Case records of the Massachusetts General Hospital. Case 20-2014. A 65-year-old man with dyspnea and progressively worsening lung disease

Development and Evaluation of a Fully Automated Molecular Assay Targeting the Mitochondrial Small Subunit rRNA Gene for the Detection of Pneumocystis jirovecii in Bronchoalveolar Lavage Fluid Specimens

The fungal pathogen Pneumocystis jirovecii causes Pneumocystis pneumonia. Although the mitochondrial large subunit rRNA gene (mtLSU) is commonly used as a PCR target, a mitochondrial small subunit rRNA gene (mtSSU)-targeted MultiCode PCR assay was developed on the fully automated ARIES platform for detection of P. jirovecii in bronchoalveolar lavage fluid specimens in 2.5 hours. The assay showed a limit of detection of 800 copies/mL (approximately equal to 22 organisms/mL), with no cross-reactivity with other respiratory pathogens. Compared with the reference Pneumocystis-specific direct fluorescent antibody assay (DFA) and mtLSU-targeted PCR assay, the new assay demonstrated sensitivity of 96.9% (31/32) and specificity of 94.6% (139/147) in detecting P. jirovecii in 180 clinical bronchoalveolar lavage fluid specimens. This assay was concordant with all DFA-positive samples and all but one mtLSU PCR-positive sample, and detected eight positive samples that were negative by DFA and mtLSU PCR. Receiver operating characteristic curve analysis revealed an area under the curve of 0.98 and a threshold cycle (C_T) cutoff of 39.1 with sensitivity of 90.9% and specificity of 99.3%. The detection of 39.1 <C_T < 40.0 indicates the presence of a low load of the organism and needs further determination of either colonization or probable/possible Pneumocystis pneumonia. Overall, the new assay demonstrates excellent analytical and clinical performance and may be more sensitive than mtLSU PCR target for the detection of P. jirovecii.

An investigation into method of diagnosis in clinicopathologic conferences (CPCs)

An analysis of 50 clinicopathologic conferences (CPCs) reveals the method of diagnosis in them to consist of construction of exhaustive differential diagnosis followed by evaluation of each disease in it by the likelihood inference approach. This method leads to 98% diagnostic accuracy in these CPCs. A probabilistic approach is found not to be employed for evaluation of a disease.

A comparison study on the clinical effects of foscarnet sodium injection and interferon on human immunodeficiency virus-infected patients complicated with herpes zoster

OBJECTIVE

To compare the clinical effects of foscarnet sodium injection and interferon on human immunodeficiency virus (HIV)-infected patients complicated with herpes zoster.

METHODS

Ninety HIV-infected patients complicated with herpes zoster were divided into a treatment group and a control group that were both treated routinely first. Then the control group and treatment group were administered with interferon and foscarnet sodium injection respectively for four consecutive weeks.

RESULTS

After four weeks, the effective rates of the treatment and control groups were 95.6% and 80.0% respectively, which were significantly different (P < 0.05). The pain scores of the two groups were similar before treatment, but the scores of the treatment group were significantly lower than those of the control group two and four weeks after treatment (P < 0.05) as well as were significantly lower than those before treatment (P < 0.05). The numbers of CD4+ cells and the contents of IL-2 of both groups two and four weeks after treatment significantly exceeded those before treatment (P < 0.05), with significant inter-group differences also (P < 0.05). Two and four weeks after treatment, the treatment group scored significantly higher in physical activity, energy, sleep, social life and emotional reaction than the control group did (P < 0.05).

CONCLUSIONS

HIV-infected patients are prone to being complicated with herpes zoster. Compared with interferon, foscarnet sodium injection better improves the clinical outcomes by effectively relieving pain and by regulating immune mediated inflammatory diseases, thus boosting the prognostic quality of life.