Effects of a higher dose of alglucosidase alfa on ventilator-free survival and motor outcome in classic infantile Pompe disease: an open-label single-center study

BACKGROUND

Though enzyme-replacement therapy (ERT) with alglucosidase alfa has significantly improved the prospects for patients with classic infantile Pompe disease, some 50 % of treated infants do not survive ventilator-free beyond the age of 3 years. We investigated whether higher and more frequent dosing of alglucosidase alfa improves outcome.

METHODS

Eight cross-reactive immunological material (CRIM) positive patients were included in the study. All had fully deleterious mutations in both GAA alleles. Four received a dose of 20 mg/kg every other week (eow) and four received 40 mg/kg/week. Survival, ventilator-free survival, left-ventricular mass index (LVMI), motor outcome, infusion-associated reactions (IARs), and antibody formation were evaluated.

RESULTS

All eight patients were alive at study end, seven of them remained ventilator-free. The patient who became ventilator dependent was treated with 20 mg/kg eow. Three of the four patients receiving 20 mg/kg eow learned to walk; two of them maintained this ability at study end. All four patients receiving 40 mg/kg/week acquired and maintained the ability to walk at study end (ages of 3.3-5.6 years), even though their baseline motor functioning was poorer. There were no apparent differences between the two dose groups with respect to the effect of ERT on LVMI, the number of IARs and antibody formation.

CONCLUSIONS

Our data may suggest that a dose of 40 mg/kg/week improves outcome of CRIM positive patients over that brought by the currently recommended dose of 20 mg/kg eow. Larger studies are needed to draw definite conclusions.

Improvement of shrimp allergy after sublingual immunotherapy for house dust mites: a case report

The appropriateness of house dust mite specific immunotherapy in patients allergic to shrimps still remains unclear We present a clinical case as an immunological model for the strong sensitization to tropomyosin with symptoms of anaphylaxis due to shrimps and coexisting asthma due to house dust mite. The improvement in respiratory symptoms for house dust mite and in the food challenge for shrimps during mite immunotherapy with a known and high dosage of tropomyosin suggests the hypothesis that efficacy of mite immunotherapy in food allergy to tropomyosin may be dose dependent.

Coexistence conditions for strains of influenza with immune cross-reaction

The accumulation of cross-immunity in the host population is an important factor driving the antigenic evolution of viruses such as influenza A. Mathematical models have shown that the strength of temporary non-specific cross-immunity and the basic reproductive number are both key determinants for evolutionary branching of the antigenic phenotype. Here we develop deterministic and stochastic versions of one such model. We examine how the time of emergence or introduction of a novel strain affects co-existence with existing strains and hence the initial establishment of a new evolutionary branch. We also clarify the roles of cross-immunity and the basic reproductive number in this process. We show that the basic reproductive number is important because it affects the frequency of infection, which influences the long term immune profile of the host population. The time at which a new strain appears relative to the epidemic peak of an existing strain is important because it determines the environment the emergent mutant experiences in terms of the short term immune profile of the host population. Strains are more likely to coexist, and hence to establish a new clade in the viral phylogeny, when there is a significant time overlap between their epidemics. It follows that the majority of antigenic drift in influenza is expected to occur in the earlier part of each transmission season and this is likely to be a key surveillance period for detecting emerging antigenic novelty.

Adiponectin levels measured in dried blood spot samples from neonates born small and appropriate for gestational age

OBJECTIVE

Adiponectin levels measured in neonatal dried blood spot samples (DBSS) might be affected by both prematurity and being born small for gestational age (SGA). The aim of the study was to measure adiponectin levels in routinely collected neonatal DBSS taken on day 5 (range 3-12) postnatal from infants.

DESIGN

A retrospective case-control study.

SUBJECTS AND METHODS

One hundred and twenty-two infants: 62 very premature (34 SGA) and 60 mature infants (27 SGA). Adiponectin concentrations were determined in stored neonatal DBSS using a sandwich immunoassay based on flow metric Luminex xMap technology.

RESULTS

Adiponectin was measurable in all samples, and repeated measurements correlated significantly (r = 0.94). Adiponectin concentrations were negatively associated with both SGA (B = -0.283, P = 0.04) and prematurity (B = -2.194, P < 0.001), independently of each other. In the premature but not the mature group, adiponectin levels increased with increasing postnatal age at blood sampling (B = 0.175, P < 0.001).

CONCLUSIONS

Reliable quantification of adiponectin in stored DBSS is feasible and may be used to study large populations of routinely collected samples. Low levels of adiponectin in neonatal DBSS are associated with SGA as well as prematurity. Blood adiponectin levels increase with postnatal age in premature infants, suggesting a rapid yet unexplained metabolic adaptation to premature extrauterine life.

