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Surfactant proteins A and D are collectins which are considered to play an important role in the innate immunity of lungs. Our aim was to investigate whether surfactant protein A or D is expressed in the porcine Eustachian tube originating from the upper airways. Both surfactant proteins A and D were present in the epithelial cells of the Eustachian tube, as shown by strong immunostaining. Using RT-PCR and Northern hybridization, these collectins were detected in the Eustachian tube. The present study is the first report demonstrating surfactant protein gene expression in the Eustachian tube. Surfactant proteins A and D may be important in the antibody-independent protection of the middle ear.

Cartilage matrix is an interacting multicomponent system of collagen fibrils, fibril-associated small proteoglycans, and large proteoglycans and glycoproteins entrapped within the fibrillar network. In order to better understand the relationships between these different components we have constructed short cDNA clones for detection of mRNAs for two major noncollagenous macromolecules of cartilage matrix, aggrecan and tenascin. We subsequently determined their corresponding mRNA levels by Northern analysis in a panel of total RNAs isolated from several newborn mouse tissues. The expression of aggrecan was strictly restricted to cartilages while tenascin mRNA was present at variable levels in most of the tissues studied. The cDNA clones were also used to identify the cells responsible for aggrecan and tenascin production in newborn mouse tissues by in situ hybridization. With this technique aggrecan mRNA was detected in chondrocytes throughout the developing skeleton in a pattern very similar but not identical to those of type II and IX collagen mRNAs. In the newborn mouse skeleton tenascin and aggrecan mRNAs were expressed essentially in a mutually exclusive manner, tenascin transcripts being present in osteoblasts, periosteal and perichondrial cells, and in cells at articular surfaces. None of these cells expressed the cartilage specific collagen or aggrecan genes. The results further suggest different patterns of gene expression in chondrocytes based on their location in the different cartilages.

The NFkB signaling pathway is a master regulator of the immune response. Recently, dominant mutations in NFKB2 have shown to cause antibody deficiency with adrenal insufficiency. We investigated two families with antibody deficiency and autoinflammatory features, with onset in teenage years and early adulthood (Fig. 1 and Table 1). In family 1, all patients available to study presented with respiratory tract infections and B cell dysfunction marked by hypogammaglobulinemia, poor antibody response to vaccines, or low switched memory B cell counts. Several experienced recurrent episodes of aphthous mucositis in upper gastrointestinal and genital area, sometimes accompanied by abdominal pain, monoarthritis, or fever with elevated inflammatory markers (peripheral blood leukocytes >10x106 cells/ml, C reactive protein >100 mg/L). A lesional biopsy revealed lymphocytic small cell vasculitis reminiscent of Behcet's disease. In family 2, all patients presented with respiratory tract infections, hypogammaglobulinemia, and poor vaccine responses. Based on the pedigrees, we assumed autosomal dominant inheritance. For family 1, we performed genotyping and linkage analysis coupled with whole genome sequencing to pinpoint the causative variant. Linkage analysis showed a 15.4 Mb haplotype on chr4 segregating with the phenotype in all affected individuals. When focusing our search on novel, heterozygous variants negatively affecting conserved residues, we identified only one variant in this genomic location, localizing to NFKB1 gene (p.H67R). In family 2, we exome sequenced one affected individual and filtered the data for novel heterozygous variants negatively affecting conserved residues. This resulted in 17 variants, out of which the I553M NFKB1 variant was considered the best candidate. Several functional analyses showed that the mutations had a negative impact on NFKB1 function. The H67R variant increased NFKB1 affinity to NEMO and delayed protein entry to nucleus, when assessed by affinity purification mass spectrometry and immunofluorescence microscopy. The mutation also decreased NFKB1 transcriptional activity, when expressed together with an NFkB-responsive luciferase reporter, and showed a neomorphic DNA binding pattern on chromatin immunoprecipitation-sequencing. Furthermore, the cell growth was hampered when the mutant NFKB1 was overexpressed in cultured HEK293 cells. The I553M showed a similar negative effect on cultured cell proliferation. Furthermore, the I553M variant negatively affected serine S907 and S893 phosphorylation, leading to defective posttranslational processing of the full-length NFKB1 upon TNF stimulation. To conclude, we show that hypogammaglobulinemia and Behcet's disease-like autoinflammatory syndrome can be caused by mutations in NFKB1. This suggests that a subset of Behcet's disease cases may be of monogenic origin, and highlights the role of NFkB complex in B cell maturation and innate immune regulation. Table 1. Patient characteristics Patient 1 2 3 4 5 6 7 8 9 10 11 12 Age 55 43# 25 29 40 30 37 7 10 60# 61 32 Sex F M F F F F M F M M F M Mutation status H67R ND H67R H67R H67R H67R H67R H67R H67R ND I553M I553M Immunodeficiency Infections URTI RTI URTI - URTI URTI URTI URTI - RTI RTI RTI Antibody deficiency Hypogammaglobulinemia, SAD ND Hypogammaglobulinemia, SAD - IgG subclass deficiency, SAD Hypogammaglobulinemia, SAD Hypogammaglobulinemia, SAD Hypogammaglobulinemia Hypogammaglobulinemia Hypogammaglobulinemia Hypogammaglobulinemia, SAD SAD Immunoglobulin replacement + - + - - + + - - - + - Immune dysregulation Febrile attacks - + + + - - + + - - - - Complex aphtae Mouth, genitalia ND Mouth, genitalia Mouth, genitalia - Mouth Esophagus Mouth, esophagus - - - - Arthritis Monoarthritis - Monoarthritis Monoarthritis - - - - - - Oligoarthritis - Gut disease Periodic abdominal pain, chronic idiopathic diarrhea ND Periodic abdominal pain, microscopic colitis Periodic abdominal pain - - - Periodic abdominal pain - ND Chronic idiopathic diarrhea Coeliac disease Other - Hyperinflammatory response and death after gallbladder surgery - Iritis, Hyperinflammatory response to tooth excision Kidney tumor - Rudimentary left kidney - - - Astma, hypothyreosis - URTI, upper respiratory tract infections; RTI, respiratory tract infections including recurrent pneumonia; SAD, Specific antibody deficiency; ND, No data; #Death age Figure 1. Family pedigrees. Figure 1. Family pedigrees. Disclosures Mustjoki: Sigrid Juselius Foundation: Research Funding; Signe and Ane Gyllenberg Foundation: Research Funding; the Finnish Cancer Societies: Research Funding; Novartis: Honoraria, Research Funding; Academy of Finland: Research Funding; Finnish Cancer Institute: Research Funding; Pfizer: Honoraria, Research Funding; Bristol-Myers Squibb: Honoraria, Research Funding. Saarela:Roche: Honoraria.

