Treatment of a patient with myasthenia gravis using antibodies against CD25.

OBJECTIVES: To measure clinical and immunological parameters in a patient with myasthenia gravis (MG) treated with antibodies against CD25 (basiliximab, Simulect). Patient and methods - Injections of basiliximab were given repeatedly together with cyclosporin A and corticosteroids for 9 months to a patient with severe MG. Her muscle function score was monitored and the immunological parameters were followed using ELISA, flow cytometry and radioimmunoassay. RESULTS: The patient improved moderately and corticosteroid treatment could be withdrawn. The percentage of activated CD4+ T cells decreased during treatment, while that of 'naïve' T cells increased. The serum levels of sCD28, sCD152, sCD80, sCD86 and IL-10 decreased. The treatment was stopped due to repeated infections. CONCLUSION: Treatment with basiliximab appears to be suitable only for severely ill patients who do not respond to conventional treatments. However, careful monitoring of side effects is necessary.

Human Soluble CD80 is generated by alternative splicing, and recombinant soluble CD80 binds to CD28 and CD152 influencing T-cell activation.

CD80 is a costimulatory factor mainly expressed on the surface of activated monocytes, B cells and dendritic cells. In this study, we demonstrate that 24% of healthy individuals have soluble forms of CD80, sCD80, in their serum. The concentration of sCD80 ranged from 0 to 1 mg/l. At the mRNA level, we detected a spliced form s1CD80 (771 bp), in unstimulated monocytes and B cells, while another form named s2CD80 (489 bp) was expressed in activated T cells as well as in freshly isolated and activated monocytes. s1CD80 lacks the transmembrane domain, and the IgC-like domain plus the transmembrane domain are spliced out of s2CD80. We also present data demonstrating that recombinant s1CD80 binds to recombinant CD152-Ig and CD28-Ig. It can also bind to T cells, preferentially to activated T cells. Recombinant sCD80 had immunomodulatory effects shown by its inhibition of the mixed lymphocyte reaction and inhibition of T-cell proliferation. sCD80 in human serum adds a new member to the family of soluble receptors, implying a network of soluble costimulatory factors with functional relevance. The inhibitory effect of the recombinant protein on T-cell activation makes it a possible candidate for treatment of diseases associated with hyperactivated T cells.

The soluble forms of CD28, CD86 and CTLA-4 constitute possible immunological markers in patients with abdominal aortic aneurysm.

OBJECTIVE: The T cell co-stimulatory factors CD28 and CTLA-4 and their ligands CD80 and CD86 occur as receptors on T cells and antigen-presenting cells and also in soluble forms in the circulation. We determined the levels of soluble co-stimulatory molecules in patients with abdominal aortic aneurysm (AAA) and normal individuals. We further correlated these soluble co-stimulatory molecules to other clinical parameters of importance such as age of the patient, presence of hypertension, size of the aneurysm and levels of matrix metalloproteinases-9 and C-reactive protein. DESIGN, SETTING, SUBJECTS: This case-control study was designed to quantify the circulating levels of soluble co-stimulatory molecules by an in-house enzyme linked immunosorbent assay. A total of 314 subjects participated in the study including 100 patients and 214 normal controls. The statistical analysis was performed by Mann-Whitney test and Spearman's correlation rank test. RESULTS: Our results show increased plasma levels of sCD28, sCD86 (P = 0.0001) and decreased plasma levels of sCTLA-4 (P = 0.0018) in the patients compared with normal individuals. The levels of these factors were not related to the age of the patient, size of aneurysm or levels of C-reactive protein in plasma. There was, however, a significant inverse relationship between the concentrations of sCTLA-4 and sCD80 with matrix metalloproteinase-9. CONCLUSIONS: We suggest that soluble co-stimulatory molecules serve as biomarkers for the estimation of immune activation in AAA patients.

A clinical and immunological study of a myasthenia gravis patient treated with infliximab.

OBJECTIVES: To measure clinical and immunological parameters in a patient with myasthenia gravis (MG) treated with antibodies against tumour necrosis factor-alpha (infliximab, Remicade). PATIENT AND METHODS: A patient with severe MG received repeated injections of infliximab. His muscle function score was monitored and the immunological parameters were followed using enzyme-linked immunosorbent assay, flow cytometry and radioimmunoassay. RESULTS: The patient improved in muscle fatigability tests and the levels of antibodies against the acetylcholine receptor decreased during treatment. The activation marker human leucocyte antigen-DR on CD4(+) T cells also decreased. CONCLUSION: Treatment with infliximab might be beneficial for patients with severe MG but demands careful monitoring of possible serious side-effects.