Impact of native, recombinant, and cross-reactive allergens on humoral and T-cell-mediated immune responses

Many native allergens have been purified to homogeneity from natural sources, and whole arrays of recombinant and cross-reactive allergens have been produced in large amounts as biologically active molecules. These allergens offer potent research tools to investigate humoral and T cell-mediated immune responses to allergens in healthy and allergic individuals, providing methods for verifying the responses in a reproducible and dose-dependent manner. Dissecting the immune responses to allergens at cellular and molecular levels provides models for studying the different aspects of T-cell activation and the development of immunologic memory and effector functions. A deep understanding of these mechanisms will fundamentally change the current practice of allergy diagnosis, treatment, and prevention.

Prevalence of serum autoantibodies and paraproteins in patients with glaucoma

PURPOSE

To investigate the possible link between normal tension glaucoma (NTG) and autoimmunity.

METHODS

We studied the serum of 95 patients: 31 with NTG, 32 with primary open-angle glaucoma (POAG), and 32 age- and sex-matched controls. Blood was drawn from each patient and serum was examined for the presence of antinuclear antigens (ANA), autoantibodies to extractable nuclear antigens (ENA), anti-double-strand DNA, serum protein electrophoresis, and immunoglobulin (IgG, IgA, and IgM) levels.

RESULTS

In the NTG group, the relative risks for ANA and ENA positivity were 2.5 and 4.4 times, respectively, that of the control group. There was a statistically significant difference between IgA levels in the NTG and control group (P=0.024), but there was no statistically significant difference between both groups regarding IgM or IgG levels. In the POAG group, the relative risks for ANA and ENA positivity were 0.77 and 2.9 times, respectively, that of the control group. The relative risk for detection of paraprotein in the POAG group was 0.97 times that of the control group. Also, there was a statistically significant difference between IgA levels in the POAG and control group (P=0.011), but there was no statistically significant difference between both groups regarding IgM or IgG.

CONCLUSION

These results support the hypothesis that humoral immune mechanisms may have a role in the pathogenesis of NTG.

Induction of cross-reactive immune responses to NTS-DBL-1alpha/x of PfEMP1 and in vivo protection on challenge with Plasmodium falciparum

The interactions of Plasmodium falciparum infected erythrocytes parasitized red blood cells (pRBC) with endothelial receptors and erythrocytes are mediated by multiple Duffy-binding like (DBL) and cysteine-rich interdomain region (CIDR) domains harboured in the Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1). The success of a subunit vaccine based on PfEMP1 depends on its ability to elicit cross-reactive responses to a substantial number of PfEMP1 variants. We have here evaluated serological PfEMP1 cross-reactivity by immunizing rats with phylogenetically diverse recombinant NTS-DBL-1alpha/x fusion domains from the 3D7 genome parasite emulsified in Montanide ISA 720. Cross-reactivity was elicited to these diverse DBL-1alpha/x domains as measured by ELISA and by immunoblotting. Employing a novel in vivo model of human infected erythrocyte sequestration, immunized animals were challenged with the FCR3S1.2 clone and cross-protection in terms of reduction in lung sequestration amounting to approximately 50% was demonstrated. Our results suggest that immunization with phylogenetically distant DBL-1alpha/x variants, can elicit partial cross-protection to challenge with the parasites harbouring a distant variant. These observations have implications for the design of multi-component vaccines against P. falciparum malaria.

How the T cell receptor sees antigen--a structural view

Structures of many of the cell surface receptor-ligand complexes mediating the interactions between T cells and target cells have been determined in the past ten years. While snapshots of T cell receptors bound to their peptide-MHC ligands appear to have defined a general interaction or "docking" solution, many of the most fundamental structural questions in antigen recognition lack detailed answers and thus pose exciting experimental challenges for the future.

Octopamine-immunoreactive neurons in the brain and subesophageal ganglion of the hawkmoth Manduca sexta

Octopamine is a neuroactive monoamine that functions as a neurohormone, a neuromodulator, and a neurotransmitter in many invertebrate nervous systems, but little is known about the distribution of octopamine in the brain. We therefore used a monoclonal antibody to study the distribution of octopamine-like immunoreactivity in the brain of the hawkmoth Manduca sexta. Immunoreactive processes were observed in many regions of the brain, with the distinct exception of the upper division of the central body. We focused our analysis on nine ventral unpaired median (VUM) neurons with cell bodies in the labial neuromere of the subesophageal ganglion. Seven of these neurons projected caudally through the ventral nerve cord. Two neurons projected rostrally into the brain (supraesophageal ganglion), and one of these was a bilateral neuron that sent projections to the gamma-lobe of the mushroom body and the lateral protocerebrum. Octopamine-immunoreactive processes from one or more cells originating in the subesophageal ganglion also form direct connections between the antennal lobes and the calyces of the mushroom bodies.