Genomic clones capable of complementing a previously isolated arginine auxotrophic mutant strain of the filamentous yeast Trichosporon cutaneum DSM 70698 have been identified by DNA-mediated transformation, and a complementing 4,082-bp subfragment was sequenced. This analysis revealed an intact gene (arg4) showing a high degree of homology with the Saccharomyces cerevisiae CPA2 gene encoding the large subunit of carbamoyl-phosphate synthetase (CPS-A). The inferred amino acid sequence of the T. cutaneum argA-encoded protein contains 1,168 residues showing 62% identity with the sequence of the S. cerevisiae CPA2 protein, and the comparison of the two sequences uncovered a putative intron sequence of 81 nucleotides close to the 5' end of the coding region of the T. cutaneum argA gene. The presence of this intron was confirmed by nuclease protection studies and by direct DNA sequence analysis of a cDNA fragment which had been obtained by PCR amplification. The T. cutaneum intron shares the general characteristics of introns found in yeasts and filamentous fungi. A major transcript of around 4 kb was found in Northern (RNA) blots. The T. cutaneum argA coding region was expressed in Escherichia coli under the control of the regulatable tac promoter. A roughly 130-kDa protein which was found to cross-react with an anti-rat CPS antibody in Western blots (immunoblots) was observed. Two putative ATP-binding domains were identified, one in the amino-terminal half of the argA-encoded protein and the other in the carboxy-terminal half. These domains are highly conserved among the known CPS-A sequences from S. cerevisiae, E. coli, and the rat. From these results we conclude that the T. cutaneum argA gene encodes the large subunit of CPS. This is the first gene to be identified and analyzed in the T. cutaneum DSM 70698 strain.

