Relationship between the isoniazid-resistant mutation katGS315T and the prevalence of MDR-/XDR-TB in Osaka, Japan.

OBJECTIVE: To determine the prevalence of katGS315T mutations in isoniazid (INH) resistant Mycobacterium tuberculosis and to elucidate the association of katGS315T mutations with the prevalence of multidrug-resistant tuberculosis (MDR-TB). DESIGN: From 2001 to 2004, 1655 isolates from all newly registered patients who visited the Osaka Prefectural Medical Centre for Respiratory and Allergic Diseases were tested for drug susceptibility. Genotyping was performed using insertion sequence (IS) 6110-restriction fragment length polymorphism (RFLP) in 1629 of 1655 (98.4%) cases. All 145 isolates of INH-resistant M. tuberculosis, including MDR strains, were tested to detect the katGS315T mutation. RESULTS: Five hundred and sixty isolates (34.4%) shared an RFLP pattern. Of the 145 INH-resistant isolates, 18/48 (37.5%) isolates belonging to the RFLP cluster had katGS315T and 23/97 (23.7%) did not have the mutation. Of the 66 MDR-TB cases, 18/29 (62.1%) isolates belonging to the RFLP cluster had katGS315T and 11/37 (29.7%) did not have the mutation. Of the 29 extensively drug-resistant (XDR) TB cases, 17/21 (80.9%) isolates belonging to the RFLP cluster had katGS315T and 3/8 (37.5%) did not have the mutation. CONCLUSION: The clustering rate by IS6110-RFLP was very high among MDR-/XDR-TB isolates with katGS315T. Our study indicates a strong correlation between the katGS315T mutation and the transmission dynamics of MDR-TB, and especially XDR-TB.

Preferential and persistent activation of the STAT1 pathway in rheumatoid synovial fluid cells.

OBJECTIVE: Inflammatory cytokines such as interleukin 1 (IL-1), IL-6, and tumor necrosis factor-alpha are produced in great quantities in inflamed rheumatoid joints. However, little is known about the pathogenic significance of each cytokine in the proliferative synovitis and destruction of bone and joint. We investigated the role of cytokine receptor signals transduced into cells at the foci of rheumatoid inflammation. METHODS: Synovial fluid (SF) cells from patients with rheumatoid arthritis (RA) and osteoarthritis (OA) were examined for the activation of a group of cytokine receptor signaling molecules, signal transducers and activators of transcription (STAT). RESULTS: DNA binding of STAT1 in SF cells was observed in 8 out of 14 patients with RA, but in none of the 10 patients with OA studied, and this was prevented by preincubation of these cells with neutralizing anti-IL-6 antibody. IL-6 activated both STAT1 and STAT3 in normal peripheral blood (PB) leukocytes, and preferentially STAT1 in rheumatoid SF cells. Moreover, STAT1 activation in rheumatoid SF cells appeared to be continuous, in contrast to the transient activation in normal PB leukocytes. CONCLUSION: STAT1 and STAT3 are differentially regulated in response to IL-6 in different cell types. The continuous STAT1 activation may be of pathogenic significance in the progression and persistence of RA.

[Comparison of the newly developed MYCOACID system with mycobacteria growth indicator tube (MGIT) and newly developed 2% Ogawa medium (S) for recovery of mycobacteria in clinical specimens].

