Association of lpr gene with graft-vs.-host disease-like syndrome.

Hemopoietic cells have been reciprocally transferred between two lines of mice (MRL lpr/lpr and MRL +/+) that are congenic, differing only at the lpr (lymphoproliferation) and possibly closely linked genes. The lpr strain develops a significantly more severe and fast-paced lupus-like syndrome than +/+ strain, along with a substantially larger lymphoid mass. The results showed that: (a) hemopoietic cells of such mice were sufficient to induce the respective disease phenotypes in lethally irradiated syngeneic recipients; (b) cells of MRL +/+ mice maturing in an MRL lpr/lpr environment essentially retained the disease-producing characteristics of the donor, i.e., they induced late-life lupus without lymphadenopathy; but (c) MRL lpr/lpr cells transferred into irradiated MRL +/+ recipients unexpectedly failed to induce the early-life severe lupus and lymphoid hyperplasia of the donor, instead they caused a severe wasting syndrome resembling, in many respects, graft-vs.-host disease (GVHD). This GVHD-like syndrome developed after transfer of MRL lpr/lpr fetal liver, bone marrow, or spleen cells, and was not abrogated by elimination of T cells from the inocula. Thymectomy of the MRL +/+ recipients retarded, but did not prevent, the wasting disease. The unidirectional nature of this disease suggests that the lpr mutation conferred either a structural or regulatory defect that interfered, blocked, or altered the expression or structure of certain lymphocyte antigen(s). As a result, the MRL +/+ cells that did express this antigen(s) were recognized as foreign, and stimulated a graft-vs.-host reaction. These findings may allow definition of a new kind of rejection phenomenon caused by non-H-2 products, and may extend our understanding of the means by which the lpr gene adversely affects lymphocyte regulation and homeostasis.

Breast cancer growth is inhibited by vasoactive intestinal peptide (VIP) hybrid, a synthetic VIP receptor antagonist.

Breast cancer vasoactive intestinal peptide (VIP) receptors were characterized. Using in vitro autoradiographic techniques, 125I-labeled VIP bound with high affinity to breast biopsy sections. 125I-labeled VIP bound specifically to give breast cancer cell lines examined using receptor-binding techniques. Specific 125I-labeled VIP binding to MDA-MB-231 cells was inhibited with high affinity by VIP and pituitary adenylate cyclase-activating polypeptide (IC50, = 2 nM) and with moderate affinity by the VIP hybrid (IC50 = 0.5 microM). VIP elevated the cAMP in a dose-dependent manner, and VIP hybrid (10 microM) inhibited the increase in cAMP caused by VIP. Using Northern blot analysis, VIP (10 nM) stimulated c-fos and c-myc mRNA, and the increase caused by VIP was reversed by the VIP hybrid. The VIP hybrid inhibited breast cancer growth in vitro and in vivo using nude mice bearing breast cancer xenografts. These data suggest that the VIP hybrid is a breast cancer VIP receptor antagonist.

The absence of cryptic insulin receptors on resting lymphocytes.

Previous experiments have demonstrated that insulin receptors emerge upon stimulated lymphocytes while resting lymphocytes lack insulin receptors. The appearance of insulin receptors is totally dependent on RNA and protein synthesis. The results suggest that insulin receptors are synthesized de novo or that new protein is synthesized that is responsible for activation of the receptor. In this study, we investigated the possibility that cryptic membrane receptors are present before lymphocyte activation. As a precedent, hypertonic salt solutions or enzymatic digestion have been reported to uncover cryptic insulin receptors in liver and fat cell membranes. Similar treatment of lymphocytes failed to reveal cryptic, stereospecific receptor sites, although nonspecific insulin binding did increase.

Heterogeneity of childhood acute lymphoblastic leukemia (ALL): monoclonal antibodies phenotyping and induction of differentiation in vitro.

