The diagnostic value of serum autoantibodies in endocrine orbitopathy and idiopathic ocular myositis

Antibody pattern analysis in the Guillain-Barré syndrome and pathologic controls

The Guillain-Barré Syndrome (GBS) is an acute inflammatory polyneuroradiculopathy, which is considered to be caused by autoimmune processes. A number of single antigenic structures has been suggested to be targeted by the immune system, but a conclusive etiological concept has not been evolved yet. We compared reactions of sera from GBS patients (N=28) and from both two pathological control groups, 25 Multiple sclerosis (MS) patients and 32 patients with other non-inflammatory peripheral polyneuropathies (ONP) and from sex- and age-matched healthy controls (N=30). Porcine peripheral nerve proteins were used as antigens in a Western blot procedure. The blots were analysed by densitometry, and a multivariate statistical comparison of the antibody repertoires was carried out. Antibody patterns of GBS patients differed significantly (p<0.001) from each of the control groups. Discriminant analysis indicated that the discrimination resulted from pattern differences of specific regions of the blots containing proteins with estimated molecular weights of 58-64 and 28-29 kDa. We conclude that statistical analysis of antibody patterns may be helpful both in clinical diagnosis and in further research concerning the pathogenesis of GBS.

Two Cases of Refractory Endocrine Ophthalmopathy Successfully Treated with Extracorporeal Immunoadsorption

Endocrine ophthalmopathy (EO) is a severe disease entity that is characterized by retrobulbar swelling due to accumulation of glycosaminoglycans on an autoimmune basis. This disorder can lead to the loss of vision and often is resistant to conventional therapy. There is a relation to Graves' hyperthyroidism, but probably no close association. Two patients with severe EO that was resistant to usual therapeutic approaches including steroids and radiological and surgical measures underwent a 20 session course of intensive immunoadsorption therapy (Plasmaselect/Therasorb Anti-IgG) with a mean 2- to 3-fold plasma volume treated. After the first sessions, both patients voiced an impressive relief of their major symptoms, which was confirmed by ophthalmological investigation. Throughout the time of therapy until present, these patients have remained at their respective levels of improvement. We consider immunoadsorption an effective therapeutic opportunity in severe EO resistant to conventional treatment.

Identification and classification of autoantibody repertoires (Western blots) with a pattern recognition algorithm by an artificial neural network

The screening of sera for autoantibodies with Western blots reveals complex repertoires. the compostion of such repertoires depends on genetic control of autoantibody-producing cells, the individual's history of exposure to its own and to foreign antigens, and also on the presence of autoimmune diseases. Our method shows how staining patterns of Western blots can be recoded as binary or grey-value vectors. Vectors are transferred to artificial neural networks for learning. Artificial neural networks are able to recognize group-specific antibody binding patterns. Staining patterns can be attributed to diagnostic groups. This may support diagnostic procedures.

Multivariate statistical comparison of autoantibody-repertoires (western blots) by discriminant analysis

A procedure for the quantification and comparison of complex (auto-) antibody repertoires of many individuals is described. It is based on multivariate statistical analyses of densitometric data of individual staining patterns, in this case Western blots. Implementation of algorithms can be based on standard software and hardware components. This procedure allows (i) the quantitative assessment of the reproducibility and reliability of any electrophoretic procedure, such as for the production of the immunological substrate, (ii) the statistical comparison of any group of staining patterns, e.g., derived from patients with autoimmune diseases or normal controls, (iii) the identification of the bands that contribute most to the differences between such groups, and (iv) the determination whether an unknown individual sample belongs to a known group. A statistical analysis of autoantibody repertoires has important possible applications: it detects spontaneous or therapeutically induced changes of repertoires, it identifies regions of interest, it supports the isolation of relevant antigens, and it will also be helpful in the diagnosis of autoimmune diseases.

Repertoires of natural autoantibodies against muscle tissue are independent of age or gender in normal human adults. A western blot study

Sera from 69 healthy blood donors were screened for autoantibodies using Western blots of human muscle fractions to assess whether prevalence and repertoires of autoantibodies against muscle tissue would change with age. Each serum contained immunoglobulins binding to a broad spectrum of antigens. Their molecular masses ranged from 20 to more than 200 kDa. Although each staining pattern appeared to be a singular combination of detected bands and staining intensities, the patterns were not different in men and women. When sera were grouped according to age (decades between 10 and over 70 years) age-dependent changes were not found. Individual repertoires of natural autoantibodies against muscle tissue are complex when examined by Western blotting. Mature normal repertoires of low-affinity autoantibodies are found at the age of 10 years which is the lower cut-off in this study. The repertoires remain stable throughout a normal lifespan.