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Purine nucleoside phosphorylase (PNP) deficiency is a rare immunodeficiency syndrome generally characterized by profound T cell deficiency and variable B cell function. More than half of PNP-deficient patients present with neurological dysfunction, with manifestations such as mental and motor retardation, spasticity, hypertonia, ataxia, and behavioral disturbances. Here, we report two siblings diagnosed with PNP deficiency in early infancy. Our patients had developmental delays, and their immunological findings indicated T-B+NK+ leaky/atypical severe combined immune deficiency. The patients are being treated with regular intravenous immunoglobulin replacement, as well as trimethoprim-sulfomethoxazole and fluconazole, for prophylaxis in preparation for transplantation. These cases draw attention to the possibility of primary immune deficiency in patients with recurrent infections and lymphopenia. In addition, PNP deficiency should be kept in mind in the presence of developmental delay, low uric acid levels, and lymphopenia. [ABSTRACT FROM AUTHOR]

Increased levels of acute‐phase reactants and lymphopenia are predictors of disease severity in coronavirus disease 2019 (COVID‐19). This study aimed to investigate the role of apoptosis in the etiology of lymphopenia in patients with COVID‐19. This multicentered, prospective, and case‐control study was conducted with polymerase chain reaction (+) severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) patients, and an age–gender‐matched control group. Samples were taken at the time of diagnosis and analyzed via flow cytometry within 24 h. The participants' demographic data and initial laboratory tests were also recorded. In total, 33 patients with COVID‐19 (mean age = 45.4 ± 17.2) and 25 controls (mean age = 43.4 ± 17.4) participated in the study. All patients were identified as having mild (16), moderate (5), or severe (12) disease severity. Both early and late apoptotic cells in B and T lymphocytes were increased in all patients with COVID‐19 (p <.05). Early apoptotic (EA) B and T lymphocytes were also higher in severe cases compared to mild cases (p =.026). There was no significant difference between lymphopenia and apoptosis in patients with COVID‐19. However, patients with lymphopenia (n = 14) and severe COVID‐19 (p =.013) had increased EA T lymphocytes. This study's results show that B and T lymphocytes' apoptosis increases in patients with COVID‐19. In addition, enhanced T lymphocyte apoptosis is associated with disease severity in lymphopenic patients with COVID‐19. Highlights: One of the causes of lymphopenia in COVID‐19 disease is lymphocyte apoptosis.All lymphocyte subsets progress towards apoptosis with the disease severity.In those with lymphopenia, T cells seem to progress to more apoptosis than B.The IgG is markedly in a negative correlation with IgM in the lymphopenia group. [ABSTRACT FROM AUTHOR]

One of the severe combined immunodeficiencies (SCIDs), which is caused by a genetic defect in the signal transduction pathways involved in T-cell activation, is the ZAP70 deficiency. Mutations in ZAP70 lead to both abnormal thymic development and defective T-cell receptor (TCR) signaling of peripheral T-cells. In contrast to the lymphopenia in most SCID patients, ZAP70-deficient patients have lymphocytosis, despite the selective absence of CD8+ T-cells. The clinical presentation is usually before 2 years of age with typical findings of SCID. Here, we present three new ZAP70-deficient patients who vary in their clinical presentation. One of the ZAP70-deficient patients presented as a classical SCID, the second patient presented as a healthy looking wheezy infant, whereas the third patient came to clinical attention for the eczematous skin lesions simulating atopic dermatitis with eosinophilia and elevated immunoglobulin E (IgE), similar to the Omenn syndrome. This study illustrates that awareness of the clinical heterogeneity of ZAP70 deficiency is of utmost importance for making a fast and accurate diagnosis, which will contribute to the improvement of the adequate treatment of this severe immunodeficiency. [ABSTRACT FROM AUTHOR]

Lung cancer is the leading cause of cancer‐related deaths, in part due to its late diagnosis. Increased epidermal growth factor receptor (EGFR) expression in cancer cells is associated with a poor prognosis, and EGFR tyrosine kinase inhibitors are widely used in cancer treatment. This study aimed to clarify the relationship between EGFR expression on T cells and cancer prognosis in patients with non‐small cell lung cancer (NSCLC). Forty patients with NSCLC and 40 healthy volunteers were included in this study. Peripheral CD4+T helper (Th1, Th2, Th9, Th17, Th1Th17, follicular and peripheral Th) and cytotoxic T lymphocyte (CD8+follicular and peripheral T) subsets were identified with flow cytometry according to their chemokine receptors. EGFR expression on T lymphocytes in relation to overall survival (OS) was investigated in patients with NSCLC. The patients [mean age (min‐max) = 64.03 (45–83); 20 stage I–III and 20 stage IV] had increased EGFR expression on CD3+T, CD4+Th, Th1, Th2, and Th17 cells compared to the controls (p < 0.05). High EGFR expression on CD3+T, CD4+Th, Th1, and Th2 cells was associated with poor OS. Also, PD‐1 expression on lymphocytes, CD3+T, and Th cells was increased in patients with NSCLC compared to controls. The high expression of EGFR and PD‐1 on Th cells and the reduced percentage of lymphocytes and Th cells, especially in stage IV patients with NSCLC, revealed that increased EGFR activity may trigger apoptosis of Th cells and promote the development of metastases, while high EGFR expression on CD3+T, CD4+Th, Th1, and Th2 cells may be an independent poor prognostic marker in NSCLC. [ABSTRACT FROM AUTHOR]