly in the pulmonary circulation, are unrecognized and left untreated. In spite of the identification of two of the disease-causing genes (endoglin and ALK-1), only a clinical diagnosis of HHT can be provided for the majority of individuals. On behalf of the Scientific Advisory Board of the HHT Foundation International, Inc., we present consensus clinical diagnostic criteria. The four criteria (epistaxes, telangiectasia, visceral lesions and an appropriate family history) are carefully delineated. The HHT diagnosis is definite if three criteria are present. A diagnosis of HHT cannot be established in patients with only two criteria, but should be recorded as possible or suspected to maintain a high index of clinical suspicion. If fewer than two criteria are present, HHT is unlikely, although children of affected individuals should be considered at risk in view of age-related penetration in this disorder. These criteria may be refined as molecular diagnostic tests become available in the next few years.

Diagnostic criteria for hereditary hemorrhagic telangiectasia (Rendu-Osler-Weber syndrome)

Hereditary Hemorrhagic Telangiectasia (HHT) is easily recognized in individuals displaying the classical triad of epistaxis, telangiectasia, and a suitable family history, but the disease is more difficult to diagnosis in many patients. Serious consequences may result if visceral arteriovenous malformations, particularly in the pulmonary circulation, are unrecognized and left untreated. In spite of the identification of two of the disease-causing genes (endoglin and ALK-1), only a clinical diagnosis of HHT can be provided for the majority of individuals. On behalf of the Scientific Advisory Board of the HHT Foundation International, Inc., we present consensus clinical diagnostic criteria. The four criteria (epistaxes, telangiectasia, visceral lesions and an appropriate family history) are carefully delineated. The HHT diagnosis is definite if three criteria are present. A diagnosis of HHT cannot be established in patients with only two criteria, but should be recorded as possible or suspected to maintain a high index of clinical suspicion. If fewer than two criteria are present, HHT is unlikely, although children of affected individuals should be considered at risk in view of age-related penetration in this disorder. These criteria may be refined as molecular diagnostic tests become available in the next few years.

Diagnostic criteria for hereditary hemorrhagic telangiectasia (Rendu-Osler-Weber syndrome)

Hereditary Hemorrhagic Telangiectasia (HHT) is easily recognized in individuals displaying the classical triad of epistaxis, telangiectasia, and a suitable family history, but the disease is more difficult to diagnosis in many patients. Serious consequences may result if visceral arteriovenous malformations, particularly in the pulmonary circulation, are unrecognized and left untreated. In spite of the identification of two of the disease-causing genes (endoglin and ALK-1), only a clinical diagnosis of HHT can be provided for the majority of individuals. On behalf of the Scientific Advisory Board of the HHT Foundation International, Inc., we present consensus clinical diagnostic criteria. The four criteria (epistaxes, telangiectasia, visceral lesions and an appropriate family history) are carefully delineated. The HHT diagnosis is definite if three criteria are present. A diagnosis of HHT cannot be established in patients with only two criteria, but should be recorded as possible or suspected to maintain a high index of clinical suspicion. If fewer than two criteria are present, HHT is unlikely, although children of affected individuals should be considered at risk in view of age-related penetration in this disorder. These criteria may be refined as molecular diagnostic tests become available in the next few years.

Diagnostic criteria for hereditary hemorrhagic telangiectasia (Rendu-Osler-Weber syndrome)

Hereditary Hemorrhagic Telangiectasia (HHT) is easily recognized in individuals displaying the classical triad of epistaxis, telangiectasia, and a suitable family history, but the disease is more difficult to diagnosis in many patients. Serious consequences may result if visceral arteriovenous malformations, particularly in the pulmonary circulation, are unrecognized and left untreated. In spite of the identification of two of the disease-causing genes (endoglin and ALK-1), only a clinical diagnosis of HHT can be provided for the majority of individuals. On behalf of the Scientific Advisory Board of the HHT Foundation International, Inc., we present consensus clinical diagnostic criteria. The four criteria (epistaxes, telangiectasia, visceral lesions and an appropriate family history) are carefully delineated. The HHT diagnosis is definite if three criteria are present. A diagnosis of HHT cannot be established in patients with only two criteria, but should be recorded as possible or suspected to maintain a high index of clinical suspicion. If fewer than two criteria are present, HHT is unlikely, although children of affected individuals should be considered at risk in view of age-related penetration in this disorder. These criteria may be refined as molecular diagnostic tests become available in the next few years.

