An escalating continuum of learning and attention difficulties from premutation to full mutation in female carriers of FMR1 expansion.

Objective: Carriers of Fragile X premutation may have associated medical comorbidities, such as Fragile X-associated tremor and ataxia (FXTAS) and Fragile X-associated premature ovarian insufficiency (FXPOI). We examined the Fragile X premutation effect on cognition, and we assumed that there is a direct correlation between the continuous spectrum of specific learning and attention deficits to the number of CGG repeats on the FMR1 gene. Methods: A total of 108 women were referred to our center due to a related Fragile X syndrome (FXS) patient, 79 women carried a premutation of 56-199 repeats, and 19 women carried a full mutation of more than 200 CGG repeats on FMR1 gene. Genetic results of CGG repeats, demographic information, structured questionnaires for ADHD, learning disabilities of language and mathematics, and independence level were analyzed in women carrying the FMR1 premutation and compared to the group carrying the full mutation. Women with FXS and FXTAS were excluded. Results: When analyzed as a continuum, there was a significant increase in the following complaints which were associated with a higher number of repeats: specific daily function skills such as driving a car, writing checks, disorientation in directions, and also specific learning difficulties such as spelling and math difficulties. Additionally, when tested as a categorical independent variable, we observe that women with the full mutation were more likely to have ADHD or other learning disability diagnoses in the past than during premutation (<200 CGG repetitions). Conclusion: Specific learning and attention difficulties and resulting daily function difficulties correlate with an increased number of CGG repeats and are more likely to be associated as a common feature of premutation and full mutation in a female premutation carrier. Despite evidence of learning and attention difficulties, it is encouraging that most female carriers of the premutation and full mutation function well in most areas. Nevertheless, they face significant difficulties in specific areas of functioning such as driving, and confusion in times and schedules. Those daily function skills are mostly impacted by dyscalculia, right and left disorientation, and attention difficulties. This may aid to design specific interventions to address specific learning deficits in order to improve daily function skills and quality of life.

Executive Function and Working Memory Deficits in Females with Fragile X Premutation.

The Fragile X premutation is a genetic instability of the FMR1 gene caused by 55-199 recurrences of the CGG sequence, whereas there are only 7-54 repeats of the CGG sequence in the normal condition. While males with the premutation of Fragile X were found to have difficulties in executive functions and working memory, little data have been collected on females. This study is among the first to address executive functions and phonological memory in females with the Fragile X premutation. Twenty-three female carriers aged 20-55 years and twelve non carrier females matched in age and levels of education (in years) participated in this study. Executive functions and phonological memory were assessed using the self-report questionnaire The Behavior Rating Inventory of Executive Function (BRIEF) and behavioral measures (nonword repetitions, forward and backward digit span). Females who were carriers of the premutation of the FMR1 gene reported less efficient executive functions in the BRIEF questionnaire compared to the control group. In addition, a relationship was found between the number of repetitions on the CGG sequence of nucleotides, nonword repetitions, and forward digit span. The findings suggest that the premutation of Fragile X in females affects their performance of executive functions and may have impact on everyday functioning.

Shared facial phenotype of patients with mucolipidosis type IV: A clinical observation reaffirmed by next generation phenotyping.

BACKGROUND: Mucolipidosis type IV (ML-IV) is a rare autosomal-recessive lysosomal storage disease, caused by mutations in MCOLN1. ML-IV manifests with developmental delay, esotropia and corneal clouding. While the clinical phenotype is well-described, the diagnosis of ML-IV is often challenging and elusive. OBJECTIVE: Our experience with ML-IV patients brought to the clinical observation that they share common and identifiable facial features, not yet described in the literature to date. Here, we utilized a computerized facial analysis tool to establish this association. METHODS: Using the DeepGestalt algorithm, 50 two-dimensional facial images of ten ML-IV patients were analyzed, and compared to unaffected controls (n = 98) and to individuals affected with other genetic disorders (n = 99). Results were expressed in terms of the area-under-the-curve (AUC) of the receiver-operating-characteristic curve (ROC). RESULTS: When compared to unaffected cases and to cases diagnosed with syndromes other than ML-IV, the ML-IV cohort showed an AUC of 0.822 (p value < 0.01) and an AUC of 0.885 (p value < 0.001), respectively. CONCLUSIONS: We describe recognizable facial features typical in patients with ML-IV. Reaffirmed by the DeepGestalt technology, the described common facial phenotype adds to the tools currently available for clinicians and may thus assist in reaching an earlier diagnosis of this rare and underdiagnosed disorder.

