Immunostaining for α1-antichymotrypsin and α1-antitrypsin in gliomas

Antisera to α₁-antichymotrypsin, α₁-antitrypsin and lysozyme were reacted with 20 cases of glioblastoma multiforme, seven anaplastic astrocytomas, eight astrocytomas, six oligodendrogliomas, four ependymomas and the cerebral cortex from six normal autopsy brains. In addition, two pleomorphic xantho-astrocytomas and two heavily lipidized malignant gliomas were similarly examined. All astrocytic lesions were confirmed with anti-GFAP antisera. Thirty astrocytic tumours (77%), four oligodendrogliomas (67%) and three ependymomas (75%) reacted positively with anti-α₁-antichymotrypsin; 25 astrocytic tumours (64%), three oligodendrogliomas (50%) and three ependymomas (75%) showed positive staining for α₁-antitrypsin. The pattern of staining with either of these two markers did not correlate with tumour grading. None of the gliomas examined stained positively with anti-lysozyme. Non-neoplastic glial elements did not react with any of the three antisera. The results of this study suggest that staining for α₁-antichymotrypsin and α₁-antitrypsin is of little value in the differential diagnosis of neuroepithelial or mesenchymal lesions in the brain.     

Increased expression of collagen receptors: α1β1 and α2β1 integrins on blood eosinophils in bronchial asthma

BACKGROUND: Eosinophils are one of the major effector cells in bronchial asthma. Their infiltration of airways correlates with the asthma severity. Recruitment and activation of eosinophils are partially mediated by integrins alpha4beta1 and alpha4beta7. Collagens type I and IV constitute important components of extracellular matrix and vascular basement membrane, respectively. Therefore, collagen-binding integrins (alpha1beta1 and alpha2beta1) may also play a role in eosinophil lung infiltration. OBJECTIVE: To evaluate the possible presence of alpha1beta1 and alpha2beta1 integrins on peripheral blood eosinophils from asthmatic subjects. METHODS: Collagen receptors were studied on eosinophils separated by immunomagnetic CD16-negative method from healthy donors (n=13) and patients with moderate persistent atopic bronchial asthma (n=15). Surface receptor identification was performed by flow cytometry and cell adhesion assay. RESULTS: Eosinophils isolated from the patients showed increased expression of both alpha1beta1 and alpha2beta1 integrins as compared with healthy controls. Moreover, adhesive function of eosinophils to collagen type IV was inhibited by snake venom disintegrins: viperistatin and obtustatin. These disintegrins contain KTS active motif and are specific inhibitors of alpha1beta1 integrin. CONCLUSION: We demonstrated for the first time that collagen receptors: alpha1beta1 and alpha2beta1 integrins are overexpressed on the surface of peripheral blood eosinophils of asthmatic subjects. Further studies may reveal potential application of KTS-disintegrins or their structural analogs for therapy of bronchial asthma.     

Association of β2-adrenergic receptor polymorphisms with severe asthma

BACKGROUND: There is considerable interest in the role of different candidate loci in the development of asthma. This study investigates the association between asthma severity and previously identified polymorphisms at two sites within the beta2-adrenergic receptor (beta2AR) gene: the Arg16-->Gly16 and Gln27-->Glu27 alleles. METHODS: Restriction enzyme analysis of amplified beta2AR gene products (PCR-RFLP) was used to analyse the frequency of the Arg16-->Gly16 and Gln27-->Glu27 polymorphisms within the beta2AR gene in 95 severe asthmatic patients (with a markedly increased risk of death from asthma), 59 mild asthmatic patients, and a control group of 92 nonasthmatic subjects. RESULTS: The Gly16 polymorphism was significantly associated with asthma severity with odds ratios (95% CI) for the Gly16 allele being 1.56 (1.02-2.40, P = 0.04) and 0. 98 (0.61-1.57, P = 0.92) for the severe and mild asthma groups, respectively. The corresponding odds ratios (95% CI) for Gly16 homozygotes were 1.91 (0.82-4.41, P = 0.13) and 0.82 (0.35-1.92, P = 0.65) for the severe and mild asthma groups, respectively. There was no significant association between either polymorphism at amino acid 27 and asthma or asthma severity. CONCLUSIONS: We conclude that the polymorphisms of amino acids 16 and 27 of the beta2AR gene are not associated with the development of asthma per se, but that the Gly16 polymorphism may play a role in the pathogenesis of asthma severity.     

13.α 1-Fetoprotein

Summary. Rocket immunoelectrophoresis suitable for both quantitation and qualitative identification of α₁-fetoprotein is presented. By a slight modification of the rocket immunoelectrophoresis it is possible to detect α₁-fetoprotein in serum in a concentration of about 0.1 mg/1. A simple method for the final purification of α₁-fetoprotein is described. The concentration of α₁-fetoprotein in cord blood from 258 newborn infants is shown to be closely related to the gestational age of the newborn infants. The confidence limits for the estimation of gestational age are± 16 days.     

