Immune status changing helps diagnose osteoarticular tuberculosis

Objective

This study is aimed to develop a new nomogram for the clinical diagnosis of osteoarticular tuberculosis (TB).

Methods

xCell score estimation to obtained the immune cell type abundance scores. We downloaded the expression profile of GSE83456 from GEO and proceed xCell score estimation. The routine blood examinations of 326 patients were collected for further validation. We analyzed univariate and multivariate logistic regression to identified independent predicted factor for developing the nomogram. The performance of the nomogram was assessed using the receiver operating characteristic (ROC) curves. The correlation of ESR with lymphocytes, monocytes, and ML ratio was performed and visualized in osteoarticular TB patients.

Results

Compared with the healthy control group in the dataset GSE83456, the xCell score of basophils, monocytes, neutrophils, and platelets was higher, while lymphoid was lower in the EPTB group. The clinical data showed that the cell count of monocytes were much higher, while the cell counts of lymphocytes were lower in the osteoarticular TB group. AUCs of the nomogram was 0.798 for the dataset GSE83456, and 0.737 for the clinical data. We identified the ML ratio, BMI, and ESR as the independent predictive factors for osteoarticular TB diagnosis and constructed a nomogram for the clinical diagnosis of osteoarticular TB. AUCs of this nomogram was 0.843.

Conclusions

We demonstrated a significant change between the ML ratio of the EPTB and non-TB patients. Moreover, we constructed a nomogram for the clinical diagnosis of the osteoarticular TB diagnosis, which works satisfactorily.

Diagnostic value of ELISPOT technique for osteoarticular tuberculosis

BACKGROUND

Osteoarticular tuberculosis (TB) is a common severe form of extrapulmonary tuberculosis. Early di- agnosis and treatment can decrease the deformity of spine and limbs and joint dysfunction.

METHODS

We compared and evaluated two commercially available rapid test kits based on the ELISPOT assay for the diagnosis of osteoarticular disease.

RESULTS

The diagnostic sensitivity and specificity of the FS-SPOT assay (50.0% and 85.7%) were similar to those of the T-SPOT-TB assay (45.5% and 81.0%). When the two test wells in the T-SPOT-TB assay were both positive, the test wells in FS-SPOT assay were usually positive with the number of SFCs exceeding those in the negative control wells by more than 30. The sensitivities, specificities, PPV, NPV, and agreement of FS-SPOT assay results in 99 TB cases and 54 non-TB disease cases were 55.6%, 83.3%, 84.7%, 52.9%, and 66.0%, respectively. SFC counts from test wells in the TB group were significantly higher than those from the non-TB group (p < 0.001).

CONCLUSIONS

Higher numbers of SFCs in the ELISPOT assay suggest higher risk of active TB. ELISPOT may be a diagnostic aide for active osteoarticular TB.

Interleukin-3 and interleukin-17 do not play a dynamic role in the immunopathogenesis of osteoarticular tuberculosis

BACKGROUND

Osteoarticular tuberculosis accounts for one to three per cent of all cases of active TB. IL-3 stimulates the proliferation, differentiation and survival of pluripotent stem cells. IL-17 has shown to promote inflammatory cell recruitment and granuloma organization throughout infection with Mycobacterium tuberculosis. During the chronic phase of the infection, a balance between Th1 and Th17 responses needs to be achieved to limit immunopathology.

AIM

To correlate the serum levels of IL-3 and IL-17 at presentation and after completion of treatment in clinicoradiologically proven cases of osteoarticular tuberculosis.

METHODS

32 clinicoradiologically confirmed cases of osteoarticular tuberculosis were included. Archived serum samples of eight patients of osteoarticular tuberculosis of an earlier study, confirmed by PCR, AFB smear or by histopathology with previously determined IL-12 and TGF-beta levels were available. A detailed history was noted and their general physical, local and relevant systemic examination was performed. Various laboratory parameters including TL-3 and IL-17 levels in serum were estimated at presentation and at six months of DOTS CAT-1 treatment.

