Antigen-induced proliferative response of lavage and blood T lymphocytes. Comparison of cells from normal subjects and patients with sarcoidosis

From COVID-19 to Sarcoidosis: How Similar Are These Two Diseases?

Coronavirus disease 2019 (COVID-19), which is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), leads to the dysregulation of the immune system, exacerbates inflammatory responses, and even causes multiple organ dysfunction syndrome in patients with severe disease. Sarcoidosis is an idiopathic granulomatous multisystem disease characterized by dense epithelioid non-necrotizing lesions with varying degrees of lymphocytic inflammation. These two diseases have similar clinical manifestations and may also influence each other and affect their clinical courses. In this study, we analyzed some possible connections between sarcoidosis and COVID-19, including the role of the renin–angiotensin system in the respiratory system, immune response, and cell death pathways, to understand the underlying mechanisms of SARS-CoV-2 infection, predisposing patients to severe forms of COVID-19. This review will provide a new prospect for the treatment of COVID-19 and an opportunity to explore the pathogenesis and development of sarcoidosis.

Differential Diagnosis of Asthma

Asthma is one of the most common chronic syndromes worldwide (Moorman et al., Vital Health Stat 3(35), 2012). It is not a diagnosis but a clinical syndrome based on a constellation of signs and symptoms (Li et al., Ann Allergy Asthma Immunol 81:415–420(IIa), 1998). The classic symptoms of asthma include chest tightness, wheeze, cough, and dyspnea (Moorman et al., Vital Health Stat 3(35), 2012). The term asthma encompasses a spectrum of pulmonary diseases sharing the hallmark of reversible airway obstruction and can be classified as allergic or non-allergic (Löwhagen, J Asthma. 52(6):538–44, 2015). Asthma designated allergic is due to an immunoglobulin E (IgE)-mediated process, but as noted not all asthma is allergic in etiology (Romanet-Manent et al., Allergy 57:607–13, 2002). The differential diagnosis for asthma is broad and requires a detailed history with supportive pulmonary function tests to be properly diagnosed.

Lymphopaenia as a predictor of sarcoidosis in patients with a first episode of uveitis

Background/aims

The diagnostic properties of conventional diagnostic tests (ACE and chest radiography) for sarcoidosis-associated uveitis are not ideal. The diagnostic value of lymphopaenia for sarcoidosis-associated uveitis is investigated.

Methods

A retrospective study of 191 consecutive patients with a first uveitis episode visiting the ophthalmology department (Erasmus Medical Center, Rotterdam, The Netherlands). Receiver operating characteristics (ROC) analysis was performed and compared with known ROC values from literature of conventional diagnostic tests for sarcoidosis-associated uveitis. An ideal cut-off was determined for lymphopaenia by calculation of the highest Youden index.

Results

Out of all patients with first uveitis attack, 32/191 or 17% were subsequently diagnosed with biopsy-proven or radiological diagnosis of sarcoidosis. Lymphopaenia (<1.5×109/L) was significantly more often observed in patients with sarcoidosis-associated uveitis compared with patients with non-sarcoidosis-associated uveitis (p<0.05). The sensitivity and specificity of lymphopaenia was 75 % and 77 %, respectively. The optimal cut-off for lymphopaenia for diagnosing sarcoidosis-associated uveitis was 1.47 ×109/L. Lymphopaenia resulted in a 12.0 (95% CI 4.7 to 30.5 fold risk for having sarcoidosis, corrected for sex, race and age at onset of uveitis in patients with a first uveitis attack.

Conclusion

Lymphopaenia is a non-invasive and useful marker for diagnosing sarcoidosis-associated uveitis.

