Microbiota intestinal y cólicos infantiles: ¿hay lugar para los prebióticos, probióticos y posbióticos? / Gut Microbiota and Infant Colic: is there a Place for Prebiotics, Probiotics, and Postbiotics?

El consumo de probióticos, prebióticos y posbióticos, o su combinación, puede contribuir a mantener una microbiota intestinal saludable ya que permite la regulación de su disbiosis en el caso de algunas enfermedades o trastornos, principalmente en los trastornos gastrointestinales funcionales (TGIF). El microbioma intestinal es protagonista esencial en la fisiopatología de los TGIF a través de sus funciones metabólicas y nutricionales, el mantenimiento de la integridad de la mucosa intestinal y la regulación de la respuesta inmunitaria. Las investigaciones realizadas hasta la fecha indican que los probióticos, prebióticos y posbióticos pueden tener efectos inmunomoduladores directos y clínicamente relevantes. Existen pruebas del uso de esta familia de bióticos en individuos sanos para mejorar la salud general y aliviar los síntomas en una serie de enfermedades como los cólicos infantiles. La colonización y establecimiento de la microbiota comienza en el momento del nacimiento; los primeros 2-3 años de vida son fundamentales para el desarrollo de una comunidad microbiana abundante y diversa. Diversos estudios científicos realizados mediante técnicas tradicionales dependientes de cultivo y más recientemente por técnicas moleculares han observado diferencias en las poblaciones bacterianas de bebés sanos y aquellos que sufren TGIF, estos últimos caracterizados por un aumento de especies patógenas y una menor población de bifidobacterias y lactobacilos, en comparación con los primeros. En tal contexto, se considera que la microbiota intestinal como protagonista en el desarrollo de esos trastornos, entre ellos los cólicos infantiles, a través de sus funciones metabólicas, nutricionales, de mantenimiento de la integridad de la mucosa intestinal y regulación de la respuesta inmunitaria. Esto ha abierto la puerta al estudio de la utilización de prebióticos, probióticos y posbióticos en el tratamiento y/o prevención de los TGIF infantiles. El parto vaginal y de término así como la lactancia son fundamentales en la constitución de una microbiota saludable. Como herramientas de apoyo, existen estudios de eficacia que sustentan la administración de esta familia de bióticos, principalmente en los casos en que la lactancia no sea posible o esté limitada. (AU)

The consumption of probiotics, prebiotics, and postbiotics, or a combination of them, can contribute to maintaining a healthy intestinal microbiota as it allows the regulation of its dysbiosis in the case of some diseases or disorders, mainly in functional gastrointestinal disorders (FGIDs). The gut microbiome is an essential player in the pathophysiology of FGIDs through its metabolic and nutritional functions, the maintenance of intestinal mucosal integrity, and the regulation of the immune response. Research results thus far indicate that probiotics, prebiotics, and postbiotics may have direct and clinically relevant immunomodulatory effects. There is evidence regarding the prescription of this family of biotics in healthy individuals to improve overall health and alleviate symptoms in many conditions like infantile colic. The colonization and microbiota establishment begins at birth; the first 2-3 years of life are critical for developing an abundant and diverse microbial community. Several scientific studies performed by traditional culture-dependent techniques and more recently by molecular techniques have observed differences in the bacterial populations of healthy infants and those suffering from FGIDs, the latter characterized by an increase in pathogenic species and a lower population of bifidobacteria and lactobacilli, compared to the former. In this context, the intestinal microbiota plays a leading role in the onset of these disorders, including infantile colic, through its metabolic and nutritional functions, maintenance of the integrity of the intestinal mucosa, and regulation of the immune response. That has opened the door to the study of prebiotics, probiotics, and postbiotics usage in the treatment and or prevention of infantile FGIDs. Vaginal and term delivery and breastfeeding are fundamental in the constitution of a healthy microbiota. As supportive tools, there are efficacy studies that support the administration of this family of biotics, mainly in cases where lactation is not possible or is limited.

A retrospective evaluation of the effect of perianesthetic hydromorphone administration on the incidence of postanesthetic signs of colic in horses.

