Background and aim: Cytotoxic T-lymphocyte antigen 4 (CTLA-4) is a co-stimulatory molecule that is expressed on activated T-cells, and is an important regulator of T-cell activation in T-cell-dependent immune responses. CTLA-4 signals lead to the downregulation of T-cell proliferation and activation. Sarcoidosis is a systemic granulomatous disorder of unknown etiology, which shows abnormal regulation of T cell activation. Polymorphisms of CTLA-4 have been reported to alter CTLA-4 expression, and are associated with many diseases. In the present study we investigated CTLA-4 polymorphisms of promoter -318(C/T) and exon 1 +49(A/G) in sarcoidosis patients and control subjects to determine whether these genetic variations affect sarcoidosis.
Methods: One hundred and six sarcoidosis patients and 100 healthy control subjects were studied. The polymerase chain reaction technique and direct genomic sequencing were used to determine the genotypes of promoter -318(C/T) and exon 1 +49(A/G) in the CTLA-4 gene.
Results: We found no difference in the distribution of either genotype between the healthy control subjects and sarcoidosis patients. Among the sarcoidosis patients, the -318(C/T) CC genotype (p = 0.011) and AG or GG genotype at position +49(A/G) (p = 0.004) were increased with ocular involvement compared with those patients without ocular involvement. Furthermore, the +49(A/G) GG genotype was increased in patients with three or more organs affected compared with patients with fewer organs affected (p = 0.019).
Conclusions: The CTLA-4 polymorphisms are not associated with disease susceptibility of sarcoidosis, but these genetic variations significantly influence phenotypes of sarcoidosis.