Keiichi Akasaka

The usefulness of monomeric periostin as a biomarker for idiopathic pulmonary fibrosis

The natural course of idiopathic pulmonary fibrosis (IPF) is variable. Predicting disease progression and survival in IPF is important for treatment. We previously demonstrated that serum periostin has the potential to be a prognostic biomarker for IPF. Our aim was to use monomeric periostin in a multicenter study to evaluate its efficacy in diagnosing IPF and predicting its progression. To do so, we developed a new periostin kit to detect only monomeric periostin. The subjects consisted of 60 IPF patients in a multicenter cohort study. We applied monomeric periostin, total periostin detected by a conventional kit, and the conventional biomarkers—KL-6, SP-D, and LDH—to diagnose IPF and to predict its short-term progression as estimated by short-term changes of %VC and % DL, CO. Moreover, we compared the fraction ratios of monomeric periostin to total periostin in IPF with those in other periostin-high diseases: atopic dermatitis, systemic scleroderma, and asthma. Monomeric periostin showed the greatest ability to identify IPF comparable with KL-6 and SP-D. Both monomeric and total periostin were well correlated with the decline of %VC and % DL, CO. Clustering of IPF patients into high and low periostin groups proved useful for predicting the short-term progression of IPF. Moreover, the relative ratio of monomeric periostin was higher in IPF than in other periostin-high diseases. Measuring monomeric periostin is useful for diagnosing IPF and predicting its short-term progression. Moreover, the ratio of monomeric periostin to total periostin is elevated in IPF compared to other periostin-high diseases.

IgM-type GM-CSF autoantibody is etiologically a bystander but associated with IgG-type autoantibody production in autoimmune pulmonary alveolar proteinosis

The granulocyte-macrophage colony-stimulating factor (GM-CSF) autoantibody (GMAb) is the causative agent underlying autoimmune pulmonary alveolar proteinosis (aPAP). It consists primarily of the IgG isotype. At present, information on other isotypes of the autoantibody is limited. We detected serum the IgM isotype of GMAb (IgM-GMAb) in more than 80% of patients with aPAP and 22% of healthy subjects, suggesting that a continuous antigen pressure may be present in most patients. Levels of the IgM isotype were weakly correlated with IgG-GMAb levels but not IgA-GMAb, suggesting that its production may be associated with that of IgG-GMAb. The mean binding avidity to GM-CSF of the IgM isotype was 100-fold lower than the IgG-GMAb isotype, whereas the IC(50) value for neutralizing capacity was 20,000-fold higher than that of IgG-GMAb, indicating that IgM-GMAb is only a very weak neutralizer of GM-CSF. In bronchoalveolar lavage fluid from nine patients, IgG-GMAb was consistently detected, but IgM-GMAb was under the detection limit in most patients, confirming that IgM-GMAb is functionally a bystander in the pathogenesis of aPAP. It rather may be involved in the mechanism for development of IgG-GMAb in vivo.

Sequential Granulocyte-Macrophage Colony-Stimulating Factor Inhalation after Whole-Lung Lavage for Pulmonary Alveolar Proteinosis. A Report of Five Intractable Cases

&NA; Autoimmune pulmonary alveolar proteinosis (aPAP) is a rare disease characterized by the excessive accumulation of surfactant proteins within the alveolar spaces and by higher titers of autoantibodies to granulocyte‐macrophage colony‐stimulating factor (GM‐CSF) in the serum and bronchoalveolar lavage fluid. The antibodies inhibit the maturation and phagocytosis of alveolar macrophages. Although the standard therapy for aPAP has been whole‐lung lavage (WLL), this procedure is invasive and needs to be repeated for several years. GM‐CSF inhalation therapy is a new procedure for treating aPAP and can induce remission with less invasiveness, although it is generally less effective in severe cases. We evaluated five cases with remarkable improvement by using sequential GM‐CSF inhalation therapy after WLL; however, the treatment failed when this therapy preceded WLL. Therefore, sequential GM‐CSF inhalation after WLL may reinforce the efficiency of WLL in patients with severe aPAP.