The detection rate of mycobacteria from patients' specimens and the time required to get positive culture were compared among newly developed MYCOACID SYSTEM, MGIT, Ogawa K medium and 2% Ogawa medium (S). A total of 249 sputum samples taken from patients were used as the study subjects and 124 kinds of mycobacteria were isolated. For 135 cases clinically diagnosed as pulmonary tuberculosis, the detection rate was 44.4% for MYCOACID, 47.4% for MGIT and 38.5% for Ogawa K medium, showing that there are no significant differences in the detection rate between MYCOACID and MGIT, and MYCOACID and Ogawa K medium but the differences was significant between MGIT and Ogawa K medium (p = 0.02). The mean days needed for detection of Mycobacterium tuberculosis complex was 12.3 days for MYCOACID, 13.4 days for MGIT, and 26.8 days for Ogawa K medium, indicating significant differences in the time to get positive culture between Ogawa K medium and either of both liquid media (p < 0.001). Furthermore, 2% Ogawa medium (S) was used only for the detection of mycobacteria among previously untreated tuberculosis and there were no significant differences in the detection rate between 2% Ogawa medium (S) and either of both liquid media. The time to get positive culture for 2% Ogawa medium (S) was 18.2 days, which was longer than that for either of liquid media, MYCOACID and MGIT, but it was significantly shorter (7.9 days) than that for Ogawa K medium (p = 0.003). These results demonstrate that the liquid culture systems both MYCOACID and MGIT were very useful for the detection of mycobacteria compared with Ogawa K medium.

[Riddles in human tuberculous infection].

Tuberculosis is indeed an infectious disease caused by Mycobacterium tuberculosis. However, only a small percentage of individuals infected develops overt disease, tuberculosis whereas the infected bacilli persist alive years long within the vast majority of persons infected but remained healthy. There are several riddles or enigmas in the natural history of M. tuberculosis infection in humans. Some of them are as follows: 1. What is the virulence of M. tuberculosis? 2. How does M. tuberculosis persist dormant within the host? 3. What determines the development of disease from remaining healthy after infection with M. tuberculosis? 4. What is the mechanism of "endogenous reactivation" of dormant M. tuberculosis within the host? 5. Can we expect more potent anti-TB vaccine than BCG in near future? Most of these issues cited above remain unsolved. What is urgently needed today to answer correctly to these questions is the production of appropriate animal model of tuberculosis infection which mimics human tuberculosis. Murine TB does not reflect human TB at all. What characterizes the mycobacterial organism is its armour-plated unique cell wall structure which is rich in lipid and carbohydrate. Cord factor or trehalose dimycolate (TDM), the main component of cell wall, has once been regarded as the virulence factor of mycobacteria. Cord factor is responsible for the pathogenesis of TB and cachexia or even death of the patients infected. However, cord factor in itself is not toxic but exerts its detrimental effect to the host through the excessive stimulation of the host's immune system to produce abundant varied cytokines including TNF-alpha. How to evade this embarrassing effect of mycobacterial cell wall component on the host immune system seems very important for the future development of better TB vaccine than the currently used BCG.

[Immunotherapy for MDR-TB (multi-drug resistant tuberculosis)--its feasibility].

MDR-TB is known to be man-made-disease. Inappropriate treatment of tuberculosis is responsible for the development of MDR-TB. MDR-TB is often accompanied with the immunosuppression of the host. Given that we are unable to develop another potent anti-TB drug in near future, immunotherapy directed at combating immunosuppression and enhancing the host's own immune response is an attractive approach to supplement conventional chemotherapy for MDR-TB. Patients with AIDS and patients with abnormalities of macrophage function have frequent problems with TB. This is suggesting that the host defenses involved in protection against mycobacteria include T-cell and monocyte/macrophage functions. That is cell-mediated immunity. Diverse cytokines are known to play an important role in anti-TB cell-mediated immunity, including IL-2, IL-12, IL-18 and IFN-gamma. Various animal experiments are indicating that administration of these cytokine (s) did recover the suppressed immunity and rescued the host from death by tuberculous infection. However, we have to keep it in mind that the results obtained from animal model of mycobacterial infection on the study of pathogenesis and immune responses in TB is not always applicable to the understanding of human TB. Clinical trial of inhalation therapy with IFN-gamma showed some improvement for drug-resistant TB. Cytokine treatment, however, often gave some deleterious side effects such as high fever, malaise, general edema and even the death of the host. Clinical trials with M. vaccae have been extensively conducted by UK group. The mechanisms underlying its possible therapeutic action remain to be clarified, but when administered at an appropriate dose, it has been shown to elicit a strong Th1 immune response. From the practical view point of immunotherapy for TB, surrogate markers of disease eradication and protective immunity are urgently required. Such markers would facilitate clinical trials by providing early evidence that test compounds or vaccines are effective. Even during the era when no potent chemotherapeutic agents were available, one third of the patients with TB survived the disease and enjoyed the entire lives. Then the question is what determines the alternative: survival or death following development of drug resistant TB. Is it host immune responsiveness or virulence of the microbe, or both? Clearly much more work seems required before we are able to find some definite means to conquer MDR-TB in human.

