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Objective: To prospectively validate the provisional criteria for the evaluation of response to therapy in children with systemic lupus erythematosus (SLE)., Methods: In this multicenter study, childhood-onset SLE patients (n = 98; 81 girls, 17 boys, 50% white, 88% non-Hispanic) were followed every 3 months for up to 7 visits (total number of visits 623). The 5 childhood-onset SLE core response variables were obtained at the time of each visit: 1) physician assessment of overall disease activity, 2) parent assessment of patient well-being, 3) Child Health Questionnaire, 4) proteinuria, and 5) global disease activity measure score, as measured by the European Consensus Lupus Activity Measure (ECLAM), the Systemic Lupus Erythematosus Disease Activity Index (SLEDAI), or the Systemic Lupus Activity Measure (SLAM). Physician-rated relevant changes in the disease course (clinically relevant improvement, no change in disease, or worsening) between visits served as the criterion standard. Mixed models were used to assess the diagnostic accuracy of the 4 highest-ranked provisional definitions of response to therapy., Results: There were 89 episodes of clinically relevant improvement between 2 consecutive visits, and 448 episodes without improvement. Irrespective of the choice of the global disease activity measure (ECLAM, SLAM, SLEDAI), sensitivities of all 4 highest-ranked definitions were low (all < or =31%), whereas their specificities were excellent (all >88%). Using logistic models, alternative definitions can be developed with both 80% sensitivity and specificity., Conclusion: The provisional criteria of response to therapy in childhood-onset SLE may have considerably lower sensitivity than previously reported. Additional validation in clinical trials is necessary to further evaluate the measurement properties of the provisional Paediatric Rheumatology International Trials Organisation/American College of Rheumatology criteria for response to therapy in children with SLE.

Lupus nephritis (LN) is among the main determinants of poor prognosis in systemic lupus erythematosus (SLE). The objective of this study was to 1) isolate and identify proteins contained in the LN urinary protein signature (PS) of children with SLE; 2) assess the usefulness of the PS proteins for detecting activity of LN over time. Using surface-enhanced or matrix-assisted laser desorption/ionization time of flight mass spectrometry, the proteins contained in the LN urinary PS were identified. They were transferrin (Tf), ceruloplasmin (Cp), alpha1-acid-glycoprotein (AGP), lipocalin-type prostaglandin-D synthetase (L-PGDS), albumin, and albumin-related fragments. Serial plasma and urine samples were analyzed using immunonephelometry or ELISA in 98 children with SLE (78% African American) and 30 controls with juvenile idiopathic arthritis. All urinary PS proteins were significantly higher with active vs. inactive LN or in patients without LN (all p < 0.005), and their combined area under the receiver operating characteristic curve was 0.85. As early as 3 mo before a clinical diagnosis of worsening LN, significant increases of urinary Tf, AGP (both p < 0.0001), and L-PGDS (p < 0.01) occurred, indicating that these PS proteins are biomarkers of LN activity and may help anticipate the future course of LN.

Progressive growth of metastatic Lewis lung carcinoma (LLC-LN7) tumors is associated with increased levels of bone-marrow-derived CD34+ cells having natural suppressor (NS) activity toward T cells. The present studies determined whether tumor-derived products are responsible for this induction of NS activity. Culturing normal bone marrow cells with LLC-LN7-conditioned medium (LLC-CM) or with recombinant granulocyte/macrophage-colony-stimulating factor (GM-CSF) resulted in the appearance of NS activity. The development of NS activity coincided with a prominent increase in the levels of CD34+ cells. That the CD34+ cells were responsible for the NS activity of the bone marrow cultures containing LLC-CM was shown by the loss of NS activity when CD34+ cells were depleted. The stimulation of CD34+ NS cells by LLC-CM was attributed to tumor production of GM-CSF, since neutralization of GM-CSF within the LLC-CM reduced its capacity to increase CD34+ cell levels. Studies also showed that the induction of CD34+ NS cells by LLC-CM and GM-CSF could be overcome by including in the cultures an inducer of myeloid differentiation, 1alpha,25-dihydroxyvitamin D3 [1,25(OH)2D3]. These results demonstrate that the mechanism by which the LLC-LN7 tumors stimulate increased levels of CD34+ NS cells from normal bone marrow is by their production of GM-CSF and that this can be blocked with the myeloid differentiation inducer 1,25(OH)2D3.

The sterol 1alpha,25-dihydroxyvitamin D3 [1,25(OH)2D3] can inhibit T cell activation as well as restore the functional competence of suppressed T cells, The present studies determined whether 1,25(OH)2D3 had a differential effect on the activation of normal T cells or of suppressed T cells from mice bearing Lewis lung carcinoma tumors. Normal spleen cell proliferation in response to immobilized anti-CD3 was unaffected by the lower doses of 0.1-10 nM 1,25(OH)2D3, and was inhibited by the higher dose of 100 nM 1,25(OH)2D3. In contrast, 1,25(OH)2D3 increased proliferation and interferon gamma secretion by T cells of tumor bearers in response to stimulation through T cell receptor/CD3. Assessment of mechanisms associated with the 1,25(OH)2D3 stimulation of tumor-bearer T cells implicated protein phosphatase 2A (PP-2A). First, PP-2A activity of spleen cells from tumor bearers was reduced compared to that of normal spleen cells but was increased by 1,25(OH)2D3. Second, 1,25(OH)2D3 stimulation of tumor-bearer T cell proliferation was dependent on this PP-2A activity as it was blocked by doses of okadaic acid that selectively inhibit PP-2A. These results suggest that 1,25(OH)2D3 preferentially enhances the responsiveness of immunosuppressed T cells from tumor bearers to TCR/CD3 stimulation by restoring PP-2A activity.