Lymphocyte production of gamma-interferon as a test for non-tuberculous mycobacterial lymphadenitis in childhood

Diagnosing nontuberculous mycobacterial cervicofacial lymphadenitis in children: A systematic review

OBJECTIVES

Widespread controversy exists regarding correct diagnosing nontuberculous mycobacterial cervicofacial (NTM) lymphadenitis. This study intends to gather the available evidence with respect to diagnosing NTM cervicofacial lymphadenitis.

METHODS

A review protocol was developed based on the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA)-statement (www.prisma-statement.org). A comprehensive search was performed in the bibliographic databases PubMed, Embase.com and Wiley/Cochrane Library. 10 Articles fulfilled the inclusion criteria and were included in the review. Assessing risk of bias of the articles was done using the revised Quality Assessment of Diagnostic Accuracy (QUADAS-2) tool.

RESULTS

This systematic review shows that diagnostic studies of high methodological quality are scarce. Diagnostic accuracy of polymerase chain reaction (PCR), culture, skin testing, auramine staining, Ziehl-Neelsen staining, and immunodiagnostic assays was studied. Culture sensitivity proved to be 41,8%, while polymerase chain reaction has a sensitivity of 71,6%. Both methods showed a specificity of 100%. Sensitivity of Immunodiagnostic assays ranged between 87,5% and 100% and specificity between 81% and 100%. Overall sensitivity of skin tests containing purified protein derivative (PPD-S) was 70% (95% CI [62%-78%]) with an overall specificity of 94% (95% CI [88%-100%]).

CONCLUSIONS

In patients with a high clinical suspicion for NTM cervicofacial lymphadenitis, a positive PPD-S skin is indicative for the diagnosis of NTM cervicofacial lymphadenitis. Either PCR or culture is necessary to confirm the diagnosis. Interferon-γ release assays with purified protein derivative stimulation appear to provide good sensitivity and specificity as a non-invasive pre-operative test, but the evidence is weak. More studies of high methodological quality are needed to validate the results of this systematic review.

Sensitivity of human gamma interferon assay and tuberculin skin testing for detecting infection with Mycobacterium tuberculosis in patients with culture positive tuberculosis

SETTING

Nine university-affiliated chest clinics in Australia.

OBJECTIVE

To evaluate the sensitivity of a whole blood human gamma-interferon assay (HGIA, QuantiFERON-TB) for specific T lymphocyte responses and Tuberculin skin testing (TST) for the detection of Mycobacterium tuberculosis infection in subjects with culture-proven M. tuberculosis disease (TBCP).

DESIGN

Prospective testing of 129 patients with recent TBCP and 100 patients with non-tuberculosis lung disease (NTBLD).

RESULTS

Using a defined level of specific IFN-gamma production and TST 10mm as positive cut-offs, the sensitivity of HGIA was 81% compared to 89% for TST (p=0.06). When positive responses in both TST and HGIA were combined, 96% of TB patients were detected. For the NTBLD group, 43% of whom were born overseas, 73% were negative for both the HGIA and TST. Prior immunization with M. bovis (bacille Calmette-Guerin) (BCG) or the type of TB had no effect on the sensitivities of the assays. For those treated for <2 months, the sensitivities for both assays were 84%, but for those treated for >2 months the sensitivity of TST (90%) tended to be higher than for HGIA (81%) (p=0.07). The distribution of TST results in TB patients showed a broad peak between 10 and 25 mm, while the results in the HGIA were bimodal in both TB and NTBLD patients.

CONCLUSION

HGIA may prove an alternative to skin testing for detecting M. tuberculosis infection in certain settings.

Nontuberculous mycobacterial adenitis of the head and neck in children: experience from a tertiary care pediatric center

OBJECTIVE

To describe our experience with the diagnosis, surgical treatment, and outcome of nontuberculous mycobacterial (NTM) adenitis of the head and neck in children, and to present a preliminary report about the use of NTM skin tests in our institution.

STUDY DESIGN

Retrospective study.

METHODS

The medical records of all children diagnosed with cervicofacial NTM adenitis were retrospectively reviewed for the period from January 1, 1995, through December 31, 2000. We also examined the use of intradermal skin tests for the diagnosis of NTM infection.

RESULTS

Fifty patients were diagnosed with NTM cervicofacial adenitis. Pertinent demographic information, clinical presentation, investigation, and type of diagnostic procedures were documented. Surgical procedures, complications, and relapses were also noted. One unusual case of retropharyngeal adenitis is illustrated. All patients were treated with complete excision of their lesion at the first operation. No major complications were noted. Only one patient relapsed and required a second operation. Forty-one children were skin-tested with NTM antigens. Of these, 30 patients were dual-tested with Purified Protein Derivative (PPD) also. No adverse reactions were noted with the use of skin tests. Sensitivity of NTM antigens alone is 87%. Sensitivity of dual testing is 78%. No patient had a PPD-dominant reaction.