Toll-like receptors (TLR:) have recently been linked to the immunostimulatory function of microbial toxins in human and mice. TLR: signals activation of nuclear factor kappaB that leads to the production of a number of proinflammatory mediators. TLR:4 mediates the endotoxin-induced inflammatory response, whereas TLR:2 may be involved in the response to yeast and Gram-positive bacterial products. To better understand age-related changes in acute inflammatory response, we studied the ontogeny of TLR:2 and TLR:4 mRNA in murine fetal lung, liver, and placenta by quantitative reverse transcriptase-PCR. Different expression patterns were seen between the tissues and between the TLR: This is in accordance with the evidence that there are differences in the receptors for different microbial toxins and that the response is organ specific. We additionally show that the expression of TLR: was dependent on the stage of differentiation. In the liver, the levels of Tlr2 and Tlr4 were high regardless of the age. In the lung, Tlr2 and Tlr4 expression levels were barely detectable in immature fetus (d 14-15). Tlr2 and Tlr4 were increased several-fold during prenatal development and further increased after birth. The present results support the finding of a deficient inflammatory response of the immature lung to microbial toxins.

Puumala hantavirus (PUUV) causes a hemorrhagic fever with renal syndrome (HFRS) also called nephropathia epidemica (NE). Recent case reports and retrospective studies suggest that NE may damage the pituitary gland. Based on these observations, our goal was to explore the nature of this complication prospectively.A total of 58 hospitalized patients with acute NE volunteered to participate. Central nervous system (CNS) symptoms were recorded, cerebrospinal fluid (CSF) samples were collected, human leukocyte antigen (HLA) haplotype was analyzed, brain magnetic resonance imaging (MRI) was acquired, and electroencephalography (EEG) was recorded. Patients with abnormal pituitary MRI finding were examined by an endocrinologist.Most patients experienced CNS symptoms, and half of the CSF samples were positive for PUUV IgM, elevated protein level, or leukocyte count. CSF of patients negative for DR15(2)-DQ6 haplotype was less frequently affected. MRI revealed pituitary hemorrhage in two patients; these two patients suffered sudden loss of vision associated with headache, and they both developed hypopituitarism. Only one patient required long-term hormonal replacement therapy.CNS-related symptoms and inflammation in the CSF are common in acute NE. Genetic properties of the host may predispose to CNS involvement. It does seem that pituitary injury and subsequent hormonal insufficiency may complicate the recovery.

A transformation system for the filamentous yeast Trichosporon cutaneum based on auxotrophic markers is presented and techniques for the induction, isolation and characterization of mutants are described. A number of auxotrophic mutants were isolated and characterized by using biosynthetic precursors and/or inhibitors. A mutant unable to grow in the presence of ornithine could be complemented successfully by spheroplast transformation experiments using the cloned Aspergillus nidulans ornithine transcarbamoylase gene (argB gene) as selection marker with an efficiency of 5-100 transformants per microgram of DNA. In these transformants the heterologous argB gene was present in multiple tandem copies and the transforming DNA was found to remain stable after more than 50 generations in non-selective media. The same mutant could be complemented by a T. cutaneum cosmid gene library and a complementary cosmid was subsequently isolated from this library by a sib-selection strategy. This cosmid transformed T. cutaneum spheroblasts with an efficiency of 50-200 colonies per microgram of DNA. Southern blot analyses were consistent with the view that the transforming sequences became stably integrated into the host genome at the homologous site.

In the past few years, yeasts other than those belonging to the genus Saccharomyces have become increasingly important for industrial applications. Species such as Pichia pastoris, Hansenula polymorpha, Schizosaccharomyces pombe, Yarrowia lipolytica and Kluyveromyces lactis have been modified genetically and used for the production of heterologous proteins.

Interleukin-1 (IL-1) increases the expression of surfactant protein A (SP-A) in rabbit, lamb and human fetal lung. The upregulation disappears towards term. Among the transcription factors, IL-1 activates nuclear factor kappaB (NF-kappaB) and CCAAT/enhancer-binding protein delta (C/EBPdelta). NF-kappaB presumably has a role in IL-1-induced upregulation of SP-A. Also, C/EBPdelta may regulate SP-A expression. The aim was to study the role of these transcription factors in the induced effect of IL-1 on SP-A expression. Explants from fetal and neonatal rabbit lung were cultured in vitro followed by studies using immunohistochemistry, electrophoretic mobility shift assay and Northern analysis. We found gestation-dependent changes in IL-1-induced immunoreactivities of NF-kappaB and C/EBPdelta in the nuclei of alveolar cells. This increase in nuclear transcription factors correlated with IL-1-induced SP-A expression levels. As studied in the explants from fetal and newborn lung, the SP-A mRNA expression additionally associated with C/EBPdelta mRNA and with the binding of nuclear extracts from the lung explants to the C/EBP consensus probe. On the basis of the present and previous studies, we propose that NF-kappaB and C/EBPdelta have potential mediator roles in IL-1-induced upregulation of SP-A in immature lung.

