UNASSIGNED: Radiation induced lymphopenia (RIL) deteriorate survival and diminishes the benefit of immune checkpoint inhibitors in combined treatment of lung cancer. Given the inconsistent data across various studies on the predictors of RIL, we aim to methodically elucidate these predictors and formulate a practical guide for clinicians.
UNASSIGNED: We conducted observational cohort study in four tertiary cancer centers. Patients with non-small cell lung cancer and small cell lung cancer, without lymphopenia grade >1, who underwent standalone radiotherapy (RT) in minimum 15 fractions were eligible. Dose-volume parameters of structures and clinical factors were comprehensively analyzed using various predictors selection methods and statistical models (Linear Regressors, Elastic Net, Bayesian Regressors, Huber Regression, regression based on k-nearest neighbors, Gaussian Process Regressor, Decision Tree Regressor, Random Forest Regressor, eXtreme Gradient Boosting, Automated Machine Learning) and were ranked to predict lymphocytes count nadir (alc_nadir).
UNASSIGNED: Two hundred thirty eight patients (stage I-3.4%, II-17.6%, III-75.2%, IV-3.8%) who underwent RT to median dose of 60 Gy were analyzed. Median alc_nadir was 0.68K/mm3. The 60 feature sets were evaluated in 600 models (RMSE 0.27-0.41K/mm³). The most important features were baseline lymphocyte count (alc_1), mean lung_dose, lung v05, lung v10, heart v05 and effective dose to immune cells (edic). In patients with alc_1 ≤ 2.005K/mm3, median alc_nadir predictions were 0.54K/mm3 for lung_v05p > 51.8% and 0.76K/mm3 for lung_v05p ≤ 51.8%. Lymphopenia was rare in patients with alc_1 > 2.005K/mm3.
UNASSIGNED: RIL was most severe in patients with low early lymphocyte counts, primarily triggered by low RT doses in the heart and lungs.

OBJECTIVE: Sepsis causes significant worldwide morbidity and mortality. Inability to clear an infection and secondary infections are known complications in severe sepsis and likely result in worsened outcomes. We sought to characterize risk factors of these complications.
METHODS: We performed a secondary analysis of clinical data from 401 subjects enrolled in the PHENOtyping sepsis-induced Multiple organ failure Study. We examined factors associated with prolonged infection, defined as infection that continued to be identified 7 days or more from initial identification, and secondary infection, defined as new infections identified ≥ 3 days from presentation. Multivariable adjustment was performed to examine laboratory markers of immune depression, with immunocompromised and immunocompetent subjects analyzed separately.
RESULTS: Illness severity, immunocompromised status, invasive procedures, and site of infection were associated with secondary infection and/or prolonged infection. Persistent lymphopenia, defined as an absolute lymphocyte count (ALC) < 1000 cells/µL twice in the first five days, and persistent neutropenia, defined as absolute neutrophil count (ANC) < 1000 cells/µL twice in the first five days, were associated with secondary and prolonged infections. When adjusted in multivariable analysis, persistent lymphopenia remained associated with secondary infection in both immunocompromised (aOR = 14.19, 95% CI [2.69, 262.22] and immunocompetent subjects (aOR = 2.09, 95% CI [1.03, 4.17]). Persistent neutropenia was independently associated with secondary infection in immunocompromised subjects (aOR = 5.34, 95% CI [1.92, 15.84]). Secondary and prolonged infections were associated with worse outcomes, including death.
CONCLUSIONS: Laboratory markers of immune suppression can be used to predict secondary infection. Lymphopenia is an independent risk factor in immunocompromised and immunocompetent patients for secondary infection.