[Analysis of Mycobacterium tuberculosis-derived substance which induces interleukin-12 production from macrophages].

Protection of hosts against tuberculosis depends on expression of cellular immunity. To express cellular immunity, interleukin 12 (IL-12) has been shown to play an important role. Although Mycobacterium tuberculosis is known to induce IL-12 from macrophages (M phi s), the mechanism for the induction is still unclear. To understand the mechanisms of IL-12 induction from M phi s by M. tuberculosis, the IL -12-inducing ability of substances derived from M. tuberculosis was investigated in vitro. Production of IL-12 in culture medium of M phi s was measured by ELISA system using specific antibodies. Live M. tuberculosis H37Rv induced slightly higher IL-12 production than live M. tuberculosis H37Ra upon stimulation of human or mouse alveolar macrophages (hAM phi s or mAM phi s). Heat-killed M. tuberculosis failed to induce IL-12 production of alveolar macrophages (AM phi). The responses of hAM phi s and mAM phi s to M. tuberculosis were remarkably different. mAM phi s produced five times larger amount of IL-12, compared with that from hAM phi s. Human peripheral blood mononuclear cells (PBMC) obtained by the density gradient centrifugation were also used for induction of IL-12 production. Although production levels of IL-12 from PBMC stimulated with M. tuberculosis were below the detectable level, addition of interferon-gamma (IFN-gamma) or neutralizing antibody against IL-10 augmented the production of IL-12 from PBMC, suggesting that IFN-gamma and IL-10 regulate the production of IL-12 from M phi positively and negatively, respectively. To characterize the physicochemical properties of IL-12-inducing molecules, M. tuberculosis H37Rv was disrupted by pressing with 1,000 bar and centrifuged and separated into cytosol and cell wall fraction. The culture filtrate was also examined on IL-12-inducing activity. Among the three subjects examined, cytosol was found to induce the highest production of IL-12 from mAM phi s 1 day after the stimulation. Addition of IFN-gamma to the cytosol fraction markedly increased the production of IL-12 from mAM phi s. The molecular weight of IL-12-inducing substance was shown to be more than 30kDa by fractionating with molecular filters. Treatment of 30kDa-fraction with IL-12-inducing activity by proteinase K completely abolished the activity. Furthermore, approximately 90% of IL-12-inducing activity of 30kDa-fraction was lost by proteinase K treatment even in the presence of IFN-gamma. These results indicate that the major component of IL-12-inducing activity is a protein. The identification of this IL-12-inducing active substance may provide a new therapeutic tool for tuberculosis.

Increased production of interleukin-10 by human blood monocytes stimulated with Mycobacterium avium-intracellulare complex.

Macrophages produce various cytokines in response to mycobacteria, including interleukin 10 (IL-10) and tumor necrosis factor alpha (TNF-alpha). IL-10 has been shown to down-regulate numerous macrophage functions, including microbicidal activity against intracellular bacteria and parasites. IL-10 also inhibits interferon-gamma (IFN-gamma) production and antigen-specific proliferation of Th1 cells mediating immunologic resistance to mycobacterial infection. In contrast, TNF-alpha activates macrophages and may augment their mycobacterial activity. In this study, peripheral blood mononuclear cells (PBMC) or blood monocytes obtained from healthy tuberculin reactors were stimulated in vitro with heat-killed Mycobacterium tuberculosis or heat-killed M. avium-intracellulare complex (MAC) to produce IL-10 and TNF-alpha. We studied a total of 26 clinical isolates of M. tuberculosis and 28 isolates of MAC. MAC-stimulated PBMC and monocytes released significantly larger amounts of IL-10 than those cells stimulated with M. tuberculosis. However, there was no difference in induction of TNF-alpha production between MAC and M. tuberculosis. When TNF-activity was neutralized by the addition of anti-TNF-alpha mAb in culture, MAC still induced more IL-10 secretion than did M. tuberculosis. These findings suggest that increased production of IL-10 by MAC-stimulated monocytes may play a role in the intractable disease caused by these organisms.

