Although substantial evidence indicates that estradiol-17 beta (E2) is conjugated to the glucuronide in the kidney and then excreted by a direct tubular secretory route and that the liver transports ...E2 glucuronides via carrier-mediated mechanisms, the transporters involved in these processes have not been identified. The so-called "organic anion-transporting polypeptide" (i.e., oatp) has a number of known substrates, including bromosulfophthalein (BSP) and taurocholic acid (TCA) (E. Jacquemin, B. Hagenbuch, B. Stieger, A. W. Wolkoff, and P. J. Meier. Proc. Natl. Acad. Sci. USA 91: 133-137, 1994). In a companion study, we determined that steroid hormones represent a class of hormones that interact strongly with oatp when the latter is transiently expressed in vitro. Here, we studied more extensively steroids and steroid anion conjugates as candidate oatp substrates. In HeLa cell monolayers transfected with a full-length oatp cDNA, 3Hestradiol 17 beta-D-glucuronide (3HE2-17G) was transported with a signal-to-noise ratio of 15:1 over that of monolayers transfected with a control plasmid. The affinity of oatp for 3HE2-17G was significantly higher than that for TCA (K(m) of 3 microM vs. 27 microM, respectively). In contrast to E2-17G, unconjugated estradiol (E2) was not significantly transported by oatp. Several unconjugated steroids and anionic steroid conjugates were tested for their ability to compete with tracer E2-17G for oatp-mediated transport. Conjugation at the 17 or 3 position with the anion of a strong acid (sulfate) resulted in a greater degree of inhibition of tracer E2-17G transport than did conjugation at the 17 or 3 position with an uncharged group (acetate), suggesting that the strength of the negative charge at these positions is an important determinant of the affinity of a given steroid conjugate for oatp. We conclude that the preferred substrates for oatp are steroids with a strong 17- or 3-position anionic group. Since steroid sulfotransferases and glucuronosyltransferases are expressed in the proximal tubule, as is oatp, the transporter may serve as an apical exit pathway for steroids following their conjugation within the tubule cell.
Multiple epiphyseal dysplasia (MED) is clinically and genetically a heterogeneous disorder that affects growth centres and results in delayed and irregular mineralisation of the ossification centres. ...1, 2 Recessively inherited MED (rMED; MIM 226900) accounts for a significant proportion of MED cases and is associated with mutations in the sulphate transporter gene, DTDST/SLC26A2. 3, 4 More often, MED is inherited as a dominant trait. ...far, five different genes have been implicated in dominantly inherited MED: the gene for cartilage oligomeric matrix protein, COMP (MIM 600310); the genes for the α1, α2, and α3 chains of collagen IX, COL9A1 (MIM 120165), COL9A2 (MIM 120260), and COL9A3 (MIM 120270); and the gene for matrilin-3, MATN3 (MIM 602109). Apparently neither sign is specific for collagen IX associated MED as it can also be seen in COMP associated MED. ...although these observations do not refute the distinction proposed by Unger et al that patient groups may tend to show differences, 19 there is considerable overlap.
We report on a 22-year-old girl with a history of recurrent febrile episodes, chronic arthritis, urticarial rash, and neurological symptoms including right hemiparesis, internal hydrocephalus, mental ...retardation, progressive deafness, and visual impairment. Treatment starting at age 20 months, including different combinations of immunosuppressive and antiinflammatory drugs such as corticosteroids and anti-TNFalpha antibody, was unsuccessful. Four years ago, we found a heterozygous S595G mutation in the NLRP3 gene of this patient. This prompted us to introduce anakinra, which resulted in considerable improvement of the patient's complaints.
Hemophagocytic lymphohistiocytosis is a hyperinflammatory syndrome defined by clinical and laboratory criteria. Current criteria were created to identify patients with familial hemophagocytic ...lmyphohistiocytosis in immediate need of immunosuppressive therapy. However, these criteria also identify patients with infection-associated hemophagocytic inflammatory states lacking genetic defects typically predisposing to hemophagocytic lymphohistiocytosis. These patients include those with primary immunodeficiencies, in whom the pathogenesis of the inflammatory syndrome may be distinctive and aggressive immunosuppression is contraindicated. To better characterize hemophagocytic inflammation associated with immunodeficiencies, we combined an international survey with a literature search and identified 63 patients with primary immunodeficiencies other than cytotoxicity defects or X-linked lymphoproliferative disorders, presenting with conditions fulfilling current criteria for hemophagocytic lymphohistiocytosis. Twelve patients had severe combined immunodeficiency with <100/μL T cells, 18 had partial T-cell deficiencies; episodes of hemophagocytic lymphohistiocytosis were mostly associated with viral infections. Twenty-two patients had chronic granulomatous disease with hemophagocytic episodes mainly associated with bacterial infections. Compared to patients with cytotoxicity defects, patients with T-cell deficiencies had lower levels of soluble CD25 and higher ferritin concentrations. Other criteria for hemophagocytoc lymphohistiocytosis were not discriminative. Thus: (i) a hemophagocytic inflammatory syndrome fulfilling criteria for hemophagocytic lymphohistiocytosis can be the initial manifestation of primary immunodeficiencies; (ii) this syndrome can develop despite severe deficiency of T and NK cells, implying that the pathophysiology is distinct and not appropriately described as "lympho"-histiocytosis in these patients; and (iii) current criteria for hemophagocytoc lymphohistiocytosis are insufficient to differentiate hemophagocytic inflammatory syndromes with different pathogeneses. This is important because of implications for therapy, in particular for protocols targeting T cells.