Recent evidence suggests a role for phosphatidylinositol (PI) 3-kinase in various inflammatory responses. In this study, the consequences of LPS-induced PI 3-kinase activation on cytokine and chemokine expression and the intracellular mechanisms of inflammatory activation were examined in mouse macrophages. LPS stimulation induced a complex formation between PI 3-kinase and myeloid differentiation factor 88 (MyD88), which was followed by an induction of IL-1beta, tumor necrosis factor-alpha (TNF-alpha) and macrophage inflammatory protein (MIP)-2. The induction of IL-1beta, but not of MIP-2 or TNF-alpha, was blocked by the PI 3-kinase inhibitors LY294002 and wortmannin. The nuclear factor-kappaB (NF-kappaB) inhibitor pyrrolidinedithiocarbamate (PDTC) blocked the induction of IL-1beta and TNF-alpha, but had no effect on MIP-2 expression. Inhibition of PI 3-kinase decreased the LPS-induced transcriptional activity of NF-kappaB, but it had no effect on the nuclear DNA binding activity of NF-kappaB. These findings suggest that, while NF-kappaB nuclear localization and DNA binding are necessary, they are not sufficient for transcriptional activation of the IL-1beta gene in the absence of PI 3-kinase activity. Taken together, our results demonstrate that activation of Toll-like receptor (TLR)-4 results in PI 3-kinase-MyD88 complex formation, and that PI 3-kinase activity selectively leads to cytokine induction downstream of TLR4.

The main extracellular matrix components of the lung, type I and III collagens, were studied in chronic allograft rejection developing in a porcine heterotopic bronchial transplantation model. Specific porcine complementary DNA probes were constructed for detection of the expression of type I and III procollagen messenger RNAs in the bronchial wall structures and in the obliterative plug by in situ hybridization. In autografts, and in allografts immunosuppressed with 40-O-(2-hydroxyethyl)-rapamycin, cyclosporine A, and methylprednisolone, no histological changes of obliterative bronchiolitis (OB) developed, and the number of fibroblast-like cells expressing type I and III procollagen mRNA remained low. In nontreated allografts obliterating within 21 d, a preponderance of fibroblast-like cells showing positivity for type III procollagen mRNA existed in the obliterative plug and bronchial wall. This study shows for the first time the temporal and spatial activation of type I and III procollagen genes during the course of obliterative bronchiolitis. The number of cells expressing procollagen III mRNA increased parallel to developing obliteration and fibrosis in nontreated allografts, whereas autografts and immunosuppressed allografts exhibited no such trend. This finding suggests a positive association between type III collagen mRNA expression in fibroblast-like cells and development of obliterative bronchiolitis.

Proteolytic degradation of collagen-rich extracellular matrices is a key feature in the development, growth and aging of skeleton. Matrix metalloproteinases (MMPs) are a family of enzymes capable of performing this function, whereas tissue inhibitors of MMPs (TIMPs) are believed to play an important role in regulating their activity. To better understand the roles of TIMP-1, -2 and -3, we have studied their mRNA levels in several different mouse tissues with special emphasis on the skeleton and the developing eye. A systematic analysis of TIMP-1, -2 and -3 mRNA levels in mouse knee joints during growth and aging demonstrated markedly different expression patterns for each TIMP. Immunohistochemical analysis revealed several time-dependent changes in the distribution of TIMP-1 and -2 in articular and growth cartilages, synovial tissue and bone. The data suggest that upon aging synovial tissue becomes the major source of synovial fluid TIMPs. In articular cartilage these inhibitors were mainly found in the deep layer and in subchondral bone. Compared with epiphyseal growth plate, the amounts of TIMP-1 and -2 in articular cartilage were quite low. These findings suggest that the capacity of articular cartilage chondrocytes to inhibit MMP activities by local production of TIMPs is limited, which may be of consequence during osteoarthritic cartilage degeneration.