OBJECTIVE: To describe the incidence of postanesthetic signs of colic (PASC) in horses and determine if perianesthetic administration of hydromorphone was associated with an increased risk of PASC. STUDY DESIGN: Retrospective, cohort study. ANIMALS: A total of 409 horses. METHODS: Anesthesia and clinical records of horses admitted for various procedures from July 2018 to September 2019 were reviewed. Signs of colic and interventions were recorded up to 48 hours after anesthesia. A binomial logistic regression model was used to evaluate the association between the type of surgery, administration of hydromorphone, the duration of anesthesia and the incidence of PASC. RESULTS: Overall, 25 (6.1%) horses developed PASC within 48 hours of general anesthesia. Of 60 horses that underwent colic surgery, 16 (26.7%) developed PASC. Of 349 horses that underwent noncolic procedures, nine (2.6%) developed PASC. Thus, the incidence of PASC was higher in horses that underwent colic surgery than in horses that underwent noncolic procedures [odds ratio (OR) = 13.74 (5.73-32.95)]. No effect of hydromorphone on the incidence of PASC was identified [OR = 1.61 (0.71-3.62)]. Longer procedures (>2 hours) were identified as an independent risk factor for PASC [OR = 4.13 (1.52-11.22)]. CONCLUSIONS: No association between hydromorphone and an increase in the incidence of PASC was identified. Anesthesia for colic surgery and duration of anesthesia were associated with an increased risk of PASC. CLINICAL RELEVANCE: Hydromorphone did not increase the incidence of PASC in this population.

Nephrosplenic space closure significantly decreases recurrent colic in horses: a retrospective analysis.

BACKGROUND: Nephrosplenic space closure is commonly used to reduce relapse of nephrosplenic space entrapment in cases of left dorsal displacement of the left colon (LDDLC). Nevertheless, studies documenting the effectiveness of this surgery are sparse in the literature. The aim of this study was to analyse clinical data of horses presented for LDDLC and evaluate the effect of nephrosplenic space closure on the incidence of colic recurrence. METHODS: Medical records of 156 horses diagnosed with LDDLC at the Equine Clinic of the University of Liège between 2004 and 2016 were retrieved for analysis. Extracted data included horse breed, sex, age and weight, initial treatment, and if a subsequent preventive surgical closure of the nephrosplenic space was carried out or not. Follow-up information was obtained by telephone interview. Statistical analyses were performed using a chi-squared test with significance set at P<0.05. RESULTS: Follow-up data were available for 65 per cent of horses. The mean follow-up was 35 months. There was a significant decrease in the total incidence of colic after closure surgery compared with non-operated horses. No horse was diagnosed with LDDLC after closure of the nephrosplenic space. CONCLUSION: Closure of the nephrosplenic space significantly decreases recurrent colic in horses compared with non-operated horses.

Preventing and Treating Colic.

Colic is a common and distressing functional gastrointestinal disorder during infancy. It is a behavioral phenomenon in infants aged 1-4 months involving prolonged inconsolable crying and agitated status with multifactorial etiology. Colic can be considered as a benign, self-limited process because the baby normally grows and feeds even with transient irritable mood. Nevertheless, infantile colic is a common difficulty causing anxiety during parenthood and a recurrent reason for them to seek medical help, especially if it is the first child. The causes of colic can be classified as non-gastrointestinal or gastrointestinal. The former includes altered feeding techniques, modified child-parent relationship, immaturity of central nervous system, behavioral etiology, and maternal smoking or nicotine replacement therapy. Instead, the latter involves inadequate production of lactase enzyme, cow's milk protein intolerance, alteration of intestinal microbiota, gastrointestinal immaturity, or inflammation which causes intestinal hyperperistalsis due to increase in serotonin secretion and motilin receptor expression.Probiotics may play a crucial part in the manipulation of the microbiota. Probiotic administration is likely to maintain intestinal homeostasis through the modulation of permeability and peristalsis, influencing the gut-brain axis and inhibiting hypersensitivity. This is a decisive field in the development of preventive and therapeutic strategies for infantile colic. However, further studies are needed for each specific formulation in order to better characterize pharmacodynamic and pharmacokinetic properties and to evaluate their application as a possible preventive strategy if administered early during infancy against the later development of pain-related FGIDs.

Prebiotic effect of an infant formula supplemented with galacto-oligosaccharides: randomized multicenter trial.