Molecular polymorphism of native gonadotropin-releasing hormone (GnRH) is restricted to mammalian GnRH and [hydroxyproline9] GnRH in the developing rat brain

Although chicken gonadotropin-releasing hormone (GnRH)-II is thought to occur in most animal species, its presence and that of two other variants (lamprey GnRH-III, salmon GnRH) is questionable in rodents. Here we report on the GnRH peptides present in the hypothalamus and the remaining brain of rat of both sexes during development. No immunoreactivity was detected in the elution zone of either native or hydroxylated forms of the above three variants in any of brain extracts chromatographed. The main peptides detected were mammalian GnRH (mGnRH) and m[hydroxyproline9]GnRH (mHypGnRH). In the hypothalamus, these peptides were associated with their free acid and precursor forms. N-terminal fragments from both native decapeptides (GnRH) and mGnRH (GnRH) were observed only in the hypothalamus. C-terminal fragments were detected in both tissues. The relative proportions of mGnRH and mHypGnRH showed no developmental changes in the remaining brain. The hypothalamic proportions of mHypGnRH were high on day 5, and decreased from day 15 onwards. The [Gly11]-precursor to mHypGnRH molar ratio was twofold lower than with the non-hydroxylated peptides. The mGnRH to GnRH molar ratio increased in males but decreased in females during development. No sex-related differences were observed in the native decapeptide to GnRH molar ratio. It was concluded that (1) chicken GnRH-II is not present in all mammals, (2) mGnRH and mHypGnRH are the main GnRH isoforms present in the rat brain, (3) the processing of [Gly11]-precursor into mHypGnRH occurs at a higher rate than that of mGnRH, and (4) the catabolism does not interfere with the developmental changes undergone by the mGnRH and mHypGnRH brain contents.

Importance of including Blomia tropicalis in the routine diagnosis of Venezuelan patients with persistent allergic symptoms

BACKGROUND

Blomia tropicalis is a common mite found in the house dust of many tropical countries including Venezuela. The prevalence of skin test and specific serum immunoglobulin (Ig)E reactivity to B. tropicalis in Venezuela has not been previously evaluated.

METHODS

In the present study we evaluated the skin reactivity by skin prick test and specific IgE by a multiple antigen blot assay, against B. tropicalis and Dermatophagoides pteronyssinus, in a group of 115 subjects who attended the Allergy Clinic of the Institute of Biomedicine, Caracas, Venezuela, and we studied possible cross reactions between similar proteins of these two mites.

RESULTS

One hundred and six patients with persistent allergic respiratory symptoms showed a positive skin prick test to at least one of the mite extracts, with the frequency of positive reactions to B. tropicalis being as high as to D. pteronyssinus. Twelve patients reacted only to D. pteronyssinus and 13 different patients only to B. tropicalis. Specific IgE to each of the mite extracts was found with similar frequency, and the results coincided with the skin test reactivity.

CONCLUSIONS

The study indicated the importance of including B. tropicalis in routine diagnostic testing in tropical and sub-tropical situations.

The Guillain-Barré syndrome: a true case of molecular mimicry

Molecular mimicry between microbial antigens and host tissue forms an attractive hypothetical mechanism for the triggering of autoimmune disease by preceding infections. Recent crucial reviews state that molecular mimicry, as the causative mechanism, remains unproven for any human autoimmune disease. However, the peripheral neuropathy Guillain-Barré syndrome (GBS) is largely overseen in this debate. Based on recent evidence, we argue that GBS should be considered as an excellent paradigm and an attractive model for elucidation of both host and microbial aspects of molecular mimicry.

Natural history and clinical features of aspirin-exacerbated respiratory disease

Aspirin-exacerbated respiratory disease (AERD) is a clinical syndrome characterized by chronic rhinosinusitis, nasal polyposis, asthma and precipitation of asthma, and rhinitis attacks after ingestion of aspirin (ASA) and most other nonsteroidal antiinflammatory drugs (NSAIDs). Although precipitation of asthma attacks by ingestion of ASA and other NSAIDs is considered a hallmark of the syndrome, the respiratory mucosal inflammatory disease process begins and continues in the absence of ongoing or even intermittent exposure to ASA or NSAIDs. The typical patient with AERD is an adult who develops refractory chronic rhinitis in the third or fourth decade of life. The chronic rhinitis evolves into chronic eosinophilic rhinosinusitis with associated nasal polyposis. Anosmia appears in most patients. CT of the sinuses most often demonstrates pansinusitis and patients often undergo multiple sinus operations resulting in only limited temporary benefit. During the evolution of the sinus disease persistent asthma develops. Finally, if patients are exposed to ASA or NSAIDs acute respiratory reactions begin to occur. Despite subsequent avoidance of ASA and other NSAIDs, the respiratory mucosal inflammatory disease persists, often requiring systemic corticosteroids for control of both upper- and lower-respiratory tract symptoms. Adequate control of asthma can often only be accomplished with the simultaneous control of the associated rhinosinusitis. With few exceptions, once AERD develops it remains for the remainder of the patient s life.

