Differences in anti-phosphatidylserine-prothrombin complex antibodies and cutaneous vasculitis between regular livedo reticularis and livedo racemosa.

OBJECTIVES We examined the prevalence of LAC, aCL antibodies (Abs), anti-beta(2)-glycoprotein I (anti-beta(2)GPI) Abs and anti-phosphatidylserine-prothrombin complex (anti-PS/PT) Abs in patients with regular livedo reticularis or with livedo racemosa to determine whether those Abs correlate with the clinical or serological features. Assuming that a correlation exists, early recognition of the serological features of the cutaneous manifestations may aid in the treatment and prediction of complications. METHODS We examined the prevalence of LAC, aCL Abs, anti-beta(2)GPI Abs and anti-PS/PT Abs in 143 Japanese patients who presented at our department with regular livedo reticularis or livedo racemosa between 2003 and 2008. LAC was determined according to the guidelines recommended by the Subcommittee on Lupus Anticoagulant/Phospholipid-Dependent Antibodies. Levels of anti-PS/PT, aCL and anti-beta(2)GPI Abs in serum samples taken from patients were measured by specific ELISAs. RESULTS Anti-PS/PT Abs were detected in 94 (65.7%) of the livedo patients. Further, IgM anti-PS/PT Abs were detected in 90 (62.9%) of the livedo patients. Serum IgM anti-PS/PT Ab levels were significantly higher in livedo racemosa patients compared with regular livedo reticularis (19.2 +/- 17.0 vs 8.93 +/- 8.48 U/ml, P = 0.0013). Cutaneous vasculitis was significantly more prevalent among patients with livedo racemosa compared with regular livedo reticularis (P = 0.0014). Livedo racemosa patients had significantly higher CRP serum levels than regular livedo reticularis patients. Livedo racemosa has a stronger association with skin ulceration and arthralgia compared with regular livedo reticularis. Overall, we found a statistically significant association between cutaneous vasculitis and ischaemic cerebrovascular events in our livedo patients. CONCLUSIONS We speculate that IgM anti-PS/PT Abs could be implicated in disease susceptibility for livedo racemosa. We further suspect that cutaneous vasculitis could be closely related to pathogenic factors that trigger the development of livedo racemosa. Early detection of cutaneous vasculitis in skin biopsies of livedo patients should be useful for prognostic evaluation, including ischaemic cerebrovascular events.