Analysis of somatic hypermutations in the IgM switch region in human B cells.

Background: The molecular mechanism of class-switch recombination (CSR) in human subjects has not been fully elucidated. The CSR-induced mutations occurring in the switch region of the IgM gene (Smu-SHMs) in in vitro CSR-activated and in vivo switched B cells have been analyzed in mice but not in human subjects.

Objective: We sought to better characterize the molecular mechanism of CSR in human subjects.

Identification of severe combined immunodeficiency by T-cell receptor excision circles quantification using neonatal guthrie cards.

Objective: To assess the feasibility of T-cell receptor excision circles (TRECs) quantification for neonatal mass screening of severe combined immunodeficiency (SCID).

Study Design: Real-time PCR based quantification of TRECs for 471 healthy control patients and 18 patients with SCID with various genetic abnormalities (IL2RG, JAK3, ADA, LIG4, RAG1) were performed, including patients with maternal T-cell engraftment (n = 4) and leaky T cells (n = 3).

Results: TRECs were detectable in all normal neonatal Guthrie cards (n = 326) at the levels of 10(4) to 10(5) copies/microg DNA.

Molecular diagnosis of cerebral aspergillosis by sequence analysis with panfungal polymerase chain reaction.

The authors describe a patient with osteosarcoma in whom a brain abscess developed after autologous peripheral stem cell transplantation. Serologic markers of fungal infection were negative, but fungal DNA was detected in the cerebrospinal fluid (CSF) by panfungal polymerase chain reaction (PCR) assay using primers derived from fungal 18S ribosomal RNA (rRNA) genes. The sequence of PCR products on the panfungal assay was identical to the 18S rRNA genes of Aspergillus species.

MRI findings of recurrent herpes simplex encephalitis in an infant.

We report the MRI findings of a 2-year-old boy with recurrent herpes simplex encephalitis (HSE). At the age of 14 months, the patient developed a high fever that lasted over 1 week and he did not receive appropriate treatment. At 6 months after the fever, MRI showed marked atrophic changes in both deep temporal lobes with hyperintensity in the hippocampi and parahippocampal gyri.