Phenotypic shift of small intestinal intra-epithelial type 1 innate lymphoid cells in celiac disease is associated with enhanced cytotoxic potential

The small intestinal (SI) epithelium harbors a heterogeneous population of lymphocytes that mediate mucosal damage and repair in celiac disease (CD). The composition and roles of human proximal SI intra-epithelial innate lymphoid cells (ILCs), and their alterations in CD, are not well understood. We report that duodenal intra-epithelial ILCs predominantly consist of natural killer (NK)p44⁺ CD127^- cytotoxic ILC1s and NKp44^- CD127⁺ helper ILC1s, while ILC3s only represent a minor population. In patients with newly diagnosed or active CD (ACD) and refractory CD type 1 (RCD I), the frequency of SI NKp44⁺ ILCs is decreased, with restoration of NKp44⁺ ILC frequency observed in patients adhering to a gluten-free diet who show evidence of mucosal healing. Moreover, the frequency of SI NKp44^- ILCs is increased in ACD and RCD I patients and correlates with the severity of villous atrophy and epithelial damage, as assessed by serum levels of fatty acid binding protein 2 (FABP2). We show that the ILC alterations in CD represent a phenotypic shift of cytotoxic ILC1s rather than an increase in helper ILC1s or transdifferentiation of ILC1s to ILC3s, and activation-induced loss of NKp44 by cytotoxic ILC1s is associated with increased interferon (IFN)-γ expression and release of lytic granules. These findings suggest that intra-epithelial NKp44^- CD127^- cytotoxic ILC1s may contribute to mucosal damage in CD.

Mechanisms underlying celiac disease and its neurologic manifestations

The extra-intestinal manifestations of celiac disease (CD), including ataxia and peripheral neuropathy, are increasingly being recognized as the presenting symptoms of this autoimmune disease. Although there is a greater understanding of the pathogenesis of the intestinal lesions in CD the mechanisms behind the neurologic manifestations of CD have not been elucidated. In this article, the authors review the cellular and molecular mechanisms behind the histopathologic changes in the intestine, discuss the presentation and characteristics of neurologic manifestations of CD, review the data on the mechanisms behind these manifestations, and discuss the diagnosis and treatment of CD. Molecular mimicry and intermolecular help may play a role in the development of neurologic complications.

Celiac neuropathy

BACKGROUND

Celiac disease (CD) is a chronic inflammatory enteropathy resulting from sensitivity to ingested gluten. Neurologic complications are estimated to occur in 10% of affected patients, with ataxia and peripheral neuropathy being the most common problems. The incidence and clinical presentation of patients with CD-associated peripheral neuropathy have not previously been investigated.

OBJECTIVE

To determine the incidence of CD in patients with neuropathy and to characterize the clinical presentation.

METHODS

The records of 20 patients with neuropathy and biopsy-confirmed CD were reviewed.

RESULTS

Six of the 20 patients had neuropathic symptoms alone without gastrointestinal involvement, and neuropathic symptoms preceded other CD symptoms in another 3 patients. All patients had burning, tingling, and numbness in their hands and feet, with distal sensory loss, and nine had diffuse paresthesias involving the face, trunk, or lumbosacral region. Only two had weakness. Results of electrophysiologic studies were normal or mildly abnormal in 18 (90%) of the patients. Sural nerve biopsies, obtained from three patients, revealed mild to severe axonopathy. Using the agglutination assay, 13 (65%) of the patients were positive for ganglioside antibodies. Excluding patients who were referred with the diagnosis of celiac neuropathy, CD was seen in approximately 2.5% of all neuropathy patients and in 8% of patients with neuropathy and normal electrophysiologic studies seen at our center.

CONCLUSION

CD is commonly associated with sensory neuropathy and should be considered even in the absence of gastrointestinal symptoms.

A surface plasmon resonance biosensor assay for measurement of anti-GM(1) antibodies in neuropathy

OBJECTIVE

To develop a rapid assay for the detection and measurement of anti-GM(1) ganglioside antibodies in patients with neuropathy, using a surface plasmon resonance-based biosensor.

BACKGROUND

Elevated levels of anti-GM(1) ganglioside antibodies are observed in patients with acute and chronic motor neuropathies. Assays for detecting anti-GM(1) antibodies in serum are increasingly being used to help the physician in the evaluation of these patients.

