[A case of exogenous lipoid pneumonia with marked elevation of serum KL-6 and interstitial lung shadows due to aspiration of liquid paraffin]

A 64-year-old man who ingested liquid paraffin as a laxative for over two years, was admitted to our hospital with a persistent interstitial lung shadow and marked elevation of serum KL-6. He had no overt symptoms although his chest radiograph revealed ground glass opacities in the left lower lung field and right middle and lower lung fields. We performed fiberoptic bronchoscopy. Exogenous lipoid pneumonia was diagnosed based on microscopic analysis of the bronchoalveolar lavage fluid that revealed the presence of lipid-laden alveolar macrophages. We instructed the patient to discontinue liquid paraffin ingestion and observed his clinical course. The chest radiograph and thoracic computed tomography revealed a tendency to improve and serum KL-6 decreased with time. Serum KL-6 may be an important index of the severity of exogenous lipoid pneumonia.

Cutting edge: a potent adjuvant effect of ligand to receptor activator of NF-kappa B gene for inducing antigen-specific CD8+ T cell response by DNA and viral vector vaccination

The ligand to receptor activator of NF-kappaB (RANK-L)/RANK interaction has been implicated in CD40 ligand/CD40-independent T cell priming by dendritic cells. In this report, we show that the coadministration of the RANK-L gene with a Trypanosoma cruzi gene markedly enhances the induction of Trypanosoma Ag-specific CD8(+) T cells and improves the DNA vaccine efficacy. A similarly potent adjuvant effect of the RANK-L gene on the induction of Ag-specific CD8(+) T cells was also observed when recombinant influenza virus expressing murine malaria Ag was used as an immunogen. In contrast, the coadministration of the CD40L gene was not effective in these systems. Our results demonstrated, for the first time, the potent immunostimulatory effect of the RANK-L gene to improve the CD8(+) T cell-mediated immunity against infectious agents.

Critical contribution of CD28-CD80/CD86 costimulatory pathway to protection from Trypanosoma cruzi infection

The CD28-CD80/CD86-mediated T-cell costimulatory pathway has been variably implicated in infectious immunity. In this study, we investigated the role of this costimulatory pathway in resistance to Trypanosoma cruzi infection by using CD28-deficient mice and blocking antibodies against CD80 and CD86. CD28-deficient mice exhibited markedly exacerbated T. cruzi infection, as evidenced by unrelenting parasitemia and 100% mortality after infection with doses that are nonlethal in wild-type mice. The blockade of both CD80 and CD86 by administering specific monoclonal antibodies also exacerbated T. cruzi infection in wild-type mice. Splenocytes from T. cruzi-infected, CD28-deficient mice exhibited greatly impaired gamma interferon production in response to T. cruzi antigen stimulation in vitro compared to those from infected wild-type mice. The induction of T. cruzi antigen-specific CD8(+) T cells was also impaired in T. cruzi-infected, CD28-deficient mice. In addition to these defects in natural protection against T. cruzi infection, CD28-deficient mice were also defective in the induction of CD8(+)-T-cell-mediated protective immunity against T. cruzi infection by DNA vaccination. These results demonstrate, for the first time, a critical contribution of the CD28-CD80/CD86 costimulatory pathway not only to natural protection against primary T. cruzi infection but also to DNA vaccine-induced protective immunity to Chagas' disease.

Activation of natural killer T cells by alpha-galactosylceramide impairs DNA vaccine-induced protective immunity against Trypanosoma cruzi

Innate immunity as a first defense is indispensable for host survival against infectious agents. We examined the roles of natural killer (NK) T cells in defense against Trypanosoma cruzi infection. The T. cruzi parasitemia and survival of CD1d-deficient mice exhibited no differences compared to wild-type littermates. NK T-cell activation induced by administering alpha-galactosylceramide (alpha-GalCer) to T. cruzi-infected mice significantly changed the parasitemia only in the late phase of infection and slightly improved survival when mice were infected intraperitoneally. The combined usage of alpha-GalCer and benznidazole, a commercially available drug for Chagas' disease, did not enhance the therapeutic efficacy of benznidazole. These results suggest that NK T cells do not play a pivotal role in resistance to T. cruzi infection. In addition, we found that the coadministration of alpha-GalCer with DNA vaccine impaired the induction of epitope-specific CD8(+) T cells and undermined the DNA vaccine-induced protective immunity against T. cruzi. Our results, in contrast to previous reports demonstrating the protective roles of NK T cells against other infectious agents, suggest that these cells might even exhibit adverse effects on vaccine-mediated protective immunity.

