Cross-reactions vs co-sensitization evaluated by in silico motifs and in vitro IgE microarray testing.

BACKGROUND AND OBJECTIVE: Using an in silico allergen clustering method, we have recently shown that allergen extracts are highly cross-reactive. Here we used serological data from a multi-array IgE test based on recombinant or highly purified natural allergens to evaluate whether co-reactions are true cross-reactions or co-sensitizations by allergens with the same motifs. METHODS: The serum database consisted of 3142 samples, each tested against 103 highly purified natural or recombinant allergens. Cross-reactivity was predicted by an iterative motif-finding algorithm through sequence motifs identified in 2708 known allergens. RESULTS: Allergen proteins containing the same motifs cross-reacted as predicted. However, proteins with identical motifs revealed a hierarchy in the degree of cross-reaction: The more frequent an allergen was positive in the allergic population, the less frequently it was cross-reacting and vice versa. Co-sensitization was analyzed by splitting the dataset into patient groups that were most likely sensitized through geographical occurrence of allergens. Interestingly, most co-reactions are cross-reactions but not co-sensitizations. CONCLUSIONS: The observed hierarchy of cross-reactivity may play an important role for the future management of allergic diseases.

Cross-sectional survey on immunoglobulin E reactivity in 23,077 subjects using an allergenic molecule-based microarray detection system.

BACKGROUND: The availability of allergenic molecules and high-throughput microtechnologies allow the collection of a large number of IgE results at the same time in a single test. This can be carried out applying the test in the routine diagnostic work-up. OBJECTIVE: The aim of this study was to make a cross-sectional evaluation of the raw prevalence of IgE reactivity to allergenic molecules in serum samples from a cohort of Italian patients using an innovative tool. METHODS: The ISAC, a microarray system, has been used for specific IgE detection using 75 different allergenic molecules. Sera were collected from 23,077 unselected consecutive individuals complaining about any allergic disease. RESULTS: Sixteen thousand four hundred and eight of 23,077 patients had IgE to at least one of 75 allergenic molecules. The top-ranked molecules in this cohort were Cup a 1 (42.7%), Der f 2 (38.7%), and Phl p 1 (37.9%), whereas all the other allergens tested scored in a range between 36.8% and 0.04%, including the first food allergen, Pru p 3, ranked 15th (9.79%). Prevalence varied quite markedly depending on the age range considered, and showing a different behaviour in the lifetime sensitization process. Unsupervised two-way hierarchical clustering analysis generated distinctive patterns of reactivity as the result of IgE recognition of either homologous allergens belonging to different biological sources or non-homologous belonging to the same biological source. CONCLUSIONS: Allergen-based microarray is a tool for the detection of IgE-related sensitization to panels of allergens and gives a more precise and comprehensive evaluation for an IgE-based epidemiology. This insight brings data for better understanding of the sensitization process.

Allergen cross reactions: a problem greater than ever thought?

BACKGROUND: Cross reactions are an often observed phenomenon in patients with allergy. Sensitization against some allergens may cause reactions against other seemingly unrelated allergens. Today, cross reactions are being investigated on a per-case basis, analyzing blood serum specific IgE (sIgE) levels and clinical features of patients suffering from cross reactions. In this study, we evaluated the level of sIgE compared to patients' total IgE assuming epitope specificity is a consequence of sequence similarity. METHODS: Our objective was to evaluate our recently published model of molecular sequence similarities underlying cross reactivity using serum-derived data from IgE determinations of standard laboratory tests. We calculated the probabilities of protein cross reactivity based on conserved sequence motifs and compared these in silico predictions to a database consisting of 5362 sera with sIgE determinations. RESULTS: Cumulating sIgE values of a patient resulted in a median of 25-30% total IgE. Comparing motif cross reactivity predictions to sIgE levels showed that on average three times fewer motifs than extracts were recognized in a given serum (correlation coefficient: 0.967). Extracts belonging to the same motif group co-reacted in a high percentage of sera (up to 80% for some motifs). CONCLUSIONS: Cumulated sIgE levels are exaggerated because of a high level of observed cross reactions. Thus, not only bioinformatic prediction of allergenic motifs, but also serological routine testing of allergic patients implies that the immune system may recognize only a small number of allergenic structures.