Diagnostic criteria for hereditary hemorrhagic telangiectasia (Rendu-Osler-Weber syndrome)

Hereditary Hemorrhagic Telangiectasia (HHT) is easily recognized in individuals displaying the classical triad of epistaxis, telangiectasia, and a suitable family history, but the disease is more difficult to diagnosis in many patients. Serious consequences may result if visceral arteriovenous malformations, particularly in the pulmonary circulation, are unrecognized and left untreated. In spite of the identification of two of the disease-causing genes (endoglin and ALK-1), only a clinical diagnosis of HHT can be provided for the majority of individuals. On behalf of the Scientific Advisory Board of the HHT Foundation International, Inc., we present consensus clinical diagnostic criteria. The four criteria (epistaxes, telangiectasia, visceral lesions and an appropriate family history) are carefully delineated. The HHT diagnosis is definite if three criteria are present. A diagnosis of HHT cannot be established in patients with only two criteria, but should be recorded as possible or suspected to maintain a high index of clinical suspicion. If fewer than two criteria are present, HHT is unlikely, although children of affected individuals should be considered at risk in view of age-related penetration in this disorder. These criteria may be refined as molecular diagnostic tests become available in the next few years.

Diffuse pulmonary arteriovenous malformations: characteristics and prognosis

OBJECTIVE

To study the clinical characteristics and prognosis of patients with diffuse pulmonary arteriovenous malformations (AVMs).

DESIGN

Retrospective chart review of all patients (n = 16) with diffuse pulmonary AVMs seen at Yale New Haven Hospital, Johns Hopkins Hospital, and St. Michael's Hospital. Up-to-date follow-up information was obtained in all living patients.

RESULTS

All patients were severely hypoxic. Neurologic complications (stroke or brain abscess) had occurred in 70% of patients by the time of diagnosis. During the follow-up period (mean, 6 years), three patients died and two others developed new neurologic complications. One of the deaths occurred perioperatively during lung transplantation. All patients underwent transcatheter embolotherapy of any large pulmonary AVMs. A selected group underwent pulmonary flow redistribution, a novel technique. Oxygenation did not improve significantly with embolotherapy of the larger AVMs, but there was a small significant improvement in those patients who underwent pulmonary flow redistribution. The majority (85%) of the living patients are currently working or studying full-time.

CONCLUSIONS

Patients with diffuse pulmonary AVMs are at increased risk of neurologic complications. Transcatheter embolotherapy does not significantly improve the profound hypoxia, but it may reduce the risk of neurologic complications. Antibiotic prophylaxis is recommended for bacteremic procedures to prevent brain abscess. These patients can live for many years and lead productive lives. We do not recommend lung transplantation because survival with disease is difficult to predict and we have observed a perioperative transplant death.

Pulmonary hypertension and cardiac function in adult cystic fibrosis: role of hypoxemia

STUDY OBJECTIVES

To determine (1) the prevalence of pulmonary hypertension and cardiac dysfunction in adult cystic fibrosis (CF) patients with severe lung disease, (2) the relationship between these cardiovascular abnormalities and hypoxemia, and (3) the impact of subclinical pulmonary hypertension on survival.

DESIGN

Single-blind, cross-sectional study.

SETTING

Ambulatory clinic of the Adult CF program at a tertiary-level hospital.

PATIENTS

Clinically stable patients with severe lung disease (FEV1 < 40% of predicted normal value) who were not receiving supplemental oxygen. A second cohort of patients in stable condition with less severe lung disease (FEV1 40 to 65% predicted) was also recruited to enable multivariate analysis for the determinants of pulmonary hypertension.

MEASUREMENTS AND RESULTS

Eighteen patients with severe lung disease (FEV1 28 +/- 7% of predicted normal value) were initially studied. Each patient had overnight polysomnography, pulmonary function tests, and Doppler echocardiography. Arterial oxygen saturation (SaO2) was reduced during wakefulness (87.1 +/- 6.1%) and fell during sleep (84.0 +/- 6.6%) while transcutaneous PCO2 was normal during wakefulness (41.1 +/- 6.9 mm Hg) and increased during sleep (46.6 +/- 4.7 mm Hg). Left ventricular size, systolic function, and diastolic function were normal except in one patient who had had a previous silent myocardial infarction due to coronary artery disease. Qualitative assessment of right ventricular function was normal in all patients. Pulmonary artery systolic pressure (PASP) was increased (> 35 mm Hg) in seven patients without clinical evidence of cor pulmonale. Regression analysis was performed by combining these data with data from an additional 15 CF patients with moderately severe lung disease (FEV1 56.3 +/- 8.9% predicted normal) who were recruited to a modified study protocol that included overnight oximetry, pulmonary function tests, and Doppler echocardiography. None of these patients had evidence of hypoxemia and only three had mild elevation of PASP (36, 37, and 39 mm Hg). Linear regression analysis revealed that PASP was significantly correlated with FEV1 (r = -0.44; p = 0.013), and SaO2 during wakefulness (r =-0.60; p = 0.0003), during sleep (r = -0.56; p = 0.0008), and after 6 min of exercise (r = -0.75; p < 0.0001). Multivariate analysis revealed that awake SaO2 was a significantly better predictor of PASP than FEV1 (p = 0.0104). Clinical follow-up of the original cohort for up to 5 years revealed that mortality was significantly higher in those with pulmonary hypertension than those without pulmonary hypertension (p = 0.0129).

