Reactive arthritis (Reiter's syndrome with conjunctivitis, urethritis, and diarrhea) ( Fig. 22 ) usually follows a bout of gastroenteritis or urethritis. Implicated organisms include Campylobacter, Shigella, Salmonella, Ureaplasma, and Yersinia species. Affected patients, usually men, often have vesicles and crusted plaques on the penis (circinate balanitis) and erythematous pustules and papules on the palms and soles (keratoderma blennorrhagicum) that can mimic pustular psoriasis. More than 50% of patients have sacroiliitis, correlating with the presence of HLA-B27 antigen, but few patients have the classic triad of urethritis, conjunctivitis, and arthritis.
Autologous hematopoietic stem cell transplantation (HSCT) is based on the assumption that autoimmune diseases like systemic sclerosis occur when the white blood cells of the immune system attack the body. In this treatment, stem cells from the patient's blood are extracted and stored to preserve them. The patient's white blood cells are destroyed with cyclophosphamide and rabbit antibodies against the white blood cells. Then the stored blood is returned to the patient's bloodstream to reconstitute a healthy blood and immune system which will not attack the body. The results of a phase 3 trial, the Autologous Stem Cell Transplantation International Scleroderma (ASTIS) trial, with 156 patients were published in 2014. HSCT itself has a high treatment mortality, so in the first year, the survival of patients in the treatment group was lower than the placebo group, but at the end of 10 years, the survival in the treatment group was significantly higher. The authors concluded that HSCT could be effective, if limited to patients who were healthy enough to survive HSCT itself. Therefore, HSCT should be given early in the progression of the disease, before it does damage. Patients with heart disease, and patients who smoked cigarettes, were less likely to survive.   Another trial, the Stem Cell Transplant vs. Cyclophosphamide (SCOT) trial, is ongoing. 
Testing for antibody to double-stranded DNA antigen (anti-dsDNA) and antibody to Sm nuclear antigen (anti-Sm) may be helpful in patients who have a positive ANA test but do not meet full criteria for the diagnosis of systemic lupus erythematosus. AntidsDNA and anti-Sm, particularly in high titers, have high specificity for systemic lupus erythematosus, although their sensitivity is low. Therefore, a positive result helps to establish the diagnosis of the disease, but a negative result does not rule it out. 46 The CAP guideline recommends against testing for other autoantibodies in ANA-positive patients, because there is little evidence that these tests are of benefit. 46