Thymus and Activation-regulated Chemokine as a Biomarker for IgG4-related Disease

Abstract

High serum concentrations of thymus and activation-regulated chemokine (TARC) are observed in allergic diseases such as atopic dermatitis and bronchial asthma. Frequent allergic symptoms have been reported in patients with IgG4-related disease (IgG4-RD). We investigated the pathogenic role of TARC as a biomarker in IgG4-RD patients. We evaluated the serum concentrations of TARC from 29 IgG4-RD patients, 28 primary Sjögren syndrome (pSS) patients, and 23 healthy controls (HCs) by enzyme-linked immunosorbent assay (ELISA). We analyzed the correlations between the TARC concentrations and the subjects' clinical parameters. To investigate the biological effect of TARC on the pathogenesis of IgG4-RD, we evaluated the in vitro induction of plasmablasts from IgG4-RD patients by TARC. The serum concentrations of TARC in the IgG4-RD patients were significantly higher than those of the pSS patients and HCs. The serum TARC concentration of the IgG4-RD group was positively correlated with the IgG4-RD responder index (IgG4-RD RI) score and with the number of organs involved, but it was not correlated with the serum IgG4 level or eosinophil number in the IgG4-RD patients' peripheral blood. The patients who had lung involvement had higher serum TARC concentrations. In vitro, TARC clearly induced the formation of plasmablasts from the IgG4-RD patients' peripheral blood mononuclear cells. Collectively, our data suggest that a systemic increment of TARC may contribute to the development of IgG4-RD through an aberrant induction of plasmablasts.

Serum immunoglobulin free light chains and their association with clinical phenotypes, serology and activity in patients with IgG4-related disease: a cross-sectional study.

“…On the contrary, a recent study by Umeda et al. found that serum thymus and activation-regulated chemokine could discriminate between IgG4-RD and SS [35]. In our study we did not nd differences in sFLC concentrations among IgG4-RD group and both control groups, however, up to half of the patients with active IgG4-RD had and elevated k/λ ratio and this nding was signi cantly different from the SS and sarcoidosis group.…”

IgG4-related disease: a contemporary review

“…Apart from IgG4,in a recent study, in the sera of 28 IgG4-RD patients, thymus and activation-regulated chemokine (TARC) levels were measured and were found to be higher than those of patients with Sjögren syndrome and control group. In addition, it was established that they were related to responder index and organ involvement and that TARC stimulated plasmablasts in vitro [76]. Serum plasmablast concentration is a more sensitive marker for the diagnosis of IgG4-RD compared to the serum IgG4 level, however, due to the difficulty of application, it has limited clinical use.…”

Serum immunoglobulin free light chains and their association with clinical phenotypes, serology and activity in patients with IgG4-related disease

“…For instance, Akiyama et al described that serum soluble IL-2 receptor was not useful for the differential diagnosis between IgG4-RD and SS 17 . On the contrary, a recent study by Umeda et al found that serum thymus and activation-regulated chemokine could discriminate between IgG4-RD and SS 29 . In our study we did not find differences in sFLC concentrations among IgG4-RD group and both control groups, however, up to half of the patients with active IgG4-RD had an elevated κ/λ ratio.…”