CONCLUSIONS

In adult CF patients with severe stable lung disease, left and right ventricular function is well maintained in the absence of significant coronary artery disease; pulmonary hypertension develops in a significant proportion of patients and is strongly correlated with oxygen status, independent of lung function; and subclinical pulmonary hypertension is associated with an increased mortality.

Spinal cord arteriovenous malformations in two patients with hereditary hemorrhagic telangiectasia

We report two cases, in first cousins, of spinal arteriovenous malformations (AVMs) of the perimedullary fistula type and hereditary hemorrhagic telangiectasia (HHT). Spinal AVMs are a rare clinical presentation of HHT, but can be the first manifestation in a child with this disorder. The importance of considering a coexisting disorder of vascular dysplasia, such as HHT, when a child presents with a spinal AVM is discussed.

The role of the cysteine-rich region of the beta2 integrin subunit in the leukocyte function-associated antigen-1 (LFA-1, alphaLbeta2, CD11a/CD18) heterodimer formation and ligand binding

The cysteine-rich region (CRR) of the beta2 integrin subunit was replaced by that of beta1 to give the chimera beta2NV1. Beta2NV1 can combine with alphaL to form a variant leukocyte-function-associated antigen (LFA)-1 on COS cell surface, suggesting that the specificity of the beta2 interaction with alphaL does not lie in the CRR. Unlike those expressing wild-type LFA-1, COS cells expressing alphaL beta2NV1 are constitutively active in intercellular adhesion molecule (ICAM)-1 adhesion. These results suggest that activation of LFA-1 involves the release of an intramolecular constraint, which is maintained, in part, by the authentic beta2 CRR.

A role for heterodimerization in nuclear localization of a homeodomain protein

The A mating type genes of the mushroom Coprinus cinereus encode two families of dissimilar homeodomain proteins (HD1 and HD2). The proteins heterodimerize when mating cells fuse to generate a transcriptional regulator that promotes expression of genes required for early steps in sexual development. In previous work we showed that heterodimerization brings together different functional domains of the HD1 and HD2 proteins; a potential activation domain at the C terminus of the HD1 protein and an essential HD2 DNA-binding motif. Two predicted nuclear localization signals (NLS) are present in the HD1 protein but none are in the HD2 protein. We deleted each NLS separately from an HD1 protein and showed that one (NLS1) is essential for normal heterodimer function. Fusion of the NLS sequences to the C terminus of an HD2 protein compensated for their deletion from the HD1 protein partner and permitted the two modified proteins to form a functional transcriptional regulator. The nuclear targeting properties of the A protein NLS sequences were demonstrated by fusing the region that encodes them to the bacterial uidA (beta-glucuronidase) gene and showing that beta-glucuronidase expression localized to the nuclei of onion epidermal cells. These observations lead to the proposal that heterodimerization regulates entry of the active transcription factor complex to the nucleus.

Current trends in HIV-related hospital admissions and their impact on hospital resource utilization in Ontario

OBJECTIVE

To assess changes in patterns of hospital admissions, in frequency of admissions and in average length of stay (ALOS) at a tertiary HIV referral centre, and to investigate the overall impact of care for patients with HIV infection of AIDS on peer hospitals in Ontario.

DESIGN

Descriptive study.

PARTICIPANTS

Data were obtained on patients with HIV infection or AIDS treated at the Wellesley Hospital in Toronto for the fiscal years (May 1 to Apr. 31) 1990-91, 1991-92 and 1992-93, and on admissions for HIV or AIDS in 9 peer hospitals in Ontario during the same period.

INTERVENTIONS

For the Wellesley Hospital, review of medical records of HIV-related admissions to determine the reasons for admission and to examine concurrent illnesses. For the Wellesley Hospital Hospital and peer hospitals, analysis of changes in ALOS and Resource Intensity Weights (RIWs).