A mathematical model to predict protein wash out kinetics during whole-lung lavage in autoimmune pulmonary alveolar proteinosis

Whole-lung lavage (WLL) remains the standard therapy for pulmonary alveolar proteinosis (PAP), a process in which accumulated surfactants are washed out of the lung with 0.5-2.0 l of saline aliquots for 10-30 wash cycles. The method has been established empirically. In contrast, the kinetics of protein transfer into the lavage fluid has not been fully evaluated either theoretically or practically. Seventeen lungs from patients with autoimmune PAP underwent WLL. We made accurate timetables for each stage of WLL, namely, instilling, retaining, draining, and preparing. Subsequently, we measured the volumes of both instilled saline and drained lavage fluid, as well as the concentrations of proteins in the drained lavage fluid. We also proposed a mathematical model of protein transfer into the lavage fluid in which time is a single variable as the protein moves in response to the simple diffusion. The measured concentrations of IgG, transferrin, albumin, and β2-microglobulin closely matched the corresponding theoretical values calculated through differential equations. Coefficients for transfer of β2-microglobulin from the blood to the lavage fluid were two orders of magnitude higher than those of IgG, transferrin, and albumin. Simulations using the mathematical model showed that the cumulative amount of eliminated protein was not affected by the duration of each cycle but dependent mostly on the total time of lavage and partially on the volume instilled. Although physicians have paid little attention to the transfer of substances from the lung to lavage fluid, WLL seems to be a procedure that follows a diffusion-based mathematical model.

Peripheral alveolar nitric oxide concentration reflects alveolar inflammation in autoimmune pulmonary alveolar proteinosis

Autoimmune pulmonary alveolar proteinosis (aPAP) is caused by an excess of autoantibodies against granulocyte-macrophage colony-stimulating factor (GM-CSF). In this situation, the clearance of intracellular debris in alveolar macrophages is impaired, and the alveolar spaces are occupied by excessive surfactant sediments. Several serum markers (lactate dehydrogenase (LDH), KL-6, carcinoembryonic antigen and surfactant protein D), alveolar–arterial oxygen difference (PA–aO2) and the percentage diffusing capacity of the lung for carbon monoxide (%DLCO) have a correlation with the disease severity and are used to evaluate the severity of aPAP [1]. Nitric oxide and alveolar macrophage inflammation http://ow.ly/czCx30i12n8

Estimation of the True Granulocyte-Macrophage Colony-Stimulating Factor (GM-CSF) Autoantibody Concentration in the Sera of Normal Subjects

According to our previous studies, Granulocyte-Macrophage Colony-Stimulating Factor (GM-CSF) autoantibodies (GMAbs) are normally present in healthy people. To date, antigen-antibody capture assay has measured the concentrations. However, nonspecific IgG other than GMAbs and immune complex formation with intrinsic GM-CSF prevents us from measuring the accurate concentrations. To solve these problems, we developed a liquid phase high-sensitivity assay using biotinylated GM-CSF (bGM-CSF) and streptavidin coated plate, which could measure the concentration of GMAbs over 0.02 ng/ml. Using this method, the true GMAbs concentration in 30 normal subjects was estimated to be 52.6 ng/ml for the median value, ranging 10.6 to 799.5 ng/ml. Thus, we propose a novel method that enables us to estimate the true concentration of GMAbs in the sera of healthy subjects.

Abstract 3597: Association between the ABCG2 polymorphisms and the gefitinib-induced side effects in Japanese patients with non-small cell lung cancer

ABCG2 is a half-size ATP-binding cassette transporter implicated in cellular gefitinib transport. Reportedly, the c.421C>A ABCG2 gene variant was associated with gefitinib-induced diarrhea in Caucasian patients with non-small cell lung cancer. c.421C>A ABCG2, resulting in p.Q141K substitution, is more prevalent in Asian populations. Therefore, the putative relationship between gefitinib-induced adverse effects and this functional polymorphism was investigated in 75 Japanese patients with non-small cell lung cancer treated with gefitinib 250 mg/d orally, and the results were correlated with treatment-related adverse effects. c.376 C>T, resulting in truncated, non-functional ABCG2, was also investigated. Forty one (54.7%) patients harbored 376T or 421A ABCG2 on at least one allele, while the remaining 34 (45.3%) were wild type for ABCG2. No significant group differences were observed in frequency of gefitinib-related diarrhea or other adverse effects. Next, DLD-1 colon cancer cells expressing wild-type (DLD-1/WT) or 141K mutant ABCG2 (DLD-1/Q141K) were established for investigation of in-vitro cell sensitivity to the ABCG2-substrate drugs, gefitinib and SN-38. ABCG2 expression was much lower in DLD-1/Q141K cells than in DLD-1/WT cells, despite similar ABCG2 mRNA levels. DLD-1/WT cells acquired more resistance to SN-38 than did DLD-1/Q141K cells, but neither cell line acquired gefitinib resistance compared with parental cells. In-vitro data also suggested that ABCG2 has only a limited role in toxicity of gefitinib, but not SN-38, in colon-derived cells. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 3597.