Prolonged Time Lag to Final Diagnosis of Fragile X Syndrome.

OBJECTIVE: To evaluate the diagnostic process in children ultimately diagnosed with fragile X syndrome (FXS), with an emphasis on the time lag between initial presentation and on diagnosis in female vs male children. STUDY DESIGN: Interviews were conducted with 89 families of children with a final diagnosis of FXS and assessment of time intervals between initial presentation and confirmed molecular diagnosis. RESULTS: Screening of 117 patients (25 female patients) from the 89 families revealed that less than 20% of patients obtained a diagnosis within the first year of seeking medical attention. Mean age at the time of initial presentation was 12.3 months in male patients and 23 months in female patients, while definitive diagnosis of FXS was made at a mean of 4 and 9 years, respectively. Presenting symptoms of developmental delays were recognized by 72% of parents, and 84% had another child with FXS before the index case diagnosis. Average age of diagnosis for children with FXS born since 2007 was significantly lower at 31.9 months, compared with 69.5 months for children born before 2007. CONCLUSIONS: Although FXS is a significant and prevalent cause of disability in children, it is underdiagnosed and diagnosed late, especially in female patients. In every male and female patient presenting with developmental delay or autism, FXS should be considered. Dysmorphic physical features may not be present in infancy, and the absence of those features cannot exclude a diagnosis of FXS.

Vaccination with Shigella flexneri 2a conjugate induces type 2a and cross-reactive type 6 antibodies in humans but not in mice.

Shigella flexneri (S. flexneri) 6 has emerged as an important cause of shigellosis. Our efficacy study of Shigella sonnei and S. flexneri 2a O-specific polysaccharide (O-SP) conjugates in 1-4year-olds had too few S. flexneri 2a cases for efficacy evaluation but surprisingly showed protection of 3-4year-olds, S. flexneri 2a-recipients, from S. flexneri 6 infection. To investigate this cross-protection antibodies to both Shigella types were investigated in all sera remaining from previous studies. Twenty to 30% of 3-44year-old humans injected with S. flexneri 2a conjugate responded with ≥4-fold increases of IgG anti type 6, p<0.00001. The specificity of these antibodies was shown by inhibition studies. S. flexneri 6 infection of 2 children induced besides S. flexneri 6, also S. flexneri 2a antibodies, at levels of S. flexneri 2a vaccinees. S. flexneri 2a antibodies induced by S. flexneri 6 conjugates could not be studied since no such conjugate was assessed in humans and mice responded almost exclusively to the O-SP of the injected conjugate, with no cross-reactive antibodies. Our results indicate induction of cross-reactive protective antibodies. The O-acetylated disaccharide shared by S. flexneri 6 and 2a O-SPs, is the likely basis for their cross-reactivity. S. flexneri 6 O-SP conjugates, alone and in combination with S. flexneri 2a, merit further investigation for broad S. flexneri protection.

[RARE DISEASES DTC: DIAGNOSIS, TREATMENT AND CARE].

Rare diseases are chronic, progressive genetic disorders, which affect around 6-8% of the general population, mainly children. Therefore, in Israel approximately 500,000 people are probably affected by a rare disease. In this article, we review some of the issues pertaining to rare diseases, such as the need for accurate diagnosis which is necessary not only for specific care and treatment but also for informed family planning. In addition, we review the impact of the activities of patients' organizations on the awareness of rare diseases and their involvement in the creation of the Orphan Drug Act, which was the leading point on the way to drug development worldwide. During the last few years networks for reaching leading specialists' opinions on the way to proper diagnosis were created. Thereafter, the next generation genetic technologies, such as exome sequencing, have been a revolution in terms of options and hope for patients with rare undiagnosed diseases. Patients with rare diseases and their families are a challenge to the health care system, not only in terms of diagnosis and therapy, but also in terms of special needs. In addition, deciphering molecular pathways of rare diseases might be the key for understanding molecular events involved in common disorders. We emphasize the duty to ensure appropriate capacity and equal access to follow-up and clinical management of patients with rare diseases in Israel.

Endocrine abnormalities in ataxia telangiectasia: findings from a national cohort.