Reduced expression of monocyte CD200R is associated with enhanced proinflammatory cytokine production in sarcoidosis

In sarcoidosis, the proinflammatory cytokines interferon gamma, tumour necrosis factor and interleukin-6 are released by monocyte-derived macrophages and lymphocytes in the lungs and other affected tissues. Regulatory receptors expressed on monocytes and macrophages act to suppress cytokine production, and reduced expression of regulatory receptors may thus promote tissue inflammation. The aim of this study was to characterise the role of regulatory receptors on blood monocytes in patients with sarcoidosis. Cytokine release in response to stimulation of whole blood was measured in healthy controls and Caucasian non-smoking patients with sarcoidosis who were not taking disease modifying therapy. Expression of the regulatory molecules IL-10R, SIRP-α/β, CD47, CD200R, and CD200L was measured by flow cytometry, and functional activity was assessed using blocking antibodies. Stimulated whole blood and monocytes from patients with sarcoidosis produced more TNF and IL-6 compared with healthy controls. 52.9% of sarcoidosis patients had monocytes characterised by low expression of CD200R, compared with 11.7% of controls (p < 0.0001). Patients with low monocyte CD200R expression produced higher levels of proinflammatory cytokines. In functional studies, blocking the CD200 axis increased production of TNF and IL-6. Reduced expression of CD200R on monocytes may be a mechanism contributing to monocyte and macrophage hyper-activation in sarcoidosis.

Sarcoidosis Th17 cells are ESAT-6 antigen specific but demonstrate reduced IFN-γ expression

RATIONALE

Sarcoidosis is a granulomatous disease of unknown etiology. Many patients with sarcoidosis demonstrate antigen-specific immunity to mycobacterial virulence factors. Th-17 cells are crucial to the immune response in granulomatous inflammation, and have recently been shown to be present in greater numbers in the peripheral blood and bronchoalveolar lavage (BAL) fluid (BALF) of sarcoidosis patients than healthy controls. It is unclear whether Th-17 cells in sarcoidosis are specific for mycobacterial antigens, or whether they have similar functionality to control Th-17 cells.

METHODS

Flow cytometry was used to determine the numbers of Th-17 cells present in the peripheral blood and BALF of patients with sarcoidosis, the percentage of Th-17 cells that were specific to the mycobacterial virulence factor ESAT-6, and as well as to assess IFN-γ expression in Th-17 cells following polyclonal stimulation.

RESULTS

Patients with sarcoidosis had greater numbers of Th-17 cells in the peripheral blood and BALF than controls and produced significantly more extracellular IL-17A (p = 0.03 and p = 0.02, respectively). ESAT-6 specific Th-17 cells were present in both peripheral blood and BALF of sarcoidosis patients (p < 0.001 and p = 0.03, respectively). After polyclonal stimulation, Th-17 cells from sarcoidosis patients produced less IFN-γ than healthy controls.

CONCLUSIONS

Patients with sarcoidosis have mycobacterial antigen-specific Th-17 cells peripherally and in sites of active sarcoidosis involvement. Despite the Th1 immunophenotype of sarcoidosis immunology, the Th-17 cells have reduced IFN-γ expression, compared to healthy controls. This reduction in immunity may contribute to sarcoidosis pathogenesis.

T cell responses to mycobacterial catalase-peroxidase profile a pathogenic antigen in systemic sarcoidosis

Sarcoidosis is a systemic granulomatous disease associated with local epithelioid granulomas, CD4(+) T cells, and Th1 cytokines. The tissue Ags that drive this granulomatous inflammation are uncertain. In this study, we used IFN-gamma-ELISPOT assays and flow cytometry to assess lung and blood T cell responses to the candidate pathogenic Ag, Mycobacterium tuberculosis catalase-peroxidase (mKatG) in patients with sarcoidosis from two centers. Despite differences in patient phenotypic, genetic, and prognostic characteristics, we report that T cell responses to mKatG were remarkably similar in these cohorts, with higher frequencies of mKatG-reactive, IFN-gamma-expressing T cells in the blood of sarcoidosis patients compared with nontuberculosis sensitized healthy controls, and (in a subset) in greater numbers than T cells reactive to purified protein derivative. In sarcoidosis, mKatG-reactive CD4(+) Th1 cells preferentially accumulated in the lung, indicating a compartmentalized response. Patients with or without Löfgren syndrome had similar frequencies of mKatG specific IFN-gamma-expressing blood T cells. Circulating mKatG-reactive T cells were found in chronic active sarcoidosis but not in patients with inactive disease. Together, these results demonstrate that T cell responses to mKatG in sarcoidosis fit a profile expected for a pathogenic Ag, supporting an immunotherapeutic approach to this disease.