RESULTS

Between May 1, 1990, and Apr. 31, 1993, the number of admissions for treatment of Pneumocystis carinii pneumonia (PCP) fell, but admissions for respiratory infections other than PCP remained very common, although they decreased slightly. Overall, infection remained the main reason for admission. The frequency of gastrointestinal complications necessitating admission increased. The frequency of admissions remained high, although the ALOS decreased significantly. In the period between Apr. 1, 1991, and Mar. 31, 1994, the proportion of HIV-related discharges and total hospital discharges among the 9 peer hospitals remained stable. The HIV-related ALOS decreased substantially. Although the HIV-related average RIW decreased slightly, this measure and the mortality rate are still much higher for HIV-related admissions than for overall admissions.

CONCLUSIONS

This contemporary survey suggests that nonrespiratory infection complications have become the main reason for admission of patients with HIV infection or AIDS, but that the HIV tertiary hospitals are coping with the load of HIV-related admissions and the high average RIW associated with these patients by reducing the ALOS.

Albuterol via Turbuhaler versus albuterol via pressurized metered-dose inhaler in asthma

BACKGROUND

Inhaled albuterol is most commonly self-administered by patients using a pressurized metered-dose inhaler (pMDI) but patients often have difficulty using the device. Dry powder devices such as the multi-dose, inspiratory flow driven inhaler (Turbuhaler) are often better handled by patients.

OBJECTIVE

We sought to compare the efficacy and tolerability of 100 micrograms of albuterol delivered by a multi-dose, inspiratory flow driven inhaler (Turbuhaler) to a standard dose (200 micrograms) delivered by a pMDI (Ventolin) in chronic reversible obstructive airways disease.

METHOD

In 6 centers, we studied 37 adults [19 men and 18 women, mean age 39 +/- 12 years; mean baseline forced expiratory volume in one second (FEV1) 72 +/- 13% (% predicted)] with stable but symptomatic reversible obstructive airways disease as demonstrated by 15% or greater increase in FEV1 following two puffs (200 micrograms) albuterol by pMDI. The crossover design comprised a 1-week run-in and two 2-week treatment periods separated by a 1-week washout. At the start and end of each treatment period, FEV1 was measured at the clinic. Patients self-administered albuterol 100 micrograms (2 x 50 micrograms) via Turbuhaler or 200 micrograms (2 x 100 micrograms) via pMDI in a double-blind fashion four times daily. Morning and evening peak expiratory flow (PEF) was noted daily. All non-study bronchodilators were withheld while open-label albuterol pMDI was offered for rescue.

RESULTS

Of the 37 patients, 30 used inhaled steroids in constant doses throughout the study, one used inhaled cromoglycate and six used no anti-inflammatory therapy. There was no difference between treatment periods in morning PEF, diurnal fluctuation in PEF, increase in PEF following study drug, baseline FEV1 and FEV1 increase following study drug. Although there was no difference in symptom scores between treatments, the use of rescue beta 2-agonist was slightly but significantly higher during the Turbuhaler treatment period (1.34 versus 1.08 inhalations/ day, P = .04). Compliance with study drug was slightly but significantly lower during the Turbuhaler treatment period (87 versus 95%) such that the total number of beta 2-agonist puffs inhaled (scheduled plus rescue) was similar between treatments. With regard to adverse events, both treatments were well tolerated.

CONCLUSIONS

These results suggest that the efficacy and tolerability of albuterol 100 micrograms qid inhaled via Turbuhaler is similar to albuterol 200 micrograms qid, inhaled via pMDI in stable reversible obstructive airways disease.

Transverse myelitis: a reversible complication of bronchial artery embolisation in cystic fibrosis

The case history is presented of a young woman with cystic fibrosis and life threatening haemoptysis. Angiography revealed enlarged bronchial vessels, one of which supplied the contralateral lung. Transverse myelitis developed following bronchial artery embolisation but recovery was rapid and nearly complete. Haemoptysis did not recur during four years of follow up.

Acute and chronic respiratory complications of toxic epidermal necrolysis

Toxic epidermal necrolysis (TEN) is a rare disease resulting in bullous necrosis of the epidermis with partial-thickness loss of skin and mucous membranes. Previous reports of TEN have not focused on respiratory complications. During a 6-year period, 12 patients with biopsy-proven TEN were referred to a regional burn unit at the Wellesley Hospital, Toronto. Five patients required mechanical ventilatory support, and nine showed roentgenographic evidence of respiratory complications that had developed. Intensive therapy in a critical care burn unit resulted in a 75% survival rate. The four nonsurvivors had severe preexisting multisystem disease. Four survivors were observed prospectively, with 3 monthly pulmonary function testings performed. The four survivors tested, even if they did not require mechanical ventilatory support, showed evidence of respiratory involvement. Three patients demonstrated a persistent reduction in carbon monoxide diffusing capacity of up to 35% to 40% below normal. From our case series we suggest that TEN, although primarily a dermatologic condition, may result in life-threatening acute respiratory decompensation requiring ventilatory support and long-term pulmonary function abnormalities. Patients with TEN should be closely monitored for pulmonary complications.

