Sirolimus treatment for intractable lymphatic anomalies: an open-label, single-arm, multicenter, prospective trial.

Introduction: Intractable lymphatic anomalies (LAs) include cystic lymphatic malformation (LM; macrocystic, microcystic, or mixed), generalized lymphatic anomaly, and Gorham-Stout disease. LAs can present with severe symptoms and poor prognosis. Thus, prospective studies for treatments are warranted. We conducted a prospective clinical trial of sirolimus for intractable LAs. Methods: This was an open-label, single-arm, multicenter, prospective trial involving five institutions in Japan. All patients with LAs received oral sirolimus once daily, and the dose was adjusted to ensure that the trough concentration remained within 5-15 ng/mL. We prospectively assessed the drug response (response rate for radiological volumetric change in target lesion), performance state, change in respiratory function, visceral impairment (pleural effusion, ascites, bleeding, pain), laboratory examination data, quality of life (QOL), and safety at 12, 24, and 52 weeks of administration. Results: Eleven patients with LAs (9 generalized lymphatic anomaly, 1 cystic LM, 1 Gorham-Stout disease) were treated with sirolimus, of whom 6 (54.5%; 95% confidence interval: 23.4-83.3%) demonstrated a partial response on radiological examination at 52 weeks of administration. No patients achieved a complete response. At 12 and 24 weeks of administration, 8 patients (72.7%) already showed a partial response. However, patients with stable disease showed minor or no reduction after 12 weeks. Adverse events, such as stomatitis, acneiform dermatitis, diarrhea, and fever, were common with sirolimus. Sirolimus was safe and tolerable. Conclusion: Sirolimus can reduce the lymphatic tissue volume in LAs and may lead to improvements in clinical symptoms and QOL.

Assessment of pulmonary artery size at birth as a prognostic factor in congenital diaphragmatic hernia: results of a multicenter study in Japan.

OBJECTIVE: To assess the reliability of pulmonary artery (PA) parameters as a prognostic marker in neonates with isolated left-sided congenital diaphragmatic hernia (IL-CDH). STUDY DESIGN: A retrospective cohort study conducted by the Japanese CDH Study Group (JCDHSG). RESULTS: 323 IL-CDH patients registered with the JCDHSG were included. 272 patients survived to 90 days of age. Right PA (RPA) and left PA (LPA) diameters and pulmonary artery index (PAIndex) at birth were significantly larger in survivors. The cutoff values of RPA and LPA diameters and PAIndex for survival up to 90 days were 3.2 mm, 2.8 mm and 83.7, respectively, and logistic regression analysis showed that these were significantly related to survival. Multiple logistic regression analysis showed that both the PA parameters and liver herniation were significantly related to survival. CONCLUSIONS: The three PA parameters at birth can predict clinical outcomes and are considered as independent risk factors of liver herniation.

Outcomes of congenital diaphragmatic hernia among preterm infants: inverse probability of treatment weighting analysis.

OBJECTIVES: To evaluate the survival and intact-survival rates among preterm infants with congenital diaphragm hernia (CDH). STUDY DESIGN: Multicenter retrospective cohort study of 849 infants born between 2006 and 2020 at 15 Japanese CDH study group facilities. Multivariate logistic regression analysis adjusted using inverse probability treatment weighting (IPTW) method was used. We also compare trends of intact-survival rates among term and preterm infants with CDH. RESULTS: After adjusting using the IPTW method for CDH severity, sex, APGAR score at 5 min, and cesarean delivery, gestational age and survival rates have a significantly positive correlation [coefficient of determination (COEF) 3.40, 95% confidence interval (CI), 1.58-5.21, p value <0.001] and higher intact-survival rate [COEF 2.39, 95% CI, 1.73-4.06, p value 0.005]. Trends of intact-survival rates for both preterm and term infants had significantly changed, but improvement in preterm infants was much smaller than in term infants. CONCLUSION: Prematurity was a significant risk factor for survival and intact-survival among infants with CDH, regardless of adjustment for CDH severity.

Development of mortality prediction models for infants with isolated, left-sided congenital diaphragmatic hernia before and after birth.

