A study of acute-phase reactant proteins in Indonesian patients with pulmonary tuberculosis

Analysis of the IgG subclass profile and IgG sum-total discrepancy in COVID-19 convalescent plasma donors: A single-centre prospective cohort study

INTRODUCTION

Although IgG1 and IgG3 have been shown to be the dominant subclasses in the acute phase of SARS-CoV-2 infection, little is known about the distribution of IgG subclasses during the recovery phase of COVID-19. The aim of the study was to analyze the profile of IgG subclasses in COVID-19 convalescent plasma donors.

METHODS

A total of 36 convalescent plasma donors were included in the analysis. IgG and IgG subclass levels were measured using a nephelometric assay in plasma samples obtained directly from the plasma container.

RESULTS

Although there was no significant difference in the concentration of IgG subclasses between the study and control groups, the contribution of IgG1 to the total IgG pool between the study and control groups was statistically significant (p = 0.0478). In addition, there was a discrepancy between the total IgG and IgG sum values in the study group, exceeding 15 % in 19,4 % of samples (n = 7), while in the control group no samples with a sum/ total IgG difference > 15 % were observed.

CONCLUSIONS

The selective affinity of the IgG1 subclass for the polyclonal anti-IgG reagent may interfere with the determination of total IgG and should be considered when interpreting the results of enzyme immunoassays DATA AVAILABILITY: The data that support the findings of this study are available on request from the corresponding author.

Altered systemic levels of acute phase proteins in tuberculous lymphadenitis and modulation after treatment

Background

Pulmonary tuberculosis (PTB) is characterized by elevated levels of acute phase proteins (APPs), but their association with tuberculous lymphadenitis (TBL) is poorly studied.

Methods

We examined the systemic levels of APPs (alpha-2-macroglobulin [⍺-2MG], serum amyloid A [SAA], C-reactive protein [CRP] and haptoglobin [Hp]) in TBL, PTB, latent tuberculosis (LTB) and healthy controls (HC) at baseline and in TBL after the completion of anti-tuberculosis treatment (ATT). We have also examined the association of these proteins with lymph node (LN) size, culture grade and multiple versus single LN involvement.

Results

TBL individuals exhibited increased systemic levels of ⍺-2MG, SAA, CRP and Hp in comparison to HCs and increased CRP levels in comparison to LTB individuals. TBL individuals also exhibited decreased systemic levels of Hp compared to PTB individuals. APPs were not significantly associated with LN size, LN involvement and culture grade, indicating a lack of association with disease severity. Following ATT, post-treatment levels of ⍺-2MG, CRP and Hp were significantly diminished compared to pre-treatment levels.

Conclusion

TBL disease is characterized by altered levels of APPs at baseline and modulated following treatment, indicating the presence of systemic inflammation.

Transcriptional profiles discriminate patients with pulmonary tuberculosis from non-tuberculous individuals depending on the presence of non-insulin diabetes mellitus

Our objective was to identify transcriptional biomarkers in peripheral blood mononuclear cells (PBMC) that discriminate individuals with latent tuberculosis infection (LTBI) from those with pulmonary tuberculosis (PTB) in subjects with non-insulin-dependent diabetes mellitus (NIDDM) and in individuals without NIDDM. Using gene expression microarrays we identified differentially expressed genes from lungs of mice infected with Mycobacterium tuberculosis (Mtb) or a mutant (ΔsigH) representing a non-inflammatory model. Genes expressed in blood, with inflammatory related functions were evaluated in humans by RT-qPCR. NCF1 and ORM transcripts have the better discriminatory capacity to identify PTB subjects from LTBI and non-infected controls (NICs) independently of the presence of NIDDM. The sequential evaluation of the mRNA levels of NCF1 and ORM as multiple diagnostic tests showed 95% Sensitivity (Se) and 80% Specificity (Sp). In addition, FPR2 promises to be a good biomarker for the PTB detection in subjects with NIDDM (Se=100%; Sp=90%).