METHODS

Antigens were immobilized by adsorption of GM(1) (active) and GM(2) (control) gangliosides onto a dextran-based sensor chip which is in contact with a flow cell carrying the sample. Interaction of specific antibodies directed against GM(1) with the ganglioside-coated sensor chip caused a change in refractive index at the surface of the chip, which was detected by an optical sensor, using the phenomenon of surface plasmon resonance. Sera from patients and healthy individuals were analyzed by the new assay and results were compared with those from ELISA. Anti-GM(1) antibody isotype was identified by using a secondary antibody.

RESULTS

The binding of anti-GM(1) antibodies to the immobilized GM(1) was observed in real time after reference subtraction of the response from GM(2) control. The response was proportional to antibody concentration. The assay exhibited high specificity for sera from patients with multifocal motor neuropathy and Guillain-Barré syndrome with antibodies against GM(1).

CONCLUSIONS

The surface plasmon resonance biosensor assay offers a rapid system for directly measuring antibody levels in serum without the use of any labels, while comparing favorably with the ELISA system in sensitivity and specificity.

Ganglioside agglutination immunoassay for rapid detection of autoantibodies in immune-mediated neuropathy

Elevated levels of serum autoantibodies directed against gangliosides are closely associated with acute and chronic autoimmune neuropathies. An agglutination immunoassay using polystyrene microparticles coated with a total extract of brain gangliosides was used to test patient sera for the presence of anti-ganglioside antibodies. Results were compared with those obtained by ELISA for anti-GM1 and anti-GQ1b ganglioside antibodies. Eight of the twelve sera from patients with multifocal motor neuropathy and seven of the thirteen sera from patients with Guillain-Barré syndrome were positive for the presence of anti-ganglioside antibodies by the ganglioside agglutination immunoassay. The assay compared favorably with the ELISA system in sensitivity and specificity, while requiring a fraction of the time and cost to perform. The new assay can serve as a rapid and effective method for detecting or screening for anti-ganglioside antibodies in patients with acute or chronic immune-mediated neuropathies. It would be particularly useful for detecting antibodies that react with multiple gangliosides, or with minor or as yet uncharacterized gangliosides.

Detection of anti-GM1 ganglioside antibodies in patients with neuropathy by a novel latex agglutination assay

Highly elevated titers of serum anti-GM1 ganglioside antibodies are closely associated with multifocal motor neuropathy, but low titers are commonly present in normal individuals or other diseases. Current systems for measuring anti-GM1 antibodies utilize the enzyme-linked immunosorbent assay (ELISA), in which serum dilutions are tested for binding to excess antigen immobilized on the surface of microwells. The ELISA system, however, is relatively time consuming, labor intensive, and costly, in addition to being prone to methodological variability. We have developed a novel agglutination assay for the detection of anti-GM1 antibodies, utilizing GM1 ganglioside-coated latex beads. In contrast to the ELISA system, antibody titers may be quantified by testing for agglutination using latex beads coated with decreasing amounts of antigen. The agglutination assay compares favorably to the ELISA system in sensitivity and specificity, but is considerably less costly and takes only a few minutes to perform.

Identification of two penicillin-binding multienzyme complexes in Haemophilus influenzae

Dansyl-labeled penicillin, reversed-phase chromatography, and peptide mapping have been used to detect, separate, and study penicillin-binding proteins (PBPs) and PBP multienzyme complexes of H. influenzae. The cross-linking of proteins in the multienzyme complex was accomplished with the aid of cyanogen, a salt-bridge specific cross-linking agent. The chromatographic profile of the PBPs clearly showed a dramatic change in the number and identity of peaks after treatment of the bacterial cells with cyanogen. The disappearance of all seven peaks corresponding to the PBPs was accompanied by the emergence of two new peaks with molecular weights between 400 kDa and 600 kDa. The results hint at the existence of two penicillin-binding multienzyme complexes, each containing subunits that interact via salt-bridges. Chromatographic active site peptide mapping of PBPs and PBP complexes was used to determine the identity of PBPs involved in each complex. It is postulated that one multienzyme complex containing PBP 2 may be involved in cell elongation while the other complex containing PBP 3 may be responsible for cell division.