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R Pirskanen

Publications and source records attributed to R Pirskanen.

At least 19 recordsLinked to original sources
PubMed1992

T-cell epitopes on the human acetylcholine receptor alpha-subunit residues 10-84 in myasthenia gravis.

In myasthenia gravis the production of anti-acetylcholine receptor antibodies is modulated by acetylcholine receptor-specific T cells. Most B- and T-cell epitopes are located on the alpha-subunit of the receptor. In order to map the fine specificity of the antigen-specific T cells in myasthenia gravis, T-cell stimulation in response to 70 hexapeptides was studied in 24 patients and 24 healthy individuals. The hexapeptides overlapped with one amino acid and represented residues 10-84 of the NH2-terminal part of the alpha-subunit of the receptor. The IFN-gamma secretion from single T cells was used to detect T-cell stimulation. A significant difference in the T-cell response to several of the peptides was found between patients and healthy controls. The majority of the hexapeptides induced T-cell stimulation in at least one of the patients. Peptide-induced T-cell stimulation was evident in all but one of the patients. The results indicate that different epitopes and multiple T-cell clones are involved in the T-cell recognition of the acetylcholine receptor.

Adult↗
PubMed1992

Levels of CD5+ B lymphocytes do not differ between patients with myasthenia gravis and healthy individuals.

CD5+ B cells might be involved in autoimmunity mainly as autoantibody-producing cells. To investigate the possible role of these cells in myasthenia gravis, we studied the numbers of CD5+ B cells, CD5- B cells, and CD19+ B cells as well as CD5+ T cells in the peripheral blood from 31 patients with myasthenia gravis and 31 healthy individuals. Both absolute percentages (percent of peripheral blood mononuclear cells) and relative percentages (percent of total CD19+ B cells) of CD5+ B cells were the same in patients as in controls. The numbers of CD5- B cells and CD19+ B cells were the same in both groups, whereas CD5+ T cells were lower in the patients. There was no correlation between clinical stage, sex, thymectomy, or pathology of thymus and the levels of CD5+ B cells, CD5- B cells, or CD19+ B cells. Patients treated with azathioprine had lower levels of CD5+ B cells than untreated patients and controls. Our results show that patients with myasthenia gravis have the same levels of CD5+ B cells as healthy individuals.

Adult↗
PubMed1991

Defective T lymphocyte function in nonthymectomized patients with myasthenia gravis.

In vitro functional properties of peripheral blood mononuclear cells were evaluated in 29 patients with myasthenia gravis and in 11 healthy controls. Spontaneous cell proliferation was higher in patients than in controls. The production of interleukin-2 and interferon-gamma and the proliferative response to different mitogens were reduced in the patients. A positive correlation was found between the production of interleukin-2 and interferon-gamma. These defects in T cell function were the most pronounced in nonthymectomized patients. Patients with severe disease had a higher percentage of cells bearing the interleukin-2 receptor and a higher spontaneous production of tumor necrosis factor alpha in cell culture than in patients with mild disease. There was no difference between patients and controls in the level of soluble interleukin-2 receptor in cell culture supernatants or in sera. The results indicate a partially suppressed T cell function in myasthenia gravis. This defect was less pronounced in patients studied after thymectomy.

Adult↗
PubMed1990

Different HLA DR-DQ associations in subgroups of idiopathic myasthenia gravis.

We have investigated the HLA-DRB and -DQB gene polymorphism in 131 myasthenia gravis (MG) patients. The HLA genotypes in these patients were assigned by means of restriction fragment length polymorphism (RFLP)-defined DR-DQ haplotypes, correlating to serologic HLA class II typing. Using this technique we could, among randomly selected non-thymomatous (NT)-MG patients, confirm the strong association to DR3, and 70% of the patients were found to carry a specific DR3-positive DR-DQ haplotype, T-3.1. Furthermore, an analysis of T-3.1- NT-MG patients revealed that 59% were T-4.1+ (DR4, DQw8). Thymic hyperplasia was found in approximately 85% of the T-3.1+, as well as of the T-4.1+/3.1- patients. As previously observed, we found a clear dominance of females among the T-3.1+ NT-MG patients. However, among T-4.1+/3.1- patients, males were as common as females. Furthermore, the T-4.1+ patients were significantly older at the onset of disease than those who were T-3.1+. In female MG patients, the DRw15-Dw2-positive haplotype T-2.1 was strongly correlated with the presence of thymoma (T-MG). These data indicate that the HLA associations in early vs late onset of NT-MG are different, and that female patients with and without thymoma differ from each other with regard to HLA markers. Thus, at least three different HLA DR-DQ associations are found in subgroups of idiopathic MG.