OBJECTIVE: The objective of the study was to investigate the effects of a galacto-oligosaccharides (GOS)-supplemented formula on the intestinal microbiota in healthy term infants, with a specific consideration for gastrointestinal symptoms as colic, stool frequency and consistency, regurgitation. METHODS: This was a randomized, double-blind, controlled, parallel-group clinical trial performed simultaneously by 6 centers in Italy. Three groups were considered: breastfed, formula-fed, and GOS-supplemented formula-fed infants. Formula-fed infants were randomized to receive either the control or the study formula and consume the assigned formula exclusively until the introduction of complementary feeding. The nutritional composition of the 2 formulas were identical, apart from the supplemented GOS (0.4 g/100 mL) in the study formula. Four different types of bacteria were evaluated in order to assess the efficacy of GOS-supplemented formula on infants: Bifidobacterium, Lactobacillus, and Clostridium, Escherichia coli. RESULTS: A total of 199 breastfed infants and 163 formula-fed infants were recruited. When considering stool frequency and consistency, GOS-supplemented formula presented normal and soft stools in the majority of episodes (89%). In the supplemented group the incidence of colic was lower with respect to the control group. A significantly lower count of Clostridium and a higher count of Bifidobacterium were found when comparing study formula and control formula in infants with colic. In children with colic the ratio between Clostridium count and Bifidobacterium and Lactobacillus count was in favor of the latter two when considering the GOS-supplemented formula group with respect to the control one. CONCLUSIONS: The prebiotic-supplemented formula mimicked the effect of human milk in promoting Bifidobacterium and Lactobacillus growth and in inhibiting Clostridium growth, resulting in a significantly lower presence of colic.

Should we routinely stent after ureteropyeloscopy?

Arguments 'for' and 'against' ureteric stenting after ureteropyeloscopy are discussed. An individualised approach balancing renal function preservation, irritative lower urinary tract symptoms and emergent return to theatre needs to be adopted while being mindful of healthcare spending.

Design, synthesis, and pharmacological evaluation of novel hybrid compounds to treat sickle cell disease symptoms.

A novel series of thalidomide derivatives (4a-f) designed by molecular hybridization were synthesized and evaluated in vitro and in vivo for their potential use in the oral treatment of sickle cell disease symptoms. Compounds 4a-f demonstrated analgesic, anti-inflammatory, and NO-donor properties. Compounds 4c and 4d were considered promising candidate drugs and were further evaluated in transgenic sickle cell mice to determine their capacity to reduce the levels of the proinflammatory cytokine tumor necrosis factor α (TNFα). Unlike hydroxyurea, the compounds reduced the concentrations of TNFα to levels similar to those induced with the control dexamethasone (300 µmol/kg). These compounds are novel lead drug candidates with multiple beneficial actions in the treatment of sickle cell disease symptoms and offer an alternative to hydroxyurea treatment.

Pathologic changes in biliary dyskinesia.

PURPOSE: For children with upper abdominal pain and evaluation for acalculous biliary disease, laparoscopic cholecystectomy is an accepted treatment with inconsistent outcomes. The purpose of this study was to identify predictors of outcomes. METHODS: One hundred sixty-seven children underwent laparoscopic cholecystectomy at a single children's hospital. Radiographic findings, histopathology, family history, and demographics (sex, age, height, weight, body mass index-for-age percentile) were evaluated as predictors of postoperative symptomatic resolution using a binomial probability model. The data for radiologic studies and pathologic specimens were obtained via re-review in a blinded fashion. RESULTS: Of 167 children, 43 (25.7%) had a preoperative diagnosis of biliary dyskinesia and 41 (95.3%) had documented follow-up. Mean follow-up was 8.4 months. Twenty-eight patients (68.3%) had symptom resolution. Ejection fraction less than or equal to 15%, pain upon cholecystokinin injection, and a family history of biliary disease were not predictors of symptomatic resolution. Nonoverweight patients (body mass index-for-age <85th percentile) were more likely to have symptom resolution than their overweight counterparts (odds ratio, 2.13). Most patients (68.3%) had a pathologic gallbladder on blinded review. However, this did not correlate with outcome. CONCLUSIONS: Most gallbladders removed for biliary dyskinesia are pathologic. Being overweight can be considered a relative contraindication to cholecystectomy for biliary dyskinesia.

Infantile colic, maternal smoking and infant feeding at 5 weeks of age.