Fifty-eight pediatric patients with non-T acute lymphoblastic leukemia (ALL) were diagnosed and evaluated at the Sambur Center of Pediatric Hematology Oncology. At least six subtypes of non-T ALLs were identified, corresponding to the various stages of B-cell differentiation, by utilizing an extensive panel of monoclonal antibodies directed against T- B- and myeloid-cell differentiation antigens. Moreover, leukemic cells expressing the phenotype of early B cells could be driven to differentiate along the B- cell lineage to express CALLA and BL antigens and cytoplasmic and/or surface immunoglobulins (IgM). A unique phenotype of non-T ALL was also identified. These leukemic cells expressed B cell antigen exclusively, i.e., HLA/DR and B4 (CD19). Myeloid-cell antigens, however, were expressed on these cells spontaneously after a 24-hour incubation in culture medium in vitro. In addition, leukemic cells of four patients with a phenotype of HLA/DR, CD19, and CD10 expressed antigens of the T-cell lineage: CD7 (3AI) and CD2 (leu 5), and/or of the myeloid cell lineage (My7). These results provide confirming evidence for the wide scope of the heterogeneity of ALL. It stresses the validity of accurate classification of leukemia to identify biologically and clinically unique subtypes of ALL, which bears specific prognostic parameters; and designates therapeutic protocols.

Production and secretion of high levels of recombinant human acetylcholinesterase in cultured cell lines: microheterogeneity of the catalytic subunit.

To allow for structural analysis of the human acetylcholinesterase (hAChE) subunit, a series of eukaryotic vectors was designed for efficient expression. Several eukaryotic multicistronic expression vectors were tested in various mammalian cell lines. All expression vectors contained the selectable neo gene under control of a weak promoter, while the hAChE cDNA was under control of the cytomegalovirus (CMV) immediate-early or Rous sarcoma virus long terminal repeat (RSV LTR) or simian virus 40 (SV40) early promoters. Optimal production and secretion of recombinant hAChE (rehAChE) was achieved in the embryonal kidney 293 cell line transfected either with the RSV-hAChE or with CMV-hAChE expression vectors. Clones expressing and secreting as much as 5-25 pg of enzyme per cell per 24 h were obtained without resorting to coamplification techniques or continuous maintenance of cells under selective pressure. The purified (specific activity of 6000 units per mg protein) homodimer and tetramer enzyme molecules displayed typical AChE biochemical properties: a Km value of 120 microM for acetylthiocholine; a kcat value of 3.9 x 10(5)/min, and selective by AChE-specific inhibitors. Catalytic subunit dimers (130 kDa) exhibit differential N-glycosylation patterns, and upon reduction resolve into 67- and 70-kDa monomeric subunits. These two forms appear as a single discrete 62-kDa band following deglycosylation by N-glycanase. The N-terminal amino acid sequence analysis of the purified mature enzyme suggests the existence of two alternative cleavage sites for the removal of the signal peptide, in which the 'mature' position 1 is either Ala31 or Gly33. Both of these positions conform with the consensus signal peptide recognition sequences and demonstrate bidirected processing of signal peptides on a native molecule.

Selective decline in differentiating capacity of immunohemopoietic stem cells with aging.

Bone marrow (BM) from young (3 months) and old (24 months) C57BL/6J mice were tested for the total number of colony forming units, which remain unchanged with age. The BM from both groups was used to reconstitute syngeneic, lethally irradiated mice that were 3 months' old. The reconstituted mice were followed for a period of 12 months for their ability to generate cell-mediated responses in mixed lymphocytic cultures and cultures containing the T mitogens--concanavalin A and phytohemagglutinin. For the first 8 months, mice given BM from young or old mice responded to a similar degree. Later, cellular immune responses of the mice reconstituted with BM from old mice declined markedly compared to those reconstituted with BM from young mice, although there was no detectable difference between the two groups in the hematopoietic compartment.

A vasoactive intestinal peptide antagonist inhibits the growth of glioblastoma cells.

The effects of a vasoactive intestinal peptide (VIP) receptor antagonist (VIPhyb) on human glioblastoma cells were characterized. Pituitary adenylate cyclase activating polypeptide (125I-PACAP-27) bound with high affinity to U87, U118, and U373 cells. Specific 125I-PACAP-27 binding to U87 cells was inhibited, with high affinity, by PACAP but not VIP or VIPhyb (IC50 = 10, 1500, and 500 nM, respectively). By reverse transcriptase-polymerase chain reaction (RT-PCR), a major 305 bp band was observed indicative of PAC1 receptors. PACAP-27 caused cAMP elevation and the increase in cAMP caused by PACAP-27, was inhibited by the VIPhyb. Also, PACAP-27 caused cytosolic Ca2+ elevation in Fura-2AM loaded U87 cells and the VIPhyb inhibited this increase. Using the MTT growth assay, the VIPhyb was shown to inhibit glioblastoma growth in a concentration-dependent manner. Using a clonogenic assay in vitro, 10 microM VIPhyb significantly inhibited proliferation of U87, U118, and U373 cells. In vivo, 0.4 microg/kg VIPhyb inhibited U87 xenograft proliferation in nude mice. These results suggest that the VIPhyb antagonizes PAC1 receptors on glioblastoma cells and inhibits their proliferation.