RESULTS

There was a significant improvement in the clinical and radiological parameters after treatment. No correlation was found between IL-3 and IL-17 levels before and after treatment. A significant correlation (p value= 0.022) was shown between levels of IL-3 and IL-12 after six months of treatment.

CONCLUSIONS

Qualitative and quantitative fluctuations in IL-3 and IL-17 levels were not able to serve as useful indices of disease activity.

Multicentric tuberculosis at two rare sites in an immunocompetent adult

The case of a 20-year-old female who presented with refractory coccydynia and sternal pain is described. She was immunocompetent, and had no systemic features. She was diagnosed with tuberculosis of the sternal and coccygeal regions based on magnetic resonance imaging and histopathology of biopsy specimens. Conservative management with oral multidrug antituberculous therapy completely cured the patient, and she had not suffered any recurrence after three years of follow-up. This case highlights the possibility of the multicentric presentation of tuberculosis at two rare sites in the same immunocompetent patient, even though the differential diagnosis was coccydynia.

The use of immunomodulators as an adjunct to antituberculous chemotherapy in non-responsive patients with osteo-articular tuberculosis

We studied 51 patients with osteo-articular tuberculosis who were divided into two groups. Group I comprised 31 newly-diagnosed patients who were given first-line antituberculous treatment consisting of isoniazid, rifampicin, ethambutol and pyrazinamide. Group II (non-responders) consisted of 20 patients with a history of clinical non-responsiveness to supervised uninterrupted antituberculous treatment for a minimum of three months or a recurrence of a previous lesion which on clinical observation had healed. No patient in either group was HIV-positive. Group II were treated with an immunomodulation regime of intradermal BCG, oral levamisole and intramuscular diphtheria and tetanus vaccines as an adjunct for eight weeks in addition to antituberculous treatment. We gave antituberculous treatment for a total of 12 to 18 months in both groups and they were followed up for a mean of 30.2 months (24 to 49). A series of 20 healthy blood donors served as a control group.

Twenty-nine (93.6%) of the 31 patients in group I and 14 of the 20 (70%) in group II had a clinicoradiological healing response to treatment by five months.

The CD4 cell count in both groups was depressed at the time of enrolment, with a greater degree of depression in the group-II patients (686 cells/mm3 (sd 261) and 545 cells/mm3 (sd 137), respectively; p < 0.05). After treatment for three months both groups showed significant elevation of the CD4 cell count, reaching a level comparable with the control group. However, the mean CD4 cell count of group II (945 cells/mm3 (sd 343)) still remained lower than that of group I (1071 cells/mm3 (sd 290)), but the difference was not significant. Our study has shown encouraging results after immunomodulation and antituberculous treatment in non-responsive patients. The pattern of change in the CD4 cell count in response to treatment may be a reliable clinical indicator.

Isolation and characterisation of in vivo released 41 kDa mycobacterial antigen in pulmonary and bone and joint tuberculosis and its identification with H37Ra in vitro released antigen

OBJECTIVE

To isolate and characterise in vivo released 41 kDa mycobacterial antigen in pulmonary and bone and joint tuberculosis (TB) and its identification with in vitro released ES-41 kDa antigen.

DESIGN

Circulating antigen was isolated from confirmed pulmonary tuberculosis serum (PTS) and bone and joint tuberculosis serum (BJS) by trichloroacetic acid precipitation and further fractionation by fast-protein liquid chromatography (FPLC).

RESULTS

Fractionation of PTS and BJS by gel filtration column gave six protein fractions each. PTS-G3 and BJS-G3 showed maximum antigenic activity with ELISA. Further fractionation of PTS-G3 and BJS-G3 on cation exchange FPLC gave four different fractions each, of which BJS-G3B was seroreactive similarly to in vitro released 41 kDa antigen (ES-41) isolated from culture medium, whereas PTS-G3C was slightly less seroreactive. BJS-G3B could inhibit binding of in vitro released ES-41 to affinity purified antibodies in inhibition ELISA at lower concentrations than PTS-G3C (2 vs. 20 ng/ml), showing the identical nature of the antigens. Biochemical characterisation showed that circulating antigen PTS-G3C, BJS-G3B and in vitro released ES-41 antigen were lipoproteins in nature.