Two major types of intercalated cells (IC) have been previously defined in rabbit collecting duct: alpha-cells have a basolateral band 3-like anion exchanger and secrete H+, whereas beta-cells bind ...peanut agglutinin (PNA) apically and are believed to secrete HCO3-. To further define IC types, we double-labeled kidney sections with anti-H(+) -ATPase antibodies and with either an anti-band 3 antibody or PNA. We found four patterns of staining: 1) IC with apical H(+)-ATPase and basal band 3, a configuration consistent with ongoing H+ secretion, which prevailed in the inner stripe of outer medulla (OMCDi); 2) diffuse H(+)-ATPase labeling across the cell and basal band 3, which was most numerous in the outer stripe of outer medulla (OMCDo); 3) IC with "bright" apical peanut lectin, diffuse H(+)-ATPase, and no band 3, which was abundant in the cortical collecting duct (CCD) and probably represents HCO3(-)-secreting cells; and 4) "hybrid" cells with various staining combinations (e.g., apical lectin binding and apical H(+)-ATPase), which although they are uncommon, were seen in the CCD. Consistent with this immunocytochemical finding of hybrid cells, cell-sorting studies on isolated CCD IC showed that 6-18% of PNA-positive cells also stained positively for band 3. We conclude that 1) band 3-positive IC in the OMCD vary axially. Most OMCDi IC are probably active proton secretors, whereas up to one-half of OMCDo IC may be latent H+ secretors. 2) The diffuse H(+)-ATPase pattern in putative beta-cells differs from comparable results in the rat and is not consistent with a "reversed" alpha-cell. HCO3- secretion by beta-cells may be driven by an H+ extrusion mechanism other than the alpha-cell pump re-sorted to the basolateral membrane. 3) The possibility of hybrid cells that might combine alpha- and beta-cell transport proteins suggests a mechanism for functional reversal of collecting duct IC polarity.
In patients with Henoch-Schoenlein purpura (HSP), particularly with severe gastrointestinal symptoms, an associated decrease of plasma factor XIII has been observed.
The authors report a case of HSP ...in a boy and describe the development of factor XIII activities throughout the course of the disease. Every relapse of severe gastrointestinal manifestation was associated with a decrease of factor XIII. No improvement was seen after treatment with prednisone. The symptoms resolved each time factor XIII concentrate was administered. With the return of factor XIII to normal values eight weeks after admission abdominal symptoms ceased.
The documented course supports the hypothesis that factor XIII activity correlates well with the severity of abdominal symptoms. Measuring factor XIII activity helps to identify those patients with severe gastrointestinal manifestation who may benefit from substitution therapy.
Hypogammaglobulinemia is a common symptom in different immunodeficiencies. It is, however, not usually associated with Epstein-Barr virus (EBV) infections. The X-linked lymphoproliferative disease ...(XLP) on the other hand shows immunological changes in response to the EBV. Here we report three previously healthy boys, all of which developed persistent hypogammaglobulinemia following severe acute infectious mononucleosis. All three patients revealed T-cell abnormalities including inverted CD4/CD8 and increased CD8(+) T-cell numbers. The number of IFN-gamma-producing T cells were markedly increased in the two patients studied so far. In addition, patient 2 showed mainly T cells, instead of B cells, to be infected with the EBV. Apart from an uncle of patient 3, who died of malignant lymphoma, family history was unremarkable in all cases. All three patients exhibited mutations in the SH2D1A gene, establishing the diagnosis of XLP. Protein expression was found on immunoblot analysis in one patient with a missense mutation. Development of persistent hypogammaglobulinemia after severe primary EBV infection seems to be a specific diagnostic sign for XLP even in males with unremarkable family history.
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