Sarcoidosis, role of tumor necrosis factor inhibitors and other biologic agents, past, present, and future concepts

Tumor necrosis factor is a potent cytokine involved in the inflammatory process of many diseases. Agents that block tumor necrosis factor have been used in the treatment of various immune-mediated diseases, including rheumatoid arthritis, Crohn disease, psoriatic arthritis, and ankylosing spondylitis. Sarcoidosis is an immune-mediated inflammatory disorder of unknown etiology characterized by the formation of noncaseating granulomas. Tumor necrosis factor plays a major role in the inflammatory process seen in sarcoidosis. Sarcoidosis therapies with activity against tumor necrosis factor and specific anti-tumor necrosis factor therapies have been used with variable success. The long-term safety and efficacy of such therapies are yet to be determined in well-designed clinical trials with long-term follow-up.

The immune paradox of sarcoidosis and regulatory T cells

Sarcoidosis is characterized by extensive local inflammation (granuloma, cytokine secretion) associated with anergy (poor response to antigens in vitro and in vivo). We postulated that this paradoxical situation would correspond to a disequilibrium between effector and regulatory T lymphocytes (T reg cells). We show that CD4⁺CD25^brightFoxP3⁺ cells accumulate at the periphery of sarcoid granulomas, in bronchoalveolar lavage fluid, and in peripheral blood of patients with active disease. These cells exhibited powerful antiproliferative activity, yet did not completely inhibit TNF-α production. Sarcoidosis is therefore associated with a global T reg cell subset amplification whose activity would be insufficient to control local inflammation. At the same time, peripheral T reg cells exert powerful antiproliferative activity that may account for the state of anergy. Altogether, these findings advance our conceptual understanding of immune regulation in a way that resolves the immune paradox of sarcoidosis and permit us to envisage a profound clinical impact of T reg cell manipulation on immunity.

Recurrent sarcoidosis in lung transplant allografts: granulomas are of recipient origin

INTRODUCTION

Sarcoidosis accounts for only 2.8% of lung transplants in the United States. It is, however, the most commonly reported disease to recur after lung transplantation. In most cases, recurrence is diagnosed as an incidental finding in transbronchial lung allograft biopsy (TBLAB) and is unrelated to clinical or radiologic abnormalities. The origin of the histiocytes composing the noncaseating granulomas in the allograft lung in patients with recurrent sarcoidosis (RS) was analyzed using DNA identity testing in 4 cases.

MATERIAL AND METHODS

Native lung resections and corresponding transbronchial biopsies from patients who underwent lung transplantation for sarcoidosis between 1990 and 2004 and who developed RS were gathered from the paraffin block archives of University of Pittsburgh Medical Center. Clinical parameters including age, sex, grade of rejection, number of episodes of RS, and follow-up were recorded. Native lungs and corresponding TBLAB showing granulomas consistent with RS were microdissected in cases where adequate material was available. DNA was extracted, and an ABI AmpflSTR commercial kit was used to simultaneously amplify 15 short tandem repeat (STR) loci as well as 1 marker for the XY chromosomes. The informative STR loci in native lung (pure recipient), nongranulomatous donor lung, and granulomas in donor lung were analyzed in 4 patients. The relative proportion of donor and recipient cells in the chimera was quantified using the fluorescence intensity of each peak on an electropherogram. FISH analysis using probes targeted to X and Y chromosomes was performed in a case of sex-mismatched lung transplantation.