CONCLUSION

This study helped to demonstrate the presence of 41 kDa antigen in the serum of pulmonary and bone and joint TB patients and its identification with H37Ra in vitro released 41 kDa antigen.

Humoral immune response against 38-kDa and 16-kDa mycobacterial antigens in bone and joint tuberculosis

SETTING

The diagnosis of bone and joint tuberculosis (BTB) is difficult, and diagnostic delays often occur. A reliable serological test detecting anti-mycobacterial antibodies would thus be of some use in this form of the disease.

OBJECTIVE

To evaluate the diagnostic accuracy of an assay detecting IgG against 38-kDa and 16-kDa recombinant mycobacterial antigens in BTB.

MATERIALS AND METHODS

In a prospective study, serum samples from 124 subjects were examined: 30 BTB cases, 40 non-specific bone and joint infection patients (NSBI), 30 lung cancer patients (LC), and 24 healthy volunteers (HC). An ELISA-based test (Pathozyme TB complex plus) was used.

RESULTS

The cut-off level was established at 150 U/ml according to receiver operating characteristic (ROC) curves. The quantified level of sensitivity of the test detecting BTB was 56%, at a specificity of 99%. The positive and negative predictive values were respectively 94% and 88%. Mean IgG level in the BTB group was 470 +/- 761 U/ml (mean +/- SD), and was significantly higher than the antibody level in the control groups (NSBI 58 +/- 42 U/ml, LC 43 +/- 38 U/ml, HC 40 +/- 29 U/ml).

CONCLUSION

The test presents an acceptable level of sensitivity and very good specificity in the diagnosis of BTB, and can be used in combination with other methods to increase diagnostic accuracy in this disease.

Differential regulation of chemokine secretion in tuberculous and staphylococcal osteomyelitis

Bone infection or osteomyelitis is characterized by uncontrolled inflammation and destructive bone loss although little is known about immunopathogenesis of infection. We investigated control of chemokine secretion from osteoblasts infected with either Mycobacterium tuberculosis, which normally elicits a granulomatous host response, or Staphylococcus aureus, which drives a host response dominated by neutrophil influx. We show that M. tuberculosis infection of cultured and primary osteoblasts induces extensive secretion of the chemokines interleukin (IL)-8, inducible protein (IP) 10, RANTES, and monocyte chemoattractant protein (MCP) 1 within 72 h (1630 +/- 280 pg/ml per 4 x 10(5) cells, 74,130 +/- 8480 pg/ml per 4 x 10(5) cells, 18,330 +/- 3040 pg/ml per 4 x 10(5) cells, and 138,670 +/- 13,340 pg/ml per 4 x 10(5) cells, respectively, for MG-63 osteoblasts). S. aureus infection also results in secretion of these chemokines but secretion is delayed and of lesser magnitude (210 +/- 10 pg/ml per 4 x 10(5) cells, 11,570 +/- 1240 pg/ml per 4 x 10(5) cells, 930 +/- 34 pg/ml per 4 x 10(5) cells, and 13,770 +/- 720 pg/ml per 4 x 10(5) cells for IL-8, IP-10, RANTES, and MCP-1, respectively). The minimal up-regulation of secretion of the neutrophil attractant IL-8 in staphylococcal infection is both striking and unexpected. In both infections, chemokine secretion was dependent on the presence of live organisms. Differences in kinetics and magnitude of chemokine secretion are associated with distinct patterns of mRNA expression, as assessed by ribonuclease protection assay (RPA) and reverse-transcription polymerase chain reaction (RT-PCR). In addition, nuclear localization of the transcription factor activator protein (AP) 1 in M. tuberculosis-infected osteoblasts also is distinct as compared with S. aureus-infected cells. In summary, this study shows that osteoblasts have an important pathogen-specific role in control of chemokine gene expression and secretion during the human immune response to osteomyelitis.