Differential Levels of Alpha-2-Macroglobulin, Haptoglobin and Sero-Transferrin as Adjunct Markers for TB Diagnosis and Disease Progression in the Malnourished Tribal Population of Melghat, India

Lack of diagnostic capacity has been a crucial barrier preventing an effective response to the challenges of malnutrition and tuberculosis (TB). Point-of-care diagnostic tests for TB in immuno-incompetent, malnourished population are thus needed to ensure rapid and accurate detection. The aim of the study was to identify potential biomarkers specific for TB infection and progression to overt disease in the malnourished population of Melghat. A prospective cohort study was conducted in the year 2009 through 2011 in six villages of the Melghat region. 275 participants consisting of malnourished cases with a) active TB (n = 32), b) latent TB infection (n = 90), c) with no clinical or bacteriological signs of active or latent TB (n = 130) and healthy control subjects (n = 23) were recruited for the study. The proteome changes of the host serum in response to Mycobacterium tuberculosis (M.tb) infection were investigated using one dimensional electrophoresis in combination with matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS). Three most differentially expressed proteins; alpha-2-macroglobulin (A-2-M), sero-transferrin and haptoglobin were identified by MALDI-TOF MS analysis, which were up-regulated in the malnourished patients with active TB and down-regulated in the malnourished patients compared with the healthy controls. Additionally, follow-up studies indicated that the expression of these proteins increased to nearly two folds in patients who developed active disease from latent state. Our preliminary results suggest that A-2-M, sero-transferrin and haptoglobin may be clinically relevant host biomarkers for TB diagnosis and disease progression in the malnourished population. This study provides preliminary framework for an in-depth analysis of the biomarkers in larger well-characterized cohorts. Evaluation of these biomarkers in follow-up cases may further aid in improving TB diagnosis.

Anemia in hospitalized patients with pulmonary tuberculosis

OBJECTIVE:

To describe the prevalence of anemia and of its types in hospitalized patients with pulmonary tuberculosis.

METHODS:

This was a descriptive, longitudinal study involving pulmonary tuberculosis inpatients at one of two tuberculosis referral hospitals in the city of Rio de Janeiro, Brazil. We evaluated body mass index (BMI), triceps skinfold thickness (TST), arm muscle area (AMA), ESR, mean corpuscular volume, and red blood cell distribution width (RDW), as well as the levels of C-reactive protein, hemoglobin, transferrin, and ferritin.

RESULTS:

We included 166 patients, 126 (75.9%) of whom were male. The mean age was 39.0 ± 10.7 years. Not all data were available for all patients: 18.7% were HIV positive; 64.7% were alcoholic; the prevalences of anemia of chronic disease and iron deficiency anemia were, respectively, 75.9% and 2.4%; and 68.7% had low body weight (mean BMI = 18.21 kg/m²⁾. On the basis of TST and AMA, 126 (78.7%) of 160 patients and 138 (87.9%) of 157 patients, respectively, were considered malnourished. Anemia was found to be associated with the following: male gender (p = 0.03); low weight (p = 0.0004); low mean corpuscular volume (p = 0.03);high RDW (p = 0; 0003); high ferritin (p = 0.0005); and high ESR (p = 0.004). We also found significant differences between anemic and non-anemic patients in terms of BMI (p = 0.04), DCT (p = 0.003), and ESR (p < 0.001).

CONCLUSIONS:

In this sample, high proportions of pulmonary tuberculosis patients were classified as underweight and malnourished, and there was a high prevalence of anemia of chronic disease. In addition, anemia was associated with high ESR and malnutrition.

Proteomic profiling of serum from patients with tuberculosis

Background

Effective treatment and monitoring of tuberculosis (TB) requires biomarkers that can be easily evaluated in blood samples. The aim of this study was to analyze the serum proteome of patients with TB and to identify protein biomarkers for TB.

Methods

Serum samples from 26 TB patients and 31 controls were analyzed by using nano-flow ultra-performance liquid chromatography coupled to quadrupole time-of-flight mass spectrometry in data-independent mode, and protein and peptide amounts were calculated by using a label-free quantitative approach. The generated data were analyzed by using principal component analysis and partial least squares discriminant analysis, a multivariate statistical method.