Long-term culture of infant leukemia cells: dependence upon stromal cells from the bone marrow and bilineage differentiation.

Infant leukemia cells with 46XY,t(11; 17)(q23; p13) karyotype and a hybrid pre B myeloid phenotype (HLA-DR, (Ia), B4 and My7-positive and CALLA and T11-negative) and immunoglobulin heavy chain gene rearrangement were maintained in long-term culture for over 10 months. The in-vitro survival and growth of the leukemia cells were strictly dependent upon the presence of their autologous marrow stromal cells. The latter could be replaced by the 14F1.1 clone of preadipocytes derived from mouse bone marrow. Neither heterologous human marrow or foreskin fibroblasts nor fibroblast or endothelial like cell lines from mouse stroma could mimic the effect of autologous stroma or 14F1.1 adipocytes. The leukemia cells maintained their original phenotype throughout the 10-month culture period with either their autologous stroma or the 14F1.1 adipocytes. They could be induced to differentiate in two distinct directions. Phorbol myristate acetate induced adherence of the leukemia cells and development of macrophage properties. In contrast, conditioned medium from a hybridoma producing B-cell growth factor caused aggregation of the leukemia cells and expression of CALLA antigen and surface IgM. This bipotency of the leukemia cells and their dependence upon marrow stroma are properties in common with stem cells.

VPAC1 receptors and lung cancer.

VIP/PACAP are autocrine growth factors for lung cancer. VIP and/or PACAP mRNA is present in most lung cancer cell lines examined. Although mRNA for VPAC2-R is not common, VPAC1-R and PAC1-R mRNA is present in many lung cancer cell lines. 125I-VIP binds with high affinity to lung cancer cells and specific 125I-VIP binding is inhibited with high affinity by (Lys15, Arg16, Leu27)VIP1-7 GRF8-27, the VPAC1-R specific agonist, but not by Ro25-1553(18), the VPAC2-R specific agonist. VIP elevates cAMP and increases c-fos gene expression. The increase in cAMP and c-fos mRNA caused by VIP is inhibited by SN(VH). (SH)VH inhibited the proliferation of NCIH1299 cells in the MTT assay, which is based on cytotoxicity. In a recent cell line screen, (SN)VH inhibited the growth of 51 of 56 cancer cell lines including leukemia, lung cancer, colon cancer, CNS cancer, melanoma, ovarian cancer, renal cancer, breast cancer, and prostate cancer (T. Moody, unpublished). It remains to be determined if (SN)VH will be useful for treatment of a wide variety of cancers.

BW 1023U90: a new GRP receptor antagonist for small-cell lung cancer cells.

Gastrin-releasing peptide (GRP) receptor antagonists were synthesized and their ability to interact with small-cell lung cancer (SCLC) cells determined. [125I] BW1023U90, bound with high affinity (Kd = 2 nM) to a single class of sites (Bmax = 55 fmol/mg protein) using SCLC cell line NCI-H345. [125I] BW1023U90 binding was time dependent and reversible even at 37 degrees C as the ligand was minimally internalized. Specific [125I] BW1023U90 binding was inhibited with high affinity by GRP as well as bombesin (BB) but not neuromedin B (NMB). BW1023U90 inhibited the ability of BB to elevate cytosolic Ca2+ and increase the growth of SCLC cells. A BW1023U90 analogue, BW2258U89 (10 micrograms/day, SC) slowed SCLC xenograft format on in nude mice and [125I] BW 1023U90 localized to SCLC tumors 1 h after injection into nude mice. BW2258U89 (4% by weight) was placed in microspheres and slowly released over a 3-week period in nude mice bearing SCLC xenografts. The microspheres containing BW2258U89 strongly inhibited SCLC growth in vivo. A radioimmunoassay was developed for the GRP receptor antagonists and the rabbit antiserum cross-reacted totally with BW2258U89 or BW1023U90. BW2258U89 immunoreactivity (5 nM) was detected in the plasma of nude mice containing the microspheres after 1 week. These data suggest that GRP receptor antagonists bind to receptors on SCLC tumors.