BACKGROUND: Many parents seek help from health professionals because of their infants' persistent crying in the early months. The aetiology of this condition, often labelled ;;infantile colic'', is still unclear. AIMS: To assess whether smoking during pregnancy, and/or smoking at infant age 5 weeks, is associated with infantile colic, and to describe how feeding at infant age 5 weeks and smoking are related to colic. METHODS: This was a community-based study, with telephone interviews in late pregnancy, and at infant age 5 weeks, covering 1,625 mother-infant dyads, i.e. 86% of the eligible population. RESULTS: Daily maternal smoking in pregnancy was related to subsequent colic, with an age-adjusted odds ratio (OR) of 1.74 (95% confidence interval 1.08-2.82). In the multivariate model, the OR was largely unaltered. The association between smoking at infant age 5 weeks and colic did not reach statistical significance. The subgroups based on smoking and infant feeding were small, but the results suggest that exclusive breast-feeding was protective against colic, including for infants of smoking mothers. CONCLUSIONS: This study presents yet another argument why smoking in pregnancy should be discouraged - some cases of infantile colic may be avoided. With regard to mothers who are not able to give up smoking, the results add some support for the conclusion that if a mother is worried about colic, she certainly should not refrain from breast-feeding even if she smokes.

Analysis of sodium carboxymethylcellulose administration and related factors associated with postoperative colic and survival in horses with small intestinal disease.

OBJECTIVE: To analyze the effect of the intraoperative use of sodium carboxymethylcellulose (CBMC) and related perioperative factors on postoperative colic and survival in horses that had abdominal surgery for colic. STUDY DESIGN: Retrospective study. ANIMALS: Horses (n=203) that had surgery for small intestinal disease; 33 horses had intraoperative administration of CBMC. METHODS: Information was obtained from medical records for 170 horses that had surgery for colic before use of CBMC and 33 horses that had intraoperative CBMC. Kaplan-Meier survival curves were used to estimate median survival time and a Cox proportional hazards model was used to estimate the hazard ratio for the effect of CBMC and other perioperative variables on survival. RESULTS: Seventy-five percent of horses administered CBMC survived to 180 days, whereas 75% of untreated horses survived 8 days (median survival time=18 days). Horses not administered CBMC were twice as likely to die compared with horses administered CBMC. Horses that had postoperative ileus (POI) were 1.4 times more likely to die than horses without ileus. Similarly, horses with signs of colic after surgery were 1.3 times more likely to die than horses without postoperative signs of colic. CONCLUSIONS: CBMC administration is seemingly protective against death and prolongs survival when used intraoperatively in horses with small intestine disease, particularly horses with postoperative colic or POI. Both POI and colic increased risk of death after surgery. CLINICAL RELEVANCE: Intraoperative administration of CBMC in horses that have surgery for small intestinal disease may improve survival, possibly by reducing early adhesion formation.

[Effects of magnetolaser radiation on pathologic process in the kidneys in experimental renal colic].

The experiments were made on 22 rabbits with induced single or recurrent renal colic. Ten animals after renal colic were exposed to magnetolaser radiation. The histological examination of renal tissue demonstrated colic-related changes both in renal body corpuscle and ductules. Parenchimal edema, parabiotic processes in epitheliocytes and even necrosis of some cells were found. In case of recurrent colic the changes were severe, much more epitheliocytes were damaged, inflammatory leucocyte infiltration appeared. Magnetolaser radiation reduces the damage, eliminates leucocyte infiltration. Lymphocytic infiltrates formed in renal interstitium after two sessions of magnetolaser therapy indicate stimulation of cell immunity. The same processes develop also in the contralateral kidney. Their activity depends on the number of colics. Therefore, magnetolaser radiation has a protective action both on the isolated organ and body as a whole.

Post anaesthetic colic in horses: a preventable complication?

REASONS FOR PERFORMING STUDY: There is little information on the prevalence of, and risk factors associated with, post anaesthetic colic (PAC) in horses undergoing nonabdominal operations. OBJECTIVES: To undertake the first prospective study of prevalence of PAC and identify risk factors in its development in nonabdominal procedures. METHODS: A multicentre prospective case-control study was conducted, on every horse undergoing anaesthesia for a nonabdominal procedure between April 2004 and June 2005. Colic cases were defined as any horse with recognised signs of abdominal pain within 72 h of general anaesthesia that could not be attributed to any concurrent disease. Five control horses per case were selected randomly from the study population at all hospitals. Multivariable logistic regression analysis was used to examine the relationship between predictor variables and the risk of developing PAC. RESULTS: The estimated mean prevalence of PAC in the study population was 5.2% (95% CI, 2.8, 8.0). However, the prevalence of colic varied between each centre. The most commonly diagnosed cause of colic was impaction. Multivariable analyses showed that the centre involved and the type of surgery performed were associated with an increased risk of PAC. Preoperative food deprivation and the use of opioid drugs were confounding factors. CONCLUSIONS: Prevalence of PAC varied significantly between the 4 hospitals studied; there may be hospital-related covariates that account for this. The type of surgery performed influenced the risk of PAC. POTENTIAL RELEVANCE: Identifying the risk factors for PAC is a prerequisite for its prevention. This study indicates horses at increased risk of PAC that might benefit from a more critical evaluation of post anaesthetic gastrointestinal function and/or the provision of preventative measures. Further investigation is required to explain the variation in prevalence of PAC between centres.

