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Disseminated tuberculosis presenting with intraocular involvement is a rare condition which can lead to profound visual loss if misdiagnosed. We report a case of a 24-year-old Nepalese male with disseminated tuberculosis who presented primarily with bilateral vision loss.

Background The role of interferon-gamma release assays (IGRAs) in diagnosis of active tuberculosis (TB) is unclear, yet they are commonly used in low-TB-incidence countries. This study sought to resolve this clinical uncertainty by determining the diagnostic accuracy and role of current and second-generation IGRAs in the diagnostic assessment of suspected TB in a low-incidence setting. Methods This was a prospective cohort study of 1,060 adults with suspected TB, conducted in routine secondary care in England. Patients were tested for M. tuberculosis (Mtb) infection at baseline using current and second-generation IGRAs, the latter incorporating novel Mtb antigens, and followed up for 6-12m to establish definitive diagnoses. Sensitivity, specificity and positive and negative likelihood ratios (LRs) and predictive values (PVs) of the tests for TB were determined. Findings TB was diagnosed in 363 (43%) of 845 patients included in analyses. Sensitivity of T-SPOT.TB was 81.4% (95%CI 76.6-85.3%), higher than Quantiferon-Gold In-Tube at 67.3% (95%CI 62.0-72.1%). Second-generation IGRA had higher sensitivity than current tests, at 94.0% (95%CI 90.0–96.4%) for culture-confirmed TB and 89.2% (95%CI 85.2–92.2%) when including highly-probable TB, giving a negative LR for all TB of 0.13 (95%CI 0.10-0.19). Specificity ranged from 86.2% (95%CI 82.3-89.4%) for T-SPOT.TB to 80.0% (95%CI 75.6-83.8%) for second-generation IGRA. Interpretation Currently-available IGRAs lack sufficient accuracy for diagnostic evaluation of suspected TB. Second-generation tests, however, may have sufficiently high sensitivity, low negative LR and correspondingly high negative PV in low-incidence settings to facilitate prompt rule-out of TB.

The immune response to human cytomegalovirus (HCMV) infection is characterized by the accumulation of HCMV-specific CD8(+) T cells, particularly in the elderly; such expansions may impair immune responses to other pathogens. We investigated mechanisms underlying HCMV-specific expansions in 12 young and 21 old healthy subjects (although not all analyses were performed on all subjects). Phenotypically, HCMV-pentamer(+) CD8(+) T cells were characterized by marked Vβ restriction, advanced differentiation (being predominantly CD27(-) CD28(-) ), and variable CD45RO/RA expression. Although more common and larger in older subjects, expansions had similar phenotypic characteristics in the young. In one old subject, repeated studies demonstrated stability in size and Vβ distribution of pentamer(+) populations over 6 years. We tested whether HCMV-specific CD8(+) T-cell expansions arose from accelerated proliferation or extended lifespan by in vivo labelling with deuterated glucose and ex vivo Ki-67 expression. Uptake of deuterated glucose was lower in pentamer(+) cells than in pentamer(-) CD8(+) CD45RO(+) or CD8(+) CD45RA(+) cells in three old subjects, consistent with reduced proliferation and extended lifespan. Similarly Ki-67 labelling showed no evidence for increased proliferation in HCMV-specific CD8(+) expansions in older subjects, although pentamer(-) CD45RA(+) cells from young donors expressed very little Ki-67. We investigated Bcl-2 and CD95 as possible anti-apoptotic mediators, but neither was associated with pentamer-positivity. To investigate whether expansion represents a compensatory response to impaired functionality, we performed two tests of functionality, peptide-stimulated proliferation and CD107 expression; both were intact in pentamer(+) cells. Our data suggest that HCMV-specific CD8(+) expansions in older subjects accumulate by extended lifespan, rather than accelerated proliferation.

The int-2 protein is related to basic fibroblast growth factor (bFGF) by amino acid sequence homology. To assess its biological activity, we constructed retroviral vectors containing four variants of mouse int-2 complementary DNA under the transcriptional control of the beta-actin promoter and tested their effects on human SW13 adrenal cortical tumor cells. This cell line specifically requires bFGF, interleukin 1, or transforming growth factor e for anchorage-independent growth in soft agar. Despite encoding a signal sequence that should direct the protein to the secretory pathway, vectors containing unmodified int-2 complementary DNA, or a form optimized for translation initiation at the AUG codon, were incapable of inducing SW13 growth in soft agar. However, SW13 transfectants expressing a construct (pSP1), in which a mouse immunoglobulin signal peptide sequence is linked to the int-2 coding sequences, grew well in soft agar. The concentrated conditioned medium from these pSP1-transfected cells supported anchorage-independent growth of SW13 indicator cells and competed with bFGF for binding to receptors. Western blot analysis with an int-2-specific antiserum detected Mr 30,000-32,000 int-2 products in cell extracts and conditioned medium from pSP1-transfected clones, whereas the conditioned medium from these and other SW13 clones contained only low levels of bFGF as measured in a specific radioimmunoassay. These data suggest that the product of the int-2 gene can functionally replace bFGF in modulating the anchorage-independent growth of SW13 cells.