Prevalence of autoantibodies in SAPHO syndrome: a single-center study of 90 patients.

OBJECTIVE: To determine the prevalence of the most often tested autoantibodies in synovitis, acne, pustulosis, hyperostosis, and osteitis (SAPHO) syndrome. METHODS: We identified 90 patients seen in our unit between June 2002 and June 2009, and diagnosed according to the proposed criteria for SAPHO syndrome. Demographic and clinical data were collected as well as immunological results, including antinuclear, antithyroid peroxydase (TPO), antithyroid globulin (Tg), antigastric parietal cell, antismooth muscle, antimitochondria, and anti-liver-kidney microsome (LKM) antibodies. Anticyclic citrullinated peptide (CCP) antibodies were analyzed in 69 patients, antibodies to soluble extractable nuclear antigens in 43, anti-double-stranded DNA (dsDNA) antibodies in 22 [depending on the type of fluorescence of antinuclear antibody (ANA)], and antiendomysium antibodies in 55. RESULTS: Autoantibodies were found in 20 patients (22.2%): 14 patients (15.5%) had positive ANA (titer >/= 1/160); among them, 10 (11%) patients never took a lupus-inducing drug. Antithyroid antibodies (anti-TPO and/or anti-Tg antibodies) were found in only 3 patients (3.3%). Three patients (3.3%) were positive for antigastric parietal cell antibodies and 4 (4.4%) were weakly positive for antismooth muscle antibodies. Antimitochondria and LKM antibodies were negative in all 90 patients. Anti-CCP and anti-dsDNA antibodies were negative in the 69 and 22 patients tested, respectively. One out of 43 patients (2.3%) had anti-SSA antibodies. Antiendomysium antibodies were negative in the 55 patients tested. CONCLUSION: Our study indicates an increased prevalence of autoantibodies in SAPHO syndrome, with no specific profile. We failed to confirm the reports of an increased prevalence of antithyroid antibodies. These results tend to support a link between autoimmunity and SAPHO syndrome.

Rheumatoid nodulosis. Two cases with destructive polyarthritis after 20 years.

The term "rheumatoid nodulosis" was coined by Ginsberg in 1975 to designate a rare and distinctive form of rheumatoid disease. Anecdotal case reports suggest a benign nondestructive course, although prolonged follow-up data are usually unavailable. We describe two cases of typical rheumatoid nodulosis with follow-ups exceeding 25 years. Onset occurred at 14 and 22 years of age, respectively. Both patients presented with palindromic rheumatism, positive tests for rheumatoid factors, negative tests for other biological markers, and normal radiographs. Multiple subcutaneous nodules developed after 4 and 6 years with palindromic flares, respectively. Functional impairments and disfigurement required several surgical procedures to remove nodules. Histology was typical for rheumatoid nodules. Neither patient responded to disease-modifying anti-rheumatic drugs (gold, antimalarials, and D-penicillamine). Treatment consisted of nonsteroidal anti-inflammatory drugs combined with prednisone as needed. After 20 and 22 years of follow-up, respectively, both patients had typical rheumatoid arthritis with deformities and radiological joint destruction. In conclusion, these two cases establish that rheumatoid nodulosis can occur as a presentation of rheumatoid arthritis with a potential for severe joint damage after many years.

Anti-glomerular basement membrane nephritis and bullous pemphigoid caused by distinct anti-alpha 3(IV)NC1 and anti-BP180 antibodies in a patient with Crohn's disease.

BACKGROUND: Anti-glomerular basement membrane (GBM) nephritis is a rare disease induced by antibodies directed against alpha3(IV)NC1, the Goodpasture antigen. We report a patient with Crohn's disease who developed anti-GBM nephritis and the skin blistering disorder bullous pemphigoid, owing to distinct autoantibodies. METHODS: Frozen sections of skin and kidney biopsies were incubated with antisera specific for human IgG, IgA, IgM, fibrin, and C3. Reactivity of the patient's serum with GBM antigens was studied by Western blot using bovine solubilized type IV collagen and by enzyme-linked immunosorbent assays using alpha1(IV), alpha3(IV), and alpha5(IV)NC1 recombinant proteins. Reactivity studies against skin antigens were done by Western blot using human keratinocyte and dermal extracts and three recombinant forms of the bullous pemphigoid antigen180 (BP180, also called BPAG2 or type XVII collagen). The patient's serum was affinity fractionated on a (IV)NC1 column, and the bound and unbound fractions were analyzed for their reactivity against GBM and skin antigens. RESULTS: The patient had deposits of IgG along the GBM and the epidermal basement membrane zone. Circulating IgG antibodies against alpha3(IV)NC1 were detected. The patient's autoantibodies immunoblotted the intracellular domain but not the extracellular domain of BP180. Reactivity of the patient's IgG with BP180 was found only in the unbound fraction of the serum. CONCLUSION: The simultaneous development of a rare renal and skin autoimmune disorder, resulting from non-cross-reactive autoantibodies, suggests that a common triggering event could be responsible for the autoimmune injury.