Laparoscopic closure of the nephrosplenic space for prevention of recurrent nephrosplenic entrapment of the ascending colon.

OBJECTIVE: To evaluate outcome after laparoscopic closure of the nephrosplenic space in horses that had previous nephrosplenic entrapment of ascending colon (left dorsal displacement of the left colon; LDDLC). STUDY DESIGN: Retrospective study. SAMPLE POPULATION: Horses that had previous LDDLC. METHODS: Medical records of horses that had LDDLC and subsequent laparoscopic nephrosplenic space closure between 2002 and 2004 were retrieved. Follow-up information was obtained by telephone interview of owners. Preoperative versus postoperative comparisons were: incidence of LDDLC, incidence of colic signs, and incidence of ventral celiotomy. Data were analyzed using a chi2-square test with significance set at P<.05. RESULTS: Ten horses met the inclusion criteria. Mean follow-up was 22 months. No horses had recurrence of LDDLC; however, 3 horses had colic signs subsequently that required surgical intervention. Over the follow-up period there was a significant decrease in the total incidence of colic and ventral celiotomy. Technique modifications included use of different cannula site locations, use of polyglyconate suture material for nephrosplenic space closure, and development of a custom cannula. CONCLUSIONS: Laparoscopic nephrosplenic space closure prevented recurrence of LDDLC, and significantly lowered the overall incidence of colic and ventral celiotomy. The custom-designed cannula provided good access to the operative site and no complications were encountered with use of polyglyconate suture material for nephrosplenic space closure. CLINICAL RELEVANCE: Closure of the nephrosplenic space will prevent LDDLC; however, other surgical lesions can occur.

[Analysis of the causes of postoperative chest or/and abdomen colic in benign prostatic hyperplasia].

OBJECTIVE: To analyze the causes of chest or/and abdomen colic with in 1 week after prostatectomy and transurethral resection of the prostate (TURP). METHODS: Retrospective studies were made on 120 cases of benign prostatic hyperplasia (BPH) with postoperative colic in the chest or/and abdomen from October 2001 to October 2002, 35 (Group A) treated by prostatectomy and the other 85 (Group B) by TURP. RESULTS: In sequence of frequency, the causes of the postoperative chest or/and abdomen colic were bladder spasm, catheter block, acute gastroenteritis, angina and acute myocardial infarction. CONCLUSION: The causes of chest or/and abdomen colic after prostatectomy are multiple. If the causes are timely established and corresponding measures immediately taken, its complications can be minimized.

[From lead colic to moderate risk]. / Dalla colica saturnina al rischio moderato.

During the 20th century, occupational and environmental exposure to lead was among the main relevant issues studied by occupational physicians, hygienists, and public health administrators. During the different decades there was a progressive reduction in exposure levels and in the mean time a progressive reduction in the severity of clinical symptoms due to very high exposure to this metal. During thefirst forty years of the 20th century, a clear decrease in the frequency of encephalopathy and paralysis of the radial nerve was observed while abdominal colics and anaemia where frequently observed until the sixties. In the first part of the seventies, there was a clear change in the preventive approach to lead poisoning both in the field of research and in the clinical-preventive and legal field. These successful results where obtained despite the disagreement of outstanding physicians and international renowed researchers and industrial associations. Every successful battle allowed a great improvement in the field of occupational and environmental prevention, but the above-mentioned disagreements caused a great delay in the solution of the problem and did not improve workers', children's and teenagers' health. In Italy, there was a very deep interest in the prevention of lead poisoning which led to very good results in a relatively short period even though the current laws did not help and also nowadays do not help the occupational professionals studying and dealing with occupational health. Lead undoubtly represents one of the most largely studied environmental industrial toxics and shows a model, also suitable for other matters involving exposure to different industrial toxics. Nevertheless, there are still problems in the understanding of some pathogenetic aspects of lead and in the significance of some of its early effects which deserve further studies. These matters, strictly linked to low-dose exposure, still present numerous questions. For example, there should be a deep interest in the standardization of its internal dose indicators, in the study the role of the metal in the pathogenesis of cardiological and nephrological diseases, in the characterization of its genetic polymorphisms and in the assessment of its carcinogenicity. A lot of these issues, already examined in old studies concerning casistics of workers affected by lead poisoning, have been analyzed in the multidisciplinary study "Progetto MIUR Piombo" (Project on lead by the Italian Ministry of University and Research) conducted by six different Institutes of Occupational Health (Cagliari, Parma, Perugia, Bari, Ancona and Brescia) which will report their results during this Congress.

