Antibodies against the N-terminal domain of annexin A2 in antiphospholipid syndrome

Annexin A2 (ANXA2, an endothelial cell receptor for plasminogen and tissue plasminogen activator) has been identified as a new autoantigen in antiphospholipid syndrome (APS). The aim of the present study was to evaluate the presence of antibodies against the N-terminal domain of annexin A2 (ANXA2) in primary APS (PAPS). By using a synthetic peptide corresponding to the 31N-terminal amino acids of ANXA2 (ANXA2(N31)) as an antigen, we performed an enzyme-linked immunosorbent assay (ELISA) to measure anti-ANXA2(N31) IgG and IgM antibodies in the serum of PAPS patients (n=19), systemic lupus erythematosus (SLE) patients (n=50) and healthy blood donors (n=106). We did not find any statistically differences between the three groups in terms of IgG and IgM anti-ANXA2(N31) titres. Elevated IgG anti-ANXA2(N31) titres were not observed in the serum of PAPS or SLE patients who had previously tested positive for anti-ANXA2 antibodies. Thus, the ANXA2 N-terminal domain does not appear to be the target antigen for anti-ANXA2 antibodies in APS.

Serum procalcitonin does not differentiate between infection and disease flare in patients with systemic lupus erythematosus

Systemic erythematosus lupus (SLE) is a common autoimmune disease. Disease flares may mimic infection with fever, inflammatory syndrome and chills, sometimes resulting in a difficult differential diagnosis. Elevated serum procalcitonin (PCT) levels have been reported to be predictive of bacterial infections, but with conflicting results. The value of serum procalcitonin has not been assessed in large series of SLE. We aimed to describe the distribution of PCT levels in SLE patients with and without flares, to assess the factors associated with increased PCT levels, and to determine the positive and negative predictive values of increased PCT for bacterial infection in SLE patients. Hospitalized SLE patients were included in a retrospective study. Serum PCT had been assayed, or a serum sample had been frozen on admission, before treatment modification. Serum PCT, measured by an automated immunofluorometric assay, and SLEDAI were assessed at the same time. Some 53 women (median age: 33.7 years, range 16–76) and seven men (median age: 52.5 years ± 19) were included. The median SLEDAI for patients with flare ( n = 16, 28%) was 2 (range: 0–29). Five patients (8%) had systemic infection. Only one patient had increased PCT levels. Men had significantly higher PCT levels than women (0.196 ± 0.23 versus 0.066 ± 0.03, p < 0.01) and a significant correlation was observed between PCT, age, erythrocyte sedimentation rate, and C-reactive protein. We conclude that PCT levels were within the normal range in infected and non-infected SLE patients and there was no ability to differentiate SLE patients with or without bacterial infection.

Clinical significance of autoantibodies recognizing Sjögren's syndrome A (SSA), SSB, calpastatin and alpha-fodrin in primary Sjögren's syndrome

The aim of our study was (i) to compare the clinical and biological characteristics of 148 (137 women, 11 men) primary Sjögren's syndrome (pSS) patients at diagnosis as a function of their sex and (ii) to assess the prognostic value of anti-calpastatin and anti-alpha-fodrin autoantibodies. In addition, the presence of anti-nuclear antibodies (ANA), anti-52- and 60-kDa Sjögren's syndrome A (SSA), anti-Sjögren's syndrome B (SSB), anti-cyclic citrullinated peptide (CCP) antibodies and rheumatoid factors (RF) of IgA, IgG and IgM isotypes was sought in sera collected at pSS onset. Raynaud's syndrome, significantly more frequent in women, was the only systemic manifestation of pSS whose frequency differed significantly as a function of the patient's sex (P = 0.02). ANA (P = 0.001) and anti-60-kDa SSA autoantibodies (P = 0.03) were significantly more common in women, while men never synthesized detectable levels of anti-SSB, anti-calpastatin or IgG anti-alpha-fodrin autoantibodies. In addition, anti-CCP autoantibodies were found in low percentages of pSS patients (4% F/18% M). The absence of autoantibodies does not exclude the diagnosis of pSS in men that will be based mainly on the anatomopathological findings of a minor salivary gland biopsy. Positivity of anti-60-kDa SSA, anti-SSB, anti-calpastatin, IgA and IgG anti-alpha-fodrin antibodies is not associated with pSS clinical and biological severity.