RESULTS

Eight patients with RS were identified. Two had bilateral lung transplantation, and the remaining 6 had single-lung transplantation. The age at transplantation ranged between 39 and 53. Five were females and 3 were men. Recurrent disease was diagnosed in 1 to 11 biopsies per patient and occurred first in the first 6 months following transplantation in 2 cases (25%), between 6 months and 1 year in 2 other cases (25%), and between 1 and 2 years in 4 cases (50%). In 4 patients, sufficient material allowed for DNA analysis. Amplification failed in 1 of the 4 cases, while the other 3 were successful. Patient 1 showed no ACR and granulomatous inflammation of RS in TBLAB. Donor (D) to recipient (R) profile changed from "normal" donor lung (37% D, 63% R) to 15% D and 85% R DNA in the granuloma. In patient 2, the TBLAB showed minimal ACR and granulomatous inflammation. D to R profile changed from 75% D and 25% R in the "normal" D lung to 54% D and 46% R in the granuloma. Patient 3 showed no ACR and RS in TBLAB. D to R profile changed from 85% D and 15% R in the "normal" D lung to 71% D and 29% R in the granuloma. FISH analysis showed a predominance of male cells of recipient origin.

CONCLUSIONS

DNA analysis of 3 cases of RS suggests that the presence of recurrent granulomas in the graft is associated with an increase in the percentage of recipient DNA in the epithelioid cell clusters, as confirmed by the FISH analysis of 1 case.

In situ activation of helper T cells in the lung

To better understand the lung and systemic responses of helper T cells mediating memory immunity to Mycobacterium tuberculosis, we used three- and four-color flow cytometry to study the surface phenotype of CD4(+) lymphocytes. Bronchoalveolar lavage (BAL) fluid and peripheral blood (PB) samples were obtained from a total of 25 subjects, including 10 tuberculosis (TB)-infected subjects, 8 purified-protein-derivative-negative subjects, and 7 purified-protein-derivative-positive subjects. In marked contrast to CD4(+) lymphocytes from PB (9% +/- 5% expressing CD45RA and CD29), the majority (55% +/- 16%) of CD4(+) lymphocytes in BAL (ALs) simultaneously expressed CD45RA, a naïve T-cell marker, and CD29, members of the very late activation family. Further evaluation revealed that CD4(+) ALs expressed both CD45RA and CD45RO, a memory T-cell marker. In addition, the proportion of CD4(+) lymphocytes expressing CD69, an early activation marker, was drastically increased in BAL fluid (83% +/- 9%) compared to PB (1% +/- 1%), whereas no significant difference was seen in the expression of CD25, the low-affinity interleukin 2 receptor (34% +/- 15% versus 40% +/- 16%). More importantly, we identified a minor population of CD69(bright) CD25(bright) CD4(+) lymphocytes in BAL (10% +/- 6%) that were consistently absent from PB (1% +/- 1%). Thus, CD4(+) lymphocytes in the lung paradoxically coexpress surface molecules characteristic of naïve and memory helper T cells as well as surface molecules commonly associated with early and late stages of activation. No difference was observed for ALs obtained from TB-infected and uninfected lung segments in this regard. It remains to be determined if these surface molecules are induced by the alveolar environment or if CD4(+) lymphocytes coexpressing this unusual combination of surface molecules are selectively recruited from the circulation. Our data suggest that ex vivo experiments on helper T-cell subsets that display distinctive phenotypes may be pivotal to studies on the human immune response to potential TB vaccines.

Increased absolute number but not proportion of gamma/delta T-lymphocytes in the bronchoalveolar lavage fluid of patients with active pulmonary tuberculosis

SETTING

The proportions and absolute cell count of gamma/delta T-lymphocytes in the peripheral blood of patients with pulmonary tuberculosis (PTB) remains controversial. Since PTB is an infections airway disease, bronchoalveolar T-lymphocytes should be a better indicator of local immune T-cell reaction after TB infection than peripheral blood T-lymphocytes.

OBJECTIVE

To quantitate the absolute cell count and proportions of gamma/delta T-lymphocytes in the bronchoalveolar lavage fluid (BALF) of patients with active PTB.