Results

Of more than 500 proteins identified, alpha-1-antitrypsin was the most discriminative, which was 4.4 times higher in TB patients than in controls. Peptides from alpha-1-antitrypsin and antithrombin III increased in TB patients and showed a high variable importance in the projection scores and coefficient in partial least square discriminant analysis.

Conclusions

Sera from patients with TB had higher alpha-1-antitrypsin levels than sera from control participants. Alpha-1-antitrypsin levels may aid in the diagnosis of TB.

Increased level of acute phase reactants in patients infected with modern Mycobacterium tuberculosis genotypes in Mwanza, Tanzania

BACKGROUND

There is increasing evidence to suggest that different Mycobacterium tuberculosis lineages cause variations in the clinical presentation of tuberculosis (TB). Certain M. tuberculosis genotypes/lineages have been shown to be more likely to cause active TB in human populations from a distinct genetic ancestry. This study describes the genetic biodiversity of M. tuberculosis genotypes in Mwanza city, Tanzania and the clinical presentation of the disease caused by isolates of different lineages.

METHODS

Two-hundred-fifty-two isolates from pulmonary TB patients in Mwanza, Tanzania were characterized by spoligotyping, and 45 isolates were further characterized by mycobacterium interspersed repetitive unit-variable number tandem repeat (MIRU-VNTR). The patients' level of the acute phase reactants AGP, CRP and neutrophil counts, in addition to BMI, were measured and compared to the M. tuberculosis lineage of the infectious agent for each patient.

RESULTS

The most frequent genotype was ST59 (48 out of 248 [19.4%]), belonging to the Euro-American lineage LAM11_ZWE, followed by ST21 (CAS_KILI lineage [44 out of 248 [17.7%]). A low degree of diversity (15.7% [39 different ST's out of 248 isolates]) of genotypes, in addition to a high level of mixed M. tuberculosis sub-populations among isolates with an unreported spoligotype pattern (10 out of 20 isolates [50.0%]) and isolates belonging to the ST53 lineage (13 out of 25 [52%]) was observed. Isolates of the 'modern' (TbD1-) Euro-American lineage induced higher levels of α1-acid glycoprotein (β = 0.4, P = 0.02; 95% CI [0.06-0.66]) and neutrophil counts (β = 0.9, P = 0.02; 95% CI [0.12-1.64]) and had lower BMI score (β = -1.0, P = 0.04; 95% CI[-1.89 - (-0.03)]). LAM11_ZWE ('modern') isolates induced higher levels of CRP (β = 24.4, P = 0.05; 95% CI[0.24-48.63]) and neutrophil counts (β = 0.9, P = 0.03; 95% CI[0.09-1.70]).

CONCLUSION

The low diversity of genotypes may be explained by an evolutionary advantage of the most common lineages over other lineages combined with optimal conditions for transmission, such as overcrowding and inadequate ventilation. The induction of higher levels of acute phase reactants in patients infected by 'modern' lineage isolates compared to 'ancient' lineages may suggest increased virulence among 'modern' lineage isolates.

Biomarker discovery in subclinical mycobacterial infections of cattle

BACKGROUND

Bovine tuberculosis is a highly prevalent infectious disease of cattle worldwide; however, infection in the United States is limited to 0.01% of dairy herds. Thus detection of bovine TB is confounded by high background infection with M. avium subsp. paratuberculosis. The present study addresses variations in the circulating peptidome based on the pathogenesis of two biologically similar mycobacterial diseases of cattle.

METHODOLOGY/PRINCIPAL FINDINGS

We hypothesized that serum proteomes of animals in response to either M. bovis or M. paratuberculosis infection will display several commonalities and differences. Sera prospectively collected from animals experimentally infected with either M. bovis or M. paratuberculosis were analyzed using high-resolution proteomics approaches. iTRAQ, a liquid chromatography and tandem mass spectrometry approach, was used to simultaneously identify and quantify peptides from multiple infections and contemporaneous uninfected control groups. Four comparisons were performed: 1) M. bovis infection versus uninfected controls, 2) M. bovis versus M. paratuberculosis infection, 3) early, and 4) advanced M. paratuberculosis infection versus uninfected controls. One hundred and ten differentially elevated proteins (P < or = 0.05) were identified. Vitamin D binding protein precursor (DBP), alpha-1 acid glycoprotein, alpha-1B glycoprotein, fetuin, and serine proteinase inhibitor were identified in both infections. Transthyretin, retinol binding proteins, and cathelicidin were identified exclusively in M. paratuberculosis infection, while the serum levels of alpha-1-microglobulin/bikunin precursor (AMBP) protein, alpha-1 acid glycoprotein, fetuin, and alpha-1B glycoprotein were elevated exclusively in M. bovis infected animals.