Coadministration of an interleukin-12 gene and a Trypanosoma cruzi gene improves vaccine efficacy

We tested the immunogenicity of two Trypanosoma cruzi antigens injected into mice in the form of DNA vaccine. Immunization with DNA encoding dihydroorotate dehydrogenase did not confer protective immunity in all mouse strains tested. Immunization with DNA encoding trans-sialidase surface antigen (TSSA) protected C57BL/6 (H-2(b)) mice but not BALB/c (H-2(d)) or C3H/Hej (H-2(k)) mice against lethal T. cruzi infection. In vivo depletion of CD4(+) or CD8(+) T cells abolished the protective immunity elicited by TSSA gene in C57BL/6 mice. Enzyme-linked immunospot assay with splenocytes from T. cruzi-infected mice or TSSA gene-vaccinated mice identified an H-2K(b)-restricted antigenic peptide, ANYNFTLV. The CD8(+)-T-cell line specific for this peptide could recognize T. cruzi-infected cells in vitro and could protect naive mice from lethal infection when adoptively transferred. Coadministration of the interleukin-12 (IL-12) gene with the TSSA gene facilitated the induction of ANYNFTLV-specific CD8(+) T cells and improved the vaccine efficacy against lethal T. cruzi infection. These results reinforced the utility of immunomodulatory adjuvants such as IL-12 gene for eliciting protective immunity against intracellular parasites by DNA vaccination.

Adenovirus vector-mediated transfer of 9 kDa granulysin induces DNA fragmentation in HuD antigen-expressing small cell lung cancer murine model cells

OBJECTIVE

Granulysin is a tumoricidal molecule secreted by cytotoxic T cells (CTL) and natural killer (NK) cells, that induces apoptotic cell death in tumour cells. It has been demonstrated that small cell lung cancer (SCLC) cell lines are susceptible to NK cells and lymphokine activated killer (LAK) cells, and HuD antigen is assumed to be a target molecule on SCLC cells for host cellular immunity.

METHODOLOGY

In order to understand the mechanism of sensitivity of SCLC to cellular immunity, we evaluated granulysin-induced apoptosis using mouse adenocarcinoma Colon 26 (Colon 26/HuD) cells transfected with the 9 kDa active form of granulysin using an adenovirus vector as a murine model of SCLC cells.

RESULTS

Adenovirus vector-mediated transfer of 9 kDa granulysin increased DNA fragmentation in Colon 26/HuD cells 2.5-fold and suppressed Colon 26/HuD proliferation by 21% on day 3 (P < 0.05 for each value) compared with the control adenovirus vector transfer. In contrast, adenovirus vector-mediated transfer of 9 kDa granulysin did not increase DNA fragmentation nor suppress the proliferation of Colon 26 parent cells.

CONCLUSIONS

The sensitivity of HuD-expressing tumour cells to granulysin is likely to partially explain the susceptibility of SCLC to cell-mediated immunity.

[A senile case of acute necrotizing myopathy presenting prolonged severe muscle paralysis due to high dose glucocorticoid and muscle relaxant]

An 82-year old man was admitted with dyspnea, productive cough and wheezing. In addition to antibiotics (meropenem trihydrate 0.5 g/day), glucocorticoids (hydrocortisone 1.250 mg, methylpredonisolone 4.250 mg) were administered for the severe bronchospasms. Since his respiratory condition deteriorated, he underwent mechanical ventilation using a muscle relaxant (vecuronium bromide, total dose 776 mg) in combination with high dose glucocorticoid. As his pneumonia improved on the 10th hospital day, we started weaning him from the ventilator. However, we were unable to complete weaning from the ventilator because of prolonged quadriplegia and paralysis of the respiratory muscles. A few days later, myoglobinuria appeared. Electrophysiological examinations suggested the involvement of both neuromuscular junctions and muscles. Muscle biopsy showed rhabdomyolysis. Acute necrotizing myopathy was diagnosed due to high doses of glucocorticoid, muscle relaxant, or both. He required about 3 months to be weaned from the mechanical ventilation, and another 3 months to leave the hospital. Based on our experience, we should consider acute myopathy as an adverse effect of glucocorticoids, muscle relaxants or both in elderly patients who require mechanical ventilation.

[Microscopic polyangitis with pleuritis as the only pulmonary complication]

A 75-year-old woman was admitted to our hospital because of high fever and appetite loss. A chest roentgenogram and computed tomographic scans revealed pleural effusion without obvious infitrative or interstitial shadows in both lung fields. Laboratory data showed microhematuria, proteinuria, and telescoped sediment with a moderate increase in C-reactive protein, suggestive of acute glomerulonephritis. Because infectious pleuritis, was initially suspected, the patient was treated with antibiotics. However, her general condition deteriorated, and the right pleural effusion increased. Levels of myeloperoxidase-specific anti-neutrophil cytoplasmic antibody (MPO-ANCA) in serum and pleural effusion were markedly elevated, yielding a conclusive diagnosis of MPO-ANCA-related vasculitis, especially microscopic polyangitis (MPA). The Patient was immediately treated treated with prednisolone, cyclophosphamide, and plasma exchange. Several weeks later, her general condition dramatically improved, and the level of MPO-ANCA in serum markedly decreased. In addition, the pleural effusion completely disappeared. Unfortunately, the patient eventually died of opportunistic infections (MRSA-pneumonia and Aspergillus-pneumonia) 6 months after admission. This was a unique case of MPA associated with pleuritis without interstitial pneumonia or alveolar hemorrhage.