Profound parental bias associated with chromosome 14 acquired uniparental disomy indicates targeting of an imprinted locus.

Acquired uniparental disomy (aUPD) is a common finding in myeloid malignancies and typically acts to convert a somatically acquired heterozygous mutation to homozygosity. We sought to identify the target of chromosome 14 aUPD (aUPD14), a recurrent abnormality in myeloid neoplasms and population cohorts of elderly individuals. We identified 29 cases with aUPD14q that defined a minimal affected region (MAR) of 11.2 Mb running from 14q32.12 to the telomere. Exome sequencing (n=7) did not identify recurrently mutated genes, but methylation-specific PCR at the imprinted MEG3-DLK1 locus located within the MAR demonstrated loss of maternal chromosome 14 and gain of paternal chromosome 14 (P<0.0001), with the degree of methylation imbalance correlating with the level of aUPD (r=0.76; P=0.0001). The absence of driver gene mutations in the exomes of three individuals with aUPD14q but no known haematological disorder suggests that aUPD14q may be sufficient to drive clonal haemopoiesis. Analysis of cases with both aUPD14q and JAK2 V617F (n=11) indicated that aUPD14q may be an early event in some cases but a late event in others. We conclude that aUPD14q is a recurrent abnormality that targets an imprinted locus and may promote clonal haemopoiesis either as an initiating event or as a secondary change.

Endoscopic excision and repair of simulated bilateral cleft lips in fetal lambs.

The use of nonpenetrating clips to accomplish wound closure as an alternative to suture in the repair of simulated cleft lips in partially exteriorized fetuses has been described previously. In this study, the fetus is approached endoscopically, and clipped (n = 8) and sutured (n = 4) intrauterine endoscopic repairs in six lambs (90- to 95-day gestation) are compared. Also used was a newly developed harmonic scalpel to create the defects in the fluid environment. Clipped repairs were nearly 10 times faster than sutured repairs (2.7 +/- 0.5 minutes compared with 24 +/- 4 minutes, respectively). Furthermore, suture incited foreign body inflammation, recruited monocytic inflammatory cells, and exhibited notable scarring. The comparison between clipped and sutured repairs extends the previous observations to the realm of endoscopy and reinforces the previous conclusions of this group that the nonpenetrating clip is more rapid and incites less inflammation than suture in fetal wound approximation and repair.

Endoscopic intrauterine surgery in primates: overcoming technical obstacles.

Current protocols for fetal surgery require cesarean section and partial fetal extraction, both of which impart significant risks to the mother and fetus. Endoscopic fetal surgery is less invasive and will likely reduce some of these risks, but the technical difficulties and feasibility in a primate model have yet to be explored fully. Four pregnant baboons (95 days gestation) were anesthetized, their uteruses exposed via an abdominal incision, and blunt-tipped flanged endoscopic ports inserted. Amniotic fluid was removed, and warmed saline was infused to dilate the uterus. To evaluate instrumentation and wound closure, the tip of the snout was externalized and bilateral cleft lip-like defects made. The lips were then endoscopically repaired by suture (Endostitch, U.S. Surgical) or unique nonpenetrating clips (VCS, U.S. Surgical). The saline was then removed, amniotic fluid returned, and the ports carefully removed. After 4 weeks, the fetuses were delivered and evaluated. Eight cleft lip-like defects were successfully repaired in all four cases. Operative time averaged 83 min. No infections, amniotic leaks, or adhesions developed. Survival was 50% with two fetuses delivering within 48 hours postoperatively: one from preterm labor, the other with fetal demise from retroperitoneal hemorrhage after operative blunt abdominal trauma. We demonstrate the feasibility of endoscopic fetal surgery in primates. The use of blunt-tipped flanged ports provides a fluid tight seal and allows appropriate closure of the fetal membranes, but requires laparotomy and uterine exposure. Distension of the uterus with warmed saline affords a larger operating field, enhancing visualization and instrumentation of the fetus. Grasping the fetus through the exposed uterus gives excellent control for repair. However, such control is also needed in a percutaneous approach. Further instrumentation development is needed to accomplish similar control for the percutaneous approach.