Female↗
PubMed1990

A limited diagnostic investigation for obstructive sleep apnea syndrome. Oximetry and static charge sensitive bed.

A simplified sleep apnea investigation consisting of combined oximetry and respiration movement monitoring was compared with conventional polysomnography. These two types of recordings were performed simultaneously during one night in 77 patients with suspected obstructive sleep apnea syndrome (OSAS). A static charge sensitive bed (SCSB) was used in the simplified recording because it provides a comfortable and reliable means of recording respiration movements. Periods of obstructive apneas gave a diamond-shaped periodic respiration movement pattern in the SCSB, usually accompanied by repetitive oxygen desaturations. The average number of desaturations greater than or equal to 4 percent per sleeping hour was termed the oxygen desaturation index (ODI) and compared with the apnea index (AI). In the whole population they were well correlated (p less than 0.0001, R2 = 0.41), but in individual cases there were considerable discrepancies. Patients with periodic respiration movements less than 18 percent of total sleeping time and ODI less than 2 never had AI greater than or equal to 5, whereas patients with periodic respiration greater than 45 percent and ODI greater than 6 always had AI greater than or equal to 5. Fifty-one of the 77 patients fulfilled these criteria. A bradycardia response to apneas was absent in 29 percent of patients with AI greater than or equal to 5. A combination of respiration movement and oximetry recording thus seems to give sufficient information to confirm or negate a diagnosis of OSAS in a majority of patients with clinical symptoms. In borderline patients, further investigations should be performed.

Adolescent↗
PubMed1989

B cell and autoantibody repertoire in a pair of monozygotic twins discordant for myasthenia gravis.

A pair of identical twins, 47 years of age, who have been discordant for myasthenia gravis for 15 years were studied with regard to clinical status, neuromuscular function, and presence and properties of myasthenia specific autoantibodies. The autoantibody repertoire was tested in serum, as produced by peripheral lymphocytes in culture and as revealed by B cell lines. The healthy twin had no clinical signs of myasthenia and no signs of impaired neuromuscular function on electrophysiological tests. The autoantibody repertoire and the avidity of the anti-receptor antibodies were similar in both individuals. Epstein-Barr virus transformation of peripheral lymphocytes revealed a higher incidence of B cells committed to make autoantibodies in the healthy twin than in her myasthenic sister.

Antibody Affinity↗
PubMed1987

Immunoactivation in the central nervous system in myasthenia gravis.

To assess signs of immunoactivation within the central nervous system in myasthenia gravis (MG) we examined the cerebrospinal fluid (CSF) of 44 MG patients for certain immunological parameters. Altogether 73% of the patients had some protein and/or cellular abnormality in their CSF. 22 (50%) out of 44 patients had a lymphoid reaction, i.e. a pathologically elevated proportion of enlarged lymphoid cells, in their CSF. In 15 (37.5%) out of 40 patients an enrichment of anti-acetylcholine receptor antibodies in the CSF was observed in relation to serum antibodies. Our findings suggest involvement of the central nervous system in many myasthenia gravis patients.

Adolescent↗
PubMed1987

Cellular production of antibodies related to the acetylcholine receptor in myasthenia gravis: correlation with clinical stage.

Spontaneous and pokeweed mitogen-induced production of specific autoantibodies were studied in cultures of peripheral blood mononuclear cells from patients with different clinical stages of myasthenia gravis. Receptor antibody-related idiotypes and anti-idiotypic antibodies were defined by binding to mouse monoclonal anti-idiotypic and anti-receptor antibodies, respectively. Patients with severe disease had a more complete spectrum of idiotypes in serum, and cells from such patients spontaneously produced more antibody species and higher concentration of both idiotypes and anti-idiotypes than patients with mild disease. The frequencies of antibody specificities in tissue culture supernatants more closely reflected disease activity than those in serum. Tissue culture for the study of different species of autoantibodies has proved to be a useful tool for monitoring the disease and the effects of treatment.

Adult↗
PubMed1985

Persistence of antibrain antibodies in cerebrospinal fluid during plasmapheresis for multiple sclerosis.