Interleukin-12 activates human gamma delta T cells: synergistic effect of tumor necrosis factor-alpha.

gammadelta T cell populations are known to expand in response to intracellular bacterial infectious agents regardless of previous priming. We have shown previously that soluble factor(s) produced by Mycobacterium-stimulated monocytes activate cord blood gammadelta T cells to proliferate. In this study, we investigated whether cytokines produced by monocytes are responsible for gammadelta T cell activation in vitro: interleukin (IL)-1beta, IL-6, IL-8, IL-12, tumor necrosis factor (TNF)-alpha and granulocyte/macrophage colony-stimulating factor were examined. Recombinant human IL-12 stimulated gammadelta T cells, but not alphabeta T cells in peripheral blood mononuclear cells, to express CD25 on their surfaces, and to expand in number in vitro. IL-12-primed gammadelta T cell numbers increased to a greater extent in the culture to which exogenous IL-2 (5 U/ml) was added. Anti-TNF-alpha monoclonal antibody inhibited IL-12-induced up-regulation of CD25 on gammadelta T cells, suggesting that endogenous TNF-alpha may play a role in IL-12-induced activation of gammadelta T cells. Recombinant TNF-alpha synergistically augmented IL-12-induced activation of gammadelta T cells. Furthermore, IL-12 up-regulated TNF receptors on gammadelta T cells in vitro: TNF-alpha binding to its receptor induced CD25 expression on the gammadelta T cells in an autocrine or paracrine fashion, or perhaps both. It also became evident that both IL-12 and TNF-alpha were produced by mycobacterial lysate-stimulated monocytes. Taken together, these results suggest that upon confrontation with mycobacterial organisms, gammadelta T cells can be quickly and antigen-nonspecifically activated by soluble factors including IL-12 and TNF-alpha, both of which are produced by mononuclear phagocytes in response to mycobacterial organisms.

[From the immunological aspect--interleukin-10 production by human blood mononuclear cells stimulated with multidrug-resistant Mycobacterium tuberculosis].

Interleukin-10 (IL-10) has been shown to down-regulate a number of different macrophage functions, including microbicidal activity against intracellular bacteria or parasites. In this study, peripheral blood mononuclear cells (PBMC) obtained from a healthy tuberculin-reactor were stimulated in vitro with various strains of multidrug-resistant Mycobacterium tuberculosis (MDRTB) or drug-sensitive M. tuberculosis (DSTB) to produce IL-10. We obtained one mycobacterial strain from each patient, preparing a total of 10 strains of DSTB, 5 strains of MDRTB. PBMC were cultured with LPS or mycobacterial preparations for 1, 3 and 5 days. IL-10 concentration in the culture supernatants was measured by ELISA using IL-10-specific monoclonal antibodies. The mean IL-10 production by PBMC stimulated with MDRTB was greater than that with DSTB, statistically significant at day 3 (MDRTB 171.4 +/- 18.2 pg/ml, DSTB 106.3 +/- 17.2 pg/ml, p < 0.05). Cell separation experiments indicated that cells producing IL-10 when stimulated with M. tuberculosis or LPS were monocytes, not T lymphocytes. Next, we examined PBMC from refractory tuberculosis patient who had continuously excreted MDRTB. PBMC from those patients secreted greater, but statistically not significant, amounts of IL-10 in response to LPS or TB bacilli than those of healthy subjects. Increased production of IL-10 by MDRTB-stimulated PBMC might be responsible for intractable tuberculosis.