Spirometry and dyspnea in patients with COPD. When small differences mean little

OBJECTIVE

To determine when a difference in FEV1 is sufficiently large to be associated with a noticeable difference in dyspnea symptoms for patients with chronic lung disease.

DESIGN

Cross-sectional analysis of 15 groups (n = 112 patients, 832 contrasts).

SETTING

Respiratory rehabilitation program.

PATIENTS

Patients with COPD (mean FEV1 = 35% predicted).

MEASURES

Patients' perspectives assessed through subjective comparison ratings of dyspnea and of overall health. Relation between the FEV1 and patients' perspectives determined the smallest difference in spirometry that was associated with a noticeable difference in patients' symptoms.

RESULTS

The FEV1 was moderately correlated with patients' ratings of dyspnea (r = 0.29; 95% confidence interval (CI), 0.22 to 0.35). In contrast, the FEV1 was minimally correlated with patients' ratings of overall health (r = 0.10; 95% CI, 0.03 to 0.17). The FEV1 needed to differ by 4% predicted for the average patient to stop rating his or her dyspnea as "about the same" and start rating his or her dyspnea as either "a little bit better" or "a little bit worse" relative to other patients (95% CI, 1.5 to 6.5). This was equivalent to the average patient's FEV1 increasing by 112 mL (starting from 975 mL and ending at 1,087 mL).

CONCLUSIONS

Some statistically significant differences in the FEV1 are so small that they may not represent important differences in symptoms for the average patient with severe COPD; an awareness of the smallest difference in FEV1 that is noticeable to patients can help clinicians interpret the effectiveness of symptomatic treatments.

Survival of acute myelogenous leukemia patients requiring intubation/ventilatory support

A 5-y (1987-1992) retrospective chart review assessed the survival of patients with acute myelogenous leukemia (AML) who required intubation/ventilatory support in the intensive care unit (ICU). Thirty-two patients were identified, average age 52 +/- 19 (range 14-82) y. Seven patients had undergone bone marrow transplantation for AML 2 weeks to 4 months prior to admission. Of the remaining 25 patients, 16 received chemotherapy prior to admission, 6 started or continued chemotherapy in the ICU, and 3 patients did not receive any chemotherapy. The Apache II score, which quantifies illness severity, on admission to the ICU was 32.5 +/- 8.8. The average length of stay was 7.4 d. Twenty-nine patients had diffuse pulmonary infiltrates on admission, 2 patients had large pleural effusions, and 1 patient had severe bronchospasm with a clear chest X-ray. The average PaO2/FiO2, when first stabilized on mechanical ventilation, was 204 +/- 83. Of the 32 patients, 28 died in the ICU, and 3 died shortly after withdrawal of aggressive therapy and discharge to the ward. A single patient survived the hospital admission but died 4 months later at home. The observed vs. the predicted ICU mortality determined by Knaus' method, was significantly greater even for those with lower Apache II scores. Acute myelogenous leukemia patients had a greater mortality than 2 other intubated patient populations in our ICU admitted during the same time period, a group of 126 consecutive admissions and 53 patients with connective tissue disease. The latter 2 control groups only included patients requiring mechanical ventilation. We conclude that AML patients who require ventilatory support for acute respiratory failure rarely survive their ICU admission.

Toxic shock syndrome as the AIDS-defining diagnosis

Toxic shock syndrome (TSS) has been infrequently reported as a complication of AIDS. We present the case of a 24-year-old man, previously unknown to be positive for the human immunodeficiency virus, presenting in septic shock. The literature on TSS in AIDS is reviewed and the association between the two diseases is presented.

Cyclosporine as possible prophylaxis for obstructive airways disease after allogeneic bone marrow transplantation