Localization of extrapulmonary tuberculosis in the synovial membrane, skin, and meninges in a patient with systemic lupus erythematosus and IgG deficiency

We report on a 31-year-old female patient with systemic lupus erythematosus (SLE) for 24 years who had a past history of skin tuberculosis (lupus vulgaris), long-term corticosteroid therapy, and IgG deficiency. She presented with monoarthritis and concomitant meningitis from skin tuberculosis after 5 years. The diagnosis of joint and meningeal tuberculosis was defined with clinical symptoms--signs and typical histopathological findings of involved synovium. Clinical improvement was achieved with antituberculous therapy. Cutaneous, articular, and cerebral manifestations of tuberculosis might have been confused with some of the lupus manifestations or lupus activation. It should be kept in mind that tuberculosis may be encountered in SLE due to the nature of the underlying disease and/or its therapy. It is also worth mentioning that, in this patient, tissues involved with extrapulmonary tuberculosis were the primary areas of involvement with SLE.

Immunodiagnosis in bone and joint tuberculosis

Fifty patients of bone and joint tuberculosis (age 15-70 years) and 30 healthy controls were studied for levels of immunoglobulin G (IgG), immunoglobulin A (IgA), immunoglobulin M (IgM), T cells and circulating immune complexes (CICs) in different stages of disease. Levels of IgG, IgA, IgM, T cells and CICs were significantly raised in fresh and healed tuberculosis patients, compared to control.

Wrist tuberculosis in cladribine--induced remission of hairy cell leukosis

A 45-year-old man with "hand-shoulder" syndrome developing eight-months after Cladribine-induced remission of an 11-year-old hairy cell leukosis is presented. Wrist bone biopsy was performed because of failure of the algodystrophy treatment and radiographic findings of progressive osteoporosis. Caseating epiteloid granulomas abundant in Langhans cells were found histologically and later Mycobacterium tuberculosis species was isolated in culture specimen. Fistulas were formed that healed after a prolonged anti-tuberculosis therapy. The role of cellular immunity deficiency in Cladribine-treated hairy cell leukosis that predisposes to mycobacterial infection is discussed.

[The immunological aspects of a hip joint lesion in childhood]

The paper presents an in-depth analysis of immunological mechanisms of the hip joint synovitis development in children. Studied in the pediatric patients with transient coxitis, Perthes disease, and tuberculous coxitis (n = 54, 15, and 15 respectively) with the aid of flow cytofluorometer FACStar PLUS was the subpopulation of immunocompetent cells with a wide spectrum of MCAB. Controls (n = 35) were sex and age-matched. Comparative analysis of immunological parameters in the above children disclosed a toxic-and-allergic origination of transient synovitis with predominant affection of the T-cell link of immunity (T-helpers failure and activation of T-suppressors). Joint mucose injury was noted to be developing against the background of reduction of serum IgA. Activation of non-specific mechanisms (natural killers, increase in SDH activity) is of compensatory character. Mechanisms of activation of cell processes (expression of panmitogenic receptor CD4+ antigen) in Perthes disease warrant further studies. In patients with tuberculous coxitis, immunological incompetence develops in the presence of cytotoxic reactions and activation of the B-link, with the production of IgM being on the increase but with no essential changes in the IgG fraction. It is necessary that selective stimulators of T-helpers be included into the treatment scheme together with drugs capable of exerting a selective effect on the T-link of immunity.