Cross-reactivity assessment of carbamazepine-10,11-epoxide, oxcarbazepine, and 10-hydroxy-carbazepine in two automated carbamazepine immunoassays: PETINIA and EMIT 2000

This study was conducted to compare the cross-reactivity of two commercially available carbamazepine (CBZ) immunoassays (PETINIA and EMIT 2000) with carbamazepine-10,11-epoxide (CBZ-E), the active metabolite of CBZ. Oxcarbazepine (OCBZ) and its main metabolite 10-hydroxy-carbazepine (HCBZ) have a chemical structure closely related to that of CBZ. The cross-reactivities of these two drugs were also investigated. In the first part of the study, Lyphocheck blank human serum and Chemonitor quality controls (containing CBZ without CBZ-E) were spiked with variable amounts of CBZ-E. The apparent CBZ levels were measured by PETINIA and EMIT 2000 methods. The interference from OCBZ and HCBZ was directly assessed by measuring the apparent CBZ levels in Chromsystems Trileptal quality controls (containing OCBZ and HCBZ). In the second part of the study, the CBZ levels of serum samples from 49 patients, including 2 patients with massive CBZ ingestion, were measured by immunoassays and compared with a high-pressure liquid chromatography (HPLC) reference technique allowing the simultaneous measurement of CBZ and CBZ-E. The antibody used in the PETINIA assay cross-reacts (about 90%) with CBZ-E. In one case of CBZ poisoning (CBZ and CBZ-E levels measured by HPLC were 26.2 and 18.2 mg/L, respectively), CBZ level measured by PETINIA was falsely elevated (42.5 mg/L). In contrast, the specificity of EMIT 2000 was satisfactory (29.5 mg/L). The two immunoassays tested showed low cross-reactivity with OCBZ and HCBZ. In conclusion, it appears that the CBZ-E metabolite present in samples can falsely increase CBZ levels measured by the PETINIA assay.

Psychological aspects of food allergy

Food allergies may impact the emotions of patients through both direct and indirect mechanisms. Direct mechanisms include the effects on the central nervous system from biologic mediators released during an allergic reaction to food. Indirect mechanisms include the stress of coping with a food allergy--for example, food preparation and avoidance--as well as managing the fear of the potential consequences of ingesting the food. Indirect effects may also be mediated through family members--for example, the impact of a parent's stress on the child. These relationships are difficult to study, in part because many patients who report food allergy symptoms do not have objective symptoms when challenged with the offending food. Symptoms may be misinterpreted as food allergy more often by patients with certain psychological profiles. In this paper, relevant literature is reviewed, and clinical treatment designed to minimize the emotional suffering of patients and their families is presented through the description of a case vignette.

Latex-fruit syndrome

Natural rubber latex immunoglobulin E-mediated hypersensitivity is probably one of the most relevant challenges that has been faced in the treatment of allergies during recent years. Additionally, allergen cross-reactivity has arisen as another very important problem, in the difficulty in diagnosing it and in its clinical implications. It is clear that some latex allergens cross-react with plant-derived food allergens, the so-called latex-fruit syndrome, with evident clinical consequences. Although the foods most frequently involved are banana, avocado, kiwi, and chestnut, several others are also implicated. Investigations point to a group of defense-related plant proteins, class I chitinases, which cross-react with a major latex allergen, hevein, as the panallergens responsible for the syndrome. This review focuses on our current understanding of the latex-fruit syndrome.

The upper and lower airway responses to nasal challenge with house-dust mite Blomia tropicalis

BACKGROUND

The house dust mite Blomia tropicalis (B. tropicalis) was found to be the most prevalent domestic mite in Singapore. However, its pathogenicity in allergic airway diseases remains to be investigated.

METHODS

Twenty adults with persistent allergic rhinitis (PAR) were studied. Five had a history of asthma, and all were asymptomatic except one who was under treatment with low-dose inhaled corticosteroid. Nasal challenge was carried out by nasal spray with phosphate-buffered saline (PBS) and with increasing concentrations of crude B. tropicalis extracts (0.6, 6.0 and 60 micro g/ml) at 15 min intervals. Subjective symptom scores and absolute number of sneezes were recorded together with objective measurements of spirometry (forced expiratory volume in 1 s, FEV1) and acoustic rhinomanometry (volume of the nasal cavity). These were performed at baseline, 5 min after each incremental challenge, and 30 min, 1 h, 3 h, 5 h and 7 h after the last challenge. Meanwhile, concentrations of mediators in nasal secretions (tryptase, leukotriene C4 (LTC4) and eosinophil cationic protein (ECP)) were measured in nasal aspirate samples at similar time intervals. An identical (control) challenge procedure with PBS alone was repeated in seven patients after a washout period of at least 2 weeks.

