Search

Testing for antinuclear antibodies is the most frequently prescribed analysis for the diagnosis of rheumatic diseases. Indirect immunofluorescence remains the gold standard method for their detection despite the increasing use of alternative techniques. In order to standardize the manual microscopy reading, automated acquisition and interpretation systems have emerged. This publication enables us to present our method of interpretation and characterization of antinuclear antibodies based on a cascade of analyses and to share our everyday experience of the G Sight from Menarini. The positive/negative discrimination on Hep cells 2000 is correct in 85% of the cases. In most of the false negative results, it is a question of aspecific or low titers patterns, but a few cases of SSA speckled patterns of low titers demonstrated a probability index below 8. Regarding the pattern recognition, some types and mixed patterns are not properly recognized. Concerning the probability index correlated in some studies to final titer, the weak fluorescence of certain patterns and the random presence of artifacts that distort the index don't lead us to continue it in our daily practice. In conclusion, automated reading systems facilitate the reporting of results and traceability of patterns but still require the expertise of a laboratory technologist for positive/negative discrimination and for pattern recognition.

Psychological stress is an important factor in susceptibility to many diseases. Our laboratory has been investigating the impact of stress on the susceptibility to Theiler’s virus-induced demyelination (TVID), a mouse model of multiple sclerosis. Using immunodominant viral peptides specific for identification of either CD4+ or CD8+ T cells, stress reduced IFN-γ-producing virus-specific CD4+ and CD8+ T cells in the spleen and CD8+ T cells in the CNS. Expression of mRNA for the Th1 transcription factor T-bet and the Th2 transcription factor GATA-3 were decreased in spleen cells isolated from stressed mice. Cytokine production by cells isolated from the CNS or spleens following stimulation with virus indicated that stress decreased both type 1 and type 2 responses. The adverse effects of stress were partially reversed by concurrent RU486 administration but mimicked by dexamethasone, indicating a major role for glucocorticoids. Global stress-induced immunosuppression resulted in higher levels of virus replication and dissemination. The higher viral load subsequently led to an earlier disease onset and more severe clinical and histological signs of demyelinating disease. Our results have important implications for understanding the pathogenesis of MS, and suggest that stressful events during early infection with an agent capable of inducing demyelination may result in immunosuppression and failure to eliminate the pathogen, which in turn may lead to the development of MS.

Background: The clinical and immunological profiles of patients with paraneoplastic cerebellar degeneration (PCD) and non-small-cell lung cancer (NSCLC) are not well known. Objective: To review the clinical and immunological features of patients with PCD, NSCLC and without well-characterised onconeural antibodies. Methods: The clinical features of nine patients with the diagnosis of classical PCD and NSCLC, included in our archives, were retrospectively reviewed. The presence of antibodies to cerebellar components was determined by immunohistochemistry and immunoblot of rat cerebellum. A cDNA library of human cerebellum was screened with the positive sera to identify the antigen. Results: Nine patients with PCD and NSCLC were identified. Six patients were men, and the median age at diagnosis of PCD was 63 (range 47–73) years. PCD was completely reversed in two patients, and partially in one, after treatment of the tumour. The serum of one of the patients with PCD showed a unique reactivity with Purkinje cells. The screening of a cerebellar-expression library resulted in the isolation of protein kinase Cγ (PKCγ). PKCγ immunoreactivity was not observed in the serum of 170 patients with non-paraneoplastic neurological syndromes, 27 patients with PCD, no onconeural antibodies and small-cell lung cancer, and 52 patients with NSCLC without paraneoplastic neurological syndromes. The NSCLC from 11 patients without PCD did not express PKCγ at either the RNA or protein level. However, many cells of the NSCLC of the patient with PKCγ antibodies expressed PKCγ. Conclusion: PCD occurs in patients with NSCLC without typical onconeural antibodies and is associated with immune reactions against key proteins of the Purkinje cells.

Background/Aims: Glucocorticoids effectively manage autoimmune hearing loss, although the cochlear mechanisms involved are unknown. Previous studies of steroid-responsive hearing loss in autoimmune (lupus) mice showed glucocorticoids and mineralocorticoids were equally effective, suggesting the ion homeostasis functions of glucocorticoids may be as relevant as immunosuppression for control of autoimmune-induced inner ear disease. Therefore, to better characterize the role of the glucocorticoid receptor in autoimmune hearing loss therapy, its function was blocked with the antagonist RU-486 (mifepristone) during glucocorticoid (prednisolone) treatments. Methods: Following baseline auditory brainstem response (ABR) thresholds, MRL/MpJ-Faslpr autoimmune mice were implanted with pellets providing combinations of 1.25 mg/kg of RU-486, 4 mg/kg of prednisolone, or their respective placebos. After 1 month, animals were retested with ABR and blood was collected for immune complex analyses. Results: Mice receiving no prednisolone (placebo + placebo and placebo + RU-486) showed continued declines in hearing. On the other hand, mice receiving prednisolone (prednisolone + placebo and prednisolone + RU-486) had significantly better hearing (p < 0.05) than the non-prednisolone groups. Immune complexes were significantly elevated in the placebo + RU-486 group, suggesting RU-486 effectively blocked glucocorticoid receptor-mediated immune suppression. These results showed that blockage of the glucocorticoid receptor with RU-486 did not prevent prednisolone’s effects in the ear, suggesting its ion homeostasis actions via the mineralocorticoid receptor were more relevant in hearing control. Conclusion: The mineralocorticoid receptor-mediated actions of glucocorticoids are potentially relevant in steroid-responsive hearing disorders, implying disrupted cochlear ion transport functions may underlie the vascular problems proposed in some forms of immune-mediated hearing loss.

To determine if myasthenia gravis (MG) with antibodies to MuSK is a distinct subgroup of seronegative MG.We assayed antibodies to muscle specific tyrosine kinase (MuSK) in 55 MG patients who had no antibodies to acetylcholine receptors and looked for the specific phenotype, comparing clinical features of anti-MuSK positive and anti-MuSK negative MG patients.MG with anti-MuSK antibodies was characterised by a striking prevalence of female patients (15 women, two men). Age at onset ranged from 22 to 52 years, with 70.6% of patients presenting at40 years of age. The majority of patients (82.4%) had prevalent involvement of facial and bulbar muscles. One third of them did not respond well to anticholinesterase drugs. Steroid immunosuppression was effective in eight patients (44.4%). Nine patients underwent thymectomy; six of these had no thymus pathology, while three had a hyperplastic thymus. At the end of the observation period, six (35.3%) patients were in remission, five (29.4%) improved, four (23.6%) did not change, and two (11.7%) had died.MG patients with antibodies to MuSK have characteristic clinical features that are different from features of the remaining seronegative MG patients. This emphasises the predictive value of anti-MuSK antibody analysis in seronegative MG patients.