DESIGN

Bronchoalveolar lavage (BAL) and analysis of lymphocytes in the BALF was performed in 25 patients with active PTB and 16 normal controls. All of the patients were negative for HIV infection and none was immunocompromised. BALF and blood were prepared for cell differential count and flow cytometry analysis using monoclonal antibodies CD3, CD4, CD8, CD25, HLA-DR and gamma/delta as well as alpha/beta T-lymphocyte receptors.

RESULTS

The number of cells per volume of recovered BALF was significantly higher in the patients with active PTB than in normal controls. BALF from active PTB patients also showed increased percentage of lymphocytes and neutrophils. The absolute number of total lymphocytes, CD3+ lymphocytes and CD3+ gamma/delta T-lymphocytes were significantly higher in the BALF, but not in the blood, of patients with TB, however, the proportions of CD3+ gamma/delta T-lymphocytes in BALF of patients with TB was comparable to that of normal controls. gamma/delta T-lymphocytes in the BALF rarely expressed CD4, CD25, and HLA-DR in both groups.

CONCLUSION

These results suggest that gamma/delta T-lymphocytes are not the major subpopulation of CD3+ lymphocytes in the BALF that react to mycobacterial infection in the patients with clinically established active TB.

Cytokine profiles of BAL T cells and T-cell clones obtained from human asthmatic airways after local allergen challenge

BACKGROUND

This study assessed the heterogeneity of cytokine expression in asthma before and after local allergen challenge.

METHODS

BAL T cells were obtained 10 min or 24 h after local endobronchial allergen challenge in atopic asthmatic subjects. T cells were cloned by direct limiting dilution. mRNA expression was assessed by RT-PCR, and cytokine protein production by ELISA.

RESULTS

Unstimulated baseline BAL T cells expressed mRNA for IFN-gamma, IL-13, and TNF-alpha. A minority of samples expressed IL-4 and IL-5, but no IL-3 mRNA was detected. PHA stimulation increased expression of IL-3, IL-4, and IL-5 mRNA in 4/6 samples. IL-13 and GM-CSF mRNA were found in BAL cells after allergen challenge, but expression of IFN-gamma was reduced. Both IL-4 and IL-3 were strongly upregulated after PHA stimulation, while the expression of TNF-alpha and IFN-gamma was reduced, compared to equivalent baseline samples. Seventeen panels of BAL T-cell clones were derived (average cloning efficiency 1/40 T cells). Seven panels survived to 8 weeks for analysis. Clones derived 4 h after saline challenge showed strong mRNA signals for IL-13, IL-4, and IFN-gamma, whereas clones derived 24 h after allergen challenge expressed IL-13, GM-CSF, IL-3, IL-4, and often IL-5 (i.e., closer to the Th2 profile). There was considerable heterogeneity in the patterns of cytokine mRNA and protein production by different clones.

CONCLUSIONS

T cells from asthmatic airways produce IL-13, IFN-gamma, and TNF-alpha, but after allergen challenge, type 2 cytokines are upregulated. mRNA and protein analysis provide complementary information on airways T-cell cytokine profiles.

Phenotypic analysis of lymphocytes and monocytes/macrophages in peripheral blood and bronchoalveolar lavage fluid from patients with pulmonary sarcoidosis

BACKGROUND

The granulomatous inflammation in sarcoidosis is driven by the interplay between T cells and macrophages. To gain a better understanding of this process the expression by these cells of cell surface activation markers, co-stimulatory molecules, and adhesion molecules was analysed.

METHODS

CD4+ and CD8+ T lymphocytes from peripheral blood (PBL) or bronchoalveolar lavage (BAL) fluid, as well as paired peripheral blood monocytes and alveolar macrophages from 27 patients with sarcoidosis were analysed by flow cytometry.