RESULTS

Significant increases in the subjective and objective nasal symptoms, together with a significant increase of tryptase and LTC4 concentrations in nasal secretion, were found 5 min after each challenge with B. tropicalis, but not with PBS. There was no definitive pattern of the late-phase nasal response in either subjective symptoms or objective measurements. Three patients (3/5) with a history of asthma showed a fall in FEV1 readings (33%, 22% and 11% from baseline, respectively) at 7 h post challenge with concomitant mild wheezing in the night.

CONCLUSIONS

Our study demonstrates direct evidence of allergic nasal response to B. tropicalis in sensitized adults. It shows that nasal provocation may also provoke concomitant asthmatic symptoms during the late-phase reaction, especially in people with a history of asthma.

Tree nut allergy

Tree nuts are clinically associated with severe immunoglobulin E-mediated systemic allergic reactions independent of pollen allergy and with reactions that are usually confined to the oral mucosa in patients with immunoglobulin E directed toward cross-reacting pollen allergens. The latter reactions can progress to severe and life-threatening episodes in some patients. Many patients with severe tree nut allergy are co-sensitized to peanut. Clinical studies on cross-reactivity between the tree nuts are few in number, but based on reports to date, avoidance of the other tree nuts once sensitivity is diagnosed appears prudent unless specific challenges are performed to ensure clinical tolerance. Even then, great care must be taken to avoid cross-contamination. As with other severe food allergies, a recurrent problem in clinical management is the failure of physicians to prescribe self-injectable epinephrine to patients who are at risk of anaphylaxis.

Restricted cross-reactivity of hybrid capture 2 with nononcogenic human papillomavirus types

Hybrid Capture 2 Test using probe B (HC2-B) is a clinical test for the detection of 13 human papillomavirus (HPV) types associated with cervical cancer (oncogenic types), but the potential clinical significance of HC2-B cross-reactivity with untargeted (nononcogenic) HPV types has not been fully evaluated. Thus, HC2-B test results on 954 clinical cervical specimens from a population-based natural history study of HPV in Costa Rica were compared with the data from testing of the same specimens twice by HPV type-specific MY09/MY11 L1 consensus primer PCR. Specimens positive by PCR for single HPV types not targeted by HC2-B were used for determining type-specific cross-reactivity. Effects of cross-reactivity on clinical performance were estimated by calculating sensitivity and specificity with and without cross-reactivity for the detection of high-grade cervical lesions. HC2-B tested positive for single infections by untargeted (cross-reactive) types 11, 53, 61, 66, 67, 70, 71, and 81. Cross-reactivity was strongly associated with PCR signal strength (P(Trend) = 0.0001) and cervical abnormalities (P = 0.0002, Pearson chi(2)). We estimated that HC2-B cross-reactivity resulted in minor changes in screening performance. Clinical sensitivity increased from 84.3% to 87.9%, clinical specificity decreased from 89.6% to 88.1%, and referral rates increased from 11.7% to 13.2% for detection of >or=cervical intraepithelial neoplasia grade 2. The clinical effect of cross-reactivity varied by cytologic interpretation. Among women with normal cytologic interpretations, cross-reactivity significantly improved the accuracy of identifying cytologically nonevident histology of >or=cervical intraepithelial neoplasia grade 2 because of increased sensitivity with maintained specificity. However, among women with equivocal or mildly abnormal cytologic interpretations, cross-reactivity decreased the accuracy of HPV testing because of substantial decreases in specificity. In summary, cross-reactivity with nononcogenic HPV types had little effect on the overall clinical performance of HC2-B as a general screening test, but reduction of cross-reactivity might improve the performance of HPV testing for triage of equivocal or mildly abnormal cytologic interpretations.

IgG4 breaking the rules

Immunoglobulin G4 (IgG4) antibodies have been known for some time to be functionally monovalent. Recently, the structural basis for this monovalency has been elucidated: the in vivo exchange of IgG half-molecules (one H-plus one L-chain) among IgG4. This process results in bispecific antibodies that in most situations will behave as functionally monovalent antibodies. The structural basis for the abnormal behaviour of IgG4 seems to be largely the result of a single amino acid change relative to human IgG1: the change of a proline in core hinge of IgG1 to serine. This results in a marked shift in the equilibrium between interchain disulphide bridges and intrachain disulphide bridges, which for IgG4 results in 25-75% absence of a covalent interaction between the H-chains. Because of strong non-covalent interactions between the CH3 domains (and possibly also between the CH1 domain and the trans-CH2 domain) IgG4 is a stable four-chain molecule and does not easily exchange half-molecules under standard physiological conditions in vitro. We postulate that the exchange is catalysed in vivo by protein disulphide isomerase (PDI) and/or FcRn (the major histocompatibility complex (MHC)-related Fc receptor) during transit of IgG4 in the endosomal pathway in endothelial cells. Because IgG4 is predominantly expressed under conditions of chronic antigen exposure, the biological relevance of this exchange of half-molecules is that it generates antibodies that are unable to form large immune complexes and therefore have a low potential for inducing immune inflammation. In contrast to monovalent immunoglobulin fragments, these scrambled immunoglobulins have a normal half-life. The significance of the ensuing bispecificity needs further evaluation, because this will be relevant only in situations where high IgG4 responses are found to two unrelated antigens that happen to be present in the body at the same time and place. In this context the significance of IgG4 autoreactivity might have to be re-evaluated. The main function of IgG4, however, is presumably to interfere with immune inflammation induced by complement-fixing antibodies, or, in the case of helminth infection or allergy, by IgE antibodies.