CONCLUSIONS/SIGNIFICANCE

The discovery of these biomarkers has significant impact on the elucidation of pathogenesis of two mycobacterial diseases at the cellular and the molecular level and can be applied in the development of mycobacterium-specific diagnostic tools for the monitoring progression of disease, response to therapy, and/or vaccine based interventions.

Immunodiagnosis of tuberculosis: An update

Tuberculosis is still a major health problem in most developing countries and its incidence is rising in many developed countries. This resurgence has been attributed to the HIV epidemic and TB has been declared as a global health emergency by WHO in 1993. The diagnosis of tuberculosis mainly depends upon initial clinical suspicion and radiographic findings with subsequent bacteriological confirmation by sputum smear examination and culture. Lack of sensitivity in smear examination, non specificity of radiological findings, extended tum around time ofMycobacterium tuberculosis culture and difficulties in diagnosing paucibacillary, childhood and extrapulmonary tuberculosis has necessitated to explore the utility of immunodiagnosis of tuberculosis as a convenient and cost effective test to supplement clinical information for definite diagnosis. Many commercial tests are available in the market for diagnosis of TB. Most of these tests are based on the detection of IgG, IgA and IgM antibodies to specific mycobacterial antigen or mixture of antigens. Indigenous immunoassay systems have explored excretory-secretory ES-31 mycobacterial antigen for immunodiagnosis of TB. Many a time there is lack of consistent elevation in all the three Ig classes in active infection thus making it more important to determine the ideal antibody isotype assay for reliable diagnosis of tuberculosis and to save the costs of the patient for unnecessary investigations.

Acute phase protein concentrations predict parasite clearance rate during therapy for visceral leishmaniasis

Visceral leishmaniasis (VL) remains a major health problem in Kenya and other parts of Africa, Central America and Asia. Currently, splenic aspirate smear and culture are the standard methods of monitoring therapy and relapse. Acute phase reactant markers, C-reactive protein (CRP), serum amyloid A protein (SAA) and alpha 1-acid glycoprotein (AGP) were evaluated as less invasive techniques for monitoring therapy in 59 patients with VL before, during and after therapy. CRP, SAA and AGP were elevated in VL patients at admission and the concentrations decreased with effective therapy to reach normal levels by the end of therapy (SAA and AGP) or by 3 months follow-up (CRP). Two groups of patients were selected on the basis of rate of parasite clearance. The acute phase protein concentrations were significantly raised in those slower to clear parasites. Analysis of sensitivity and specificity of acute phase proteins as predictors of parasite clearance suggested that they might represent useful non-invasive markers for monitoring disease activity, response to therapy and relapse in VL.

Impact of tuberculosis in children with idiopathic nephrotic syndrome

Forty black South African children (mean age 4.7 +/- 2.6 years) with idiopathic nephrotic syndrome due to focal glomerulosclerosis (FSGS) were evaluated. Tuberculosis (TB) was found in 37.5% of children with FSGS (FSGS-TB) compared with 6% of a comparable group with minimal lesion nephrotic syndrome. No significant differences were found in the initial mean serum albumin, cholesterol, triglyceride and creatinine levels in FSGS-TB compared with children with glomerulosclerosis but without TB (FSGS-nonTB). The mean serum levels of C4, IgA and IgM were increased by 30%, 25% and 23%, respectively in children with FSGS-TB compared with FSGS-nonTB. Initial estimated creatinine clearance was similar in the two groups, but after a mean follow-up of 2.4 years, the mean estimated creatinine clearance of children with FSGS-TB was significantly reduced by 46% from the initial value, but remained stable in the FSGS-nonTB group. FSGS-TB children also had significantly increased requirements for renal replacement therapy compared with children with FSGS-nonTB. We conclude that TB infection is commonly associated with FSGS in black South African children; this may have deleterious effects on renal function.

