Background Autoantibodies against interferon-γ are associated with severe disseminated opportunistic infection, but their importance and prevalence are unknown. Methods We enrolled 203 persons from sites in Thailand and Taiwan in five groups: 52 patients with disseminated, rapidly or slowly growing, nontuberculous mycobacterial infection (group 1); 45 patients with another opportunistic infection, with or without nontuberculous mycobacterial infection (group 2); 9 patients with disseminated tuberculosis (group 3); 49 patients with pulmonary tuberculosis (group 4); and 48 healthy controls (group 5). Clinical histories were recorded, and blood specimens were obtained. Results Patients in groups 1 and 2 had CD4+ T-lymphocyte counts that were similar to those in patients in groups 4 and 5, and they were not infected with the human immunodeficiency virus (HIV). Washed cells obtained from patients in groups 1 and 2 had intact cytokine production and a response to cytokine stimulation. In contrast, plasma obtained from these patients inhibited the activity of interferon-γ in normal cells. High-titer anti–interferon-γ autoantibodies were detected in 81% of patients in group 1, 96% of patients in group 2, 11% of patients in group 3, 2% of patients in group 4, and 2% of controls (group 5). Forty other anti-cytokine autoantibodies were assayed. One patient with cryptococcal meningitis had autoantibodies only against granulocyte–macrophage colony-stimulating factor. No other anti-cytokine autoantibodies or genetic defects correlated with infections. There was no familial clustering. Conclusions Neutralizing anti–interferon-γ autoantibodies were detected in 88% of Asian adults with multiple opportunistic infections and were associated with an adult-onset immunodeficiency akin to that of advanced HIV infection.

Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) has recently been introduced into the clinical microbiology laboratory as a rapid and accurate method to identify bacteria and yeasts. In this paper we describe our work on the use of MALDI-TOF MS for the identification of mycobacterial isolates. We developed a protocol for protein extraction from mycobacteria and utilized it to construct a database containing 42 clinically relevant type and reference strains of mycobacteria. The database was used to identify 104 clinical isolates of mycobacteria. All members of the Mycobacterium tuberculosis complex were identified accurately at the complex level but could not be separated at the species level. All other organisms were identified at the species level, with the exception of one strain of M. kansasii (accurately identified but with a low spectral score) and three pairs of closely related strains: M. abscessus and M. massiliense, M. mucogenicum and M. phocaicum, and M. chimaera and M. intracellulare. These pairs of organisms can currently be identified only by multilocus gene sequence analysis. We conclude that MALDI-TOF MS analysis can be incorporated into the work flow of the microbiology laboratory for rapid and accurate identification of most strains of mycobacteria isolated from solid growth media.The genus Mycobacterium consists of nearly 150 species, many of which are clinically significant. These organisms cause significant morbidity in humans, including pulmonary infections, skin and soft tissue infections, and disseminated disease. Rapid and accurate diagnosis of mycobacterial infections is of utmost importance due to the fact that inappropriate treatment may lead to drug resistance or unnecessary exposure to drug toxicities. Accurate identification in the microbiology laboratory is challenging because biochemical testing is slow and unable to identify less common species, molecular probes are available for a limited number of species, and gene sequencing is technically cumbersome and relatively expensive.Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) is recognized as a powerful tool for the identification of bacteria and yeasts in the clinical laboratory (2,16,17,18,21). This technique allows identification of organisms on the basis of unique spectral fingerprints produced by extracted proteins (9). The method is relatively simple, rapid, and associated with significantly lower consumable costs than traditional microbiological identification methods (16). Although the MALDI-TOF MicroFlex LT mass spectrometer (Bruker Daltonics Inc., Billerica, MA) and associated software are expensive initially (approximately $200,000), the continuing consumable costs are inexpensive (less than $1 per isolate).There has been limited work thus far on the use of MALDI-TOF MS for the identification of mycobacteria (5, 6, 10). This paper describes our efforts to develop and validate MALDI-TOF MS for the identification of mycobacterial organ...

Nontuberculous mycobacteria (NTM) are ubiquitous in the environment and cause a wide range of diseases in humans. Pulmonary involvement, the most common disease manifestation of NTM infection, is being increasingly encountered in clinical settings. In addition, specific phenotypic and genetic characteristics of persons predisposed to contract pulmonary NTM disease are now beginning to be recognized. Prior to treatment, patients should meet clinical and microbiologic criteria for NTM disease. Treatment involves prolonged courses of antibiotics in various combination regimens that are often discontinued because of serious side effects. In some cases, complete cure of pulmonary disease is difficult to achieve. Rather, clinical improvement may be a more feasible goal. Surgical treatment is warranted for select patients.