The objective of this study was to evaluate the impact of cyclosporine (cyclosporin A; CyA) prophylaxis for graft-versus-host disease (GVHD) on the development of obstructive airways disease (OAD) after allogeneic bone marrow transplantation (BMT) in leukemic patients. Patients with normal pulmonary function tests (PFTs) prior to BMT were followed with serial PFTs for the development of OAD. Follow-up PFTs were performed at 3, 6, 9, and 12 months, and thereafter at consecutive yearly intervals. Obstructive airways disease was defined as FEV1 less than 80 percent, ratio of FEV1 over the forced vital capacity (FEV1/FVC) less than 80 percent of predicted, maximal midexpiratory flow rate at 50 percent vital capacity less than 65 percent of predicted, or residual volume greater than 120 percent of predicted. In the period prior to CyA prophylaxis for GVHD development (March 1983 to September 1986), 17 (39 percent) of the 44 patients undergoing BMT developed OAD, compared with 2 (4 percent) of 45 in the post-CyA period (September 1986 to March 1990) (chi 2 = 17; p < 0.00005). Age, sex, type of leukemia, severity of GVHD, histocompatibility status, presence of acute GVHD, and sex mismatch between donor and recipient were not associated with development of OAD. Although chronic GVHD was associated with OAD in univariate analysis, a multivariate logistic regression analysis showed that the only significant independent predictor for OAD was the use of CyA. We conclude that CyA is protective against the development of OAD after BMT in leukemic patients.

Sustained improvement in asthma with long-term use of formoterol fumarate

Inhaled formoterol fumarate, a long acting beta 2 agonist, produces bronchodilatation that is sustained for approximately 12 hours. To determine whether such bronchodilator effects are maintained and asthma control sustained during chronic administration, we monitored airflow indices and clinical control in 112 asthmatic patients who self administered formoterol twice daily for periods ranging from 9 to 12 months. Subjects were recruited immediately following completion of a 3-month double-blind comparison of formoterol, 12 micrograms, bid versus salbutamol, 200 micrograms, qid. Assessments were conducted at baseline, 3, 6, and 9 months, where baseline represents the final visit of the 3-month comparative study. Patients were asked to complete diary cards and twice daily PEFR for a 2-week period before each assessment. Throughout the follow-up study, there was no indication of worsening of asthma control or deteriorating lung function. For the patients who continued to receive formoterol, the previous improvement in asthma control and lung function was maintained at the level reached in the 3-month study. There was an improvement in flow rates and asthma symptoms in the group switched from salbutamol to formoterol by the first clinic visit. This improvement in asthma control and lung function was maintained over the subsequent 6 months. Formoterol was well tolerated during the study period. We conclude that prolonged use of formoterol fumarate twice daily results in sustained improvement in symptoms and flow rates in asthma with no evidence of tachyphylaxis.

A three-month comparison of twice daily inhaled formoterol versus four times daily inhaled albuterol in the management of stable asthma

We compared the efficacy of inhaled formoterol, a long-acting beta 2-agonist, with inhaled albuterol in 145 stable adult asthmatics in a 12-wk multicenter trial. Patients were allocated in randomized double-blind fashion to maintenance therapy with either formoterol 12 micrograms twice a day or albuterol 200 micrograms four times a day in addition to their other asthma medications. Patients were allowed to use "rescue" 100-micrograms albuterol puffs on an as-needed basis. Mean baseline FEV, in the morning before bronchodilator was 2.14 +/- 0.76 L and 1.98 +/- 0.71 L for the formoterol and albuterol groups, respectively, these values being used as baseline covariates in subsequent analysis of predrug and postdrug FEV1. Measured at each clinic visit, morning predrug FEV1 rose significantly with formoterol treatment and was significantly greater at all visits than in the albuterol group, the greatest difference being in Week 8 (2.40 +/- 0.77 versus 1.92 +/- 0.66 L, p less than 0.001). Morning FEV1 30 min postdrug was significantly higher in the formoterol group at Weeks 2 and 8, the trend not reaching statistical significance at other times. Diurnal variation in prebronchodilator peak flow rates was significantly reduced in the formoterol group throughout the trial (17 versus 42 L/min at Week 12, p less than 0.0001). The number of asthma episodes per week was significantly less in the formoterol group during Weeks 4, 8, and 12 as were the number of sleep disruptions during Weeks 2, 4, 6, 8, and 12. Significantly more rescue albuterol was required in the albuterol group by Week 2 and throughout the remainder of the study.(ABSTRACT TRUNCATED AT 250 WORDS)

Aerosol pentamidine for secondary prophylaxis of AIDS-related Pneumocystis carinii pneumonia. A randomized, placebo-controlled study

OBJECTIVE

To assess the safety and efficacy of aerosol pentamidine for secondary prophylaxis of Pneumocystis carinii pneumonia in patients with the acquired immunodeficiency syndrome (AIDS).

PARTICIPANTS

Patients recovering from a first confirmed episode of AIDS-related P. carinii pneumonia who had no evidence of either another active AIDS-defining opportunistic infection or another pulmonary abnormality were considered eligible for the study but were included only if they had received no immunomodulators or antiretroviral agents other than zidovudine within 30 days of entry. One hundred sixty-two patients were randomized and started on the study drug.