[Immunology of tuberculosis and cytokines].

One of the unique features characterizing human tuberculosis (TB) is its pathogenesis. The pathogenesis of TB involves cell-mediated immune responses against Mycobacterium tuberculosis. Concisely, macrophages activated by various soluble mediators or cytokines released through the cellular interactions after infection with M. tuberculosis play a pivotal role in the pathogenesis of human TB. In fact, very complex cellular interactions are going on within the host after infection with or endogenous reactivation of M. tuberculosis. Cells communicate by cell-cell contact and by the release of mediators which may originate locally, called cytokines. In TB infection, macrophages can be activated by two ways; directly with mycobacterial organisms or lipid fractions of their cell walls at the earlier phase of infection, and indirectly with cytokines produced by CD4+ T cells specifically activated by mycobacterial peptide antigens at the later phase of infection. The various clinical features of TB are the summarized outcome of cell to cell interactions mediated by diverse cytokines produced by various immune cells which are initially triggered by M. tuberculosis infection. CD4+ T cells can be classified into two subsets according to the patterns of cytokines they produce; Th1 cells give rise to cell-mediated immunity and are characterized by the production of IL-2 and IFN-gamma, whereas Th2 cells are more efficient in mediating antibody production and secrete IL-4, IL-5, IL-6 and IL-10. Th2 cells can control Th1 cells and vice versa. Th2 cells therefore inhibit the production of cytokines by Th1 cells by releasing IL-4 and IL-10. Infection with mycobacteria stimulates macrophage IL-12 production which appears to act directly on naive CD4+ T cells to induce Th1 development and initiation of cell-mediated immunity. IL-12 is a critical component in the development of cell-mediated immunity. In addition, IL-12 also activates NK cells and gamma/delta T cells, both of which secrete various macrophage-activating factors to kill M. tuberculosis. One of the structural characteristics of M. tuberculosis is the cell wall rich in lipid components. Of importance among various biological activities of the cell wall lipids is the stimulation of mononuclear phagocytes to produce a certain number of cytokines or monokines including IL-12 and IL-10, both of which play important roles in regulation of immune responses in mycobacterial infection and in pathogenesis of TB.(ABSTRACT TRUNCATED AT 400 WORDS)

Increase of gamma/delta T cells in hospital workers who are in close contact with tuberculosis patients.

gamma/delta T cells are likely to participate in the immune response to tuberculous infection in humans. In this study, we carried out an investigation to characterize the responsiveness of gamma/delta T cells from tuberculous patients and healthy individuals to mycobacterial stimulation in vitro. Healthy subjects were assigned to the following two groups: those who had been exposed to tuberculosis (contacts) and those who had not been exposed (noncontacts). The percent gamma/delta T cells in fresh peripheral blood obtained from health care workers who were tuberculin skin test positive and who had constant contact with patients with active tuberculosis (healthy contacts) was significantly higher, whereas healthy noncontacts showed the normal range of gamma/delta T cells. Patients with active pulmonary tuberculosis also had low levels of gamma/delta T cells. HLA-DR antigen-bearing activated gamma/delta T cells were observed in higher percentages among healthy contacts than among healthy noncontacts or patients with pulmonary tuberculosis. In healthy contacts, gamma/delta T cells increased as a percentage of peripheral blood mononuclear cells after in vitro stimulation with purified protein derivative (PPD) tuberculin compared with the percentage of fresh peripheral blood mononuclear cells that they made up, whereas no such increase was observed in patients with tuberculosis or in healthy noncontacts. Phenotypic analysis of the gamma/delta T cells in healthy contacts, which increased in number in vitro in response to PPD, revealed the preferential outgrowth of CD4+ V gamma 2+ gamma/delta T cells. This expansion of gamma/delta T cells by PPD required accessory cells, and it was inhibited by the addition of an antibody against HLA-DR in culture. Proteolytic digestion of PPD showed that gamma/delta T cells increased in number in response to peptide, but not nonpeptide, components of PPD. These findings suggest that gamma/delta T cells, especially CD4+ V gamma 2+ gamma/delta T cells, may participate in the immune surveillance of tuberculous infections in humans.

