HLA-G may predict the disease course in patients with early arthritis

The current management of early arthritis (EA) with negative prognostic factors is to start an intensive treatment. To avoid under/overtreatment, it is important to identify EA evolution biomarkers. Several factors have been suggested but their predictive value is still limited. Human leukocyte antigen-G (HLA-G) molecules are expressed as membrane bound and soluble isoforms (mHLA-G and sHLA-G) that act as ligand for immune-inhibitory receptors (ILT2, ILT4 and KIR2DL4). Expression of HLAG is influenced by a 14-bp insertion/deletion polymorphism in exon 8 of the gene, where the deletion is associated with mRNA stability. sHLA-G levels are positively correlated with RA disease activity and treatment response. We suggest a role both in disease immunopathology and as a biomarker of disease course and treatment response. We analyzed 14 EA patients during a 12 months follow-up pharmacological treatment. We evaluated sHLA-G levels in plasma samples by enzyme-linked immunosorbent assay, mHLA-G and IL-T2 expression on peripheral blood cells by flow cytometry and typed HLA-G 14-bp polymorphism by real-time polymerase chain reaction. Disease status parameters (DAS28) and laboratory data were checked. The sHLA-G levels, mHLA-G and IL-T2 expression inversely correlated with DAS28 parameter during the 12 months follow-up (P < 0.0001). The distribution of HLA-G polymorphism tends to a correlation between the homozygosity for the deletion, the high producer genotype and a lower DAS28 (P = 0.069). On the basis of these preliminary results, HLA-G may be a candidate biomarker to evaluate early prognosis and disease activity in EA patients.