Induction and expression of protective T cells during Mycobacterium avium infections in mice.

Mycobacterium avium is an opportunistic pathogen that infects individuals suffering from chronic lung disease or immunocompromised patients such as AIDS patients. Here we show that a highly virulent isolate of M. avium proliferated as extensively in T cell deficient as in immunocompetent mice. T cell deficient mice allowed a progressive growth of a less virulent AIDS-derived isolate of M. avium while immunocompetent mice arrested the growth of this isolate. Adoptive transfer of T cell enriched spleen cells between congenic strains of mice differing at the Bcg/Ity/Lsh locus showed that only naturally resistant BALB/c.Bcgr (C.D2) mice infected with the highly virulent strain of M. avium or the naturally susceptible BALB/c mice infected with the lower virulence isolate developed protective T cells and that these cells only mediated protection when transferred to naturally susceptible, but not to naturally resistant, mice. Both strains of M. avium proliferated in bone marrow-derived macrophages cultured in vitro and they were both susceptible to the bacteriostatic effects induced in the macrophages by crude lymphokines produced by concanavalin A-stimulated spleen cells.     

CT evaluation of gastric wall pathology

The purpose of this study is to show the CT features of common and infrequent pathological lesions of the gastric wall. Although CT features are not often specific, familiarity with the most frequent pathological gastric findings on CT can assist in differential diagnosis.     

Multiple myeloma in an adolescent

The radiographic findings of a 15-year-old Brazilian male with diagnosis of multiple myeloma are described. He presented with claudication and recent onset of tender painful swelling of the right mid leg. Radiographs showed wide spread soap bubble lesions of the skull, long bones, spine, pelvis, ribs, shoulders, and clavicles. The diagnosis was confirmed by the presence of a plasmacytoma on tissue biopsy (femur), serum IgG gammopathy and Bence-Jones proteinuria.Supported by grants (CA-20180 and CA-21765) from the National Cancer Institute and the American Lebanese Syrian Associated Charities (ALSAC)     

Analytical validation of anti-toxoplasma IgG immunoassays

There are often discrepancies when using different methods to measure anti-Toxoplasma gondii IgG levels in patient samples. The diagnostic performance of a chemiluminescent immunoassay (CLIA) and an enzyme-linked fluorescent assay (ELFA) used as confirmatory tests for samples identified as positive or equivocal by an electrochemiluminescent immunoassay (ECLIA) were examined. Cut-off values were those stated by the manufacturer, and Western blot was used to confirm the results of all methods. All samples identified as positive by ECLIA (n = 93) were confirmed as positive by Western blot, as were 14 of the 28 samples identified as equivocal. When these 121 samples were retested, the sensitivities of CLIA and ELFA were 64.4% and 73.8%, respectively. Both methods exhibited a specificity of 100%. This study confirms that the results obtained from the different immunoassays are not comparable, and neither CLIA nor ELFA should be used to confirm ECLIA results, which should instead be confirmed by methods such as Western blot or Sabin-Feldman dye test.