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BACKGROUND: Common variable immunodeficiency (CVID) is considered the most symptomatic type of inborn errors of immunity in humans. Along with infectious complications, which have numerous consequences, noninfectious complications are a major challenge among CVID patients.
METHODS: All CVID patients registered in the national database were included in this retrospective cohort study. Patients were divided into 2 groups based on the presence of B-cell lymphopenia. Demographic characteristics, laboratory findings, noninfectious organ involvement, autoimmunity, and lymphoproliferative diseases were evaluated.
RESULTS: Among 387 enrolled patients, 66.4% were diagnosed with noninfectious complications and 33.6% with isolated infectious presentations. Enteropathy, autoimmunity, and lymphoproliferative disorders were reported in 35.1%, 24.3%, and 21.4% of patients, respectively. Some complications, including autoimmunity and hepatosplenomegaly, were reported to be significantly more frequent among patients with B-cell lymphopenia. As for organ involvement, the dermatologic, endocrine, and musculoskeletal systems were predominantly affected in CVID patients with B-cell lymphopenia. Among autoimmune manifestations, the frequency of rheumatologic, hematologic, and gastrointestinal autoimmunity was reported to be higher than that of other types of autoimmunity not associated with B cell-lymphopenia. Furthermore, hematological cancers, particularly lymphoma, were the most common type of malignancy. The mortality rate was 24.5%, and respiratory failure and malignancies were the most common causes of death, with no significant differences between the 2 groups.
CONCLUSIONS: Considering that some of the noninfectious complications might be associated with B-cell lymphopenia, regular patient monitoring and follow-up with proper medication (in addition to immunoglobulin replacement therapy) are highly recommended to prevent sequelae and increase patient quality of life.

Overwhelming evidence has shown that aging is a significant risk factor for COVID-19-related hospitalizations, death and other adverse health outcomes. Particular T cell subsets that susceptible to aging and associated with COVID-19 disease severity requires further elucidation. Our study recruited 57 elderly patients with acute COVID-19 and 27 convalescent donors. Adaptive immunity was assessed across the COVID-19 severity spectrum. Patients underwent age-dependent CD4+ T lymphopenia, preferential loss of circulating T follicular regulatory cells (cTfh) subsets including cTfh-em, cTfh-cm, cTfh1, cTfh2, cTfh17 and circulating T follicular regulatory cells (cTfr), which regulated antibody production through different pathways and correlated with COVID-19 severity, were observed. Moreover, vaccination improved cTfh-cm, cTfh2, cTfr proportion and promoted NAb production. In conclusion, the elderly had gone through age-dependent cTfh subsets deficiency, which impeded NAb production and enabled aggravation of COVID-19 to critical illness, whereas SARS-CoV-2 vaccine inoculation helped to rejuvenate cTfh, cTfr and intensify NAb responses.

BACKGROUND: Severe combined immunodeficiency (SCID) is a life-threatening genetic disorder caused by critical defects of the immune system. Almost all cases are lethal if not treated within the first two years of life. Early diagnosis and intervention are thus essential for improving patient outcomes. In 2013, Ontario became the first Canadian province to perform newborn screening (NBS) for SCID by T cell receptor excision circles (TRECs) analysis, a surrogate marker of thymic function and lymphocyte maturation.
METHODS: This retrospective study reports on nearly 10 years of NBS for SCID at a quaternary referral centre.
RESULTS: From August 2013 to April 2023, our centre\'s densely populated catchment area flagged 162 newborns with low TRECs levels, including 10 cases with SCID. Follow-up revealed other causes of low TRECs, including non-SCID T cell lymphopenia (secondary/reversible or idiopathic causes, and syndromic conditions) and prematurity. A small number of cases with normal repeat TRECs levels and/or T cell subsets were also flagged. Province-wide data from around this period revealed at least 24 diagnosed cases of SCID or Leaky SCID.
CONCLUSIONS: This is the first report of NBS outcomes in a Canadian province describing the causative genetic defects, and the non-SCID causes of a positive NBS for SCID.