A VIP antagonist distinguishes VIP receptors on spinal cord cells and lymphocytes.

Vasoactive intestinal peptide (VIP) is a neuropeptide which also interacts with cells of the immune system. The paucity of specific VIP receptor antagonists has hampered studies of possible receptor heterogeneity and of VIP function. To aid in achieving these goals, a new VIP antagonist, a hybrid between neurotensin and VIP, has been synthesized. This peptide interacted with VIP receptors on spinal cord cells with an affinity 10-fold greater than VIP itself. In contrast, 1000-fold higher concentrations of the antagonist were required to displace labeled VIP from its receptor on lymphoid cells as compared to VIP itself, suggesting VIP receptor heterogeneity between immune and spinal cord cells.

Conditioned media from activated lymphocytes maintain sympathetic neurons in culture.

Nerve growth factor (NGF) is vital for the development and maintenance of sympathetic neurons. In the present report, we demonstrate that NGF maintenance activity can be substituted by lymphoid cells. Indeed, coculturing lymphoid cells with sympathetic neurons in the absence of exogenous NGF resulted in neuronal survival, as measured by morphological and biochemical criteria. In addition, conditioned media from concanavalin A-activated lymphoid cells could replace NGF. The lymphoid secreted factor differs from NGF in its inability to induce neuronal differentiation, and in its lack of cross-reactivity with NGF in radioimmunoassays. We thus discovered a potential novel source for a factor essential for neuronal survival.

Sodium dodecylsulphate induces a breach in the blood-brain barrier and enables a West Nile virus variant to penetrate into mouse brain.

A novel and convenient assay was used to determine the effect of recombinant Interleukin-2 (IL-2) on the function of the blood-brain barrier (BBB). The assay is based on a variant of the West Nile virus, WN-25, which had lost its neuroinvasiveness but not its neurovirulence. WN-25, when injected intravenously, can cause the death of mice only if the function of the BBB is impaired. Sodium dodecylsulphate (SDS), a component in IL-2 excipient, was found to cause a short term breach in the BBB, enabling the penetration of viruses into the brain. Minimal amounts (30 ng/mouse) can induce a breach of about 10 min, which allows 0.1% of the injected virus to enter the brain. These findings demonstrate the possible use of SDS as a mean for intentional introduction of drugs into the brain, however they also call attention to the danger of using detergents as additives for drugs given intravenously.

Antiserum to activity-dependent neurotrophic factor produces neuronal cell death in CNS cultures: immunological and biological specificity.

Activity-dependent neurotrophic factor (ADNF) is a glia-derived protein that is neuroprotective at femtomolar concentrations. ADNF is released from astroglia after treatment with 0.1 nM vasoactive intestinal peptide (VIP). To further assess the biological role of ADNF, antiserum was produced following sequential injections of purified ADNF into mice. Anti-ADNF ascites fluid (1:10,000) decreased neuronal survival by 45-55% in comparison to untreated cultures or those treated with control ascites. The neuronal death after anti-ADNF treatment was observed in cultures derived from the spinal cord, hippocampus or cerebral cortex at similar IC50's. Using a terminal deoxynucleotidyl transferase in situ assay to estimate apoptosis in cerebral cortical cultures, anti-ADNF was shown to produce a 70% increase in the number of labeled cells in comparison to controls. In spinal cord cultures, anti-ADNF treatment produced a 20% decrease in choline acetyltransferase activity in comparison to controls. Neuronal cell death produced by the antiserum to ADNF was prevented in cultures co-treated with purified ADNF or ADNF-15, an active peptide derived from the parent ADNF. In vitro binding between the anti-ADNF and ADNF-15 was demonstrated with size exclusion chromatography. Comparative studies with other growth factors (insulin-like growth factor-1, platelet-derived growth factor, nerve growth factor, epidermal growth factor, ciliary neurotrophic growth factor, and neurotrophin-3) demonstrated that only ADNF prevented neuronal cell death associated with electrical blockade. These investigations indicated that an ADNF-like substance was present in cultures derived from multiple locations in the central nervous system and that ADNF-15 exhibited both neuroprotection and immunogenicity. ADNF appears to be both a regulator of activity-dependent neuronal survival and a neuroprotectant.