CONCLUSION

Surgical excision is the treatment of choice of NTM adenitis because of the high cure rate with a single procedure, the excellent cosmetic result, and the low complication rate. NTM skin tests are safe and could be useful in early diagnosis of the infection but further investigation is needed.

BOVIGAM: an in vitro cellular diagnostic test for bovine tuberculosis

BOVIGAM which is based on the detection of gamma interferon (IFN- gamma) is a rapid, laboratory assay of a cell mediated immune response that may be used for the detection of tuberculosis (TB) infection in animals. Whole blood is first incubated overnight with bovine PPD, avian PPD or negative control antigens, and IFN- gamma in the supernatant plasma is then measured by EIA. TB infection is indicated by a predominant IFN- gamma response to bovine PPD. Since 1988, BOVIGAM has been extensively trialed on more than 200 000 cattle in Australia, Brazil, Ireland, Northern Ireland, Italy, New Zealand, Romania, Spain and the USA. Sensitivity has varied between 81.8% and 100% for culture-confirmed bovine TB and specificity between 94% and 100%. The IFN- gamma assay detects M. bovis infection earlier than the skin test and in New Zealand is applied to detect skin-test negative cattle with TB, where after slaughter a significant number of IFN- gamma reactors have TB. BOVIGAM is also approved in New Zealand for serial testing skin test positive cattle when non-specificity is suspected. Cattle are tested 7-30 days after a positive caudal fold test. The boosting effect of the skin test on T-cell activity allows blood to be cultured with PPD up to 30 h after collection without effecting accuracy. The BOVIGAM results are not affected by poor nutritional condition and are only mildly and briefly affected by dexamethasone treatment and parturition. IFN- gamma responses of cattle vaccinated with BCG are dose-dependent and short-lived. The BOVIGAM kit is now used routinely in many countries for the detection of M. bovis infected cattle, buffalo and goats.

Management of non-tuberculous mycobacterial peri-sialadenitis in children: the Sheffield otolaryngology experience

Non-tuberculous mycobacterial infection (NTM) has been recognized as an important cause of infection in the head and neck in children since 1956. It is important to differentiate NTM from the more serious Mycobacterium tuberculosis (TB) since the management differs significantly. The causative organisms of NTM infection are resistant to the most commonly used anti-tuberculous preparations, though they do show sensitivity to the newer antibiotics such as clarithromycin, ciprofloxacin and azithromycin. Between 1986 and 1997, 15 patients with NTM infection involving the major salivary glands were treated at the Sheffield Children's Hospital Department of Otolaryngology. There were 11 girls and four boys. In all patients the onset of symptoms was between September and April. Resolution occurred in two patients without surgery. The remaining 13 underwent formal surgical exploration with excision of the mass, associated nodes and of the overlying skin if necessary. There were nine parotid explorations. There were no long-term facial nerve deficits as a result of surgery and no recurrence of the disease. Co-operation between the Paediatrician and the Otolaryngologist is important for effective management since NTM may also affect the lungs, soft tissues, bones and joints. Diagnosis relies upon culture, histology, chest radiography, purified protein derivative (PPD) testing, clinical features and skin testing. The use of antibiotics such as azithromycin with ciprofloxacin may be justified while waiting for the results of investigations, especially with small, early lesions, as resolution is possible. In patients who have no history of exposure to TB, are not immunocompromised, have a normal chest radiograph and have a Mantoux test with < 15 mm diameter induration, the treatment should be surgical excision rather than prolonged antibiotic therapy.

Cell-mediated immune response to tuberculosis antigens: comparison of skin testing and measurement of in vitro gamma interferon production in whole-blood culture