BACKGROUND: Mortality prediction of congenital diaphragmatic hernia (CDH) is essential for developing treatment strategies, including fetal therapy. Several researchers have reported prognostic factors for this rare but life-threatening condition; however, the optimal combination of prognostic factors remains to be elucidated. OBJECTIVES: This study aimed to develop the most discriminative prenatal and postnatal models to predict the mortality of infants with an isolated left-sided CDH. METHODS: This multi-institutional retrospective cohort study included infants with CDH born at 15 tertiary hospitals of the Japanese CDH Study Group between 2011 and 2016. We developed multivariable logistic models with every possible combination of predictors and identified models with the highest cross-validated area under the receiver operating characteristic curve (AUC) for prenatal and postnatal predictions. RESULTS: Among 302 eligible infants, 44 died before discharge. The prenatal mortality prediction model was based on the observed/expected lung area to head circumference ratio (O/E LHR), liver herniation, and stomach herniation (AUC, 0.830). The postnatal mortality prediction model was based on O/E LHR, liver herniation, and the lowest oxygenation index (AUC, 0.944). CONCLUSION: Our models can facilitate the prenatal and postnatal mortality prediction of infants with isolated left-sided CDH.

A predictive scoring system for small diaphragmatic defects in infants with congenital diaphragmatic hernia.

PURPOSE: To develop a predictive score for small diaphragmatic defects in infants with congenital diaphragmatic hernia (CDH) for determining thoracoscopic surgery indication. METHODS: The Japanese CDH Study Group cohort was randomly divided into derivation (n = 397) and validation (n = 396) datasets. Using logistic regression, a prediction model and weighted scoring system for small diaphragmatic defects were created from derivation dataset and validated with validation dataset. RESULTS: Six weighted variables were selected: no hydramnios, 1 point; 1 min Apgar score of 5-10, 1 point; apex type of the lung (left lung is detected radiographically in apex area), 1 point; oxygenation index < 8, 1 point; abdominal nasogastric tube (tip of the nasogastric tube is detected radiographically in the abdominal area), 2 points; no right-to-left flow of ductus arteriosus, 1 point. In validation dataset, rates of small diaphragmatic defects for Possible (0-3 points), Probable (4-5 points), and Definite (6-7 points) groups were 36%, 81%, and 94%, respectively (p < 0.001). Additionally, sensitivity, specificity, positive predictive value, and C statistics were 0.78, 0.79, 0.88, 0.76, and 0.45, 0.94, 0.94, 0.70 for Probable and Definite groups, respectively. CONCLUSION: Our scoring system effectively predicted small diaphragmatic defects in infants with CDH.

The efficacy of the postnatal nasogastric tube position as a prognostic marker of left-sided isolated congenital diaphragmatic hernia.

PURPOSE: The prenatal diagnosis of the stomach position in congenital diaphragmatic hernia (CDH) has been a reliable prognostic factor, but few studies have focused on the postnatal position. We therefore evaluated the significance of the nasogastric (NG) tube position just after birth. METHODS: The Japanese CDH Study Group database enrolled 1037 CDH neonates over 15 years. In our multicenter retrospective study, 464 cases of left-sided isolated CDH with prenatal diagnoses were divided into two groups: NG tube below the diaphragm (BD; n = 190) or above the diaphragm (AD; n = 274). The primary outcome was the 90-day survival rate, and the secondary outcomes were mechanical ventilation duration, hospitalization duration, and recurrence rate. RESULTS: The BD group had a significantly higher 90-day survival rate (98.4 vs. 89.4%, p < 0.001), shorter mechanical ventilation (11 vs. 19 days, p < 0.001), shorter hospitalization (38 vs. 59 days, p < 0.001), and lower recurrence rate (p = 0.002) than the AD group. A multivariate analysis showed that BD (adjusted odds ratio, 3.68; 95% confidence interval 1.02-13.30) was a favorable prognostic factor for the 90-day survival. CONCLUSION: The assessment of the NG tube position revealed it to be a reliable prognostic factor of left-sided isolated CDH. Therefore, it should be included as a routine assessment.

IL13 and periostin in active fibrogenic areas of the extrahepatic bile ducts in biliary atresia patients.