A man with chronic progressive multiple sclerosis received a 10 day course of treatment with adrenocorticotrophic hormone without beneficial effect. He then received six sessions of plasmapheresis, again without improvement. Treatment with adrenocorticotrophic hormone had no effect on serum antibrain antibody titres, but plasmapheresis virtually eliminated the antibodies from serum and caused a fall in serum IgG concentrations; neither treatment had any effect on the IgG concentration and antibody titre in the cerebrospinal fluid. Treatment with plasmapheresis may fail in patients with multiple sclerosis because it does not remove antibrain antibodies from the intrathecal space.

Adrenocorticotropic Hormone↗
PubMed1985

Anti-idiotypic antibodies, acetylcholine receptor antibodies and disturbed neuromuscular function in healthy relatives to patients with myasthenia gravis.

Fifty-eight first-degree relatives to 40 patients with myasthenia gravis were investigated regarding presence of acetylcholine receptor antibodies, anti-idiotypic antibodies against the receptor antibodies and clinical and electrophysiological signs of disturbed neuromuscular function. No relative had clinical signs of muscle weakness. The prevalence of low concentrations of receptor antibodies was 54%, of anti-idiotypic antibodies 37% and of pathological and borderline single fibre EMG 45%. No sibling, only 2/11 children and 3/14 parents were normal in all three tests. A combination of receptor antibodies and anti-idiotypic antibodies was the most common finding and was especially frequent in children. In female siblings and children there was a positive correlation between the presence of HLA-antigen A1 and/or B8 and that of receptor antibodies and anti-idiotypic antibodies. Male siblings and children showed no such correlation but had a higher frequency of pathological single fibre EMG than females.

Autoantibodies↗
PubMed1979

Myasthenia gravis and monoclonal IgG gammopathy.

Monoclonal IgG gammopathy of the lambda light-chain type was detected in a 51-year-old woman who had unexplained fever, muscle fatigue, and myalgia. One year later, myasthenia gravis was diagnosed. There was no evidence of myelomatosis or other malignancy. On the assumption that her M-component (gammopathic paraprotein) was related to myasthenia, she was treated with melphalan and cyclophosphamide, but her clinical condition was not improved. Despite therapeutic trials of other agents and a time course of 6 years, the quantity of the M-component remained unchanged. Serum AChR antibody activity was not located in the paraprotein peak. The findings do not support a relationship between the M-component and myasthenia gravis.

Acetylcholine↗
PubMed1978

Determination of acetylcholine receptor antibody in myasthenia gravis: clinical usefulness and pathogenetic implications.

Antibodies to cholinergic receptor structures were found in 75% of 76 Finnish and 93% of 175 Swedish patients with myasthenia gravis. The amount of antibodies showed a positive correlation to the severity of the disease, and was reduced during immunosuppressive treatment, and by thymectomy. Thymoma patients had high values. The antibody was also found in the cerebrospinal fluid. Two healthy newborn babies of myasthenic mothers had antibodies during the first weeks of life, in spite of no clinical symptoms. The occurrence of IgM antibodies before IgM antibodies in two patients during the early stages of myasthenia gravis suggests that the antibody is not a primary cause of the disease.

Adrenocorticotropic Hormone↗
PubMed1977

Social aspects in myasthenia gravis.

The myasthenics in Finland (n = 240) have been registered and treated in one center for more than 10 years. Of this material, an investigation was performed of their medico-social state as of 1 January, 1975. The study comprised 88 per cent (210) of the patients. In the working age (16-64 years) were 181 patients. Compared to the total Finnish population, the myasthenic patients lived more often in urban districts, had had more intermediate-school and university--but less vocational-school education, and belong as a whole to "higher" social classes. The severity and the variability of the disease naturally influenced the disability. A change from severe to slight symptoms occurred in 38 per cent, and 12 per cent of the myasthenics were in complete remission (2/3 of whom had had severe symptoms). One third (72) got a full pension because of myasthenia, and about one tenth (25) because of some other reason. Of these who got a full pension for myasthenia, 7 per cent were in complete remission without any myasthenic symptoms. The influence of thymectomy on the degree of disability was impressive, since more than 50 per cent of disabled myasthenic patients returned to work thereafter. Thus, because of the unpredictable, but on the long term quite favourable course, a full pension should not be prescribed early (during the first 5 years) of the disease. An active treatment may also change the outlook for even the most severely disabled patients.

Adolescent↗