Tumor necrosis factor-alpha, interleukin-6, and interleukin-8 secretion and the acute-phase response in patients with bacterial and tuberculous osteomyelitis

Osteomyelitis, or bone infection, is a major worldwide cause of morbidity. Treatment is frequently unsatisfactory, yet little is known about pathogenesis of infection. Plasma tumor necrosis factor (TNF), interleukin (IL)-6, and IL-8 concentrations were measured before and after lipopolysaccharide stimulation of whole blood from patients with bacterial and tuberculous osteomyelitis and from controls. Patients with bacterial and tuberculous osteomyelitis mounted an acute-phase response and were anemic and febrile. However, plasma IL-6 concentrations were significantly elevated in only tuberculous osteomyelitis patients (vs. controls, P < .05). IL-6 concentrations correlated with erythrocyte sedimentation rate, C-reactive protein level, and plasma albumin concentration, all acute-phase markers. There were no other correlations between cytokine concentrations and clinical data. Following ex vivo stimulation, TNF, IL-6, and IL-8 were secreted equally by patients and controls. In summary, tuberculous osteomyelitis is characterized by elevated systemic IL-6 concentrations associated with an acute-phase response. For further insight into immunopathology of osteomyelitis, studies on infected bone are required.

Comparison of rheumatoid factors of rheumatoid arthritis patients, of individuals with mycobacterial infections and of normal controls: evidence for maturation in the absence of an autoimmune response

We analyzed the rheumatoid factors (RF) produced by Epstein-Barr virus-transformed monoclonal B cells established from four patients with rheumatoid arthritis (RA), three individuals with a history of Mycobacterium tuberculosis (TB) and four normal controls (NI). Fifty-eight RF were analyzed for specific activity (international units-RF/microgram) for the Fc part of IgG and their interaction with tetanus toxoid (TT) and DNA (polyspecificity). Furthermore, we sequenced the V-D-J heavy chain region of 16 (9TB-/7RA-) RF. Significant differences were observed between the NI-RF and the TB- and RA-RF. While the RF repertoire of normal individuals comprised of low-avidity RF of which the majority (15/17) were polyspecific, more than half of the TB- and RA-RF were monoreactive. Furthermore, the monospecific TB- and RA-RF were of significantly higher avidity than the NI-RF (RA > TB > > NI). With respect to polyspecificity specificity, the RF in the three groups were comparable: the interaction with DNA, TT as well as with Fc was inhibited either by an increase of the ionic strength to 0.3-0.5 M NaCl or by addition of the polyanion dextran sulfate, indicating that the antibodies interacted with similar anionic epitopes shared by the three antigens. Analysis of the V-D-J heavy chain regions showed significant differences between the respective RF. The salt-sensitive binding was highly correlated with the presence of arginine in the complementarity-determining region 3 (CDR3). Furthermore, whereas the polyspecific RF consisted predominantly of germ-line encoded antibodies, the genes of the monospecific RA/TB-RF were somatically mutated (RA > TB). It is therefore likely that maturation of RF can be initiated by chronic infections and that monospecific, somatically mutated RF are not a unique characteristic of autoimmune diseases.

[Immunological reactivity in tuberculosis in children]

Immunological reactivity was assessed comparatively in respiratory, intrathoracic and osteoarticular, urinary tuberculosis (122, 133, 38 children, respectively, versus 44 controls). References for age were made. The changes in immune system varied in nature, severity and relationships. Basing on these findings the author has created a complex of most informative tests in the diagnosis of childhood tuberculosis adjusted for age and site of the infection focus.

Levamisole as an immunopotentiator for T cell deficiency

Levamisole, a widely used antihelminthic drug has been shown to restore cutaneous delayed hypersensitivity in anergic patients with cancer and to amplify the activation of T lymphocytes by in vitro mitogens. Levamisole has been approved for the treatment of colon cancer in combination with 5 Fluorouracil. Herein we report a case of a 5 1/2 y.o. male who presented with a fulminant, disseminated mycobacterial infection of his joints secondary to a deficiency in his cellular mediated immunity in association with chemotherapy for a T cell leukemia. The patient was treated with Levamisole resulting in restoration of his T cell functions and resolution of his mycobacterial infection.