BACKGROUND: The leading pathology of biliary atresia (BA) is inflammatory and fibrous obstruction of extrahepatic bile duct, but the pathogenesis remains unclear. IL13 is a cytokine associated with allergies and inflammatory fibrosis, and periostin induces fibrogenesis by stimulation with IL13. We analyzed the involvement of IL13 and periostin in inflammatory fibrosis in the extrahepatic bile duct of BA patients. MATERIALS AND METHODS: Surgically resected tissues from the hepatic hilar area of BA patients were immunostained with CD45, α-SMA, IL13 and periostin and statistically analyzed. Fibroblasts from the resected tissue were cultured with recombinant IL13, and periostin production was analyzed by quantitative polymerase chain reaction and Western blotting. RESULTS: IL13 was stained in 93% of large and micro bile ducts, and 92.1% matched with the CD45 location (p = 0.006) around the large bile ducts. Periostin staining correlated with the localization of IL13 and αSMA (p < 0.001) around the large bile ducts. Periostin mRNA and protein were upregulated by IL13 stimulation in cultured fibroblasts. CONCLUSION: IL13 was associated with induced periostin expression by fibroblasts, playing a vital role in the pathogenesis of fibrogenesis around the extrahepatic bile duct in BA.

Prenatal predictors of mortality in fetuses with congenital diaphragmatic hernia: a systematic review and meta-analysis.

PURPOSE: This study aimed to evaluate prenatal predictors of mortality in fetuses with congenital diaphragmatic hernia (CDH). METHODS: A systematic literature search was performed to identify relevant observational studies that evaluated the ability of lung-to-head ratio (LHR), observed-to-expected LHR (o/e-LHR), observed-to-expected total fetal lung volume (o/e-TFLV), lung-to-thorax transverse area ratio (L/T ratio), intrathoracic herniation of the liver and the stomach, and side of diaphragmatic hernia, using a threshold for the prediction of mortality in fetuses with CDH. Study quality was assessed using the QUADAS-2 tool. Hierarchical summary receiver operating characteristic curves were constructed. RESULTS: A total of 50 articles were included in this meta-analysis. The QUADAS-2 tool identified a high risk of bias in more than one domain scored in all parameters. Among those parameters, the diagnostic odds ratio of mortality with o/e-LHR < 25%, o/e-TFLV < 25%, and L/T ratio < 0.08 were 11.98 [95% confidence interval (CI) 4.65-30.89], 11.14 (95% CI 5.19-23.89), and 10.28 (95% CI 3.38-31.31), respectively. The predictive values for mortality were similar between the presence of liver herniation and retrocardiac fetal stomach position. CONCLUSIONS: This systematic review suggests that o/e-LHR, o/e-TFLV, and L/T ratio are equally good predictors of neonatal mortality in fetuses with isolated CDH.

Long-Term Outcomes of Congenital Diaphragmatic Hernia: Report of a Multicenter Study in Japan.

BACKGROUND: Treatment modalities for neonates with congenital diaphragmatic hernia (CDH) have greatly improved in recent years, with a concomitant increase in survival. However, long-term outcomes restrict the identification of optimal care pathways for CDH survivors in adolescence and adulthood. Therefore, we evaluated the long-term outcomes within the Japanese CDH Study Group (JCDHSG). METHODS: Participants were born with CDH between 2006 and 2018 according to the JCDHSG. Participants were enrolled in the database at 1.5, 3, 6, and 12 years old. Follow-up items included long-term complications, operations for long-term complication, and home medical care. RESULTS: A total of 747 patients were included in this study, with 626 survivors (83.8%) and 121 non-survivors (16.2%). At 1.5, 3, 6, and 12 years old, 45.4%, 36.5%, 34.8%, and 43.6% developed complications, and 20.1%, 14.7%, 11.5%, and 5.1% of participants required home care, respectively. Recurrence, pneumonia, pneumothorax, gastroesophageal reflux disease, and intestinal obstruction decreased with age, and thoracic deformity increased with age. CONCLUSIONS: As CDH survival rates improve, there is a need for continued research and fine-tuning of long-term care to optimize appropriate surveillance and long-term follow-up.

Predictive factors for fundoplication following esophageal atresia repair.

BACKGROUND: One of the most frequent complications after repair of esophageal atresia (EA) is gastroesophageal reflux disease (GERD). Although GERD-associated EA is known to often require anti-reflux surgery, the predicting factors remain unclear. We retrospectively analyzed EA in our institution. METHODS: Of 65 children with EA treated in our hospital from 1995 to 2018, 45 with Gross C type EA, followed for over 1 year, were enrolled in this study. The patients were divided into fundoplication and non-fundoplication groups and compared in terms of their clinical features. RESULTS: The fundoplication and non-fundoplication groups included 13 and 32 cases, respectively. On univariate analysis, gestational age, body weight, prenatal diagnosis, polyhydramnios, re-do surgery, and gap length of the esophagus differed significantly between the groups (P < 0.05). CONCLUSION: Early delivery, low body weight, and a long gap length are, are considered to be risk factors for fundoplication. However, the present study further showed that prenatal diagnosis and polyhydramnios were also significant contributing factors. The presence of a prenatal diagnosis and polyhydramnios may induce preterm delivery, therefore, cases of polyhydramnios due to suspected EA should be managed to prevent early delivery. Better understanding of the postnatal course after surgery is required, especially for prenatal diagnosis cases.