Activity-dependent neurotrophic factor: a potent regulator of embryonic growth and development.

Activity-dependent neurotrophic factor is a potent, neuroprotective molecule released from astroglia following stimulation by vasoactive intestinal peptide and, at least in part, accounts for the neuroprotective actions of vasoactive intestinal peptide. As well as enhancing neuronal survival, vasoactive intestinal peptide is known to regulate embryonic growth during the early postimplantation period of development. The current study was designed to assess activity-dependent neurotrophic factor's role in the growth-regulatory properties of vasoactive intestinal peptide. Treatment of whole cultured day-9 mouse embryos with activity-dependent neurotrophic factor (10(-13) M) resulted in a growth of 3.1 somites, compared with 1.6 somites in control embryos after a 4 h incubation period. Significant increases were also seen in cross-sectional area, protein and DNA content and bromodeoxyuridine incorporation. Activity-dependent neurotrophic factor-treated embryos were morphologically indistinguishable from control embryos of the same size. Anti-activity-dependent neurotrophic factor ascites significantly inhibited growth. In addition, co-treatment of embryos with anti-activity-dependent neurotrophic factor ascites inhibited vasoactive intestinal peptide-stimulated growth. Although anti-vasoactive intestinal peptide treatment inhibited growth, it did not inhibit activity-dependent neurotrophic factor-induced growth. These data indicate that an activity-dependent neurotrophic factor-like substance is an endogenous and potent growth-promoting factor in the early postimplantation embryo and that vasoactive intestinal peptide-regulated growth of embryos occurs, at least in part, through the action of activity-dependent neurotrophic factor.

Protection by extracellular glutathione against sulfur mustard induced toxicity in vitro.

1. The present study characterizes the role of extracellularly added glutathione in protection against sulfur mustard (HD) toxicity in a macrophage monocyte cell line J774. 2. Toxic effects of HD depend on dose and duration of exposure with an ED50 of 50 and 75 microM for dividing and confluent cells respectively. 3. Exposure to HD, 100-200 microM caused approximately 15% decrease in the cellular glutathione (GSH) content 2 h after exposure, pretreatment with GSH, 0.2-10 mM, elevated cellular GSH approximately x 1.5. 4. GSH pretreatment increased cell viability after HD 2-3-fold. Similar protective effects of GSH treatment were found in a human epidermoid carcinoma cell line (KB). 5. Protection by post treatment with GSH was apparent even 60 min post HD exposure. 6. No protection was afforded when the intracellular GSH concentration was elevated prior to exposure and the extracellular GSH had been washed out. However, GSH depleted cells were more sensitive to HD than normal cells, and were also protected by addition of GSH to the growth medium, although the intracellular GSH content remained low. 7. We conclude that it is essential for the GSH to be present extracellularly in order to protect cells from HD toxicity. 8. Our findings have therapeutic implications in particular for the protection of lungs after inhalation exposure to HD vapor.

Syngeneic GvH induced in popliteal lymph nodes by spleen cells of old C57BL/6 mice.

The frequency of autoimmune processes seems to increase with age. We have studied here whether lymphoid cells of aged mice have the potential to express autoreactivity by the use of the in vivo graft-vs-host (GvH) assay. It was found that spleen cells from old (104 weeks) C57BL mice caused significant enlargement of the popliteal lymph node upon injection into the footpads of syngeneic young or old recipients. Histologically this enlargement presented characteristics of a GvH reaction. This effect, which was not abolished by irradiation of the hosts, was totally cancelled by in vitro irradiation or by anti-theta treatment of the donor cells. These results indicate that T cells from aged mice have the potential to manifest autoimmune reactivity.

Human cell lines secreting lymphokines. I. Establishment of T-T hybridomas.

