Mycobacterium Avium Complex Lung Research Articles

1316. Uncommon Presentations of Common Variable Immunodeficiency

BackgroundCommon Variable Immunodeficiency (CVID) is a primary immunodeficiency disorder which affects B lymphocyte function and differentiation causing decreased levels of Immunoglobulin G (IgG), Immunoglobulin A (IgA) and Immunoglobulin M (IgM).1 The objective of this study is to highlight how hypogammaglobulinemia can lead to respiratory infections with microbes that are lesser known in the background of CVID with the help of a two-case series.MethodsMedical records of two patients with CVID were reviewed who were found to have mycobacterium avium-complex intracellulare and streptococcus agalactiae lung infections respectively.ResultsDecreased IgG in CVID means reduced antibody production, low IgA leads to mucosal inflammation and increased susceptibility to respiratory infections2 and lower IgM memory B-cells causes infections with encapsulated microorganisms.3 Table 1 highlights the various respiratory infections and their etiologies that have been reported with CVID, the most common being encapsulated organisms like Haemophilus influenza, Streptococcus pneumonia, Neisseria meningitidis along with enterovirus. Table 2 demonstrates our findings. In the first case we have reported a patient with mycobacterium avium-complex intracellulare (MAC-I). This could be because of hypogammaglobulinemia, decreased B and T-cell interaction and reduced T-cell signaling caused by CVID.4 Although, mycobacterium tuberculosis, simiae and hominis lung infections and mycobacterium bovis systemic infections have been reported before, MAC-I is relatively rare in CVID.5 In our second case, the patient developed streptococcus agalactiae or Group-B streptococcus (GBS) empyema. Most cases of GBS have been reported in pregnant women and infants. Infections with other encapsulated organisms have been reported in CVID but GBS empyema is less frequent and can happen due to decreased bacteria-specific CD4 cells, microbial translocation and hypogammaglobulinemia.6 .Table 1. Respiratory Infections reported in CVID along with their etiologies. Figure 1. CT image of MAC-I infection.ConclusionWe encountered two unique cases of CVID with rare infectious etiologies. The cases are intended to create an awareness and vigilance regarding CVID induced hypogammaglobulinemia which can cause respiratory infections with lesser known pathogens where antibodies may be important. Disclosures All Authors: No reported disclosures

Amikacin Liposome Inhalation Suspension for Mycobacterium avium Complex Lung Disease

OBJECTIVE: To review the pharmacology, pharmacokinetics, pharmacodynamics, clinical efficacy, safety, administration, and role of amikacin liposome inhalation suspension (ALIS) in treatment of Mycobacterium avium complex (MAC) lung disease.<br/> DATA SOURCES: A PubMed search using the terms "amikacin inhaled," "nebulized," and "liposome suspension" was performed. Selected infectious diseaseconference posters were also examined for relevant information. In addition, pertinent guidelines were reviewed.<br/> STUDY SELECTION/DATA EXTRACTION: Guidelines for the management of nontuberculous mycobacterial infections from the American Thoracic Society/ Infectious Diseases Society of America and the British Thoracic Society were used to summarize guidelinebased therapy (GBT). A phase II and a phase III clinical trial were reviewed to evaluate the role of ALIS in the treatment of MAC lung disease.<br/> DATA SYNTHESIS: ALIS is a new formulation of inhaled amikacin (AMK) indicated for the treatment of MAC lung disease refractory to GBT in adults who are not candidates for intravenous AMK. An ongoing clinical trial has demonstrated that once-daily ALIS plus GBT results in higher rates of culture conversion compared with GBT alone by month 6 among patients with a mean age of 65 years. The most common adverse reactions associated with ALIS were dysphonia, cough, bronchospasm, hemoptysis, and ototoxicity. Nephrotoxicity was uncommon.<br/> CONCLUSION: ALIS has been shown to increase culture conversion rates when added to GBT in adults with difficult-to-treat MAC lung disease. ALIS is associated with high rates of pulmonary and auditory adverse reactions and a low risk of renal adverse reactions. ALIS may be an attractive treatment option for older adults who are at high risk for nephrotoxicity.

Distinguishing tuberculosis from &lt;I&gt;Mycobacterium avium&lt;/I&gt; complex disease using an interferon-gamma release assay

The QuantiFERON-TB Gold (QFT-G) test can be used to distinguish between tuberculosis (TB) and non-tuberculous mycobacterial disease, but a high background TB infection rate may pose a problem. Although the QuantiFERON-TB (QFT) test, the first-generation QFT-G test, employs a non-specific PPD antigen, avium sensitin is also used as a stimulating antigen. To evaluate the utility of these two interferon gamma release assays (IGRAs), QFT-G and QFT, and the tuberculin skin test (TST), to differentiate TB from Mycobacterium avium complex (MAC) disease in an intermediate TB burden country. We compared the diagnostic performance of these three tests in 38 prospectively enrolled patients with TB and 40 with MAC lung disease. The TST yielded positive results in 70.6% of TB and 47.5% of MAC patients; the proportions were respectively 89.5% and 34.3% for QFT-G and 86.8% and 35.3% for QFT. The three tests were of similar accuracy, sensitivity and specificity in diagnosing TB. Our findings indicate that the TST and IGRAs could not discriminate between active TB and MAC disease or latent TB infection in a TB-endemic area.