Background/Purpose: Growing evidence suggest that autoantibodies may present in patients with ankylosing spondylitis. Here, we aim to determine the association of inflammatory back pain  and autoantibodies in patients with systemic lupus erythematosus (SLE) which is a protype autoimmune disease.

Methods: One hundred thirty two SLE patients (130 females, 2 males) and 100 healthy controls (98 females,2 males) were questionnaired for having inflammatory low back pain (LBP). The SI joints of SLE patients with LBP were evaluated by conventional radiography followed by color and duplex Doppler ultrasonography (CDDUS) examination. X-Rays were scored according to the modified New York criteria. CDDUS evaluations included the presence of a vessel in and/or around the SI joints and measurement of the RI, which is expected to decrease by inflammation of the joint. The CDDUS results of 44 SLE patients (88 SI joints) were compared with 17 healthy controls (HC) (34 SI joints) without any low back pain.

Results: The incidence of LBP was 58/132 (43.9%) in SLE patients and 15/100 (15%) in HC (p<0.05). Forty four of SLE patients gave consent to participate the study. Within these patients 20/132 (15%) had inflammatory, 24/132 (18%) had noninflammatory LBP. None of the HC has inflammatory LBP. The mean age was 38.6±11.3 years and mean disease duration was 6.8±5.7 years. Mean SLEDAI was 1.94±1.94, BASDAI was 4.11±1.63. In SLE patients; Anti ds-DNA seropositivity was 17(38.6%), anti Sm was 6 (13.6%), anti RNP was 14 (31.8%), anti Ro was 9 (20.5%) and Anti La was 6 (13.6).Two of 16 (12.5%) HC had unilateral grade 1 sacroiliitis and 11/44 (25%) patients had unilateral, 2/44 (4.5%) patients had bilateral grade 1-2 sacroiliitis on X-ray of the SI joints. Vascularisation inside or around the SI joints was seen in 25/44 (56.8%)  SLE patients with 41 of 88 SI joints (46.5%) and 12/17 (70.6%) HC with 18 of 34 SI joints (52.9%) (p>0.05). The mean RI of the SI joints was 0.66 ± 0.11 in SLE patients and 0.64 ± 0.07 in HC with no significant difference between the groups (p>0.05). Prevalence of sacroiliitis on X ray and power Doppler signal inside the SI joints on CDDUS examination had no correlation (Pearson: 0.06). Clinical features and autoantibody seropositivity were not related to sacroiliitis (p>0.05), except anti Sm antibodies (p=0.026).

Conclusion:

Although a significant subset of SLE patients had inflammatory LBP, most patients had no severe radiological or CDDUS evidence of sacroiliitis implicating a mild axial disease. The association with anti-Sm antibodies needs further evaluation.

---

« Back to 2012 ACR/ARHP Annual Meeting

ACR Meeting Abstracts - https://acrabstracts.org/abstract/inflammatory-back-pain-is-increased-in-sle-and-associated-with-anti-sm-antibodies/