Although delayed-type hypersensitivity skin testing with tuberculin purified protein derivative (PPD) is the standard for tuberculosis screening, its variability suggests the need for a more sensitive, noninvasive test. An in vitro whole-blood assay has been proposed as an alternative. Using health care worker volunteers, we confirmed the correlation between PPD skin test (PPD-ST) results (positive, induration of >15 mm) and a standardized gamma interferon (IFN-gamma) assay, QuantiFERON-TB (Q-IFN), manufactured by CSL Biosciences in Australia, and we evaluated Mycobacterium tuberculosis culture subfractions as potential substitutes for PPD. Twenty healthy volunteers with positive PPD-ST results and 20 PPD-ST-negative controls were enrolled. Whole blood was cultured with human PPD antigens (HuPPD), Mycobacterium avium complex (MAC) PPD, phytohemagglutinin (PHA), and four M. tuberculosis culture subfractions: low-molecular-weight culture, filtrate, culture filtrate without lipoarabinomannan, soluble cell wall proteins, and cytosolic proteins, all developed from M. tuberculosis strain H(37)RV. Secretion of IFN-gamma (expressed as international units per milliliter) was measured by an enzyme immunoassay. The PPD or subculture fraction response as a percentage of the PHA response was used to determine positivity. Sixteen of 20 PPD-ST-positive individuals were classified as M. tuberculosis positive by Q-IFN, and 1 was classified as MAC positive. Sixteen of 20 PPD-ST-negative individuals were M. tuberculosis negative by Q-IFN, 2 were MAC positive, and 2 were M. tuberculosis positive. The tuberculosis culture subfractions stimulated IFN-gamma production in PPD-ST-positive volunteers, and significant differences could be seen between the two PPD-ST groups with all subfractions except soluble cell wall protein; however, the response was variable and no better than the Q-IFN PPD. The agreement between the Q-IFN test and the PPD-ST was good (Cohen's kappa = 0.73). The Q-IFN assay can be a useful tool in further studies of immune responses to M. tuberculosis antigens.

Results of multiple diagnostic tests for Mycobacterium avium subsp. paratuberculosis in patients with inflammatory bowel disease and in controls

Mycobacterium avium subsp. paratuberculosis has been incriminated as a cause of Crohn's disease (CD); however, studies to date have been relatively small and generally only used a single diagnostic assay. The objective of the study was to reexamine the association of M. avium subsp. paratuberculosis and CD using multiple diagnostic tests. Five methods were used to detect M. avium subsp. paratuberculosis infections in 439 inflammatory bowel disease (IBD) patients and 324 control subjects in the United States and Denmark. Most assays were adaptations of diagnostic tests for this infection performed routinely on animals. PCR for IS900, a genetic element unique to M. avium subsp. paratuberculosis, was positive significantly more often on resected bowel and lymph node tissues from CD patients (19.0%) and ulcerative colitis (UC) patients (26.2%) than from controls (6. 3%) (P < 0.05). Positive IS900 PCR results occurred more often in U. S. than in Danish IBD patients, 32.0 versus 13.3% (P = 0.025). The majority of Danish patients were bacillus Calmette-Guérin (Mycobacterium bovis BCG) vaccinated (CD, 77.5%; UC, 86.6%; controls, 83.0%) whereas none of the U.S. patients with IBD and only 2% of U. S. controls were vaccinated. Among Danish IBD patients, positive PCR findings were four times more common among subjects who were not BCG vaccinated (33.3%) than among BCG vaccinates (8.8%, P = 0.02). Culture of the same tissues tested by PCR using modified BACTEC 12B medium failed to grow M. avium subsp. paratuberculosis from patients or controls. U.S. CD patients had the highest serological evidence (enzyme-linked immunosorbent assay [ELISA] for serum antibodies) of M. avium subsp. paratuberculosis infection (20.7% of patients positive) which was higher than for all UC patients studied (6.1%) or healthy controls (3.8%, P < 0.005). Among Danish patients alone, however, no significant differences in rates of ELISA-positive results among CD, UC, or control patients were found. For 181 study subjects, both IS900 PCR and ELISA were performed. Although 11 were ELISA positive and 36 were PCR positive, in no instance was a patient positive by both tests, suggesting that these states are mutually exclusive. Evaluation of cytokine-mediated immune responses of IBD patients was complicated by the influence of immunosuppressive therapy given most IBD patients. Gamma interferon (IFN-gamma) release by peripheral blood leukocytes after M. avium purified protein derivative PPD antigen stimulation showed significantly lower responses in CD patients than in UC patients or controls in both U.S. (by ex vivo assay) and Danish (by in vitro assay) populations (P < 0.05). Interleukin-5 responses were not different among CD, UC, or control groups. Collectively, the PCR, ELISA, and IFN-gamma tests for M. avium subsp. paratuberculosis together with the unexpected observation that BCG vaccination influenced M. avium subsp. paratuberculosis detection, lead us to conclude that M. avium subsp. paratuberculosis, or some similarly fastidious mycobacterial species, infects at least a subset of IBD patients. Whether the infection is primary (causal) or secondary, it may contribute to the etiopathogenesis of IBD.

