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- Ahmad, Awais, 1987-
(författare)
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Autoantibodies in healthy blood donors, rheumatic and autoimmune liver diseases
- 2024
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Autoimmunity is a common phenomenon where the immune system recognises the body's own tissues. Autoimmunity can lead to disease if tissue damage occurs. Autoimmune diseases affect 5–10% of the global population and in many of these autoantibodies can be detected. The autoantibodies can be detected with several different methods. In this thesis, line immunoassays and fluorescence enzyme immunoassay were used to investigate the presence of autoantibodies in blood donors and various disease groups. Line immunoassays use strips while fluorescence enzyme immunoassay uses wells. The strips and wells are coated with proteins that are allowed to react with serum samples from the patient. In the presence of autoantibodies, either a color change (line immunoassay) or a light reaction (fluorescence enzyme immunoassay) occurs.Study I and II: With the EuroLine -Autoimmune Liver Diseases- (IgG) line immunoassay, the presence of autoantibodies associated with autoimmune liver diseases was analysed in blood donors, patients with autoimmune liver diseases and patients with SLE. Autoantibodies could be detected in several blood donors. A very rare autoantibody, anti-LC- 1, was more common in blood donors than in patients with autoimmune liver diseases. Despite the presence of the autoantibodies, no association was seen with abnormal liver values in blood donors or patients with SLE. By raising the cut-off, the number of "false positive" results decreased. However, this could not correct the problem with anti-LC-1, which seems to indicate that there is a problem with the LC-1 antigen so that non-specific reactions are detected. The risk of developing autoimmune liver disease was considered to be low in the SLE patients, as none of these patients developed autoimmune liver disease despite several years of follow-up. Most of the positive findings with the EuroLine immunoassay could not be confirmed with other methods, indicating that this method is very sensitive.Study III: With the EuroLine Systemic Sclerosis (Nucleoli) Profile (IgG) line immunoassay, the rare autoantibodies anti-Th/To and anti-NOR90 could be detected as frequently in blood donors as in patients with systemic sclerosis. Most of the other autoantibodies were more common in patients with systemic sclerosis compared to blood donors and other disease groups. Some of these autoantibodies were associated with specific clinical manifestations, including renal involvement in patients with SLE. These findings need to be verified.Study IV: Autoantibodies that bind the U1-RNP protein (anti-U1-RNP) can be detected in patients with SLE. Patients with anti-U1-RNP can be further analysed for the presence of autoantibodies against the protein RNP 70kDa (anti-RNP70). However, the clinical value of further analysis of anti-RNP70 is uncertain. In this study, fluorescence enzyme immunoassay was used to analyse anti-U1-RNP positive samples for anti-RNP70 to evaluate whether it added anything of clinical value in SLE patients. Presence of anti-U1-RNP was associated with low white blood cell counts and less organ damage. However, analysis of anti-RNP70 in patients with SLE did not add any additional clinical information.Conclusion: Euroline -Autoimmune Liver Diseases- (IgG) and EuroLine Systemic Sclerosis (Nucleoli) Profile (IgG) are tools that are of value in the diagnosis of autoimmune liver diseases and systemic sclerosis, but the methods have high sensitivity which can lead to false positive results. By raising the cut-off, the risk of this can be reduced. Some rare antibodies were found more frequently in blood donors than in patients with the different disease groups, suggesting potential problems with the antigen source. Subtyping of anti-RNP70 in SLE patients with anti-U1-RNP did not add anything of clinical value.
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