Spectrum of immune reactivity to mycobacterial (BCG) antigens in healthy hospital contacts in south India

In an effort to study the immunological responses to antigens of tubercle bacilli, 49 tuberculin positive and 41 tuberculin negative hospital contacts aged 20-29 years (staff nurses and students working in Government Rajaji Hospital, Madurai, South India) were studied for serum antibodies (IgG, IgM and IgA classes) to BCG by ELISA and diameter of induration to PPD by Mantoux procedures. The two immunological parameters were correlated in regression analysis. The results have revealed higher anti-BCG serum antibody levels in hospital contacts than in non-contacts, significantly higher antibodies in tuberculin negative hospital contacts than in tuberculin positive hospital contacts, an inverse correlation of tuberculin reactivity and antibodies and a bimodal decline (regression) of antibodies against the increase in skin test induration. This study has thus suggested the existence of an immunological spectrum in hospital contacts from south India; persons at one pole of the spectrum were tuberculin negative and possessed significantly elevated antibody levels and those at the other pole of the spectrum were tuberculin positive and possessed low antibody levels. Thus the spectrum of immune reactivity may be due to an inherent susceptibility/resistance of an individual to Mycobacterium tuberculosis.

New approaches to the diagnosis of tuberculosis in childhood with special reference to neurotuberculosis

Bacteriological diagnosis of tuberculosis in childhood is often unsuccessful owing to the difficulty in obtaining suitable specimens. Many attempts have been made to diagnose tuberculosis immunologically but with very limited success. Positive tuberculin reactions may be the result of nonspecific sensitization while negative reactions occur in undernourished children. Serodiagnostic tests suffer from problems of specificity, even when very specific antigens are used, and are often least helpful in diagnostically difficult cases. Detection of antigen has proved to be of more value, especially with clean specimens such as cerebrospinal and pleural fluids. Detection of specific components of Mycobacterium tuberculosis by linked gas chromatography and mass spectroscopy is very sensitive and specific but the equipment is very costly. Detection of specific DNA sequences of M. tuberculosis in specimens by use of labelled 'DNA probes' is rather insensitive although the sensitivity may be increased greatly by use of the polymerase chain reaction to amplify small amounts of the specific DNA. Non specific indicators of tuberculosis are generally unhelpful although the bromide partition test and assay of the enzyme adenosine deaminase in cerebrospinal fluid appear to be of value in the diagnosis of tuberculous meningitis. More research is required to develop a simple, specific and automated test for tuberculosis in childhood.

Changes in serum proteins (albumin, immunoglobulins and acute phase proteins) in pulmonary tuberculosis during therapy

Serum levels of three immunoglobulins (IgG, IgA & IgM), albumin and six acute phase proteins (alpha 1-antitrypsin, haptoglobin, transferrin, alpha 2-macroglobulin, complements C3 & C4) were measured by immunoelectrophoresis in 57 patients with pulmonary tuberculosis when they were first diagnosed, and followed at 1 month, 2 month and 4 month intervals during anti-tuberculosis treatment. These values were compared to those from 41 healthy controls. Significant increases were observed in the initial values of serum IgG, IgM, alpha 1-antitrypsin and haptoglobin, while transferrin and alpha 2-macroglobulin levels were significantly reduced. No changes were observed in the levels of serum albumin, IgA and complement C3. Levels of all measured proteins decreased with treatment. However, at 4 months, IgG and alpha 1-antitrypsin were still significantly elevated when compared to control values, while the level of haptoglobin had decreased to a level significantly lower than that of the control value.