BACKGROUND: Ataxia telangiectasia (AT) is a genetic multisystem disorder, presenting with progressive ataxia, immune deficiency, and propensity toward malignancy. Endocrine abnormalities (growth retardation, reproductive dysfunction, and diabetes) have been described, however detailed information regarding this aspect is lacking. We aimed to characterize endocrine anomalies and growth patterns in a large cohort of AT patients. METHODS: Retrospective study comprising all 52 patients (aged 2-26.2 y) followed at a national AT Clinic. Anthropometric and laboratory measurements were extracted from the charts. RESULTS: Median height-SDS was already subnormal during infancy, remaining negative throughout follow up to adulthood. Height-SDS was more impaired than weight-SDS up to age 4 y, thereafter weight-SDS steadily decreased, resulting in progressively lower BMI-SDS. IGF-I-SDS was low (-1.53 ± 1.54), but did not correlate with height-SDS. Gonadal failure was present in all 13 females older than 10 y but only in one male. Two patients had diabetes and 10 had dyslipidemia. Vitamin D deficiency was observed in 52.2% of the evaluated patients. CONCLUSION: Our results suggest a primary growth abnormality in AT, rather than secondary to nutritional impairment or disease severity. Sex hormone replacement should be considered for female patients. Vitamin D levels should be followed and supplementation given if needed.

Cough ability measurements and recurrent respiratory symptoms in individuals with Ataxia Telangiectasia.

OBJECTIVES: Ataxia-Telangiectasia (A-T) individuals often present with respiratory muscle weakness, causing recurrent respiratory system infections, asthma-like symptoms, and chronic cough life-threatening events. The cough flow volume maneuver may reveal powerless airflow needed for efficient cough. The study aims to explore cough ability in relation to the flow/volume maneuver. METHODS: Data collected retrospectively from clinical charts of 35 A-T patients (age 12.7 ± 4.9 years) included forced expiratory and cough flow/volume maneuvers performed on the same day. Analysis compared among the maneuvers matching indices, numbers of cough-spikes, flow rate decay, and the reference data of similar ages. Adjusted to age, BMI, and number of hospitalizations prior to the tests, values were correlated with the cough indices. RESULTS: Cough peak-flow (C-PF) was propagated within 90 ± 20 ms compared with peak expiratory flow (PEF > 200 ms). C-PF measured values were higher than expiratory peak-flow measured values (3.27 ± 1.53 L/s versus 3.02 ± 1.52 L/s, respectively, but C-PF (%predicted) values were significantly lower than expiratory peak-flow (%predicted) (46 ± 15 versus 68 ± 20 %predicted, respectively, p < 0.002). The number of spikes/maneuver was low when compared with reference (2.0 ± 0.8 versus 6-12 spikes) and cough vital-capacity was lower than expiratory vital capacity (0.95 ± 0.43 versus 1.03 ± 0.47; p < 0.01). Inefficient C-PF was more prevalent in patients suffering from recurrent respiratory illness. The length of wheelchair confinement duration mostly influenced the C-VC level. CONCLUSIONS: The cough flow-volume curve can be applied as a method to follow cough ability in patients with A-T who showed a significantly reduced cough capacity. Further studies are needed to establish if the findings may aid decisions regarding cough assistance.

Disturbed B and T cell homeostasis and neogenesis in patients with ataxia telangiectasia.

OBJECTIVE: Ataxia telangiectasia (AT) is a rare genetic, multi-system disorder characterized by neurodegeneration, chromosome instability, B and T cell immunodeficiency and a predisposition to cancer. We examined immunologic parameters reflecting cell development and proliferation and their relevancy to the clinical phenotype in affected individuals. PATIENTS AND METHODS: AT patients from the AT National Clinic in Israel underwent immunological investigation. Their T and B cell workup included lymphocyte subset counts, immunoglobulin levels, responses to mitogenic stimulations, TCR-Vß families and BCR immunoglobulin heavy chain spectratyping, TCR rearrangement excision circles (TRECs) and Kappa-deleting recombination excision circles (KRECs). RESULTS: Thirty-seven AT patients (median age 12.7 years, range 4.2-25.1) were evaluated. CD20 B and CD3 T lymphocytes were decreased in 67 % and 64 % of the patients, respectively, while only 33 % of the patients had reduced lymphoproliferative responses. Almost all AT patients displayed extremely low TRECs and KRECs levels, irrespective of their age. Those levels were correlated to one another and to the amounts of CD3+ and CD20+ cells, respectively. Abnormal TCR-Vß repertoires were found with different degrees of clonality or reduced expression in these AT patients. There was no clear clustering of expansions to specific TCR-Vß genes. PCR spectratyping analysis of the FR2 IgH BCR gene rearrangements in peripheral blood was abnormal in 50 % of the patients. CONCLUSION: The immunodeficiency associated with AT is combined, remains low over time and not progressive. It is characterized by low TREC and KREC copies suggestive of abnormal T and B cell neogenesis.

