Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0024312 (lymphopenia)
 4,859 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Severe acute respiratory syndrome (SARS) is a zoonotic infectious disease caused by a novel coronavirus (CoV). The tissue tropism of SARS-CoV includes not only the lung, but also the gastrointestinal tract, kidney and liver. Angiotensin-converting enzyme 2 (ACE2), the C-type lectin CD209L (also known L-SIGN), and DC-SIGN bind SARS-CoV, but ACE2 appears to be the key functional receptor for the virus. There is a prominent innate immune response to SARS-CoV infection, including acute-phase proteins, chemokines, inflammatory cytokines and C-type lectins such as mannose-binding lectin, which plays a protective role against SARS. By contrast there may be a lack of type 1 interferon response. Moreover, lymphopenia with decreased numbers of CD4+ and CD8+ T cells is common during the acute phase. Convalescent patients have IgG-class neutralizing antibodies that recognize amino acids 441-700 of the spike protein (S protein) as the major epitope.
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PMID:Pathogenesis of severe acute respiratory syndrome. 1595 Apr 49

Pneumocystis jirovecii pneumonia (PCP) incidence is increasing in kidney transplant recipients (KTR), but risk factors remain poorly defined. CD4+ T lymphopenia and mannose-binding lectin (MBL) deficiency are common immunodeficiencies in KTR. Here, we investigated whether CD4+ T lymphopenia and/or MBL deficiency would be risk factors for PCP in KTR. Furthermore, the role of thymic function in CD4+ T lymphopenia and outcome was studied by assessing CD45RA+CD31+CD4+ T cell numbers (RTE, recent thymus emigrants). In 321 de novo KTR serial determinations of peripheral T lymphocyte subsets (n=281, mean 4.2 times between days 0-365) and/or MBL levels (n=112, mean 1.8 times between days 30-180) were performed. 22/321 patients developed a PCP episode on average at day 199 (107-398) post-Tx. Age correlated inversely with RTE, CD4+ and CD8+ T-cell counts until day 180 post-Tx. RTE correlated with CD4+ T-cell counts at all time-points pre- and post-Tx. PCP patients had more CMV infections (p=0.045) within the first 3 months compared to controls. Importantly, PCP patients were older (p=0.008), and had lower RTE (p=0.046) pretransplant, and lower CD4+ T-cell counts pretransplant (p=0.017), at day 60 (p=0.032) and for the average of all post-Tx values (p=0.027) compared to controls. Though treatment with T-cell depleting antibodies was associated with consecutive CD4+ T lymphopenia in the whole cohort, the number of patients who received T-cell depleting antibodies was comparable between PCP and control patients (p=0.754). A multivariate stepwise logistic regression model identified only pretransplant CD4+ T-cell counts (OR 0.011, p=0.010) and acute rejection (OR 4.66, p=0.023) as predictors of PCP. In contrast, MBL levels and incidence of MBL deficiency (<500 ng/ml) at days 30, 90 and 180 post-Tx were not different between PCP patients and controls. In conclusion, PCP risk was associated with higher age and related to both thymic functional impairment and long-lasting CD4+ T-lymphopenia that started already before transplantation. Despite frequent occurrences in KTR, low levels of serum MBL were not associated with increased risk for PCP. CD4+ T-cell counts and function should be addressed in prospective studies for more individualized approaches to PCP prophylaxis.
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PMID:Impaired thymic function and CD4+ T lymphopenia, but not mannose-binding lectin deficiency, are risk factors for Pneumocystis jirovecii pneumonia in kidney transplant recipients. 2368 46