UNASSIGNED: Current standard management in adult grades 2-4 gliomas includes maximal safe resection followed by adjuvant radiotherapy (RT) and chemotherapy. Radiation-induced lymphopenia (RIL) has been shown to possibly affect treatment outcomes adversely. Proton beam therapy (PBT) may reduce the volume of the normal brain receiving moderate radiation doses, and consequently RIL. Our aim was to evaluate the incidence and severity of RIL during proton beam therapy (PBT).
UNASSIGNED: We identified patients with grades 2-4 glioma treated with PBT at our center between January 2019 and December 2021. We evaluated the incidence and severity of RIL from weekly complete blood count (CBC) data collected during PBT and compared it to the patients who were treated with photon-based RT (XRT) at our center during the same time.
UNASSIGNED: The incidence of any degree of lymphopenia (48% in PBT, vs. 81.2% in XRT, P value = .001) and severe lymphopenia (8% in PBT, vs. 24.6% in XRT, P value = .093) were both significantly lesser in patients who received PBT. Severe RIL in patients receiving PBT was seen in only CNS WHO Gr-4 tumors. Mean whole brain V20GyE and V25GyE inversely correlated to nadir ALC and were both significantly lower with PBT. Patients with lymphopenia during PBT showed a trend toward poorer progression-free survival (P = .053) compared to those with maintained lymphocyte counts.
UNASSIGNED: Proton therapy seems to have a superior sparing of normal brain to moderate dose radiation than photon-based RT and reduces the incidence of lymphopenia. Glioma patients with lymphopenia possibly have worse outcomes than the ones with maintained lymphocyte counts.

UNASSIGNED: The purpose of this study is to evaluate the association between lymphopenia and survival in women with locally advanced cervical cancer (LACC) treated with definitive chemoradiation (CRT).
UNASSIGNED: We retrospectively reviewed patients with LACC treated at a single institution from 2004 to 2021. Patient and treatment characteristics were recorded along with baseline absolute lymphocyte counts (ALC). Overall survival (OS), progression free survival (PFS), and local control (LC) were calculated from start of treatment to date of last follow-up. Cox regression and competing risks regression model were performed to evaluate whether baseline ALC was associated with OS, PFS, or LC.
UNASSIGNED: 246 patients met study inclusion criteria with stage IB - IV disease with a median follow up of 2.8 years (range 0.2-13.4 years). 5-year OS, PFS, and LC were 68.4 % (95 % CI 61.7-75.9), 57.2 % (95 % CI 50.4-64.8), and 79.0 % (95 % CI 73.0-84.4), respectively. Baseline lymphopenia (ALC < 1000 cells/mm3) was present in 12.5 % of patients. OS was improved in the patients without lymphopenia, with a 5-year OS of 69.0 % (95 % CI 61.6-77.3) versus 63.0 % (95 % CI 47.6-83.3)in the lymphopenia group (p = 0.233), though this did not meet statistical significance. PFS also trended towards improvement in patients without baseline lymphopenia, with a 5-year PFS of 58.5 % (95 % CI 51.2-66.8) versus 48.5 % (95 % CI 32.8-71.7), p = 0.220. No significant difference was found for LC in the patients without lymphopenia, p = 0.745.
UNASSIGNED: In this single institution experience of LACC treated with definitive CRT, we found that baseline lymphopenia trends toward inferior OS and PFS.

BACKGROUND: Diroximel fumarate (DRF) and dimethyl fumarate (DMF) are similar disease-modifying therapies (DMTs) that reduce disease activity in patients with relapsing-remitting multiple sclerosis (MS). We expect that patients on DRF would experience a similar incidence and severity of lymphopenia, given that it is a well-documented side effect of DMF treatment.
METHODS: We utilized linear mixed-effects models to test for differences in white blood cell count (WBC), absolute lymphocyte count (ALC), absolute CD3+ count, absolute CD4+ count, and absolute CD8+ count over time in clinically stable patients with MS on DMF who switched to DRF.
RESULTS: Twenty-two patients with MS who were clinically stable on DMF switched to DRF. Linear mixed-effects models showed a decrease in ALC when switching medications (β = -225.70, p < 0.040). In addition, the models showed a decrease in absolute CD8+ counts after switches from DMF to DRF (β = -85.59, p = 0.034).
CONCLUSIONS: Patients with MS who are stable on DMF and switch to DRF may experience worsening of lymphopenia and lower absolute CD8+ counts, which may increase their risk of opportunistic infections. These findings indicate that close lymphocyte subset monitoring is clinically important when switching patients with MS from DMF to DRF.