Dermatologic manifestations of ataxia-telangiectasia syndrome.

BACKGROUND: Previous reports on the cutaneous manifestations of ataxia-telangiectasia (A-T) have relied on data from small series, in patients not genetically tested for A-T. OBJECTIVE: The aim of our study was to characterize the dermatologic manifestations in patients with A-T followed up at the national A-T clinic in Israel. METHODS: This retrospective cross-sectional study included 32 patients followed up at a multidisciplinary A-T clinic from 2010 to 2012. Complete skin examination was done by a single dermatologist. Information about mutations and neurologic status was extracted from the patients' charts. Relevant demographic, clinical, and laboratory characteristics of all patients were collected and summarized. RESULTS: Of the 32 patients, 97% had ocular telangiectasia, the hallmark of the disease. Telangiectasia on other body parts was less frequent. Pigmentary anomalies included café-au-lait macules (84%), hypopigmented macules (44%), and melanocytic nevi (37%). A facial papulosquamous rash was found in 41% of cases. Other manifestations included hypertrichosis and birdlike facies. We did not observe premature hair graying or poliosis. No genotype-phenotype correlation was found in terms of skin manifestations. LIMITATIONS: There was a modest sample size, because of the rarity of the disease. CONCLUSION: Recognition of the ocular and dermatologic manifestations of A-T can facilitate early diagnosis in a child with neurologic deterioration.

Movement disorder in ataxia-telangiectasia: treatment with amantadine sulfate.

Ataxia-telangiectasia is a cerebellar neurodegenerative disorder presenting with ataxia, chorea, myoclonus, and bradykinesia. Literature on treatment of movement disorders is scarce. We treated 17 children (aged 11.2 ± 3.9 years) for 8 weeks with the dopaminergic and anti-N-methyl-d-aspartate (NMDA) agent amantadine sulfate 6.3 ± 0.87 mg/kg/d. Ataxia was assessed by using the International Cooperative Ataxia Scale, parkinsonism by the Unified Parkinson Disease Rating Scale, and chorea/myoclonus by the Abnormal Involuntary Movement Scale. Responders were considered those patients who had at least 20% improvement in the summation of the 3 scales. Overall, 76.5% of patients were responders, with a mean 29.3% improvement. Ataxia, involuntary movements, and parkinsonism improved significantly (25.3%, 32.5%, and 29.5%, respectively); (P < .001, t test). Side effects were mild and transient, and they did not lead to drug discontinuation. Amantadine is a well-tolerated and effective treatment for motor symptoms in ataxia telangiectasia. Assessment of long-term effects and a double-blind study should follow.

Neurologic presentation in children with ataxia-telangiectasia: is small head circumference a hallmark of the disease?

OBJECTIVE: To define the neurologic characteristics and course of ataxia-telangiectasia (A-T). STUDY DESIGN: Retrospective cross-sectional chart study of 57 children (ages 2 to 19 years) followed at an A-T clinic. Cerebellar and extracerebellar symptoms were graded according to degree of functional impairment. Head circumferences were plotted from the charts and z-scores were calculated and compared with that of family members. RESULTS: Ataxia was present in 87.7%, followed by dysarthria (82.1%), dysmetria (75.4%), bradykinesia (69.2%), hyperkinetic movements (58.9%), and dystonia (15.8%). All features aggravated with age. The most striking clinical observation in our patients was low head circumference (z-score below 1), which was present in 60.9%; 17% had true microcephaly (z-score below 2). Microcephaly appeared postnatally, was proportionate to height and weight, and did not correlate with severity of ataxia or genotype. CONCLUSIONS: In addition to cerebellar ataxia, extrapyramidal symptoms, especially bradykinesia, were frequent and disabling. Microcephaly is an integral part of A-T; understanding its pathogenesis may shed light on the mechanism by which ATM mutation causes dysfunction in the nervous system.

The feasibility and validity of forced spirometry in ataxia telangiectasia.