[A case of spontaneous remission of paragonimiasis miyazakii].

A 52-year-old man was admitted with fever and chest pain. Chest X-ray showed a soft infiltration in the right lung and bilateral pleural effusions. A strong tuberculin reaction was elicited. Significant laboratory findings included eosinophilia (37% in peripheral blood and 78% in pleural fluid) and elevated IgE levels (577 IU/ml in sera and 6700 IU/ml in pleural fluid). Adenosine deaminase activity in the pleural fluid was high. No helminth eggs were detected after repeated examination of the pleural fluid and sputum. No definitive diagnosis was made. Three months of chemotherapy with INH and rifampicin resulted in little improvement. Corticosteroid was then administered orally under a tentative diagnosis of idiopathic eosinophilic pleurisy, which proved to be a successful treatment and resulted in a marked reduction of pleural fluid volume. Two years after discharge, the patient's chest X-ray was normal and laboratory findings were normal including the eosinophil count and IgE level. The pleural fluid obtained at the first admission and kept frozen was subjected to immunological analysis for anti-parasite antibody activity. The pleural fluid showed an unexpectedly high titer of antibody activity (x6400 dilution) against Paragonimus miyazakii antigen assayed by double diffusion Ouchterlony method. Examination of the sera obtained from the patient two years after discharge, however, revealed no detectable antibody activity against the parasite antigens assayed either by Ouchterlony or ELISA method. We concluded from the clinical as well as laboratory findings that the patient had recovered from Paragonimiasis miyazakii without specific intervention for the disease.

Differential regulation of formation of multinucleated giant cells from concanavalin A-stimulated human blood monocytes by IFN-gamma and IL-4.

We found that in vitro multinucleated giant cells (MGC) could be produced by incubation of highly purified human blood monocytes with Con A alone, and the effect of Con A was dose- and time-dependent. Any of the cytokines considered as macrophage-activating factor, such as IFN-gamma, IL-2, IL-4, GM-CSF, or TNF-alpha, did not induce MGC by itself. When added to monocyte cultures, however, IFN-gamma enhanced Con A-induced MGC formation in a dose-dependent manner. In contrast, IL-4 suppressed this response in a dose- and time-dependent manner. IL-4 antagonized the enhancing effect of IFN-gamma on Con A-induced MGC formation. This ability to suppress the formation of MGC was completely abrogated after treatment with anti-IL-4 antibody. In addition, the involvement of monokines (IL-1 alpha, IL-1 beta, IL-6, and TNF-alpha) in Con A-induced monocyte fusion was investigated by adding various antimonokine polyclonal antibodies in cultures. Normal rabbit IgG, anti-IL-1 alpha rabbit antibody, and anti-IL-1 beta rabbit antibody had no effect on Con A-induced MGC formation. However, anti-TNF-alpha rabbit antibody had suppressed the monocyte fusion induced by Con A in a dose-dependent manner, and a high dose of anti-IL-6 rabbit antibody had a partially suppressive effect. Anti-TNF-alpha mAb also had an inhibitory effect on monocyte fusion. Furthermore, the enhancing effect of IFN-gamma on this response was entirely abrogated by anti-TNF-alpha rabbit antibody. There was a highly significant positive correlation between the fusion rates of monocytes and the levels of TNF-alpha produced by monocytes (r = 0.68, p < 0.0005). Our results indicate that T cell-derived lymphokines, such as IFN-gamma and IL-4, have mutually antagonistic effects on Con A-induced human MGC formations in vitro, in which the expression of TNF-alpha in human monocytes plays a key role in the fusion process of monocytes.

