table_1.DOC

<p>Idiopathic mast cell activation syndrome can be a rare cause for chronic abdominal pain in children. It remains a diagnosis by exclusion that can be particularly challenging due to the vast variety of possible clinical manifestations. We present a 13-year-old boy who suffered from a multitude of unspecific complaints over a long period of time. In this case, an assessment of mast cell-derived metabolites and immunohistochemical analysis of bioptic specimen was worthwhile. After ruling out, primary (oncologic) and secondary causes for mast cell activation, pharmacologic treatment adapted to the patient’s salicylate intolerance resulted in a major relief of symptoms.</p

The calcineurin inhibitors tacrolimus and CsA inhibit IL-10 expression of B-cells <i>in vitro</i> and <i>in vivo</i>.

<p>Freshly isolated PBMCs from healthy subjects (n = 9) and renal transplant recipients (n = 9) were mitogen/toll-like-receptor 9 stimulated for 72 hours and subsequently stained for surface CD19 and intracellular IL-10 or with the respective isotype control antibodies <b>(A).</b> The representative dot plots on the upper left in <b>A</b> show the intracellular IL-10 expression of stimulated CD19⁺ B-cells from a healthy subject and representative renal transplant recipients receiving either tacrolimus or CsA (after gating on CD19⁺ B-cells). The scatter plot in <b>B</b> summarizes the results of multiple unrelated experiments. PBMCs of healthy subjects were stimulated like described before in presence or absence of different concentrations of tacrolimus (n = 4) <b>(C)</b> or CsA (n = 4) <b>(D)</b>, as indicated. The bar graphs in <b>E</b> depict the decline of IL-10 production (in %) of PBMCs vs. positively isolated CD19⁺ B-cells after stimulation co-cultured with CsA (n = 9 healthy subjects). 7-AAD staining was performed to ensure viability of cell culture.</p

Renal Transplant Recipients Treated with Calcineurin-Inhibitors Lack Circulating Immature Transitional CD19⁺CD24^hiCD38^hi Regulatory B-Lymphocytes - Fig 4

<p>The amount of peripheral circulating CD19⁺CD24^hiCD38^hi cells correlated with the clinical outcome after kidney transplantation A low amount of peripheral circulating CD19⁺CD24^hiCD38^hi cells was associated with a lower eGFR <b>(A).</b> The orange-framed box in <b>B</b> indicates a subgroup of 29 patients that exhibited <1% of CD24^hi38^hi expressing CD19⁺ peripherally circulating B-cells. 31% (n = 9) of these patients experienced a biopsy proven rejection event 24 months before or after the analyses (5 patients before and 4 patients within 24 months after sample assessment).</p

Calcineurin inhibitors reduce the expression of CD24 and CD38 on CD19⁺ B lymphocytes.

<p>The expression of CD24, CD38 and IL-10 after gating on CD19⁺ B-cells is shown in a representative healthy subject, indicating that only a minority of IL-10 producing B-cells highly express CD38 <b>(A)</b>. The dot blots in <b>B</b> depict CD24^hiCD38^hi B-cells (red-framed boxes) in a representative healthy subject, a renal transplant recipient receiving a CsA or tacrolimus based immunosuppression. The respective isotype control staining is depicted in between. The scatter plot graphs in <b>C</b> and <b>D</b> summarize the results and show that treatment with tacrolimus (n = 35) or CsA (n = 11) not only reduce the percentage of peripherally circulating B-lymphocytes <b>(C)</b> but also affect the CD24^hiCD38^hi B-cell subset <b>(D)</b>. In contrast to healthy subjects (n = 16), the CD24^hi38^hi expressing B-cell subset of renal transplant patients receiving a calcineurin inhibitor were significantly reduced or even blunted <b>(B, D)</b>. No correlation was found between the amount of CD24^hiCD38^hi B-cells and time of sample assessment after transplantation <b>(E</b>, Spearman test, <i>r</i> = -0,01, <i>p</i> = 0,9450).</p