OBJECTIVES: To explore the feasibility and validity of forced spirometry in patients with ataxia telangiectasia (A-T). STUDY DESIGN: Twenty-eight patients (aged 3.7-19.3 years) performed spirometry on 47 occasions. Parameters studied were technical quality and relation to: predicted values, pulmonary illness. RESULTS: Start of test criteria for correct expiratory effort was significantly prolonged (183 ± 115 ms; P < 0.001). The rise-time to peak flow in children free of respiratory symptoms (Group-FRS; n = 8) increased by 16.2 ± 12.5 ms/year above recommended and in children having recurrent infections (n = 8) 30.4 ± 16.1 ms/year, P < 0.01. Expiration-time was significantly shorter than requested (1.21 ± 0.47 sec) and was ended abruptly in 57% of the patients. FEV(1) could not be established by 8/20 patients. The intra-subject reproducibility met criteria (4.4 ± 2.7%, 5.2 ± 2.8%, 2.9 ± 3.2%, 6.3 ± 5.3%, for FVC, FEV(0.5), PEF, FEF(25-75), respectively). Group-FRS showed yearly deterioration in FVC of 2.2%, while patients with hyper-reactive airways (Group-HRA; n =12) had a deterioration rate of 3.6%/year. FEV(0.5) deterioration rate was similar in both groups (2.2 and 2.0, respectively), but baseline values in Group-HRA were significantly lower than those of Group-FRS (P = 0.029) in similar young ages, indicating airway obstruction at early ages in Group-HRA. FEV(0.5) values deterioration also correlated with body mass index (P < 0.017). CONCLUSION: Forced spirometry in A-T patients is reproducible and has a distinct pattern, although curves do not meet other recommendations for acceptable criteria. The study insinuates that a rapid deterioration in lung function occurs in A-T patients with recurrent respiratory infection, suggesting that early intervention may prevent further deterioration or improve their lung function. Further studies are needed to confirm our results.

Reversible airway obstruction in children with ataxia telangiectasia.

INTRODUCTION: Lung disease is a significant cause of the short life span of ataxia telangiectasia (A-T) patients. Objective lung function measurements are difficult to achieve in A-T. AIM: To assess lung function by spirometry in relation to the clinical characteristics of A-T patients followed up at the Israeli Ataxia Telangiectasia National Clinic. PATIENTS AND METHODS: Medical and spirometry data were collected from 27 A-T patients during 2004-2007. Laboratory, nutritional condition, mode of treatment, pulmonary status, and malignancies were assessed. The spirometry values FVC, FEV(1), FEV(0.5), FEF(25-75), PEF and time rise to peak flow were analyzed individually and values were compared to those of healthy age-matched children. RESULTS: Eleven patients (40.7%) were found to suffer from asthma according to clinical symptoms and response to bronchodilators. We found significant reduction in FEV(1) and FEV(0.5) (z-scores: -0.84 + or - 0.7 SD, -0.7 + or - 0.6 SD; P = 0.0014 and P = 0.003, respectively), in relation to healthy predicted values. FEF(25-75) was significantly lower than that in healthy children in 5 of 11 asthmatic patients. All 27 patients showed higher than healthy FEV(1)/FVC and FEV(0.5)/FVC ratios (z-scores 0.68 + or - 0.99 SD, P < 0.0015, and 2.12 + or - 1.50 SD, P < 0.0015, respectively). The rise time to peak flow was three-fold longer than that of healthy children. CONCLUSION: Obstructive lung disease is common among A-T patients. Maximal peak flow reduction and prolonged rise time to peak flow may be the first signs of pulmonary involvement in these patients. Early treatment with anti-asthma therapy, bronchodilators, and steroids, may prevent further pulmonary deterioration and improve the prognosis of A-T patients.

Age-related efficacy of Shigella O-specific polysaccharide conjugates in 1-4-year-old Israeli children.

BACKGROUND: Despite its high worldwide morbidity and mortality, there is yet no licensed vaccine for shigellosis. We reported the safety and immunogenicity of Shigella O-specific polysaccharide-protein conjugates in adults and young children and efficacy of Shigella sonnei conjugate in young adults. METHODS: A double-blinded, randomized and vaccine-controlled Phase 3 evaluation of S. sonnei and Shigella flexneri 2a O-SP-rEPA conjugates, 25 microg, injected IM twice, 6 weeks apart, into healthy 1-4 years old, is reported. The children were followed for 2 years by telephone every other week and stool cultures were obtained for each episode of acute diarrhea (> or =3 loose stools/day or a bloody/mucous stool). Sera were taken randomly from 10% of the participants for IgG anti-LPS and anti-carrier levels. RESULTS: Of the 2799 enrollees, 1433 received S. sonnei and 1366 S. flexneri 2a conjugates; 2699 (96.4%) completed the 2-year follow-up. Local reactions occurred in approximately 5% and approximately 4% had temperatures > or =38.0 degrees C lasting 1-2 days. There were no serious adverse events attributable to the vaccines. Of the 3295 stool cultures obtained, 125 yielded S. sonnei and 21 S. flexneri 2a. Immunogenicity and efficacy were age-related. The overall efficacy of the S. sonnei conjugate was 27.5%; 71.1% (P=0.043) in the 3-4 years old. The numbers for S. flexneri 2a were too few for meaningful analysis. Cross-protection by S. flexneri 2a for non-vaccine S. flexneri types was found, but the numbers were too few for statistical significance. There was an age-related rise of vaccine-specific IgG anti-LPS in both groups, peaking at about 10 weeks and declining thereafter, but remaining > or =4-fold higher than in the controls 2 years after the second dose. CONCLUSIONS: Shigella conjugates are safe and immunogenic in 1-4 years old. The S. sonnei conjugate elicited 71.1% efficacy in the 3-4 years old and can be predicted to be efficacious in individuals older than 3 years of age. These results urge studies with our improved conjugates.