Best pre-ductal PaO2 prior to extracorporeal membrane oxygenation as predictor of mortality in patients with congenital diaphragmatic hernia: a retrospective analysis of a Japanese database.

PURPOSE: Predicting lethal pulmonary hypoplasia in infants with congenital diaphragmatic hernia (CDH) before extracorporeal membrane oxygenation (ECMO) initiation is difficult. This study aimed to predict lethal pulmonary hypoplasia in patients with CDH prior to ECMO. METHODS: This was a multicenter cohort study involving neonates prenatally diagnosed with isolated unilateral CDH (born 2006-2020). Patients who required ECMO due to respiratory insufficiency were included in this study. Patients who underwent ECMO due to transient disorders were excluded from analysis. Blood gas analysis data within 24 h of birth were compared between survivors and non-survivors. Predictive abilities were assessed for factors with significant differences. RESULTS: Overall, 34 patients were included (18 survivors and 16 non-survivors). The best pre-ductal PaO2 was significantly lower in non-survivors than in survivors (50.4 [IQR 30.3-64.5] vs. 67.5 [IQR 52.4-103.2] mmHg, respectively; p = 0.047). A cutoff PaO2 of 42.9 mmHg had a sensitivity, specificity, and positive predictive value of 50.0%, 94.4%, and 88.9%, respectively, to predict mortality. CONCLUSION: The best PaO2 within 24 h after birth predicted mortality following ECMO initiation. This should be shared to families and caregivers to optimize the best interests of the infants with CDH.

Optimal timing of delivery for pregnancies with prenatally diagnosed congenital diaphragmatic hernia: a propensity-score analysis using the inverse probability of treatment weighting.

OBJECTIVE: To evaluate the optimal timing of neonates with prenatally diagnosed congenital diaphragmatic hernia (CDH). METHODS: Data from a retrospective cohort study conducted by the Japanese CDH Study Group between 2011 and 2018 were divided into two groups according to delivery timing: 36-37 and 38-41 weeks of gestation (wg). Death before 90 days as the primary outcome and the duration of hospitalization, oxygen therapy and tube feeding at discharge as the secondary outcomes were analyzed with generalized linear model applying inverse probability of treatment weighting method. We also performed layered analysis according to stomach position. RESULT: Among 493 neonates with prenatally diagnosed, isolated and left CDH, 237 were born at 38-41wg. The duration of hospitalization was significantly shorter in those born at 38-41wg, especially among those with stomach malposition, and the other outcomes showed no difference. CONCLUSIONS: Delivery at 38-41wg could be beneficial for those with high grade stomach position.

Thoracoscopic repair of congenital diaphragmatic hernia in neonates: findings of a multicenter study in Japan.

PURPOSE: We compared the efficacy of thoracoscopic repair (TR) with that of open repair (OR) for neonatal congenital diaphragmatic hernia (CDH). METHODS: The subjects of this multicenter retrospective cohort study were 524 infants with left-sided isolated CDH, diagnosed prenatally, and treated at one of 15 participating hospitals in Japan between 2006 and 2018. The outcomes of infants who underwent TR and those who underwent OR were compared, applying propensity score matching. RESULTS: During the study period, 57 infants underwent TR and 467 underwent OR. Ten of the infants who underwent TR required conversion to OR for technical difficulties and these patients were excluded from the analysis. The survival rate at 180 days was similar in both groups (TR 98%; OR 93%). Recurrence developed after TR in 3 patients and after OR in 15 patients (TR 7%, OR 3%, p = 0.40). The propensity score was calculated using the following factors related to relevance of the surgical procedure: prematurity (p = 0.1), liver up (p < 0.01), stomach position (p < 0.01), and RL shunt (p = 0.045). After propensity score matching, the multivariate analysis adjusted for severity classification and age at surgical treatment revealed a significantly shorter hospital stay (odds ratio 0.50) and a lower incidence of chronic lung disease (odds ratio 0.39) in the TR group than in the OR group. CONCLUSIONS: TR can be performed safely for selected CDH neonates with potentially better outcomes than OR.

