Diagnosis of Mycoplasma pneumoniae Pneumonia with Measurement of Specific Antibody-Secreting Cells

Mycoplasma pneumoniae (Mp) is reported to be the most common bacterial cause of community-acquired pneumonia (CAP) in hospitalized U.S. children (1). However, current diagnostic tests, including PCR of upper respiratory tract (URT) specimens and serology, do not differentiate between Mp infection and carriage (2). Mp carriage in the URT is found in up to 56% of healthy children (2, 3). A ≥4-fold increase in IgG levels is still used in most centers to confirm Mp infection but has low sensitivity (4) and is not helpful in acute clinical management (3). In the absence of an accurate diagnostic test, it is not surprising that studies and meta-analyses on the efficacy of antibiotics are inconclusive for Mp CAP in children (5, 6). Circulating antibody-secreting cell (ASC) responses have been demonstrated to be more rapid and shorter-lived than antibody responses (7). We hypothesized that Mp-IgM-ASCs circulate in peripheral blood only for a few days or weeks after Mp infection, whereas Mp-DNA in the URT and serum antibodies persist for months. We aimed to evaluate the measurement of Mp-IgM-ASCs by enzyme-linked immunospot (ELISpot) assay as a new test for diagnosing Mp CAP. Methods Pediatric patients with CAP (n = 152) and control subjects (n = 156) were enrolled from May 2016 to April 2017 after written informed consent. Inclusion criteria for patients with CAP were clinical diagnosis of pneumonia (fever >38.5°C and tachypnea [8]) in previously healthy children aged 3–18 years. Children <3 years were excluded because of a high probability of viral coexistence in the URT (8). Control individuals included healthy children (undergoing elective surgical procedures) and siblings of patients with CAP (with higher chance of being asymptomatic carriers) without recent (≤1 wk) respiratory tract infections. In all enrolled children, pharyngeal swabs were taken for Mp real-time PCR (9). If additional consent was given, blood samples also were collected in control individuals and patients with CAP (before antibiotic treatment) to test for the presence of Mp-IgM-ASCs by ELISpot assay (detailed in the legend of Figure 1) (10) and Mp-IgM, Mp-IgG, and Mp-IgA by ELISA (2). Finally, we only included children with fresh (isolated ≤4 h) peripheral blood mononuclear cells to avoid poor ELISpot assay performance resulting from decreased ASC viability (in case of isolation >4 h after sampling) or reduced ASC recovery (after a freeze–thaw cycle) (10). Samples and clinical data (using a standardized questionnaire) were collected at follow-up visits at <2 weeks, 2 weeks to 2 months, and 2–6 months

Improved diagnostics help to identify clinical features and biomarkers that predict Mycoplasma pneumoniae community-acquired pneumonia in children

BACKGROUND There are no reliable signs or symptoms that differentiate Mycoplasma pneumoniae (Mp) infection in community-acquired pneumonia (CAP) from other etiologies. Additionally, current diagnostic tests do not reliably distinguish between Mp infection and carriage. We previously determined that the measurement of Mp-specific IgM antibody-secreting cells (ASCs) by enzyme-linked immunospot (ELISpot) assay allowed for differentiation between infection and carriage. Using this new diagnostic test, we aimed to identify clinical and laboratory features associated with Mp infection. METHODS This is a prospective cohort study of children, 3-18 years, with CAP from 2016-2017. Clinical features and biomarkers were compared between Mp-positive and -negative groups by Mann-Whitney U test or Fisher's exact test, as appropriate. Area under the receiver operating characteristics curves (AUC) differences and optimal thresholds were determined by using the DeLong's test and Youden's J statistic, respectively. RESULTS Out of 63 CAP patients, there were 29 Mp-positive (46%). Mp-positive was statistically associated with older age (median 8.6 vs. 4.7 years), no underlying disease, family with respiratory symptoms, prior antibiotic treatment, prolonged prodromal respiratory symptoms and fever, and extrapulmonary (skin) manifestations. Lower levels of C-reactive protein, white blood cell count, absolute neutrophil count, and procalcitonin (PCT), specifically PCT 5 years (AUC=0.77), prodromal fever and respiratory symptoms >6 days (AUC=0.79), and PCT <0.25 μg/L (AUC=0.81) improved diagnostic performance (AUC=0.90, p=0.05). CONCLUSIONS A combination of clinical features and biomarkers may aid physicians in identifying patients at high risk for Mp CAP

Transsphenoidal extension of heterotopic glioneuronal tissue: pathoanatomic considerations in symptomatic neonates

PURPOSE: In this clinical investigation, we aimed (1) to re-evaluate the nature of glioneuronal tissue with transsphenoidal extension and how it fits into the nomenclature of midline malformations and mass lesions; (2) to find out if our imaging findings support current pathoanatomic concepts of clefts and canals in the sphenoid body of newborns. METHODS: In two neonates with respiratory distress due to nasopharyngeal masses, 3T MRI was performed, and CT in one of them. Imaging features were analyzed in consensus by two pediatric neuroradiologists with histological reports being available. An interdisciplinary panel compared the findings to those of case publications and differential entities from our institutional case collection. RESULTS: Referring to our rare case of transsphenoidal cerebral heterotopia and unique case of hypothalamic hamartoma with transsphenoidal herniation, glioneuronal heterotopia may definitely extend through the sphenoid bone. Consequently, there is reason for brain heterotopias to be labeled as such also in case of an intracranial component. Connection between heterotopic glioneuronal tissue in the nasopharynx and a hypothalamic hamartoma may go along with indistinct margins to normal brain. Neither extension through a transsphenoidal cleft nor association with a cleft palate are specific for cerebral heterotopia. Our findings support the hypothesis that transsphenoidal cerebral heterotopias do not or at least not invariably follow the route of Rathke's pouch, known as the craniopharyngeal canal. CONCLUSION: Transsphenoidal glioneuronal heterotopia should be the top differential diagnosis in MR imaging if a non-enhancing nasopharyngeal mass of an infant extends through a craniopharyngeal cleft within the intersphenoid synchondrosis

Bone marrow T helper cells with a Th1 phenotype induce activation and proliferation of leukemic cells in precursor B acute lymphoblastic leukemia patients

Precursor B cell acute lymphoblastic leukemia (BCP-ALL) constitutes the leading cause of cancer-related death in children. While chromosomal alterations contribute to BCP-ALL pathogenesis, they are insufficient for leukemia development. Epidemiological data and evidence from a mouse model suggest that immune responses to infections may trigger the emergence of leukemia, but the mechanisms remain unclear. Here, we show that T helper (Th) cells from bone marrow of pediatric BCP-ALL patients can be attracted and activated by autologous BCP-ALL cells. Bone-marrow Th cells supportively interacted with BCP-ALL cells, inducing upregulation of important surface molecules and BCP-ALL cell proliferation. These Th cells displayed a Th1-like phenotype and produced high levels of IFN-γ. IFN-γ was responsible for the upregulation of CD38 in BCP-ALL cells, a molecule which we found to be associated with early relapse, and accountable for the production of IP-10, a chemokine involved in BCP-ALL migration and drug resistance. Thus, our data provide mechanistic support for an involvement of Th cell immune responses in the propagation of BCP-ALL and suggest that BCP-ALL cell-supportive Th cells may serve as therapeutic target