Intra-amniotic interleukin (IL)-1 increases surfactant components in immature fetal lung, whereas high IL-1 after birth is associated with surfactant dysfunction. Our aim was to investigate whether the fetal age influences the responsiveness of surfactant proteins (SPs) to IL-1. Rabbit lung explants from fetuses at 19, 22, 27, and 30 d of gestation and 1-d-old newborns were cultured in serum-free medium in the presence of recombinant human (rh) IL-1alpha or vehicle. The influence of IL-1alpha on SP-A, -B, and -C messenger RNA (mRNA) content was dependent on the conceptional age. In very immature lung on Day 19, rhIL-1alpha (570 ng/ml for 20 h) increased SP-A, -B, and -C mRNA by 860+/-15%, 314+/-108%, and 64+/-17%, respectively. The increase in SP-A mRNA was evident within 4 to 6 h. IL-1alpha increased the SP-A concentration in alveolar epithelial cells and in the culture medium within 20 h. In contrast, at 27 to 30 d of gestation and in newborns, IL-1alpha decreased SP-C, -B, and -A mRNA by means of 64 to 67%, 48 to 59%, and 12 to 15%, respectively. SP-B protein decreased by 45 to 60%. The decrease in mRNA became evident within 8 to 12 h and was dependent on IL-1 concentration. On Day 27, IL-1alpha accelerated the degradation of SP-B mRNA in the presence of actinomycin D. IL-1 did not increase the degradation rate of SP-A mRNA unless both actinomycin D and cycloheximide were added to the explants. The present findings may explain some of the contrasting associations between inflammatory cytokines and lung diseases during the perinatal period. The determinants of the direction of the IL-1 effect on the expression of SPs remain to be identified.

Cysteine proteinases, cathepsins B, H, K, L and S, have been implicated in several proteolytic processes during development, growth, remodeling and aging, as well as in a variety of pathological processes. For systematic analysis of cathepsin gene expression we have produced cDNA clones for mouse and human cysteine cathepsins. Northern analysis of a panel of total RNAs isolated from 16–19 different human and mouse tissues revealed the presence of mRNAs for cathepsin B, H, K, L and S in most tissues, but each with a distinct profile. Of the different cathepsin mRNAs, those for cathepsin K were clearly the highest in bone and cartilage. However, relatively high mRNA levels for the other cathepsins were also present in these tissues. To better understand the roles of different cathepsins during endochondral ossification in mouse long bones, cathepsin mRNAs were localized by in situ hybridization. Cathepsin K mRNAs were predominantly seen in multinucleated chondroclastic and osteoclastic cells at the osteochondral junction and on the surface of bone spicules. The other cathepsin mRNAs were also seen in osteoclasts, and in hypertrophic and proliferating chondrocytes. These observations were confirmed by immunohistochemistry and suggest that all cysteine cathepsins are involved in matrix degradation during endochondral ossification.

The genus Trichosporon includes yeasts which are characterized by budding cells of various shapes, a more or less developed pseudomycelium or a true mycelium and arthrospores. Trichosporon yeasts may form asexual endospores but sexual reproduction has not been demonstrated so far (Do Carmo-Sousa, 1970). Biochemical characteristics such as hydrolysis of urea, utilization of mono-, di-, tri-, or polysaccharides etc., as well as studies concerning DNA base composition and DNA relatedness led Gueho et al. (1984) to propose that Trichosporon yeasts should be classified into two separate groups. The first group, which appears to be related to the Ascomycetes, includes thirteen species with a G+C content lower than 50% (34.7%–48.8%) and lacks urease. The second group appears to be related to the Basidiomycetes and contains fifteen species with a G+C content higher than 50% (57%–64%) including T. cutaneum, T. beigelii and T. pullulans, and has the ability to hydrolyze urea. The basidiomycetous nature of some of the Trichosporon yeasts is demonstrated by the lamellar structure of the cell walls (Kreger-Van Rij and Veenhuis, 1971) and the presence of xylose (Weijman, 1979). Hara et al. (1989) have grouped 44 different strains of T. beigelii and related organisms based on differences in the ubiquinones and assimilation of melibiose and raffinose. The findings suggest that T. beigelii is a heterogeneous group of yeasts consisting of at least four different types of organisms.