Lymphokines (Lks) are conventionally produced by mitogen stimulation of T lymphocytes. However, this procedure results in a mixture of factors, some of which may have antagonistic effects. An alternative method of producing Lks is the construction of monoclonal T-T hybridomas which secrete distinct Lks. By adapting the hybridoma technology for T cells, one can select distinct T hybridomas which may serve as constant sources for the production of uniform and well defined Lks. Since the compatibility of a certain cell line to serve as a fusion partner is unpredictable, several lines were tried in the hybridization procedure. An obligatory requirement of such a mutant line is its sensitivity to a selective medium, in which only the hybrid cell would survive. For this purpose three 8-azaguanine (8AG) resistant mutant lines (Jurkat/12 CEM/14 and Molt-4/10) were established from the respective T leukemic cell lines. This was achieved by culturing the cells in the presence of 200 microM 8AG. The surviving resistant cells were sensitive to aminopterin and azaserine inhibitors. Depending on the cell line and the inhibitor, death of these mutants was complete in 7 to 14 days. Non-adherent peripheral blood lymphocytes (PBL) stimulated for 48 hours with 1 microgram/ml phytohemagglutinin (PHA), were fused with the CEM/14 line. Fifteen hybridomas secreted a substance with B cell growth factor (BCGF) activity, nineteen hybridomas secreted T cell growth factor (IL-2), and eight hybridomas secreted gamma-interferon (gamma-IFN). The six lines which exhibited BCGF activity only, were expanded and cloned. The BCGF activity in the supernatant of a positive clone, designated TH-5, was found to be 3-fold more potent than a preparation of BCGF obtained by stimulation of PBL with PHA.

Insulin-like growth factor receptors and their ligands in gonads of a hermaphroditic species, the gilthead seabream (Sparus aurata): expression and cellular localization.

Expression of insulin-like growth factor (IGF)-I, IGF-II, and IGF type I receptor (IGF-1R) genes was studied in gonads at different developmental stages of the protandrous hermaphroditic species the gilthead seabream (Sparus aurata) by reverse transcription-polymerase chain reaction and Northern blot analysis. Both IGF-I and IGF-II mRNA levels were highest in bisexual gonads and decreased during gonadal development. Regardless of the stage of gametogenesis, IGF-II mRNA levels exceeded those of IGF-I. Transcripts for IGF-1R RNA were detected in gonads at all stages studied. A major transcript of 11 kb was found in gonads and in gill arch and brain, but it was not found in liver and muscle. Distribution of the two types of IGF-1R and IGF-I in gonads was studied by immunohistochemistry. Immunoreactive IGF-I was found in the granulosa and theca cells of follicles at different vitellogenic stages and in oocytes at the chromatin-nucleolus and perinucleolus stage. In the testis, immunoreactive IGF-I was found in somatic cells of the cyst wall, interstitial cells, and spermatogonia A. In addition, IGF-1R was detected in the membrane of previtellogenic oocytes and in the theca and granulosa cells of vitellogenic and late vitellogenic follicles. In the testis, a positive reaction was identified in spermatogonia A and spermatids for the germ cells and in somatic cells of the cyst walls and interstitial cells. Local expression and production of IGFs and their receptors in fish gonads support a role for the IGF system in fish gonadal physiology.

Sulfur mustard toxicity in macrophages: effect of dexamethasone.

Cells from the murine macrophage-like cell line J774A.1 (J774) and cultures of primary alveolar macrophages (PAM) obtained from guinea pigs were exposed to sulfur mustard (HD, 50-200 microM) and treated with dexamethasone (2.5 microM) 10 min after HD exposure. Cell cultures were studied at 3 and 24 h after exposure by the cleavage of Thiazolyl blue reaction (MTT) reaction and crystal violet staining (viability assays), by morphological observation and by [3H]thymidine incorporation. Exposure of J774 cells to HD caused a dose-dependent decrease in viability that was evident at 24 h. Although no significant change in viability was observed at 3-4 h after HD exposure, a dose-dependent decrease in [3H]thymidine incorporation was observed. Treatment with dexamethasone caused a dose-dependent decrease in viability. However, the combined exposure to HD and dexamethasone had a synergistic effect on the decrease of cell viability. This synergistic effect is not due to a change in DNA synthesis rate because [3H]thymidine incorporation was not affected by dexamethasone. In PAM cultures, HD caused some 'activating' effect on [3H]thymidine incorporation and an increase in cell number at the lower dose (100 microM) but this was less at 200 microM. Both effects were reduced by dexamethasone treatment. We conclude that macrophages derived from different sources exhibit a different responsiveness to immunomodulators (HD and dexamethasone) and that dexamethasone can reduce the 'inflammatory' effect of HD in PAM.