INTERVENTION

Patients were randomly assigned to receive aerosol pentamidine, 60 mg per dose, or placebo, delivered using a hand-held, patient-triggered, ultrasonic nebulizer. The induction phase of treatment consisted of 5 doses over 14 days, followed by a maintenance phase beginning on day 21 and consisting of one dose every 2 weeks.

RESULTS

Thirty-two cases of P. carinii pneumonia were diagnosed before the termination of the trial; 27 cases occurred among 78 patients receiving placebo and 5 occurred among 84 patients receiving aerosol pentamidine. Estimates of the cumulative relapse rate of P. carinii pneumonia by 24 weeks were 50% and 9% for the placebo and pentamidine groups, respectively (P less than 0.001). Adverse reactions attributed to the study drug occurred in 15 of 78 patients receiving placebo and in 28 of 84 patients receiving pentamidine (P = 0.04). These were all mild or moderate in severity and did not preclude continued administration of the study drug.

CONCLUSION

Intermittent therapy with aerosol pentamidine is highly effective and well tolerated as secondary prophylaxis for AIDS-related P. carinii pneumonia.

The malignancy-sarcoidosis syndrome

In a retrospective review of six patients with malignancy preceding sarcoidosis, we found four cases of malignant lymphoproliferative disease (LD) and one case each of ovarian cancer and breast cancer. The median interval from onset or relapse of malignancy to sarcoidosis was nine months. Of the four patients with LD, sarcoidosis appeared within six months of termination of chemotherapy for three of the patients and 15 months after allogeneic bone marrow transplantation for the fourth patient. At the time of diagnosis of sarcoidosis, there was no clinical or pathologic evidence of malignancy in the chest. We conclude that in contradistinction to the previously described syndrome of sarcoidosis preceding LD, there exists a syndrome of sarcoidosis following malignancy with or without chemotherapy.

Pulmonary complications following bone marrow transplantation

Pulmonary complications are a common cause of morbidity and mortality after bone marrow transplantation. Some of these complications are infectious and related to the degree of ongoing immunosuppression, and thus vary with the posttransplant marrow reconstitution and the need for continued immunomodulating drugs. Noninfectious complications are related to previous chemotherapy, the transplantation protocol and conditioning regimen, and, in allogeneic transplants, the presence of graft-versus-host disease. The various complications are classified based on their timing after the transplant procedure. A diagnostic and therapeutic approach is outlined and the prognosis is discussed.

A comparison of enprofylline and theophylline in the maintenance therapy of chronic reversible obstructive airway disease

To compare the efficacy and side effects of two xanthine derivatives in the maintenance therapy of reversible obstructive airway disease, 242 patients were assigned in randomized, double-blind fashion to receive either oral enprofylline or theophylline for 5 weeks in addition to their usual maintenance regimens. After a week of placebo xanthine therapy, enprofylline-treated patients received 150 mg of this drug twice daily (b.i.d.) for 3 days, 300 mg b.i.d. for 2 weeks, and 450 mg b.i.d. for 2 weeks. Theophylline was administered in identical doses, except that the final dosage increase was not made if plasma theophylline was 12 mg/ml or higher. At 300 mg b.i.d., both drugs significantly increased morning peak expiratory flow rate (PEFR), the mean increase above baseline being significantly higher for theophylline-treated patients (29.9 +/- 37.2 L/min) than for enprofylline-treated patients (17.4 +/- 36.9 L/min) (p = 0.023). At 450 mg b.i.d., improvement in morning PEFR was not significantly different between theophylline-treated (31.5 +/- 44.4 L/min) and enprofylline-treated groups (23.5 +/- 48.4 L/min). Evening PEFR, FEV1, and asthma symptom scores also improved significantly, demonstrating no significant difference between groups. The incidence of side effects was also similar between groups. We conclude that both enprofylline and theophylline offer useful bronchodilatation in the maintenance therapy of asthma, enprofylline, 450 mg b.i.d., being approximately equivalent to theophylline, 300 or 450 mg b.i.d.

Pulmonary complications of AIDS: a clinical strategy

Infectious and noninfectious forms of pulmonary disease are the most common complications of acquired immune deficiency syndrome (AIDS), and many are amenable to treatment. We describe the clinical and radiologic features of the most common causes of lung disease in AIDS patients and review the drugs available for treatment. In addition, we provide a strategy for the clinical assessment and management of patients with human immunodeficiency virus infection who have lung infiltrates.

Esophageal candidiasis associated with beclomethasone dipropionate aerosol therapy

A 23-year-old woman with asthma developed severe heartburn while using beclomethasone dipropionate. Esophageal candidiasis was diagnosed on endoscopy and confirmed by biopsy. Subsequent studies revealed mild hypogammaglobulinemia and mild impairment of neutrophil candidacidal activity, the significance of which is unknown. Esophageal candidiasis associated with the use of inhaled beclomethasone has not been previously reported.