BACKGROUND: It is unknown whether lymphopenia is a risk factor for the reactivation of Chagas disease in heart transplantation (HTx), as recently described in the reactivation of cytomegalovirus in transplant patients.
OBJECTIVE: To evaluate whether lymphopenia in the perioperative period of heart transplantation is related to early Trypanosoma cruzi parasitemia.
METHODS: This observational, retrospective study analyzed a sample from January 2014 to January 2023). Parasitemia was evaluated in the first 3 months after HTx using serum polymerase chain reaction (PCR) and compared with the total lymphocyte count in the perioperative period of HTx using receiver operating characteristic curves. Baseline characteristics were compared with PCR for Chagas using independent Cox proportional hazards models. A significance level of 5% was adopted.
RESULTS: The sample (n = 35) had a mean age of 52.5 ± 8.1 years, and 22 patients (62.8%) had positive PCR for Chagas. The mean lowest lymphocyte values in the first 14 days after HTx were 398 ± 189 and 755 ± 303 cells/mm3 in patients with and without parasitemia, respectively, within 3 months after HTx (area under the curve = 0.857; 95% confidence interval: 0.996 to 0.718, sensitivity and specificity of 83.3% and 86.4%). A cutoff value of less than 550 lymphocytes/mm3 was determined as a risk factor for the presence of parasitemia. Patients with lymphocytes < 550 units/mm3 in the first 14 days after HTx presented positive PCR in 80% of cases. For every increase of 100 lymphocytes/mm3, the risk of PCR positivity was reduced by 26% (hazard rate ratio = 0.74; 95% confidence interval: 0.59 to 0.93, p = 0.009).
CONCLUSIONS: There was an association between lymphopenia in the perioperative period of HTx and early T. cruzi parasitemia detected by PCR.
OBJECTIVE: É desconhecido se a linfopenia é fator de risco para a reativação da doença de Chagas no transplante cardíaco (TxC), como recentemente descrito na reativação de citomegalovírus em pacientes transplantados.
OBJECTIVE: Avaliar se a linfopenia no perioperatório do TxC está relacionada à parasitemia precoce pelo Trypanosoma cruzi.
UNASSIGNED: Amostra analisada (janeiro de 2014 a janeiro de 2023) em estudo observacional e retrospectivo. A parasitemia foi avaliada nos primeiros 3 meses após o TxC por meio da reação em cadeia da polimerase sérica (PCR) e comparada com a contagem total de linfócitos no perioperatório do TxC por curvas ROC. Comparadas características de base com a PCR Chagas por modelos de risco proporcionais de Cox independentes. Nível de significância adotado de 5%.
RESULTS: Amostra (n = 35) apresentou idade média de 52,5 ± 8,1 anos e PCR Chagas positiva em 22 pacientes (62,8%). As médias dos menores valores de linfócitos nos primeiros 14 dias do TxC foram 398 ± 189 e 755 ± 303 células/mm3 em pacientes com e sem parasitemia nos 3 meses após o TxC, respectivamente (área sob a curva = 0,857; intervalo de confiança de 95%: 0,996 a 0,718, sensibilidade e especificidade de 83,3% e 86,4%). Determinado valor de corte inferior a 550 linfócitos/mm3 como fator de risco para presença de parasitemia. Pacientes com linfócitos < 550 unidades/mm3 nos primeiros 14 dias do pós-TxC apresentaram PCR positiva em 80% dos casos. Para cada aumento de 100 linfócitos/mm3, o risco de positividade da PCR é reduzido em 26% (razão de riscos = 0,74; intervalo de confiança de 95%: 0,59 a 0,93, p = 0,009).
UNASSIGNED: Houve associação entre a linfopenia no perioperatório do TxC com a parasitemia precoce pelo T. cruzi detectada por PCR.