Characterization of the expanded T-cell populations in patients with Wegener's granulomatosis.

OBJECTIVES: Wegener's granulomatosis (WG) is a chronic inflammatory disease characterized by granulomatosis inflammation, systemic vasculitis and glomerulonephritis. In patients, the peripheral T cells are characterized by mono/oligoclonal CD4+/CD8+ T-cell AV/BV receptor expansions, with aberrant expression of activation markers. This study was designed to characterize the phenotypic differences between the expanded and nonexpanded T-cell populations. Expression of markers for activation, costimulation and adhesion molecules was examined. As earlier studies have shown aberrant expression of CD28/CD152, we also analysed the expression of another costimulatory system, the tumour necrotic factor receptor (TNFR) superfamily proteins. DESIGN: Fluorocrome-conjugated monoclonal antibodies and flow cytometry was used to analyse the expression of the different markers on the surface of the expanded and nonexpanded subsets of T cells. SETTING: The Karolinska Hospital and Karolinska Institutet in Stockholm, Sweden. SUBJECTS: Nine patients with WG (six men and three women) had 16 TCRAV/BV CD4+/CD8+ expanded populations that were characterized. RESULTS: The expanded TCRA/BV CD4+ and CD8+ cells had lower percentages of cells expressing CD28 and higher of those expressing CD152 (CTLA-4). The expanded CD4+ population had more cells expressing HLA-DR, CD57 and CCR5 (CD195), whilst the expression of CD25 was present on fewer of the expanded cells. The expanded CD8+ population contained more cells expressing CD137 (4-1BB), CD137 (4-1BBL), CD30 (Ki-1), CD40 and CD134 (OX40). CONCLUSIONS: There were marked differences in the phenotypes of expanded and nonexpanded T-cell populations.

The autoimmune T and B cell repertoires in monozygotic twins discordant for myasthenia gravis.

Two pairs of monozygotic twins, discordant for myasthenia gravis (MG) for more than 30 years, were studied regarding T cell and antibody reactivity against disease related autoantigens, the acetylcholine receptor, one idiotypic and one anti-idiotypic human monoclonal antibody. The healthy and myasthenic twins had very similar autoantibody repertoires. IgG fractions from both healthy and myasthenic twins had the same capacity to decrease the free acetylcholine receptor content in mice after passive transfer. In comparison with their myasthenic sisters, the healthy twins had lower T cell responses against the acetylcholine receptor.

CDS1 and promoter single nucleotide polymorphisms of the CTLA-4 gene in human myasthenia gravis.

The cytotoxic T lymphocyte associated protein 4 (CTLA-4) gene (Ctla-4) is a candidate gene for autoimmune disease. We here report results of two single nucleotide polymorphisms (SNPs) in the Ctla-4, a +49 A/G SNP in CDS1 and a C/T promoter SNP at position -318. There were no differences in these two SNPs between patients and healthy individuals. The frequency of allele G and genotype G/G at position +49 in CDS1 was increased in patients with thymoma when compared with patients with normal and hyperplastic thymic histopathology. Patients with the G/G genotype had signs of immune activation manifested as higher levels of serum IL-1beta and higher percentage of CD28(+) T lymphocytes. There was a strong linkage between the 86bp allele in the 3'-UTR and the A(+49) allele in CDS1. Our results suggest that the SNP at position +49 in CDS1 might be associated with the manifestations of MG.

Radon survey in Kalamata (Greece).

A national radon survey is still lacking for Greece. Some groups have carried out several more or less local or extended radon surveys and valuable experience has been gained. After the first preliminary survey carried out by our group, where 500 Kodak LR-115 etched track detectors were placed in Greek schools and dwellings for one year, indoor radon measurements were continued by placing the same number of detectors in a restricted area, covering the city of Kalamata (a medium size city with 60,000 inhabitants), situated in the south of Peloponnese. Although Kalamata was not of special radon interest, the local authorities insisted on knowing for their citizens' sake the level of this natural radiation. At first, the intention was to use a different method of organisation and distribution of the etched-track detectors from the previous one, attempting mainly to acquire more reliable results and to collect as many detectors as possible. Secondly, it was of great importance to test the statistics of the indoor radon concentrations for a rather small area, and thirdly, to estimate independently the annual absorbed dose by children, taking into account radon concentrations measured both in their home and at school. The set of detectors' readings (about 370), revealed, in general, lower values for Kalamata, compared to the ones found in the preliminary radon survey in Greece and almost all concentrations were found to be below the NRPB action level (200 Bq.m-3).