Disseminated skeletal tuberculosis with skull involvement

We report a patient with widespread osteolytic lesions, including extensive involvement of the skull, due to Mycobacterium tuberculosis. Response to treatment with antituberculosis drugs was slow with appearance of new lesions while on therapy despite a sensitive organism. Excision of diseased skull bone was eventually done, after which no new lesions appeared in the ensuing 14 months.

[Immune status in patients with bone and joint tuberculosis and effect of HLA genotype]

The study included 41 patients (Uzbeks by nationality) with tuberculosis of the bones and joints. Of them 19 had localized tuberculosis and 22 disseminated process. The condition of T lymphocytes, B-lymphocytes and specific immunity were investigated by standard immunological methods. Typing by antigens HLA-DR was made with the help of standard microlymphocytotoxic test. It was established that patients with tuberculosis of the bones and joints have worse qualitative and quantitative characteristics of T lymphocytes, reduced number of B-lymphocytes, high specific response of lymphocytes to tuberculin compared to healthy subjects. Such patients have low B-cell level when they are free of antigen HLA-DR4. Carriers of HLA-DR2 antigen exhibit inhibited specific cellular immunity compared to those without this antigen.

[HLA antigens in patients with osteoarticular tuberculosis and chronic hematogenic osteomyelitis]

There have been examined 93 patients with the tuberculosis of bones and joints, 28 patients with chronic hematogenic osteomyelitis. All patients have been typed in accordance with the antigens of loci HLA-A, B, C and DR by means of standard microlymphocytotoxic test. 135 healthy donors have been typed according to the same loci++ HLA as controls (105 persons have been typed according to antigens of locus HLA-DR). All examined persons have been Uzbeks. There have been stated that in the patients with the tuberculosis of bones and joints, as compared with osteomyelitis, is observed the increase of frequency of antigens HLA-B27 and HLA-DR2, while in case of bone osteomyelitis is noted association with antigens HLA-A9, B7 and B18.

[Detection of serum antibody against lipoarabinomannan-B in Mycobacterium tuberculosis (H37Ra)]

The serum antibody to lipoarabinomannan-B(LAM-B) purified from mycobacterium tuberculosis (H37Ra) was tested by ELISA in 250 sera, including sera from patients as follows: tuberculosis 96, tubercular pleurisy 11, renal tuberculosis 2, bone and joint tuberculosis 33, tubercular meningitis 16, pulmonary cancer 22, leprosy 20 and normal subjects 50. The positive rate of pulmonary tuberculosis is 69.8%, which is of a similar extent in sera from patients with tuberculosis of miscellaneous organs to be tested except tubercular meningitis, in which only 18.8% positive rate was observed, indicating the blockage of antibody releasing from pathologic foci into blood stream by blood-brain barrier. The positive rates of leprosy and normal subjects are 50.0% and 2.0% respectively. No antibody was found among 22 patients with pulmonary cancer. It is suggested that the existence of an active tubercular lesion in the host might be the basic prerequisite for a positive LAM-B antibody detection. Although LAM-B is a common antigen of both mycobacterium tuberculosis and mycobacterium leprae, the low prevalence of leprosy in China makes little influence of the practicability of using this ELISA in epidemiological study and in clinic as a adjutant tool for tuberculosis diagnosis and differential diagnosis.

Humoral immune response in human tuberculosis: immunoglobulins G, A, and M directed against the purified P32 protein antigen of Mycobacterium bovis bacillus Calmette-Guérin