Massive overdose of colchicine

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Management of chronic ventilatory insufficiency with electrical diaphragm pacing

We have had experience with diaphragm pacing in 24 patients at the Toronto Western Hospital. Fourteen patients have undergone bilateral implants to treat chronic ventilatory insufficiency (CVI) caused by traumatic tetraplegia at the C1/2 level (eight patients), neurogenic apnea (five) and one case of neonatal apnea. Unilateral stimulators for nocturnal pacing have been implanted in five patients with central alveolar hypoventilation (sleep apnea) and five patients who suffered CVI resulting from various etiologies. Of the patients who were ventilatory dependent, 80% were successfully weaned and in the entire series, 58% of the patients are living. Diaphragm pacing was successful in 67%, partially successful in 8% and ineffective in 25%. The major complications were: death by pneumonia, failure of the radio receivers, and infection. Diaphragm pacing is the treatment of choice for patients who are ventilator dependent and tetraplegic from upper cervical trauma or in some cases of neurogenic apnea; it may be life saving for patients who suffer central alveolar hypoventilation.

Idiopathic small airways pathology in patients with graft-versus-host disease following allogeneic bone marrow transplantation

In a retrospective analysis (July 1979 to March 1984) of 120 allogeneic adult bone marrow transplant recipients, we identified seven patients with small-airway disease for whom no microbiologic agent was detected. Six had pulmonary function studies demonstrating air flow obstruction. Five of the seven patients had an open-lung biopsy showing pathologic changes within small airways; these varied from early bronchiolar wall damage to bronchiolitis obliterans. The inflammatory cell infiltrate was peribronchiolar, and consisted of polymorphonuclear leukocytes and lymphocytes in varying proportions. Three of the seven patients recovered following increased immunosuppressive therapy; the other four died. Because all seven patients had acute and chronic graft-versus-host disease, in the absence of any identifiable pathogen, we postulate that small-airway damage represents one of the facets of graft-versus host-disease. An additional analysis of 26 patients with respiratory symptomatology and available histologic material supports the hypothesis that small-airway disease in bone marrow transplant patients represents a risk factor for the subsequent development of respiratory opportunistic infections.

Pulmonary tumor embolism: a critical review of clinical, imaging, and hemodynamic features

Pulmonary tumor embolism is a common finding at autopsy but is generally perceived as a difficult diagnosis to make ante mortem. After a retrospective review of 164 reported cases of pulmonary tumor embolism, we identified a typical profile of clinical, laboratory, and imaging features that may permit confident clinical diagnosis in most patients with this condition. The clinical features include a documented or suspected underlying malignancy, acute to subacute onset of dyspnea, and signs of cor pulmonale. Supportive laboratory features are hypoxemia or increased alveolar-arterial oxygen gradient, and invasive or noninvasive evidence of pulmonary artery hypertension. Typical imaging findings are normal chest radiographs; multiple, subsegmental, peripheral perfusion defects on ventilation-perfusion lung scans; and delayed filling with or without subsegmental filling defects but without a thrombus on pulmonary angiogram. Radiolabeled monoclonal antibody imaging and pulmonary microvascular cytology sampling techniques are promising diagnostic tests for early diagnosis of pulmonary tumor embolism.

Small-airways disease in recipients of allogeneic bone marrow transplants. An analysis of 11 cases and a review of the literature

In a retrospective review of 116 consecutive allogeneic bone marrow transplants (BMT), severe obstructive airways disease was identified in 11 patients. Lung pathology demonstrated bronchiolitis in 9 patients and physiologic studies showed small-airways disease consistent with bronchiolitis in the other 2. None of the 5 patients with associated infection survived, while 3 of the 6 patients without an identified pathogen stabilized or improved. Analysis of the 11 cases presented and all 25 cases reported in the literature (1982 to 1985) supports the conclusion that graft-versus-host disease is a major risk factor for bronchiolitis in BMT recipients. Among the proposed mechanisms for the development of bronchiolitis after allogeneic BMT, the 2 most likely are graft-versus-host disease directly causing bronchiolitis, and increased immunosuppressive therapy given for graft-versus-host disease predisposing to viral bronchiolitis. The available evidence would suggest that it is prudent to obtain serial pulmonary function tests even in asymptomatic patients post-BMT, and particularly in those with chronic graft-versus-host disease, in the hope that early detection will allow for early intervention that will arrest or reverse the progression of the obstructive airways disease.