A study of antigen-specific anti-cytomegalovirus antibody reactivity in patients with systemic sclerosis and concomitant anti-Ro52 antibodies

Anti-Ro52 autoantibody (autoAb), highly prevalent in Sjogren's syndrome (SjS) and systemic lupus erythematosus (SLE), is also frequent in systemic sclerosis (SSc). Viral agents, such as human cytomegalovirus (HCMV), have been considered as a trigger for SSc and SSc-associated autoAbs. To seek for antigen-specific anti-HCMV associations with anti-Ro52, we assessed the dominant anti-HCMV ab responses in anti-Ro52 antibody (ab)-positive and -negative patients with SSc and compared them with those in SLE and SjS. 116 Anti-HCMV ab(+) sera were analyzed, including 70 from anti-Ro52(+) patients (29 SSc, 23 SLE and 18 SjS) and 46 from anti-Ro52(-) patients (29 with SSc, 9 with SLE and 8 with SjS) as negative controls. Abs against specific HCMV pp130/UL57, pp65/UL83, pp55/UL55, pp52/UL44, p38 and pp28/UL99 antigens were tested by immunoblotting. Anti-Ro52(+) SSc patients reacted more frequently against pp52/UL44 and p38 compared to anti-Ro52(-) [(13/29, 44.8%; 95% CI 26.7-62.9% vs. 1/29, 3.4%; 95% CI 0-10%, p < 0.001, and 9/29, 31.0%; 95% CI 14.2-47.8% vs. 2/29, 6.9%; 95% CI 0-16.1%, p = 0.041, respectively]. No such differences were noted between anti-Ro52(+) and anti-Ro52(-) SLE or SjS patients. Also, antibody titres against HCMV pp65/UL83, pp52/UL44 and p38 antigens were higher in anti-Ro52(+) than anti-Ro52(-) SSc patients (p < 0.01). Ab responses against specific HCMV antigens differ among anti-Ro52 ab-positive and -negative patients with SSc (as well as between SSc and SLE or SjS), but whether these differences are epiphenomenal remains to be seen.