Thymic differentiation of TCRαβ+ CD8αα+ IELs

Summary:  Intraepithelial lymphocytes (IELs) contain several subsets, but the origin of the T-cell receptor (TCR)αβ⁺ CD8αα⁺ IELs has been particularly controversial. Here we provide a synthesis, based on recent work, that attempts to unify the divergent views. The intestine has a primordial function in lymphopoiesis, and precursors with the potential to differentiate into T cells are found both in the epithelium and underlying lamina propria. Moreover, the thymus has been reported to export cells to the intestine that are not fully differentiated. TCRαβ⁺ CD8αα⁺ IELs can differentiate in the intestine from each of these sources, but in normal euthymic mice, the thymus appears to be the major source for TCRαβ⁺ CD8αα⁺ IELs. This unique IEL subset is a self-reactive population that requires exposure to self-agonists for selection in the thymus, similar to other regulatory T-cell populations. IELs transition through a double-positive (DP) intermediate in the thymus, but they originate from a subset of the DP cells that can be identified by its expression of CD8αα homodimers. The agonist-selected cells in the thymus are TCRβ⁺ but CD4 and CD8 double negative. The evidence suggests that reacquired expression of CD8αα and downregulation of CD5 occur after thymus export, perhaps in the intestine under the influence of interleukin-15. As a result of agonist exposure, a new gene expression program is activated. Therefore, the increased understanding of the developmental origin of TCRαβ⁺ CD8αα⁺ IELs may help us to understand how they participate in immune regulation and protection in the intestine.     

Immunosuppressive Properties of α1-Microglobulin

α₁-Microglobulin (α₁m), a serum glycoprotein (26,000 d). was found to impede the proliferative response of human lymphocytes to purified protein derivative (PPD) and tetanus toxoid. The data suggest that, α₁m operates through an unstable suppressor mechanism, which no longer can function after 24 h of preculturing. This effect of α₁m on antigen stimulation did not seem to be due to binding of α₁m to PPD or cells, to altered kinetics of the PPD response, or to non-specific cytotoxicity. In contrast, PPD-induced leucocyte migration inhibition was not reversed by α₁m. α₁m did not cause significant inhibition in experiments in which lymphocytes were stimulated by the mitogens phytohaemagglutinin or concanavalin A. Finally, α₁m had its own leucocyte migration inhibitory effect.     

Heterozygous α-antichymotrypsin and PiZ (α1-antitrypsin deficiency

In a case-control study we compared the prevalence of heterozygous deficiency of two closely related anti-neutrophil protease inhibitors, alpha 1-antitrypsin and alpha 1-antichymotrypsin, in 172 consecutive children with asthma. In a cohort study the clinical spectrum and severity were compared. On the basis of family studies 5/172 (2.9%) were classified as heterozygotes for alpha 1-antichymotrypsin deficiency, a high prevalence compared with that of an unselected adult population (prevalence ratio 4.5 (1.7-11.9), P less than 0.005). This finding suggests that the carrier state of this rare allele (prevalence 0.64%) may predispose to asthma in children. Among these heterozygous patients the prevalence of positive RAST tests for foodstuffs was significantly increased (prevalence ratio 4.8 (1.7-13.2), P less than 0.005) and 2/5 manifested food allergy with Quincke oedema. Either the PiMZ or SZ phenotype of alpha 1-antitrypsin deficiency was found in 12 (7.0%) of the 172 patients, a prevalence similar to that of a normal population (prevalence ratio 1.3 (0.67-2.6), P = 0.44). However, the asthma was more severe among the Z allele carriers, judged by the number of hospital admissions, compared with the non-Z asthmatic children (mean 2.92 vs. 1.72, P less than 0.05). The results indicate that heterozygous deficiency of protease inhibitors directed against neutrophil proteases may affect the severity and clinical spectrum of childhood asthma, and to some degree be predisposing.     

Complexes in Human Plasma between α1-Antitrypsin and IgA, and α1-Antitrypsin and Fibrinogen

Crossed immunoelectrophoretic analyses revealed that plasma contains a complex between α₁-antitrypsin¹ and IgA. Normally the complex constitutes 1–2% of these proteins. The amount varies mainly with the IgA and to some extent with the α₁-at content of the plasma. The complex is sensitive to thiol reagents and is reduced in vivo by penicillamine. The size of the complex and the amount of reduction products are compatible with the assumption of 1 IgA monomer or dimer per α₁-at molecule. An α₁-at complex with fibrinogen is also a regular plasma constituent. This complex is not susceptible to thiol reagents.