Complement activation in pulmonary tuberculosis

The alterations in serum/plasma levels of total haemolytic complement activity (CH50), complement components C3 and C3d, and circulating immune complexes (CICs) in patients with pulmonary tuberculosis were analysed in relation to the severity of disease and treatment status. The mean levels of CH50, C3, C3d and CICs were significantly higher in untreated than treated patients and in normal controls. In the untreated group, the level of each of these four parameters except C3d was significantly higher in patients with far advanced disease than in those with moderately advanced disease, whereas the difference between treated patients and normal controls was not statistically significant for any of the four parameters tested. There were statistically significant correlations between levels of CICs and both C3 and C3d in the untreated tuberculosis patients. However, the correlations for the same parameters were not significant when treated patients were considered. The CH50 levels in tuberculosis patients suggest a functional classical complement pathway, which is essential for immune complex solubilisation. High C3d level in untreated patients is indicative of increased complement activation, which in turn shows significant correlation with levels of CICs. It appears that the intact and elevated complement proteins and their proper activation by CICs prevents tuberculosis from becoming a typical immune complex disease.

Total and anti-mycobacterial IgE levels in serum from patients with tuberculosis and leprosy

A radioallergosorbent assay (RAST) was developed and used to determine the levels of IgE antibodies to soluble antigens of Mycobacterium tuberculosis (BCG vaccine strain) in sera from patients with tuberculosis and leprosy and in healthy control subjects. Total IgE levels in the same sera were quantitated with a commercial radioimmunoassay kit. Patients with tuberculosis and leprosy had higher total and specific IgE levels than the control groups but the overlap of levels in patients and controls was too great to render the difference diagnostically useful. Specific IgE levels were elevated in both tuberculosis and leprosy patients, suggesting that this antibody response is towards the shared mycobacterial antigens. No differences in total or specific IgE levels were found between healthy hospital workers occupationally exposed to patients with tuberculosis and factory workers who are not exposed.

Relationship between radiological classification and the serological and haematological features of untreated pulmonary tuberculosis in Indonesia

Immunological and metabolic responses were studied in 110 patients with newly diagnosed pulmonary tuberculosis and 32 healthy controls from similar socioeconomic backgrounds. The severity of lung involvement was assessed radiologically, but this was not related to the current features of cell mediated immunity or to those of many aspects of the serological response to Mycobacterium tuberculosis. However, the patients with more extensive pulmonary tuberculosis showed higher titres of IgG2 antibody to whole killed M. tuberculosis and to the ML34 epitope shared by many species of mycobacteria. The patients with more extensive pulmonary tuberculosis showed a more marked metabolic response to infection as manifested by changes in serum levels of acute phase reactant proteins. Accordingly, the metabolic responses are considered to be more likely to prove of value in clinical monitoring of patients for severity of infection, or of reactivation of infection with M. tuberculosis, than immunological responses.

Association of HLA and other genetic markers in South Indian patients with pulmonary tuberculosis

Histocompatibility antigens (A, B & C loci) and 23 other single gene characters were studied in 204 pulmonary tuberculosis patients belonging to a single endogamous group in South India. None of the previously reported associations with HLA antigens was confirmed, nor any new one found. The blood O and Rh negative associations were also not confirmed, although a new association with the Jk blood group system appears possible. Of particular interest is the association with the phosphoglucomutase (PGM1) system, which parallels that found in a different population located some 1000 km away. Relative risks were calculated to measure the resistance of individuals with the PGM1*2+ allele.

The effect of exposure of hospital employees to patients with tuberculosis on dermal reactivity to four new tuberculins

An early (6-8 h) erythematous response to Purified Protein Derivative and to sonicate antigens (new tuberculins) prepared from Mycobacterium tuberculosis, M. vaccae, M. scrofulaceum, and M. leprae occurred much more frequently amongst hospital employees exposed to patients with tuberculosis than amongst factory workers. Biopsies taken from the skin test sites at 48 h revealed a more intense inflammatory cell infiltrate in response to PPD and the sonicate of M. tuberculosis, but not to the antigens of the other mycobacteria, amongst the hospital employees thus indicating a degree of specificity. The early response appears to be directed towards species specific antigens, but not, apparently, to the same as those that elicit the 48 h reactions. The hospital employees also had higher peripheral blood B-cell counts and total IgG levels, suggestive of an adjuvant effect. It is postulated that the early reaction results from repeated exposure to tubercle bacilli and the possible nature of the reaction is discussed.