Expression of surfactant proteins. Interaction between interleukin-1 (IL-1) and dexamethasone (Dx)

Endotoxin-induced changes in expression of surfactant proteins are dependent on the degree of lung maturity

Effects of IL-1 on the expression of surfactant proteins are dependent on degree of maturity

An efficient transformation system for the filamentous yeast, Trichosporon cutaneum , has been developed. Transformation was obtained with plasmids carrying either the Escherichia coli hygromycin B phosphotransferase-encoding gene ( hph ) or the Streptoalloteichus hindustanus phleomycin-resistance gene ( ble ), as dominant selection markers. Expression of both resistance-conferring genes was controlled by the gpd promoter and the trpC terminator, from Aspergillus nidulans . The transformation frequency was up to 500 colonies/μg of transforming DNA, using the ble gene, and up to 100 colonies/μg of transforming DNA, using the hph gene. Co-transformation frequencies using unselected DNA varied between 50 and 65%. The transforming DNA was found to consist of multiple tandem plasmid copies of high M r . This polymeric structure, in nonselective media, was mitotically unstable, possibly indicating that it existed in an episomal state.

Two fusions of the Bacillus stearothermophilus α-amylase gene (amyS) with lacpoZ′ were constructed. The first, being a transcriptional fusion, placed amyS directly under lac promoter control eliminating interference by the endogenous promoter. IPTG induction of amyS transcription in this construction resulted in liberation of periplasmic proteins and eventually cell lysis. The other fusion replaced eight N-terminal amino acid residues from the signal sequence by 11 residues from the lacZ′ moiety in pUC-18. Translation initiation signals were also replaced by those from lacpoZ′. In this case IPTG induction resulted in secretion of approx. 35% of total α-amylase activity in the growth medium after 24 h growth without detectable cell lysis.

Phosphatidylcholine (PC) is the main phospholipid in lung surfactant and, more specifically, dipalmitoyl PC (PC16:0/16:0) is the major surface-active component. Several studies have tentatively shown that eustachian tube lavage fluid (ETLF) contains surface-active material. The aim of the present study was to determine, using electrospray ionization mass spectrometry, whether the phospholipid molecular species composition of ETLF is similar to that of lung surfactant. PC was the main component of both ETLF and bronchoalveolar lavage fluid (BALF). The concentration of phosphatidylethanolamine was higher and phosphatidylglycerol was undetectable in ETLF compared with BALF. The molecular species composition of PC in ETLF was notably different from that of BALF, palmitoyloleoyl PC being the major component. Importantly, given its predominance in BALF PC, the concentration of PC16:0/16:0 was low in ETLF. As expected on the basis of this molecular species composition of PC, ETLF did not generate low surface tension values under dynamic compression in a pulsating bubble surfactometer. We conclude that the surfactant in ET is different from lung surfactant, and that low surface tension is not a major determinant of ETLF function. —Paananen, R., A. D. Postle, G. Clark, V. Glumoff, and M. Hallman. Eustachian tube surfactant is different from alveolar surfactant: determination of phospholipid composition of porcine eustachian tube lavage fluid. J. Lipid Res. 2002. 43: 99–106.

Intra-amniotic lipopolysaccharide (LPS) and cytokines may decrease respiratory distress syndrome (RDS) and increase chronic lung disease in the newborn. The aim was to identify the primary inflammatory mediators regulating the expression of surfactant proteins (SP) in explants from immature (22-day-old fetus) and mature (30-day term fetus and 2-day-old newborn) rabbits. In immature lung, interleukin (IL)-1alpha and IL-1beta upregulated the expression of SP-A and SP-B. These effects of IL-1 were diminished, and SP-C mRNA was suppressed additively in the presence of tumor necrosis factor (TNF)-alpha and either LPS or interferon (IFN)-gamma. LPS, TNF-alpha, or IFN-gamma had no effect alone. In explants from the term fetus and the newborn, LPS, IL-1alpha, and TNF-alpha additively suppressed the SPs. LPS acutely induced IL-1alpha in alveolar macrophages in mature lung but not in the immature lung. IFN-gamma that generally has low expression in intrauterine infection decreased the age dependence of the other agonists' effects on SPs. The present study serves to explain the variation of the pulmonary outcome after an inflammatory insult. We propose that IL-1 from extrapulmonary sources induces the SPs in premature lung and is responsible for the decreased risk of RDS in intra-amniotic infection.