Role of T cell subsets in the modulation of Mycobacterium avium growth within human monocytes

Mycobacterium avium frequently causes disseminated disease in patients with advanced AIDS with low CD4 counts. The effects of T lymphocyte on intracellular M. avium replication were examined. Plastic adherent monocytes and nonadherent lymphocytes were separated from peripheral blood mononuclear cells. After infection with M. avium, monocytes were cultured with or without autologous lymphocytes (1-10 cells/monocyte) for up to 7 days. Addition of lymphocytes to M. avium-infected monocytes significantly decreased intracellular M. avium growth after 7 days culture (n = 11, P < 0.01, paired t test) and increased IFN-gamma production compared to monocytes alone. Neutralizing IFN-gamma partially abrogated lymphocyte activity. CD4 depletion diminished anti-mycobactericidal effects and CD8(+) lymphocytes increased intracellular M. avium growth (P < 0.05, n = 5, t test). These data suggest that interactions between monocytes and nonadherent cell fractions such as CD4(+) T cells and NK cells are important in intracellular M. avium growth modulation in monocytes from healthy humans.

In vitro cellular and cytokine responses to mycobacterial antigens: application to diagnosis of tuberculosis infection and assessment of response to mycobacterial vaccines

Mycobacterial infection leads to the development of specific cell-mediated immune responses that have been measured clinically by assessing delayed-type hypersensitivity with Mantoux skin testing. Several characteristics of Mantoux skin testing for tuberculosis infection can make the procedure inaccurate, inconvenient, and sometimes misleading. It is also a poor predictor of immunity to tuberculosis in bacille Calmette-Gúerin vaccinees, yet decisions to revaccinate often are based on skin test responses after initial immunization. Skin testing with other mycobacterial antigens has similar limitations. In vitro assessment of cellular immunity to mycobacteria offers multiple, potential advantages over skin testing and has become technically feasible in recent years. Measurement of the effector functions that comprise cell-mediated immunity (eg, cytokine secretion and cytotoxicity) rather than cutaneous delayed-type hypersensitivity responses is more likely to reflect meaningfully specific mycobacterial immunity and, therefore, provide a means for determining mycobacterial immunity after immunization. Eliminating the variability in placement and interpretation inherent in skin testing could provide a more stable foundation for comparative studies in populations and improve decision making for individuals. Finally, in vitro testing permits the use of discrete mycobacterial antigens instead of crude protein preparations, allowing greater specificity in the detection of infection as well as assessment of responses to defined candidate vaccine antigens. Several studies have compared skin testing with in vitro proliferation of lymphocytes stimulated by mycobacterial antigens for the detection of Mycobacterium tuberculosis infection. Preliminary veterinary and human studies suggest that in vitro assessment of gamma-interferon production in response to mycobacterial antigens can be used to detect prior infection with organisms of the M tuberculosis complex. Streamlined techniques for in vitro testing of cellular immunity may allow its practical adoption in the clinical setting and lead to its use as a replacement for Mantoux skin testing.

Non-tuberculous mycobacterial lymphadenitis

BACKGROUND

Non-tuberculous mycobacterial lymphadenitis has been recognized since medieval times by an array of names. The condition is familiar to paediatricians and paediatric surgeons but it often is not recognized in its early stages. A paediatric surgeon's experience of the condition in Newcastle over 30 years is reviewed.

METHODS

A personal series of children with non-tuberculous mycobacterial lymphadenitis treated in Newcastle from 1966 to 1994 is reviewed. Clinical diagnosis was supported by multiple Mantoux skin testing in most patients using human purified protein derivative (PPD) and avian antigens. All were treated surgically with histological confirmation of the diagnosis. A total of 89 patients were encountered. Twenty-two were seen in hospital practice between 1966 and 1976 and have already been reported. The current paper presents the results of analysis of the clinical features, diagnosis and surgical treatment of the remaining 67 patients seen in paediatric surgical practice between 1976 and 1994.

RESULTS

There was equal sex distribution. Ages ranged from 1 to 10 years, with none under 1 year, and 82% of the patients were in the pre-school age group. Cervical lymph nodes were involved in all, the majority being jugulo-digastric or submandibular. Surgical excision by limited dissection of lymph nodes was performed in 55 patients with one recurrence, and by excision and curettage in eight patients with two recurrences. Simple bacterial wound infection occurred in four patients and two had prolonged postoperative suppuration as a result of mycobacterial wound infection. Paresis of the mandibular or cervical branch of the facial nerve occurred in 50% of patients where the nerve was at risk, but the majority of these recovered although it took over 6 months in some children. Culture for mycobacterial organisms was positive in only 29 patients.

CONCLUSIONS

The diagnosis of non-tuberculous mycobacterial lymphadenitis is clinical and its early recognition requires an awareness of the condition. It can be confirmed by multiple Mantoux testing or fine needle aspiration biopsy. The treatment is local excision of the affected lymph nodes. Histological examination and mycobacterial culture should be performed.