A study of vitamin D levels in Indonesian patients with untreated pulmonary tuberculosis

The levels of serum vitamin D, measured as 25-hydroxycholecalciferol (25-OHD3), among 40 Indonesian patients with pulmonary tuberculosis and 38 healthy controls were very similar. In both groups the distribution of the serum 25-OHD3 levels were bimodal with about a quarter of the individuals belonging to the group with higher levels. There was a tendency for controls in this group to be tuberculin negative and for patients in this group to have less extensive active pulmonary disease. Although it is uncertain whether such associations result from a direct effect of vitamin D on protective immune reactions, the use of this vitamin as an adjunct to antituberculosis therapy merits consideration.

Haptoglobin: an immunoregulatory role in tuberculosis?

A significant correlation was found between levels of haptoglobin in sera from Indonesian patients with tuberculosis and the extent to which these sera suppressed mitogen-driven activation of normal lymphocytes in vitro. As in a previous study we showed that there was an inverse relationship between haptoglobin levels and the circulating lymphocyte count in the same group of patients, it is now suggested that this protein has an immunoregulatory role in tuberculosis. Similar observations have been made by other workers on patients with cancer. There was no difference in the distribution of the 3 allotypes of haptoglobin in patients and healthy subjects nor was there any association between such allotypes and the lymphocyte count, the dermal reactivity to tuberculin or the degree of suppression.

Human leukocyte antigens and circulating immunoglobulin levels in Indian patients with pulmonary tuberculosis

Histocompatibility antigens (-A, -B and -C loci) and circulating antibodies (IgG, IgM, IgA and IgE) were studied in 63 pulmonary tuberculosis patients and regionally matched healthy volunteers from Uttar Pradesh, India. A previously described association with antigen B15 in an heterogeneous sample of North India was not confirmed but a slight increase of antigen B18 was found. The levels of immunoglobulins in the plasma of these patients showed a significant increase in IgG, IgA and IgE. Although the increased levels of IgG and IgA are in agreement with previous studies, the role of the increased IgE is not clear and needs further investigation. Patients who were antigen B14 and B18 positive tend to show significantly low levels of IgG, which suggests a possible genetic influence on the expression of immunoglobulin levels.

Qualitative differences in tuberculin reactivity in patients with tuberculosis, occupational contacts and non-contacts

Qualitative differences in tuberculin reactivity between patients with pulmonary tuberculosis, occupational contacts and non-contacts were observed. An erythematous reaction at 6-8 hours was frequently observed in both patients and contacts but much less frequently in non-contacts. Itching and the presence of superficial bullae occurred principally in the contact group, and the erythematous reactions at 48 hours were largest in this group. Attention needs to be paid therefore to several characteristics, other than size, of the tuberculin reaction.

Serum angiotensin-converting enzyme and delayed hypersensitivity in pulmonary tuberculosis

In contrast to sarcoidosis, there was no difference between serum angiotensin-converting enzyme (ACE) levels in a group of 100 adult Indonesian patients with active pulmonary tuberculosis and in 108 matched healthy control subjects. There was a significant inverse correlation between the diameter of the cutaneous reaction to tuberculin and serum ACE levels. It is postulated that, as both delayed hypersensitivity and ACE synthesis within granulomas appear to be the result of T-cell induced secretory activities of macrophages, this inverse relationship results from competition for receptor sites for the relevant signal molecules on the macrophage surface.

Serum phosphorus levels in pulmonary tuberculosis

The mean level of phosphorus was significantly higher in a group of 96 Indonesian patients with pulmonary tuberculosis than in 100 control subjects. The levels in disease showed a moderate correlation with those of the globulin proteins, but not the gamma-globulins. There was an association between levels of phosphorus and those of transferrin but not with those of seven other acute-phase associated proteins. There was a tendency for phosphorus levels to be higher in those with elevated polymorphonuclear leucocyte counts and, although not significantly so, in those with more extensive active disease, suggesting an association with tissue destruction. It appears therefore more relevant to study the behaviour of this element than that of calcium in tuberculosis.