Circulating CXCR5+CD4+helper T cells in systemic lupus erythematosus patients share phenotypic properties with germinal center follicular helper T cells and promote antibody production.

OBJECTIVE: Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by the production of autoantibodies. Recently, a specific highly activated T helper cell subset, follicular helper T (Tfh) cell, has emerged as a key immunoregulator of germinal center (GC) formation and high-affinity antibody production. To identify the pathophysiological role of Tfh cells in SLE patients, we compared the phenotypic and functional properties of circulating Tfh-like cells in lupus patients to GC-Tfh cells, and correlated the percentage of Tfh-like cells with autoantibody production and SLE disease activity. METHODS: Peripheral blood was collected from 29 lupus patients and 25 healthy controls. Tonsils were obtained surgically from non-SLE controls and used as a source of GC-Tfh cells. Tfh cells were defined by their signature surface markers (CXCR5, ICOS, CD57, PD-1 and BTLA) via flow cytometry. IL-21 expression levels from Tfh cells were measured by real-time PCR and intracellular staining. The function of Tfh cells was carried out by co-culture of Tfh cells and autologous B cells in vitro. IgG in the culture supernatant was detected by ELISA. RESULTS: The frequency of circulating Tfh-like cells was significantly increased in SLE patients compared to healthy controls (p < 0.05). The Tfh-like cells not only display similar phenotypes and signature cytokines with GC-Tfh cells, but also are capable of driving B cells to differentiate into IgG-secreting plasma cells in vitro. In addition, the frequency of Tfh-like cells correlated positively with the percentage of circulating plasmablasts, levels of serum anti-dsDNA antibodies and ANA. CONCLUSION: The accumulated circulating Tfh-like cells in lupus patients share phenotypic and functional properties with GC-Tfh cells. Tfh-like cells may serve as perpetuators in the pathogenesis of SLE by enhancing the self-reactive B cell clones to further differentiate into auto antibody-producing plasmablasts, and ultimately cause autoimmunity.

False negative bone scans in neuroblastoma metastatic to the ends of long bones.

Studies of 12 children with neuroblastoma were performed to assess the comparative sensitivity of skeletal radiography and 99mTc pyrophosphate bone scintigraphy in the detection of metastases to the ends of long bones. A total of 18 lesions were detected in six patients. Fourteen were demonstrated only by radiography, whereas four were positive by both methods. In no case was a lesion detected by scintigraphy alone. Small lesion size, lytic radiographic appearance, metaphyseal location, and technical difficulties in imaging the knee all contribute to the high incidenmce of false negative scans. Lesions in two of the nine patients with metastatic disease to bone would have been missed on the basis of bone scans alone. Accordingly, the radiographic skeletal survey seems to remain a necessary part of the neuroblastoma workup.