Progressive B Cell Loss in Revertant X-SCID.

We report the case of a patient with X-linked severe combined immunodeficiency (X-SCID) who survived for over 20 years without hematopoietic stem cell transplantation (HSCT) because of a somatic reversion mutation. An important feature of this rare case included the strategy to validate the pathogenicity of a variant of the IL2RG gene when the T and B cell lineages comprised only revertant cells. We studied the X-inactivation of sorted T cells from the mother to show that the pathogenic variant was indeed the cause of his SCID. One interesting feature was a progressive loss of B cells over 20 years. CyTOF (cytometry time of flight) analysis of bone marrow offered a potential explanation of the B cell failure, with expansions of progenitor populations that suggest a developmental block. Another interesting feature was that the patient bore extensive granulomatous disease and skin cancers that contained T cells, despite severe T cell lymphopenia in the blood. Finally, the patient had a few hundred T cells on presentation but his TCRs comprised a very limited repertoire, supporting the important conclusion that repertoire size trumps numbers of T cells.

Shifts in Asthma Evaluation and Management During COVID-19.

Purpose of Review: The comprehensive management of asthma has historically relied on in-person visits to obtain a detailed history, thorough physical exam, and diagnostic and monitoring tools such as pulmonary function testing. The COVID-19 pandemic has posed numerous challenges to adequately utilizing these strategies. Despite these limitations, telemedicine has provided an important means to deliver asthma care. In this review, we discuss how these challenges have created paradigm shifts in not only the clinical aspects of asthma management, but also in patient attitudes and physician-patient relationships. Recent Findings: Different strategies have been suggested to address asthma during COVID-19. Telemedicine has taken on an important role during the pandemic. The emphasis on asthma questionnaire use, education regarding lapsed asthma control, and as-needed oral corticosteroid courses have proven to be important instruments in the remote management of asthma. Overall, asthma exacerbations have decreased during this time. This is thought to be due to a variety of factors such as decreased exposure to common triggers. Summary: Although the COVID-19 pandemic significantly limited an allergist's ability to provide conventional comprehensive asthma management, we also found that patient outcomes have actually improved. In addition to the decreased exposure to asthma triggers, this may also be an effect of increased patient ownership of their asthma, and subsequent improved therapeutic alliance.

Electrical impedance myography in the assessment of disuse atrophy.

UNLABELLED: Tarulli AW, Duggal N, Esper GJ, Garmirian LP, Fogerson PM, Lin CH, Rutkove SB. Electrical impedance myography in the assessment of disuse atrophy. OBJECTIVE: To quantify disuse atrophy using electrical impedance myography (EIM), a noninvasive technique that we have used successfully to study neurogenic and myopathic atrophy. DESIGN: We performed EIM of the tibialis anterior of subjects with disuse atrophy secondary to cast immobilization and in their contralateral normal leg. Subjects were studied shortly after cast removal and again several weeks to months after the cast was removed and normal mobility was restored. SETTING: Outpatient neurology and orthopedic practices at a tertiary care medical center. PARTICIPANTS: Otherwise healthy subjects (N=10) with unilateral leg fracture. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Resistance, reactance, and phase measured at 50kHz. RESULTS: The main EIM outcome parameter, phase at 50kHz, was lower in the immobilized leg in 9 of 10 cases. Additionally, when normal mobility was restored, the phase of the casted leg increased relative to its initial measurement in all 10 cases, while it increased inconsistently in the contralateral leg. CONCLUSIONS: EIM may be a powerful tool for the assessment of disuse atrophy.