The P32 protein antigen of Mycobacterium bovis BCG, identified as antigen 85A in the BCG reference system, was used to investigate the humoral immune response in human tuberculosis (TB). Immunoglobulin G (IgG), IgA, and IgM directed against P32 were measured by an enzyme-linked immunosorbent assay. Mean IgG and IgA antibody levels differed significantly (P less than 0.001) between active-TB patients (50 untreated and 52 treated) and healthy control subjects (111 unvaccinated tuberculin negative, 38 unvaccinated tuberculin positive, and 72 recently BCG vaccinated). Mean IgG antibody levels, but not mean IgA antibody levels, were higher (P less than 0.05) in patients with positive microscopic examination for acid-fast bacilli than in patients with negative microscopic examination. A positive relation was found between mean levels and the extent of disease. There was no difference in mean IgM antibody levels between patients and controls. By setting the upper normal limit at the 95th percentile of the 221 healthy subjects, the sensitivities were 46% in untreated and 63% in treated patients for IgG and 30 and 50%, respectively, for IgA. Of the untreated patients, 56% were positive for either IgG or IgA antibodies. Among the untreated patients with negative direct smear, 35% were positive for IgG and 24% were positive for IgA. When both immunoglobulin classes were combined, the serological test was positive in 47% of those patients. Neither naturally acquired tuberculin hypersensitivity nor BCG vaccination affected positivity frequencies in healthy subjects. Only active TB seemed to induce significant anti-P32 antibody levels and to be associated with positivity. A serological test with P32 as the antigen might therefore be helpful for the rapid diagnosis of TB.

Multiple joint tuberculosis presenting as HLA-B27 disease

A case of multifocal osteoarticular tuberculosis in a young Caucasian male is presented. The diagnostic difficulty, compounded by slow progression of the disorder and the presence of the tissue antigen HLA-B27, is discussed.

[Clinical and immunologic findings in BCG osteomyelitis]

BCG-osteomyelitis is a rare but serious late complication of BCG-immunisation. Be present clinical and immunological findings in 2 children aged 9 months and 5 years, who developed BCG-osteomyelitis, following immunisation with BCG-vaccine. The affected bones were the first metacarpal bone in one and the 6th rib in the other patient. Both children remained free of recurrences after surgical removal of the granulomatous tissue. Immunological investigations in both cases demonstrated normal humoral immunity (Complement CH50, C3, C4, immunoglobulins). Except for a diminished proportion of circulating B-cells, determination of lymphocyte subpopulations and in-vitro lymphocyte stimulation with Phytohemagglutinin and PPD were normal. In both children spontaneous cell mediated cytotoxicity (SCMC) against the tumor cell line L1210, in one patient also against tumor cell line K562 was decreased. Antibody dependent Cytotoxicity (ADCC) was normal.

Serologic diagnosis of bone and joint tuberculosis by an enzyme-linked immunosorbent assay

Sera from patients receiving treatment for active bone and joint tuberculosis and sera from patients with inactive bone and joint tuberculosis were examined by an enzyme-linked immunosorbent assay for antibody to antigen 6, a homogeneous protein prepared from Mycobacterium tuberculosis strain H37Ra by immunosorbent affinity chromatography. Sera from 21 control subjects had a geometric mean titer of 1:6 with no difference between tuberculin purified protein derivative-positive and -negative patients. Sera from 20 patients with inactive disease had a geometric mean titer of 1:19. Fifteen patients receiving treatment for M. tuberculosis infection had a geometric mean titer of 1:179, which is significantly different from the geometric mean titers of both of the patients with inactive tuberculosis (P less than 0.001) and the control subjects (P less than 0.001). At a cut-off titer of 1:32, the sensitivity of the assay is 94% and the specificity for the control subjects and patients with inactive disease was 100%.

Serological tests in the differentiation of staphylococcal and tuberculous bone disease

The haemagglutination test for antileucocidin is frequently positive in cases of bone tuberculosis in the absence of obvious staphylococcal infection. This test is therefore of little practical use in the differentiation of staphylococcal and tuberculous bone disease, and its use has been discontinued at the Royal National Orthopaedic Hospital. The antigamma haemolysin test in bone tuberculosis appears to give rise to few false positive results. Our observations confirm that the anti-alpha haemolysin and antigamma haemolysin tests used together reveal about 80 percent of cases of staphylococcal bone infection on first presentation or relapse.