Rheumatoid arthritis-associated antibodies in healthy first-degree relatives of RA patients.

Rheumatoid arthritis (RA) affects approximately 1.5% of the population worldwide and 0.5-3.3% of the Mexican population. The presence of rheumatoid factor (RF), anti-citrullinated protein antibodies (ACPA) and anti-carbamylated protein (anti-CarP) antibodies has been described in populations at risk of RA development, such as first-degree relatives (FDR). Anti-CarP antibodies are present in RA patients (44%), FDR of RA patients (18%) and healthy controls (4.7%). Anti-CarP antibodies have not been described in FDR of the Mexican population. The objective of this study was to determine the prevalence of Rheumatoid Factors (RF) isotypes, ACPA and anti-CarP antibodies isotypes in FDR of RA patients. An observational, cross-sectional study, in an FDR of RA cohort, was performed. We measured IgA, IgG and IgM isotypes of RF, ACPA and anti-CarP antibodies. A total of 144 FDRs from 99 RA patients were enrolled. The prevalence of anti-CarP antibodies was 2.8% for IgA, 4.2% for IgG, whereas IgM was not detected. The serologic association was for RF/ACPA 4.48%, RF/anti-CarP 2.7%, FR 64.5%, ACPA 1.3%, ACPA/anti-CarP 0.69%, anti-CarP 3.4%, and no RF/ACPA/anti-CarP was observed. We found a low prevalence of anti-CarP antibodies in our cohort of FDR of RA patients, but the prevalence of ACPA and RF were higher than other cohorts previously reported.

Low-dose rituximab therapy in steroid-refractory thrombocytopenia due to systemic lupus erythematosus.

Systemic lupus erythematosus (SLE) is an autoimmune disease, characterized by multi-organ symptomatology. 16% of the patients with autoimmune thrombocytopenia have SLE and are associated with high mortality. Intravenous methylprednisolone or high-dose steroids are the first-line treatments in those patients who experienced life-threatening bleeding or have a severely low platelet count, whereas a second line includes splenectomy, as well as other immunosuppressive agents as monotherapy or combined therapy, including azathioprine, cyclophosphamide, cyclosporine, and mycophenolate mofetil. However, response rates of these therapies vary considerably. Rituximab (RTX) became a useful tool in the treatment of autoimmune diseases, due to the decrease of autoantibodies production. In addition, there is evidence that low doses of RTX (100 mg IV per week for 4 weeks) can have a similar effect compared to the standard dose. The objective of this study was to describe the response to low doses of RTX in patients with lupus-induced thrombocytopenia. We present a report of four female patients with newly diagnosed SLE, accompanied by purpuric syndrome and severe thrombocytopenia (< 30 × 109/L) as the clinical debut that was refractory to glucocorticoids (GC) therapy and treated with low doses of RTX. By week 5, complete response (> 100 × 109/L) was achieved in two patients, partial response (> 50 × 109/L) in 1 patient, and no response in one patient. There is little information on the treatment of SLE-associated autoimmune thrombocytopenia. The most extensive study found at the time of our search was the study of 10 Asian patients. They found that 80% of the patients responded by week four and maintained until week 24 of follow-up. At week 36, a follow-up for two patients showed relapse; this occurred on patients with the most disease duration (> 5 years) and was associated with a lower response rate. In contrast, our study with four patients found that half of them presented a complete response: one patient added concomitant therapy with azathioprine (AZA) and another patient without the concomitant therapy. A third patient with a partial improvement, this was seen by week five of treatment. Moreover, a fourth patient who did not have a response by week five of treatment presented a clinical response in subsequent appointments with a count of > 100 at week 24. Those patients who required concomitant use of AZA were patients who had positive antiphospholipid serology. The use of low-dose RTX for the management of severe thrombocytopenia refractory to GC in patients with SLE has a good response. It could be a safe, economical, and effective therapy.