[Evidence-based prevention of cholecystolithiasis]. / Evidenzbasierte Prävention der Cholezystolithiasis.

Evidence based prevention of cholecystolithiasis. Cholesterol cholelithiasis is one of the most common and expensive gastroenterological diseases. Beside common exogenous risk factors, recent molecular genetic studies have identified genetic risk factors for both cholesterol and pigment stone formation. Examples are low phospholipid-associated cholelithiasis due to mutations of the gene encoding the hepatocanalicular phosphatidylcholine transporter, and pigment stones in association with mutations of the ileal bile salt transporter gene. Evidence-based options for primary prevention of cholecystolithiasis include physical activity, slow weight reduction, regular vitamin C supplementation, and moderate coffee consumption. The ongoing genome projects provide the basis for future epidemiological studies of human gallstone (LITH) genes, which might offer new prospects for individual risk assessment and prevention of gallstones.

The effect of fennel (Foeniculum Vulgare) seed oil emulsion in infantile colic: a randomized, placebo-controlled study.

CONTEXT: Despite its benign, natural course, colic is a significant problem in infants and imparts a psychological, emotional, and physical burden to parents. Dicyclomine hydrochloride is the only pharmacological treatment for infantile colic that has been consistently effective. Unfortunately, 5% of infants treated with dicyclomine hydrochloride develop serious side effects, including death. Fennel seed oil has been shown to reduce intestinal spasms and increase motility of the small intestine. However, there have not been any clinical studies of its effectiveness. OBJECTIVES: To determine the effectiveness of fennel seed oil emulsion in infantile colic. DESIGN: Randomized placebo-controlled trial. SETTINGS: Two large multi-specialty clinics. SUBJECTS: 125 infants, 2 to 12 weeks of age, who met definition of colic. INTERVENTION: Fennel seed oil emulsion compared with placebo. OUTCOME MEASURE: Relief of colic symptoms, which was defined as decrease of cumulative crying to less than 9 hours per week. RESULTS: The use of fennel oil emulsion eliminated colic, according to the Wessel criteria, in 65% (40/62) of infants in the treatment group, which was significantly better than 23.7% (14/59) of infants in the control group (P < 0.01). There was a significant improvement of colic in the treatment group compared with the control group [Absolute Risk Reduction (ARR) = 41% (95% CI 25 to 57), Number Needed to Treat (NNT) = 2 (95% CI 2 to 4)]. Side effects were not reported for infants in either group during the trial. CONCLUSION: Our study suggests that fennel seed oil emulsion is superior to placebo in decreasing intensity of infantile colic.

6-Methylprednisolone does not impair anti-thymocyte globulin (ATG) immunosuppressive activity in non-human primates.

BACKGROUND: Induction treatments with anti-thymocyte globulin (ATG) in solid organ transplantation may enhance the efficacy of maintenance immunosuppressive therapy. Since ATG can trigger Fas (CD95) mediated T cell apoptosis, a process antagonized in vitro by corticosteroids, an important issue is whether corticosteroids could interfere with T cell depleting and immunosuppressive activities of ATG. METHODS: MHC mismatched skin allografts were performed on cynomolgus and rhesus monkeys treated with ATG (20 mg/kg) associated or not with 6-methylprednisolone (10 mg/kg). RESULTS: There was no difference between the two immunosuppressive regimens as regards the intensity and duration of peripheral T lymphocyte depletion and the appearance of anti-ATG antibodies. Skin graft survival was increased in monkeys treated with 6-methylprednisolone as compared with ATG alone. CONCLUSIONS: In vivo, corticosteroids do not interfere with ATG ability to induce massive T cell depletion and to delay skin allograft rejection in non-human primates.