RESULTS

CD26, CD54, CD69, CD95, and gp240 were all overexpressed in T cells from BAL fluid compared with those from PBL in both the CD4+ and CD8+ subsets, while CD57 was overexpressed only in BAL CD4+ cells. In contrast, CD28 tended to be underexpressed in the BAL T cells. Monocyte/macrophage markers included CD11a, CD11b, CD11c, CD14, CD16, CD54, CD71, CD80 and CD86 and HLA class II. CD11a expression in alveolar macrophages (and peripheral blood monocytes) was increased in patients with active disease and correlated positively with the percentage of BAL lymphocytes. Expression of CD80 in macrophages correlated with the BAL CD4/CD8 ratio.

CONCLUSIONS

Our data indicate substantial activation of both CD4+ and CD8+ lung T cells in sarcoidosis. There were also increased numbers of BAL lymphocytes whose phenotypic characteristics have earlier been associated with clonally expanded, replicatively senescent cells of the Th1 type.

T cell receptor (TCR) Vbeta gene usage in bronchoalveolar lavage and peripheral blood T cells from asthmatic and normal subjects

T cells are thought to play an important regulatory role in asthma, but little is known about the T cell repertoire of the human lung or whether asthma is associated with any specific repertoire changes. Flow cytometry and MoAbs to TCR VB (TCRBV) families were used to quantify bronchoalveolar lavage (BAL) and blood T cells from normal and atopic individuals. Clonality was then assessed by polymerase chain reaction (PCR) amplification of cDNA and gene scanning using consensus and family-specific TCRBV primers and confirmed by sequence analysis. In addition, blood and BAL T cell populations were studied pre- and post-allergen challenge in four patients with allergic asthma. The majority of TCRBV families detected in blood by MoAb staining were also represented in BAL. While differences between BAL and blood populations were evident in each individual studied, these differences were not consistent between individuals or between CD4+ and CD8+ T cell subpopulations. These results are in broad agreement with other published studies, but in contrast to previous work we found a consistent difference between TCRBV7 family usage in blood and BAL in all individuals studied, and a consistently increased proportion of CD4+ BAL T cells bearing BV5S2/3 in asthmatics only. After allergen challenge, the pattern of TCRBV gene usage was largely unchanged as judged by flow cytometry. Gene scanning of PCR products generated from consensus VB primers revealed polyclonal lymphocyte populations in blood and BAL from all seven atopic individuals: in one normal tested polyclonal populations were found in blood and oligoclonal populations in BAL. Selected families amplified with family-specific primers BV5S2/3, BV6 and BV7 (chosen because of their predominance in BAL compared with blood) were more variable and revealed predominant polyclonal populations in blood and polyclonal or oligoclonal populations in BAL. In one asthmatic patient a clonal BV5S2 family was found in BAL. Following allergen challenge there were no significant changes in polyclonality/oligoclonality/clonality in three cases, but in one case a clonal BV5S2 population was found after challenge, that had not been evident beforehand. The lung T cell repertoire is thus broadly representative of blood T cells, but shows population differences that may result from response to persistent exposure to airborne antigens common to normal and atopic individuals. Oligoclonal TCRBV family expansion appears to be primarily lung-specific but independent of atopic asthma, although our challenge data in one case support the concept that clonal populations may follow local allergen challenge. These data are consistent with selection and amplification of specific T cell families in the lung in response to local antigenic exposure.

Characterization of local memory cells in stage-classified pulmonary tuberculosis: preliminary observations