Optimal timing of surgery in infants with prenatally diagnosed isolated left-sided congenital diaphragmatic hernia: a multicenter, cohort study in Japan.

PURPOSE: To date, there is no compelling evidence of the optimal timing of surgery for congenital diaphragmatic hernia (CDH). This study aimed to establish the optimal timing of surgery in neonates with isolated left-sided CDH. METHODS: This multicenter cohort study enrolled 276 patients with isolated left-sided CDH at 15 institutions. Based on the timing of surgery, the patients were classified into four groups [< 24 h (G1), 24-47 h (G2), 48-71 h (G3), and ≥ 72 h (G4)]. The clinical outcomes were compared among the groups using a logistic regression model, after adjusting for potential confounders, such as disease severity. RESULTS: Multivariate analyses showed that G2 also had a lower mortality rate than the other groups. In mild and severe cases, there were no significant differences in mortality across the four groups. In moderate cases, G2 resulted in significantly increased survival rates, compared with G1. CONCLUSION: The study results suggest that surgery within 24 h of birth is not recommended for patients with moderate severity CDH, that there is no benefit in the delay of surgery for more than 72 h in mild severity CDH patients, and that there is no definite optimal time to perform surgery in severe cases of CDH.

Maldevelopment of intrapulmonary bronchial cartilage in congenital diaphragmatic hernia.

BACKGROUND: Pulmonary hypoplasia is an important cause of morbidity and mortality in infants with congenital diaphragmatic hernia (CDH). This study aimed to verify our hypothesis that the abnormal development of bronchial cartilage as well as alveolar immaturity, might play a central role in hypoplasia of the lung in human CDH. METHOD: We retrospectively analyzed autopsied lungs from 10 CDH cases and compared with nine age-matched controls to assess the bronchial cartilage and alveolar maturity using morphological techniques. RESULT: Ki-67 and thyroid transcription factor-1 (TTF-1) expression in the alveoli significantly increased in bilateral lungs with CDH. The shortest distance from the bronchial cartilage to the pleura was significantly shorter in ipsilateral (left) lungs with CDH, showing a positive correlation with the radial alveolar count (RAC). Regarding the small bronchial cartilages less than 20 000 µm2 , the average cartilage area significantly decreased in left lungs with CDH, and tended to decrease in right lungs with CDH. In addition, cartilage around the bronchi less than 200 µm in diameter tended to be smaller in left lungs with CDH. In contrast, regarding the cartilage around the bronchi 200 to 400 µm in diameter, the ratio of the total cartilage area relative to the bronchial diameter tended to be higher in left lungs with CDH, although there was a large variation. CONCLUSIONS: These opposite directional cartilage abnormalities around the distal and more proximal bronchi support our hypothesis that abnormal development of bronchial cartilage might play an important role in the hypoplastic lung in CDH.

Risk factors for pneumothorax associated with isolated congenital diaphragmatic hernia: results of a Japanese multicenter study.

PURPOSE: This study aimed to elucidate the clinical characteristics of neonates with congenital diaphragmatic hernia (CDH) associated with pneumothorax and evaluate the risk factors for the development of pneumothorax. METHODS: A retrospective cohort study was conducted in the 15 institutions participating in the Japanese CDH Study Group. A total of 495 neonates with isolated CDH who were born between 2011 and 2018 were analyzed in this study. RESULTS: Among the 495 neonates with isolated CDH, 52 (10.5%) developed pneumothorax. Eighteen (34.6%) patients developed pneumothorax before surgery, while 34 (65.4%) developed pneumothorax after surgery. The log-rank test showed that the cumulative survival rate was significantly lower in patients with pneumothorax than in those without pneumothorax. Univariate analysis revealed significant differences between patients with pneumothorax and those without pneumothorax with regard to the best oxygenation index within 24 h after birth, mean airway pressure (MAP) higher than 16 cmH2O, diaphragmatic defect size, and need for patch closure. Multiple logistic regression analysis indicated that only the MAP was associated with an increased risk of pneumothorax. CONCLUSIONS: The cumulative survival rate was significantly lower in isolated CDH patients with pneumothorax than in those without pneumothorax. A higher MAP was a risk factor for pneumothorax in CDH patients.

Gallbladder wall abnormality in biliary atresia of mouse Sox17+/- neonates and human infants.