[Immunological aspects of Mycobacterium avium complex infection].

Tuberculin anergy is common in patients with Mycobacterium avium complex (MAC) infection. We examined in vitro cell-mediated immunity in these patients with MAC infection. Peripheral blood lymphocytes of patients, as compared with those of tuberculous patients or tuberculin-positive healthy donors, showed depressed in vitro blastogenic responses to purified protein derivative of tuberculin (PPD), not only to PPDs of Mycobacterium tuberculosis but also to PPD-B and PPD-Y of M. intracellulare and M. kansasii, respectively. Analysis of defective in vitro PPD-induced lymphocyte blastogenic responses in these patients revealed that PPD-induced interleukin 2 (IL-2) production was impaired whereas PPD-induced IL-2 responsiveness was normally developed after PPD stimulation. In the second half of this report, study was carried out to examine the mechanism of depressed T cell activity in these patients. Heat-killed MAC organisms and their lipid component impaired the capacity of peripheral blood lymphocytes to proliferate in vitro in response to concanavalin A (Con A), PPD, and to a lesser degree, phytohemagglutinin (PHA) stimulation. Inhibition by MAC was not contingent upon prior exposure of the donor to MAC or other mycobacteria and occurred with lymphocytes from tuberculin-negative as well as -positive subjects. The suppression was not due to the toxicity of MAC. Adherent cell depletion and cell mixing experiments with T cells indicated that monocytes and not T cells were a major contributor to the immunosuppression observed. Treatment of monocytes with MAC or MAC-derived lipid resulted in significant decreases in CD11b, a member of the LFA-1 and Leu M3 (CD14) molecule.(ABSTRACT TRUNCATED AT 250 WORDS)

[Prediction formulas for pulmonary function tests expressed in linear and exponential form for healthy Japanese adults].

We studied 21 parameters of pulmonary function in 172 healthy Japanese adult smokers and non-smokers ranging from 18 to 83 years of age. Prediction formulas for each parameter were calculated in both linear and exponential form using multiple regression analysis with regard to sex, age, height and weight. The exponential form was superior to the linear form for V25, V50, PEF, FVC, VC, FEV1.0, FEV1.0%, TLC, DLCo and DL/VA, namely, the parameters whose predictive value decreases with aging. In particular for V25, only the exponential form of the predictive formula could be applied for subjects with advanced age. For PMI, LCI, IDI, pulmonary N2 clearance delay, and single breath delta N2, indices for unevenness of intrapulmonary gas distribution, there has been no previous report about their predictive formulas and ours is the first. These predictive formulas all showed increasing values with aging, and showed higher predictive values in females than in males, except for delta N2. These parameters require further study with respect to their normal value ranges and differences between males and females.

A raised level of soluble CD8 in bronchoalveolar lavage fluid in summer-type hypersensitivity pneumonitis in Japan.

We used ELISA to measure soluble CD8 (sCD8) in the bronchoalveolar lavage fluid (BALF) and serum of patients with summer-type hypersensitivity pneumonitis (HP). The sCD8 levels in BALF were significantly higher in the patients with summer-type HP, surpassing those found in sarcoidosis and the other pulmonary diseases studied; however, the sCD8 levels in the serum of patients with summer-type HP did not differ from the levels of the healthy controls. The numbers of CD8+ T cells were increased in the BALF of the patients with summer-type HP, and there was a correlation between the sCD8 levels and the concentrations of CD8+ T cells. Gel filtration and polyacrylamide gel electrophoresis of the fluid revealed that the anti-CD8 monoclonal antibody-reactive components in the BALF of patients with pneumonitis corresponded to a protein with a molecular weight of between 52 and 54 kDa. Soluble CD8-rich fraction purified from the BALF of patients with summer-type HP augmented in vitro lymphocytes' proliferative responses stimulated with Cryptococcus neoformans, one of the causative agents for summer-type HP. Our result suggests that soluble CD8 in the BALF may play an important role in the pathogenesis of summer-type HP.