Immunophenotype analysis and proliferative responses were investigated in bronchoalveolar lavage (BAL) cells from 21 patients with stage-classified tuberculosis: six with localized pulmonary infiltrate (LPI); seven with diffuse pulmonary infiltrate (DPI); and eight with pleural effusions (PE). Bronchoalveolar lavage cells from these patients contained a high number of cells/ml. The macrophage number was significantly lower in the DPI group (P < 0.05) compared to the LPI or PE groups. Conversely, neutrophils were markedly increased in DPI patients compared to LPI (P < 0.01) and PE (P < 0.01) patients. Lymphocyte infiltration (97.7 +/- 2.3% CD3+, > 83% alphabeta+ and CD4+ > CD8+) was observed in the three groups. A significant increase in the number of total lymphocytes (P < 0.01) and CD4+ cells (P < 0.05) was observed in the LPI group compared to the PE group. In the LPI group CD4+CD45RO+ cell infiltration was higher than CD4+CD45RA+ cells (P < 0.001), contrasting to similar numbers of these subpopulations in the DPI group. Lymphocytes from three out of three LPI patients (alphabeta+CD4+CD45RO+) responded against tuberculin purified protein derivative contrasting to the unresponsiveness of five patients with either DPI or PE. This impaired response was reverted in two out of five patients by using peripheral blood monocytes instead of alveolar macrophages. It is suggested that, in humans, alphabetaCD4+CD45RO cells are the main lymphocyte type involved in the initial local cell-mediated immune response against Mycobacterium tuberculosis.

TCR expression and clonality analysis in pulmonary sarcoidosis

Pulmonary sarcoidosis is a granulomatous disease characterized by the accumulation of activated T cells in the lower respiratory tract. To evaluate the hypothesis that sarcoidosis is characterized by a selective activation and expansion of a limited repertoire of T cell receptor (TCR)-specific T cells, we analyzed TCRAV and TCRBV gene expression in bronchoalveolar lavage (BAL) T cells from sarcoidosis patients and, for comparison, from patients with other pulmonary diseases where lymphocyte accumulation is not observed. Increased expression of TCRAV9 and TCRAV14 in BAL T cells was observed in sarcoidosis patients compared to these controls. To ascertain whether the accumulation of AV9 and AV14 expressing BAL T cells in sarcoidosis was the result of clonal expansion, the lengths of the CDR3 regions in AV9 and AV14 transcripts were determined. Some individual patient samples showed evidence of oligoclonality. However, in most cases, the data were consistent with the presence of many different clones. These data suggest that the bulk of BAL T cells in sarcoid patients are either nonspecifically recruited or are responding to a complex mixture of antigens.

Bronchoalveolar lavage fluid profiles in sarcoidosis, tuberculosis, and non-Hodgkin's and Hodgkin's disease. An evaluation of differences

The aim of this study was to identify characteristic features in bronchoalveolar lavage fluid (BALF) samples of patients with tuberculosis, non-Hodgkin's or Hodgkin's disease and to investigate whether these differences facilitate the distinction of those disorders from sarcoidosis presenting with a similar clinical picture. Nonsmoker patients with histologically verified sarcoidosis (n = 29), tuberculosis (n = 6) proven by positive culture, non-Hodgkin's disease, (n = 6) or Hodgkin's disease (n = 7), both histologically verified, were investigated by BAL. A control group consisted of subjects without any pulmonary history. The presence of CD4+ and CD8+ T lymphocytes, as well as the CD4/CD8 ratio in BALF, aided in the differentiation between the various groups. Patients with malignant lymphomas had the lowest CD4/CD8 ratio in BALF, as well as in peripheral blood, and occasionally, plasma cells were present in BALF samples. The most important feature of BALF analysis in tuberculosis was detection of the causal microbial agent. In conclusion, although malignant lymphomas and tuberculosis require histologic evaluation and a positive culture, respectively, for diagnosis, BALF analysis may be of additional value in distinguishing those disorders from sarcoidosis.

Relationship between presentation of sarcoidosis and T lymphocyte profile. A study in bronchoalveolar lavage fluid

One hundred patients with histologically verified sarcoidosis were studied. They were divided into three groups, based on their clinical presentation and smoking status. Group A consisted of patients whose disease was detected by routine chest x-ray film, without symptoms; group B included those with respiratory and general constitutional symptoms; and group C included patients with erythema nodosum and/or arthralgia and hilar lymphadenopathy. Group A showed an increased CD4/CD8 ratio of 4.7 +/- 1.1; group B, 8.0 +/- 1.2; and group C counted for the highest ratio of 10.7 +/- 1.5. Cigarette smoking modifies the immunologic bronchoalveolar lavage (BAL) fluid sample profile, since alveolitis was less pronounced in smokers. In addition, BAL fluid samples obtained from sarcoidosis patients with hilar lymphadenopathy showed the most characteristic features of alveolitis, suggesting a disseminated instead of a local immune response. Therefore, the clinical presentation of sarcoidosis and the smoking status of a sarcoidosis patient are crucial for interpreting individual lavage analysis results.