Biliary atresia (BA) is characterized by the inflammation and obstruction of the extrahepatic bile ducts (EHBDs) in newborn infants. SOX17 is a master regulator of fetal EHBD formation. In mouse Sox17+/- BA models, SOX17 reduction causes cell-autonomous epithelial shedding together with the ectopic appearance of SOX9-positive cystic duct-like epithelia in the gallbladder walls, resulting in BA-like symptoms during the perinatal period. However, the similarities with human BA gallbladders are still unclear. In the present study, we conducted phenotypic analysis of Sox17+/- BA neonate mice, in order to compare with the gallbladder wall phenotype of human BA infants. The most characteristic phenotype of the Sox17+/- BA gallbladders is the ectopic appearance of SOX9-positive peribiliary glands (PBGs), so-called pseudopyloric glands (PPGs). Next, we examined SOX17/SOX9 expression profiles of human gallbladders in 13 BA infants. Among them, five BA cases showed a loss or drastic reduction of SOX17-positive signals throughout the whole region of gallbladder epithelia (SOX17-low group). Even in the remaining eight gallbladders (SOX17-high group), the epithelial cells near the decidual sites were frequently reduced in the SOX17-positive signal intensity. Most interestingly, the most characteristic phenotype of human BA gallbladders is the increased density of PBG/PPG-like glands in the gallbladder body, especially near the epithelial decidual site, indicating that PBG/PPG formation is a common phenotype between human BA and mouse Sox17+/- BA gallbladders. These findings provide the first evidence of the potential contribution of SOX17 reduction and PBG/PPG formation to the early pathogenesis of human BA gallbladders.This article has an associated First Person interview with the joint first authors of the paper.

Novel Risk Score for Fetuses with Congenital Diaphragmatic Hernia Based on Ultrasound Findings.

INTRODUCTION: We aimed to establish and validate a risk score for fetuses with congenital diaphragmatic hernia (CDH) using only prenatal ultrasound findings. MATERIAL AND METHODS: Derivation (2011-2016, n = 350) and validation (2006-2010, n = 270) cohorts were obtained from a Japanese CDH study group database. Using a logistic regression analysis, we created a prediction model and weighted scoring system from the derivation dataset and calculated the odds ratio of an unsatisfactory prognosis (death within 90 days of life or hospitalization duration exceeding 180 days). Five adverse prognostic factors obtained using prenatal ultrasound, including an observed/expected lung area-to-head circumference ratio (o/eLHR) <25%, liver herniation occupying more than one-third of the thoracic space, thoracic stomach, right-side CDH, and severe malformations, were used as predictors. The obtained model was validated using the validation cohort. RESULTS: The unsatisfactory prognosis prediction model was obtained based on the adjusted odds ratios. The C statistics of the model were 0.83 and 0.80 in the derivation and validation datasets, respectively. The five variables were weighted proportionally to their adjusted odds ratios for an unsatisfactory prognosis (o/eLHR <25%, 1 point; liver herniation occupying more than one-third of the thoracic space, 1 point; thoracic stomach, 1 point; right-side CDH, 2 points; and severe malformations, 3 points). Unsatisfactory prognosis rates for the low- (0-2 points), intermediate- (3-5 points), and high-risk (6-8 points) groups were 17, 46, and 100%, respectively (p < 0.001), in the validation cohort. CONCLUSION: Our simple risk score effectively predicted the prognosis of fetuses with CDH.

Immunologic Effects of Sirolimus in Patients With Vascular Anomalies.

Emerging data have suggested that sirolimus may be a treatment option for complicated vascular anomalies (VAs). The present study aimed to investigate the immunologic effects of sirolimus treatment for 6 months in patients with VAs. Blood samples obtained from the patients enrolled in 2 multicenter studies to investigate the efficacy of sirolimus for VAs before and after sirolimus treatment for 6 months were used. Data for total white blood cell count, absolute lymphocyte count, serum immunoglobulins (Igs) levels (IgG, IgA, IgM), lymphocyte proliferation assays with mitogens including phytohemagglutinin and concanavalin A, and flow cytometric analysis of lymphocyte subsets were evaluated. A total of 18 patients with VAs receiving sirolimus treatment were included in the study. Comparisons of white blood cell, absolute lymphocyte count, IgG, IgA, IgM, and reaction rates of phytohemagglutinin and concanavalin A revealed no significant differences before and after treatment. No significant differences were observed in the absolute counts of lymphocyte subtypes before and after treatment, except for regulatory T-cell counts, which were significantly decreased after treatment. Severe infections were not observed during sirolimus treatment. The immunologic parameters assessed in the present study were hardly affected by sirolimus treatment for 6 months in patients with VAs.