Distribution of the high-affinity choline transporter in the central nervous system of the rat

In cholinergic nerve terminals, Na(+)- and Cl(-)-dependent, hemicholinium-3-sensitive, high-affinity choline uptake is thought to be the rate-limiting step in acetylcholine synthesis. The high-affinity choline transporter cDNA responsible for the activity was recently cloned. Here we report production of a highly specific antibody to the high-affinity choline transporter and distribution of the protein in the CNS of the rat. The antibody stained almost all known cholinergic neurons and their terminal fields. High-affinity choline transporter-immunoreactive cell bodies were demonstrated in the olfactory tubercle, basal forebrain complex, striatum, mesopontine complex, medial habenula, cranial nerve motor nuclei, and ventral horn and intermediate zone of the spinal cord. Noticeably, high densities of high-affinity choline transporter-positive axonal fibers and puncta were encountered in many brain regions such as cerebral cortex, hippocampus, amygdala, striatum, several thalamic nuclei, and brainstem. Transection of the hypoglossal nerve resulted in a loss of high-affinity choline transporter immunoreactivity in neurons within the ipsilateral hypoglossal motor nucleus, which paralleled a loss of immunoreactivity to choline acetyltransferase. The antibody also stained brain sections from human and mouse, suggesting cross-reactivity. These results confirm that the high-affinity choline transporter is uniquely expressed in cholinergic neurons and is efficiently transported to axon terminals. The antibody will be useful to investigate possible changes in cholinergic cell bodies and axon terminals in human and rodents under various pathological conditions.

Citrus red mite (Panonychus citri) may be an important allergen in the development of asthma among exposed children

BACKGROUND

Recent investigations have demonstrated that spider mites are important allergens in the development of asthma in fruit-cultivating farmers.

OBJECTIVE

The aim of this study was to evaluate the sensitization rate to the citrus red mite (Panonychus citri) in children living in rural areas, and to determine the allergenic cross-reactivity with other mites.

METHODS

A total of 7254 children (ages 7-15 years) living in rural areas were enrolled, and each subject was evaluated by a questionnaire and a skin prick test. Allergenic cross-reactivity was evaluated by ELISA inhibition tests.

RESULTS

The most common sensitizing allergens were house dust mites, followed by citrus red mite and cockroach. High serum-specific IgE bindings to the citrus red mite were detected in 21 of 100 randomly selected subjects. The prevalence of asthma was higher among those with positive skin responses to the citrus red mite than with negative skin responses to this mite. ELISA inhibition tests showed that IgE bindings to this mite were minimally inhibited with additions of domestic mites.

CONCLUSION

Spider mites such as the citrus red mite may be important outdoor allergens among children living in rural areas, and spider mite-derived allergens have unique allergenic determinants compared with domestic mites.

Long-term serological follow up and cross-challenge studies in rhesus monkeys experimentally infected with hepatitis E virus

BACKGROUND/AIMS

The aims of this study were to examine the decline of IgG anti-HEV antibodies over a period of 7 years in rhesus monkeys experimentally infected with hepatitis E virus, and to assess the protectivity of these antibodies by challenging the monkeys with a heterologous isolate of hepatitis E virus, 5 years after the primary inoculation.

METHODS

Nine rhesus monkeys (six non-pregnant and three pregnant at the time of hepatitis E virus inoculation) were followed serologically and biochemically for 7 years post-inoculation. Based on regression analysis, estimated time for IgG anti-HEV titers to reach 1:100 or 1:50 was calculated. Three of the monkeys inoculated initially with AKL-90 isolate and challenged 2 years later with PUN-85 isolate of hepatitis E virus were rechallenged with KOL-91 isolate of the virus, 5 years post-primary inoculation. Evidence of viral replication was assessed by measuring serum alanine aminotransferase levels, excretion of the virus in feces or bile (reverse-transcription polymerase chain reaction) and rise in IgG anti-HEV titers (ELISA).

