Immunostimulatory and immunomodulatory peptides derived from the alpha1 domain of HLA-B27 in experimental autoimmune diseases in Lewis rats

Keratin 8 is a potential self-antigen in the coronary artery disease immunopeptidome: A translational approach

Background

Inflammation is an important risk factor in atherosclerosis, the underlying cause of coronary artery disease (CAD). Unresolved inflammation may result in maladaptive immune responses and lead to immune reactivity to self-antigens. We hypothesized that inflammation in CAD patients would manifest in immune reactivity to self-antigens detectable in soluble HLA-I/peptide complexes in the plasma.

Methods

Soluble HLA-I/peptide complexes were immuno-precipitated from plasma of male acute coronary syndrome (ACS) patients or age-matched controls and eluted peptides were subjected to mass spectrometry to generate the immunopeptidome. Self-peptides were ranked according to frequency and signal intensity, then mouse homologs of selected peptides were used to test immunologic recall in spleens of male apoE-/- mice fed either normal chow or high fat diet. The peptide detected with highest frequency in patient plasma samples and provoked T cell responses in mouse studies was selected for use as a self-antigen to stimulate CAD patient peripheral blood mononuclear cells (PBMCs).

Results

The immunopeptidome profile identified self-peptides unique to the CAD patients. The mouse homologs tested showed immune responses in apoE-/- mice. Keratin 8 was selected for further study in patient PBMCs which elicited T Effector cell responses in CAD patients compared to controls, associated with reduced PD-1 mRNA expression.

Conclusion

An immunopeptidomic strategy to search for self-antigens potentially involved in CAD identified Keratin 8. Self-reactive immune response to Keratin 8 may be an important factor in the inflammatory response in CAD.

Clinical features of ankylosing spondylitis may correlate with HLA-B27 polymorphism

The objective of this study is to investigate the relationship between clinical features of ankylosing spondylitis (AS) and HLA-B27 status or its subtypes. Clinical data and blood samples were collected with patients' informed consent. Luminex liquid array combining polymerase chain reaction-sequence specific oligonucleotide probe was used to do the low-resolution HLA-B genotype typing. Polymerase chain reaction-sequence specific primer was applied to do the high resolution HLA-B27 typing. In 98 subjects, 93 were HLA-B27 positive, of which three subtypes were detected: B*2704 (n = 76), B*2705 (n = 12), and B*2715 (n = 5). The onset age for B27 negative and positive group was 28 +/- 7.9 and 21.1 +/- 6.2 years, respectively (chi(2) = -2.047, P = 0.041). The onset age for B*2704, B*2705 and B*2715 group was 20.45 +/- 4.50, 26.67 +/- 9.95 and 17.8 +/- 11.12 years, respectively (chi(2) = 7.888, P = 0.019). No significant difference was found between B27 positive and negative group, or among three B27 subtypes groups for other clinical features. In conclusion, the clinical features of AS may be correlated with HLA-B27 status and its polymorphism.