The roles of eotaxin and the STAT6 signalling pathway in eosinophil recruitment and host resistance to the nematodes Nippostrongylus brasiliensis and Heligmosomoides bakeri

Expulsion of adult Nippostrongylus brasiliensis worms from the small intestine is profoundly impaired in signal transducer and activator of transcription (STAT)6-deficient mice. IL-5 transgenic (Tg) mice with constitutive eosinophilia show profound early resistance in the skin and/or later pre-lung phase of primary infections with N. brasiliensis. This study was designed to assess the importance of the eosinophil chemokine eotaxin and the STAT6/interleukin (IL)-4/IL-13 signalling pathway in early resistance to N. brasiliensis. Eosinophil recruitment into the skin following injection of N. brasiliensis larvae was reduced in STAT6- or eotaxin-deficient/IL-5 Tg double mutant mice. While ablation of eotaxin did not impair resistance in the pre-lung phase of N. brasiliensis infections in IL-5 Tg mice, elimination of STAT6 caused a modest reduction in resistance in both primary and secondary infections on this genetic background. STAT6(-/-)-, IL-13(-/-)- and IL-4Ralpha(-/-)-deficient single mutant and IL-13(-/-)/IL-4Ralpha(-/-) double mutant mice were more susceptible than WT mice during the pre-lung phase of secondary N. brasiliensis infections. In contrast, primary or secondary resistance were unaffected at either the pre-lung or gut stages of infection in eotaxin(-/-) single mutant mice. STAT6(-/-) and eotaxin(-/-) mice with or without the IL-5 transgene, were no more susceptible than WT or IL-5 Tg mice to protracted primary infections with Heligmosomoides bakeri, a parasitic nematode that is restricted to the gut. Our data suggest that parasitic nematodes that transit through the skin and lungs en route to the gut may be susceptible to early (pre-lung) innate and adaptive immune mechanisms that are dependent on the STAT6/IL-4/IL-13 signalling pathway, and this may be important for the development of effective therapies and vaccines.

Measurement of diamine oxidase activity in vaginal fluid -- an aid to diagnosis of ruptured fetal membranes

Measurement of diamine oxidase (DAO) activity in vaginal fluid as an aid to diagnosis of premature rupture of the fetal membranes was studied. In 76 patients following artificial rupture of the membranes and in 70 patients with known intact membranes, the accuracy was 100%. One hundred and forty-nine patients were admitted to hospital with suspected ruptured membranes; using the criteria outlined in this paper, 51 had ruptured membranes and in 98 the membranes were intact. The overall accuracy was 96%.