RESULTS

None of the challenged monkeys showed evidence of disease. In contrast to extensive replication of the virus in anti-HEV-negative control monkeys, limited replication was noted in one of the challenged monkeys. The estimated time for the titers to reach 1:100 or 1:50 varied from 3.15 to 44.9 years (19.4+/-11.6 years) and 6.9 to 84.3 years (35.4+/-21.3 years), respectively. Decline in titers was independent of the pregnancy status at the time of infection or reexposure of the monkeys to HEV CONCLUSION: The results show persistence of IgG anti-HEV antibodies for a long time and protectivity of low titered antibodies against reinfection, leading to disease even after intravenous exposure to a heterologous isolate of hepatitis E virus.

Determination of transforming growth factor-beta 2 (TGF-beta 2) in bovine colostrum samples

Transforming growth factor-beta 2 (TGF-beta 2) is the major TGF-beta form in bovine colostrum. A colostrum pool of the five first milkings was made to validate an ELISA specific for human TGF-beta 2 for measure TGF-beta 2 concentration in bovine colostrum samples. According to this test > 90% of total TGF-beta 2 (74.5 +/- 4.4 ng/ml) in colostrum pool was in a latent form that could be activated by acetic acid treatment, whereas the concentration of the active form was only 4.19 +/- 0.27 ng/ml. Activated colostrum samples of the first milkings of five cows contained 150-1150 ng TGF-beta 2/ml and its concentration declined in correlation (r = 0.86) with total protein concentration to 12-71 ng/ml by the fifth milkings. Most of the TGF-beta 2 (94%) was found in the whey fraction of colostrum. The ELISA results were also compared with a TGF-beta 2 bioassay, the fibroblasts migration assay. This assay detected 9.8 +/- 1.0 ng/ml and 4.4 +/- 0.7 ng/ml in the activated and non-activated samples of colostrum pool respectively.

The fibronectin binding domain of the Sfb protein adhesin of Streptococcus pyogenes occurs in many group A streptococci and does not cross-react with heart myosin

Sfb protein, a fibronectin binding adhesin of Streptococcus pyogenes (Lancefield group A streptococcus), mediates streptococcal adherence to human epithelial cells via its fibronectin binding domain coded by a repetitive gene region named fnbr. In the present study, Southern blot analysis using the fnbr gene region as a probe to screen genomic DNA from 51 epidemiologically unrelated clinical isolates of S. pyogenes revealed that 70% carried a sequence homologous to the fnbr probe. Among ten other streptococcal strains belonging to serological groups B, C, and G, DNA from only two human S. equisimilis (group C) strains reacted with the probe. Further analysis by PCR-mediated amplification of the binding repeat coding sequences revealed that repeats of different S. pyogenes isolates were identical in size but varied in number, ranging from one to five. Most of the isolates were shown to carry multiple repeats. Presence of the probe-positive sequence correlated strongly with streptococcal binding to purified fibronectin and adherence to HEp2 human epithelial cells; of the 36 probe-positive isolates, 95% bound fibronectin and 89% adhered strongly to epithelial cells, whereas among the 15 probe-negative isolates only 27% had binding activities for fibronectin and 27% showed strong adherence to HEp2 cells. Antibodies raised against the fibronectin binding domain of Sfb protein recognized streptococcal fibronectin binding surface proteins in most of the clinical isolates but did not react with heart or skeletal muscle myosin in an enzyme immunoassay, as is the case with antibodies directed to M protein, another major surface protein of group A streptococci. The results of the present study suggest that Sfb protein could be a potential candidate for a streptococcal vaccine.

HLA-A2-binding peptides cross-react not only within the A2 subgroup but also with other HLA-A-locus allelic products

Seven A2-binding peptides were tested by the HLA class I alpha-chain refolding assay previously described for their direct binding to HLA class I alpha chains derived from a panel of 18 HLA-homozygous B-cell lines of various HLA specificities, including four A2 subtypes: A*0201, A*0204, A*0205, and A*0206. All but one test peptide possessed the major anchor residue motifs, L-V, L-L, or I-L, of A2(A*0201)/A2(A*0205)-binding peptides or the closely related motifs, I-V or V-V. This cell panel analysis confirmed the high A2 allele specificity of the test peptides, but also revealed the existence of a broad cross-binding within the A2 subgroup. Most peptides bound to the alpha chains of the A2 subtypes tested, although their binding patterns showed differences. Furthermore, the A2-binding peptides carrying the I-V or V-V motif were found to cross-react also outside of the A2 subtypes, probably with A24, A26, A28, and A29. Other A-locus allelic products, A1, A3, A11, A30, and A31, and the B-locus allelic products carried by the cells tested were essentially negative, although a few exceptions were seen.