Impaired G-proteins and cyclic nucleotide phosphodiesterase activity in T-lymphocytes from patients with sarcoidosis

Among the various immune abnormalities which characterize active sarcoidosis, a low proliferative response of peripheral blood lymphocytes to mitogenic lectins has long been observed. Since membrane-associated G-proteins are very likely to be crucial elements in lectin signal transduction, we investigated the binding of 5'-guanylylimidodiphosphate (GppNHp), a non hydrolyzable GTP analogue, to blood total lymphocyte membranes and to blood T-lymphocyte membranes from patients with active sarcoidosis, and from healthy control subjects. GppNHp binding was markedly decreased in peripheral cells from patients with sarcoidosis as compared to controls, suggesting the occurrence of a defect at the level of G-protein(s). A further characterization of G-proteins in these cells by means of ADP-ribose-labelling in the presence of bacterial toxins brought forward a significant decrease in the labelling of a 40 kDa protein, the major pertussis toxin substrate, in membranes from sarcoid patients, while the labelling of the major 44 kDa cholera toxin substrate proved to be unchanged with respect to control membranes. It is hypothesized that, in sarcoid lymphocytes, a defect in the negative control of adenylate cyclase mediated by the inhibitory G-protein Gi, prevents the lowering of cAMP necessary to normal mitogenic response of blood lymphocytes to stimulation. cAMP degradation by the specialized enzyme phosphodiesterase constitutes another critical step in the control of cAMP levels. Both cAMP and cGMP phosphodiesterase activities were found decreased in blood total lymphocyte preparations from sarcoid patients. With purified T-cells, although the mean cAMP and cGMP phosphodiesterase activities from sarcoid patients were found more markedly decreased with respect to healthy donors, only the decrease in cGMP phosphodiesterase was found statistically significant. The role these defects in cyclic nucleotide degradation potentially play in the disturbance of blood lymphocytes response associated with sarcoidosis is discussed.

Characterization of gamma/delta T-lymphocytes in the peripheral blood of patients with active tuberculosis. A comparison with normal subjects and patients with sarcoidosis

Studies in experimental animals have suggested that gamma/delta T-cells play an important role in the immune response against mycobacteria, but evidence for the participation of these cells in the course of human tuberculosis remains fragmentary. We have evaluated the number and state of activation of gamma/delta T-cells in the peripheral blood of patients with active tuberculosis using two-color cytofluorometry, and we have sought evidence that these cells might play a role in the impaired responses to recall antigens seen in some patients by comparing the proliferation of blood T-lymphocytes before and after removing gamma/delta T-cells by panning. Results were compared with those obtained for cells from normal subjects and from patients with sarcoidosis. The proportion and absolute number of circulating CD3+ gamma/delta T-cells were not significantly different comparing blood from patients with tuberculosis and that from control subjects [54.6 +/- 39.9 (n = 17) and 59.1 +/- 30.2 cells/microliters (n = 10), respectively, p > 0.2], and the proportion of cells expressing receptors using the V delta 1 variable region remained unchanged in patients with tuberculosis. Few gamma/delta T-cells from patients with tuberculosis expressed surface antigens associated with activation (IL-2R, < 1%; HLA-DR, 2.6 +/- 3.4%). Four of 15 patients with sarcoidosis had a proportion of gamma/delta T-cells that was outside the range observed in normal subjects, but the absolute number of CD3+ gamma/delta T-lymphocytes was not different comparing the two groups (p > 0.2).(ABSTRACT TRUNCATED AT 250 WORDS)