Laiana Schneider

Diminished expression of complement regulatory proteins on peripheral blood cells from systemic lupus erythematosus patients.

CD55, CD59, CD46, and CD35 are proteins with complement regulatory (Creg) properties that ensure cell and tissue integrity when this system is activated. The aim of this study was to evaluate the Creg expression on peripheral blood cells from SLE patients and its association with cytopenia and disease activity. Flow cytometric analyses were performed on blood cells from 100 SLE patients and 61 healthy controls. Compared with healthy controls, we observed in SLE patients with lymphopenia and neutropenia decreased expression of CD55, CD59, and CD46 (P < 0.05). In SLE patients with anemia, CD59 and CD35 were decreased on red blood cells. Furthermore, there was a negative correlation between CD55 and CD59 on neutrophils and the disease activity. The results suggest there is an altered pattern of Creg expression on the peripheral blood cells of SLE patients, and the expression is correlated with disease activity and/or with activation of the complement system.

Expressão de proteínas reguladoras do complemento CD55, CD59, CD35 e CD46 na artrite reumatoide

Rheumatoid arthritis (RA) is an autoimmune disease associated with polyarticular inflammatory synovitis affecting mainly peripheral joints. It affects approximately 1% of the world population, being two to three times more prevalent in women. Rheumatoid arthritis has a complex and multifactorial pathogenesis. The synovium of the affected joints is infiltrated by T and B lymphocytes, macrophages, and granulocytes. The rheumatoid synovium has proliferative characteristics, forming the pannus, which invades cartilage and bone, leading to normal architecture destruction and function loss. The decreased expression of complement regulatory proteins (CRP) seems to play an important role in RA activity, and is associated with worsening of the clinical symptoms. In several models of autoimmune diseases, the overactivation of the complement system (CS) is the cause of disease exacerbation. This article aimed at reviewing the main aspects related to CS regulation in RA in order to provide a better understanding of the potential role of this system in the pathophysiology and activity of the disease.

The expression of CD56 antigen is associated with poor prognosis in patients with acute myeloid leukemia

Background The expression of CD56 is considered a bad prognostic factor for overall survival, lower rates or short complete remission and extramedullary invasion but the results are controversial. The importance of validating new prognostic parameters in acute leukemias was the reason to investigate the CD56 expression in blast cells of patients with acute myeloid leukemia. Methods A cohort of 48 patients treated at Hospital de Clinicas de Porto Alegre and diagnosed with acute myeloid leukemia as classified by the French-American-British group (FAB) criteria using cell morphology, cytochemistry and flow cytometry were evaluated. Results Eight cases (16.7%) were CD56 positive without correlation to age or gender. The highest incidence of CD56 positivity was in FAB subtypes M4 and M5. The death rate during induction was not significantly different between patients with and without CD56 expression (62.5% vs. 27.5%; p-value = 0.097). However, patients that expressed CD56 had significantly lower overall survival than those who did not (mean 4.0 months vs. 14.5 months; p-value = 0.03). Conclusions The data suggest that expression of CD56 in acute myeloid leukemia may be indicative of poor prognosis because it is associated with a shorter overall survival. The death rate during induction was not significantly different despite an apparent difference in proportions between groups.

Exercise on Progenitor Cells in Healthy Subjects and Patients with Type 1 Diabetes.

PURPOSE To evaluate the acute effect of aerobic exercise (AE) and resistance exercise (RE) on the release of endothelial progenitor cell (EPCs, CD34+/KDR+/CD45 dim) and vascular function in type 1 diabetes (T1DM). METHODS Fourteen men with T1DM and 5 nondiabetic controls were randomly assigned to 40-min AE (60% VO 2peak) and RE sessions (60% 1-RM). The study had a crossover design, and interventions were 1 wk apart. Venous occlusion plethysmography (blood flow, reactive hyperemia, and vascular resistance) and blood collection (EPC levels, flow cytometry) were done immediately before and after exercise sessions. RESULTS Patients were 30.3 ± 1.6 yr-old, HbA1c 7.7% ± 0.2%; controls were 26.8 ± 2.3 yr-old. Groups did not differ in EPC levels at baseline or in relation to exercise. Over time, exercise did not induce changes in patients with T1DM, whereas, in controls, EPCs were decreased after AE (-10.7%, P = 0.017) and increased after RE (+12.2%, P = 0.004). Compared with baseline, blood flow increased and vascular resistance decreased after RE in both groups. Reactive hyperemia was increased 10 min after AE and RE sessions in patients with T1DM (36.5% and 42.0%, respectively) and in controls (35.4% and 74.3%), but no group differences were observed between groups in response to exercise. CONCLUSIONS Despite the increased vascular reactivity in both groups after both exercise sessions, EPCs were only influenced by exercise in controls. The unchanged number of EPCs in T1DM after exercise sessions might indicate a blunted endothelium regenerating capacity, revealing an early deterioration of the functional arterial characteristics not disclosed by only evaluating vascular functional variables.

Correlation between cellular expression of complement regulatory proteins with depletion and repopulation of B-lymphocytes in peripheral blood of patients with rheumatoid arthritis treated with rituximab

OBJECTIVES To correlate the basal expression of complement regulatory proteins (CRPs) CD55, CD59, CD35, and CD46 in B-lymphocytes from the peripheral blood of a cohort of 10 patients with rheumatoid arthritis (RA) initiating treatment with rituximab (RTX) with depletion and time repopulation of such cells. METHODS Ten patients with RA received two infusions of 1g of RTX with an interval of 14 days. Immunophenotypic analysis for the detection of CD55, CD59, CD35, and CD46 on B-lymphocytes was carried out immediately before the first infusion. The population of B-lymphocytes was analyzed by means of basal CD19 expression and after 1, 2, and 6 months after the infusion of RTX, and then quarterly until clinical relapse. Depletion of B-lymphocytes in peripheral blood was defined as a CD19 expression <0.005×109/L. RESULTS Ten women with a median of 49 years and a baseline DAS28=5.6 were evaluated; 9 were seropositive for rheumatoid factor. Five patients showed a repopulation of B-lymphocytes after 2 months, and the other five after 6 months. There was a correlation between the basal expression of CD46 and the time of repopulation (correlation coefficient=-0.733, p=0.0016). A similar trend was observed with CD35, but without statistical significance (correction coefficient=-0.522, p=0.12). CONCLUSION The increased CD46 expression was predictive of a faster repopulation of B-lymphocytes in patients treated with RTX. Studies involving a larger number of patients will be needed to confirm the utility of basal expression of CRPs as a predictor of clinical response.