Activated human T lymphocytes express albumin binding proteins which cross-react with alpha-fetoprotein

The kinetics of iodinated human serum albumin ([125I]Hu-SA) and alpha-fetoprotein ([125I]Hu-AFP) binding and endocytosis by resting and phytohemagglutinin (PHA)-activated human T lymphocytes were studied comparatively. The binding of both SA and AFP appeared considerably increased upon blastic transformation. SA, like AFP, binds in a saturable way to the surface of PHA-stimulated human T lymphocytes at 4 degrees C and is endocytosed at 37 degrees C. Two saturation plateaus were observed by incubating at 4 degrees C activated T lymphocytes with [125I]Hu-AFP at different concentrations (10 ng-250 micrograms/ml), while only one saturation plateau was obtained by incubating cells with [125I]Hu-SA in the same conditions. Scatchard analysis of binding data revealed two types of binding sites for Hu-AFP and one for Hu-SA. Competition experiments using proteins of human and bovine origin are in favor of the presence on the surface of these cells of a common binding site for AFP and SA. Pulse-chase experiments showed that internalized [125I]SA was released mainly in a degraded form from the cells, in agreement with detection by ultrastructural cytochemistry of peroxidase-conjugated SA in lysosome-like bodies by ultrastructural cytochemistry. This contrasts with the intracellular pathway of AFP, which as previously described (Geuskens, M., et al., Eur. J. Cell Biol. 50, 418-427 (1989)), moves to tubular-vesicular structures in the Golgi region and is recycled for the most part undegraded.

Cross-reactivity between streptococcal M surface antigen and human skin

Psoriasis can be triggered by haemolytic streptococcal infections. As M protein is a major pathogenic surface antigen in these streptococci, the cross-reactivity between streptococcal M protein surface antigens and human epidermis was investigated. The conserved component common to the few M proteins investigated consists of an alpha-helical 'coiled-coil' configuration, similar to sub-units of human keratin. The amino acid sequence of protein M6, one of the M proteins that has been fully sequenced, was compared with that of 4721 ubiquitous peptides, by computer-assisted analysis using a protein-sequence data bank. Of all human proteins in the data bank 50-kDa keratin type 1 showed the closest homology with protein M6. Further evaluation revealed that this homology mainly involved the heptapeptide repeat patterns, which form the alpha-helical 'coiled-coil' structure, in both M6 and 50-kDa keratin. Cryostat sections of normal, involved and uninvolved psoriatic skin were studied for cross-reactivity with rabbit antisera raised against 10 different M proteins. All these antisera reacted with the stratum corneum of normal and psoriatic epidermis to a variable extent. Staining of keratinocyte cytoplasm was also observed, but this tended to be more prominent in lesional than in uninvolved and normal skin. Some of the M antisera also stained dendritic cells in the upper dermis as well as endothelium and smooth muscle. These cross-reactivities might be relevant to the pathogenesis of post-streptococcal psoriasis.

Is rheumatoid arthritis in Indians associated with HLA antigens sharing a DR beta 1 epitope?

HLA class II antigens were identified in a group of 44 patients with rheumatoid arthritis (RA) originating largely from the north or northeast of the Indian subcontinent and resident now in east London. Compared with 67 locally typed east London Asian controls, the prevalence of three HLA-DR antigens was raised in the patients: DR1 18.2% v 6.0% chi 2 = 3.99, DR4 20.5% v 11.9% chi 2 = 1.48, and DRw10 27.3% v 8.9% chi 2 = 6.56. These differences were also found when the patients with RA were compared with a larger control group of 110 northern Indians: DR1 18.2% v 7.2% chi 2 = 4.02, DR4 20.5% v 7.2% chi 2 = 5.56, and DRw10 27.3% v 8.1% chi 2 = 9.7. Twenty five (57%) of the patients expressed at least one of these antigens. All patients were also characterised for HLA-Dw types by mixed lymphocyte culture typing. The prevalence of the HLA-DR4 associated Dw types in the patients was: Dw4 2.3%, Dw10 0%, Dw14 11.4%, and Dw15 6.8%. The DR beta 1 chains of DR1 and DRw10 together with the Dw types of DR4 other than Dw10 share amino acid residues in a region of the third hypervariable region considered to be critical in antigen presentation. It is concluded that RA in Indians is associated with these HLA antigens, and data from this study support the hypothesis of a cross reactive epitope common to HLA specificities associated with RA.

Characteristics of antineuronal antibodies in systemic lupus erythematosus patients with and without central nervous system involvement: the role of mycobacterial cross-reacting antigens

Sera of 16 patients with systemic lupus erythematosus (SLE) and active involvement of the CNS were examined for the presence of antibodies to human brain neurons, using indirect immunofluorescence of human brain tissue sections. Thirteen of the 16 patients (81%) had high antineuronal titers, which declined during convalescence, compared with 18 of 105 (17%) SLE patients who had no CNS disease. Competition assays showed that the binding of the antineuronal antibodies was blocked by mycobacterial glycolipids and bovine brain extracts. This finding suggests an additional link between mycobacterial infection and SLE.