Arthritis & Rheumatism, Volume 62,
November 2010 Abstract Supplement

Abstracts of the American College of
Rheumatology/Association of Rheumatology Health Professionals
Annual Scientific Meeting
Atlanta, Georgia November 6-11, 2010.


Anti C1q Antibodies in Patients with Systemic Lupus Erythematosus and Cutaneous Vasculitis: A Controlled Study.

Sangle1,  Shirish R., Lin2,  Loh Yet, Sanchez2,  Esther, Rachel2,  Davies, D'Cruz2,  David P.

St Thomas' Hospital, London, United Kingdom
St Thomas' Hospital, United Kingdom

Objective:

To evaluate the prevalence of anti-C1q antibodies (aC1q) in patients with systemic lupus erythematous (SLE) as a possible marker for cutaneous vasculitis (CV).

Material and Methods:

We prospectively enrolled 46 patients with SLE who fulfilled ACR classification criteria. Twenty three patients had clinically documented CV while 23 had no previous evidence of CV. The BILAG disease activity score was documented and active CV rashes were photographed. aC1q were measured by using ELISA and a aC1q titre above 15 units/ml was considered as positive. Statistics was by chi square test. This study was approved by the St Thomas' Hospital Ethics committee and all patients gave written informed consent.

Result:

The median age of patients in the CV group was 37 years (27–46) and that of the non –CV patients was 44 (29 –66) years. In the CV group, 9 were Caucasian, 6 Asian and 8 Afro Caribbean and in the non-CV group 13 Caucasian, 5 Afro Caribbean and 5 Asian in origin. In the CV group the median BILAG score for vasculitis manifestations was 3 (3–4). In the CV group 22 had positive ANA, 18 ds DNA, 10 ENA, 13 Ro (SSA) and 6 had La (SSB) antibodies. In the non –vasculitis group 22 had positive ANA, 16 ds DNA, 10 ENA, 12 Ro and 6 had La antibodies. The median complement (C3) levels in the CV were 0.88 (0.24 – 1.49) and C4 0.16 (0.03–1.17) as compared to 1.31 (0.33 – 1.65) and 0.17 (0.02–0.34) in the non-CV groups respectively.

Eighteen of 46 (8 in the CV) patients had positive antiphospholipid antibodies (aPL). Six patients in the CV group had renal involvement with none in the non-CV group. aC1q were positive in 14 of 23 (52%) in the CV group compared to 3 (13%) in the non-CV group (p <0.0023). The median titre of aC1q in the CV group was 35 (5–400) u/ml compared to 6 (5–53) in the non-CV group. All patients with positive aC1q had positive ANA and ds DNA antibodies, 13 had ENA positive, 8 had Ro antibodies, 3 La antibodies, 4 each had RNP and RNP with Smith antibodies. In the CV group 13 patients had low C3, C4 levels of which 10 were aC1q positive and in the non-CV group 1 aC1q positive patient had low C3 and C4 levels. The median C3 and C4 levels in aC1q positive patients in the CV group were 0.55 (0.24–0.64) and 0.08 (0.03-0.017) as compared to 0.7 (0.33–0.91) and 0.17 (0.02–0.08) in the non-CV group respectively. Hypocomplementemia was significantly more prevalent in the CV group (p< 0.046). Six patients with positive aC1q were positive for aPL. Three of 6 patients with renal involvement were positive for aC1q in the CV group. aC1q were significantly more prevalent (p<0.024) in the CV without previous renal disease compared to the non-CV non-renal group of patients. There was a statistically significant positive correlation between patients with positive C1q anti ds DNA, ANA antibodies and low C3 C4 levels.

Conclusion:

Anti C1q antibodies may be a marker of activity in cutaneous vasculitis in patients with systemic lupus erythematosus even in the absence of lupus nephritis.

To cite this abstract, please use the following information:
Sangle, Shirish R., Lin, Loh Yet, Sanchez, Esther, Rachel, Davies, D'Cruz, David P.; Anti C1q Antibodies in Patients with Systemic Lupus Erythematosus and Cutaneous Vasculitis: A Controlled Study. [abstract]. Arthritis Rheum 2010;62 Suppl 10 :444
DOI: 10.1002/art.28213

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