Use of a computerized database to study the effectiveness of an attenuated varicella vaccine.

BACKGROUND: The varicella vaccine Varilrix (GlaxoSmithKline) was introduced in Israel in June 2000 as an optional vaccination for children. METHODS: We used the database of a single health maintenance organization that serves 25% of the population in Israel to assess the effectiveness of the vaccine retrospectively. Incidence and complications of varicella were derived from the database from January 1, 1998 until December 31, 2002. RESULTS: Since licensure >30000 individuals younger than 10 years in this health maintenance organization have been immunized with the vaccine. Annual incidence of disease per 1000 in the study population was 86.6 in 1998, 74.6 in 1999, 74.0 in 2000, 37.1 in 2001 and 44.6 in 2002. This declining trend in incidence of disease was statistically significant. Complications of varicella occurred in approximately 1% of patients throughout the 5-year study period, but there was a parallel decline in the number of patients with complications corresponding to the decline in disease incidence. Vaccine effectiveness for prevention of clinical disease in this population was 92% (95% confidence interval, 91.0 to 92.7). There were varying rates of utilization within communities of varied socioeconomic class, so that in the higher socioeconomic class there was an increased utilization and a corresponding decrease of attack rate; whereas in communities where there were lower utilization rates, corresponding increased numbers of varicella cases were seen. CONCLUSION: This database enables long term follow-up of the effectiveness of this vaccine in a large population.

Safety and immunogenicity of Shigella sonnei-CRM9 and Shigella flexneri type 2a-rEPAsucc conjugate vaccines in one- to four-year-old children.

BACKGROUND AND OBJECTIVE: Shigella conjugate vaccines have been shown to be safe, immunogenic and efficacious in adult volunteers. We have now investigated the safety and immunogenicity of investigational Shigella sonnei and Shigella flexneri 2a conjugate vaccines in 1- to 4-year-old children, the age group at greatest risk for shigellosis. METHODS: The O-specific polysaccharides of S. sonnei and S. flexneri 2a, the two most common shigellae from patients in Israel, were bound to medically useful carrier proteins to form conjugates. Eighty healthy 1- to 4-year-olds were randomized to receive two 0.5-ml im injections 6 weeks apart of either S. sonnei-CRM(9) or S. flexneri 2a-rEPA(succ). Blood was taken before, 6 weeks after the first injection, 4 weeks after the second injections and 2 years after immunization for assay of IgG anti-lipopolysaccharide, diphtheria toxin and Pseudomonas aeruginosa exotoxin A antibodies by enzyme-linked immunosorbent assay. RESULTS: During an 8-day surveillance period after each immunization, low fever (37.8-39.0 degrees C) lasting only 24 to 48 h occurred in 2 of 40 recipients after the first injection and 4 of 40 recipients after the second injection of S. flexneri 2a-rEPA(succ) and in 2 of 38 of S. sonnei-CRM(9) after the second injection; no fever was detected after the first injection. Liver function tests were normal in all vaccinees. S. sonnei-CRM(9) elicited a >4-fold rise in IgG anti-LPS in 92.1% and S. flexneri 2a-rEPA(succ) in 85% (P < 0.0001) after the second injection; both conjugates elicited type-specific booster responses. At 2 years the geometric mean concentrations of both IgG anti-lipopolysaccharides were significantly higher than preimmunization levels. A >4-fold rise of IgG anti-diphtheria (65.8%) and IgG anti-ETA (77.5%) was observed. CONCLUSION: These experimental Shigella conjugate vaccines were safe and immunogenic in 1- to 4-year-old children.