The CXCR5 T follicular helper cell compartment in children with antibody deficiencies—in search of a prognostic marker of childhood hypogammaglobulinemia

Background Novel immunodiagnostic markers are required in order to discriminate between mild hypogammaglobulinemia and severe humoral primary immune deficiencies in children. The efficacy of an antibody response to infections and vaccines is underpinned by T follicular helper (Tfh) cells, activating an immunoglobulin class switch recombination, somatic hypermutations, and affinity maturation. Objective To determine the formation of the Tfh cells in antibody deficient children and to define their importance as prognostic markers helpful in defining the severity of hypogammaglobulinemia. Methods We retrospectively reviewed medical records of 200 children aged from 2 months to 10 years, in whom hypogammaglobulinemia was assessed, from January to December 2019. In all the children studied, a flow cytometric analysis of the Tfh cell compartment was performed. Results In young infants aged from 2 to 9 months, the mean relative frequency of the Tfh population was lower than in the control population. Concomitantly, the relative values of Tfh cells, corresponding with the 95th percentile, were below the reference values in all age groups. Conclusions A deficiency of Tfh cells in young infants mirrors the immaturity of the humoral immune response, whereas in older children Tfh cells are proposed as a prognostic marker facilitating to distinguish between mild hypogammaglobulinemia and the developing common variable immunodeficiency (AU)

The CXCR5 T follicular helper cell compartment in children with antibody deficiencies-in search of a prognostic marker of childhood hypogammaglobulinemia.

BACKGROUND: Novel immunodiagnostic markers are required in order to discriminate between mild hypogammaglobulinemia and severe humoral primary immune deficiencies in children. The efficacy of an antibody response to infections and vaccines is underpinned by T follicular helper (Tfh) cells, activating an immunoglobulin class switch recombination, somatic hypermutations, and affinity maturation. OBJECTIVE: To determine the formation of the Tfh cells in antibody deficient children and to define their importance as prognostic markers helpful in defining the severity of hypogammaglobulinemia. METHODS: We retrospectively reviewed medical records of 200 children aged from 2 months to 10 years, in whom hypogammaglobulinemia was assessed, from January to December 2019. In all the children studied, a flow cytometric analysis of the Tfh cell compartment was performed. RESULTS: In young infants aged from 2 to 9 months, the mean relative frequency of the Tfh population was lower than in the control population. Concomitantly, the relative values of Tfh cells, corresponding with the 95th percentile, were below the reference values in all age groups. CONCLUSIONS: A deficiency of Tfh cells in young infants mirrors the immaturity of the humoral immune response, whereas in older children Tfh cells are proposed as a prognostic marker facilitating to distinguish between mild hypogammaglobulinemia and the developing common variable immunodeficiency.

A case of bizarre posttransplant anti-glomerular basement membrane disease.

The non-collagenous (NC1) domain of α3 and α5 chains of type IV collagen are eminent targets of abnormal immune response in anti-glomerular basement membrane (anti-GBM) disease, which can be diagnosed by the presence of strong linear IgG staining along GBM detected by direct immunofluorescence. The presence of linear GBM fixation in renal allograft is a rare finding. We observed a 33-year-old male with de novo renal failure in a kidney transplant. An examination of a kidney biopsy specimen revealed, in light microscopy, mild mesangial hypercellularity together with mild focal interstitial fibrosis and sparse inflammatory infiltrate. In immunofluorescence microscopy strong linear IgG staining along the capillary walls was seen. Serum anti-GBM antibodies were negative and no mutation in exons coding NC1 domains of α3 and α5 chains of type IV collagen were detected. We described a rare case of a patient with atypical anti-GBM disease in renal allograft, caused probably by the same process which affected the native kidneys.

Threatened preterm labour - analysis of the cytokine profile and progesterone treatment efficiency.

OBJECTIVE: Preterm labour is defined as the onset of labour between weeks 23 and before 37 of gestation. The purpose of this study was to compare the cytokine profile in the blood serum of patients experiencing threatened premature labour, along with the time of delivery and the foetus body mass at birth. METHODS: The study included 89 women hospitalised at the Obstetrics and Gynaecology Clinical Hospital in the period 2011-2013. Group 1 comprised 31 patients diagnosed with threatened preterm labour, prior to tocolytic treatment. Group 2 comprised 32 patients with tocolytic treatment. Group 3 constituted the control group. RESULTS: Groups 1, 2 and 3 differed considerably in terms of the week of delivery of pregnancy (p = 0.006). Analogous results were obtained by analysing the body mass at birth, where a statistically significant difference in body mass at birth was found between Groups 1, 2 and 3 (p < 0.001). Our analysis focussed on the cytokine profile of the women included in the study, but no considerable changes in cytokine concentration were observed. CONCLUSIONS: No statistically significant differences were found in the cytokine profile among those patients in normally progressing pregnancy or in threatened preterm labour. No suitability of progesterone treatment in threatened preterm labour was observed.

The B-cell compartment in antibody-deficient infants and young children - developing common variable immunodeficiency or transient immune maturation?

BACKGROUND: Hypogammaglobulinemia in early childhood is a common feature characterized by distinct intrinsic and extrinsic factors leading to disturbed peripheral blood lymphocyte homeostasis. Detailed flow cytometric immunophenotyping of the peripheral blood B cell compartment is an informative tool for delineating disturbed generation of B cell subpopulations crucial for the diagnosis of hypogammaglobulinemia in young children. METHODS: We analyzed by flow cytometry the proportions and absolute values of total, naïve, memory - non-switched and switched, transitional and immature B lymph cells as well as plasmablasts in the peripheral blood of 50 hypogammaglobulinemic children aged from 3 to 50 months. RESULTS: Beyond physiological, age-related changes within the B cell pool, a proportion of children manifested defective differentiation into switched memory and accumulation of CD21lo immature B cells. CONCLUSIONS: Dynamic shifts within B cell subpopulations of the immature immune system being most prominent during the first two years of life contribute to the age-related developmental abnormalities of the B cell compartment. Therefore, a reliable diagnosis of common variable immunodeficiency (CVID) in young hypogammaglobulinemic children cannot yet be established despite their clinical and immunological phenotypes sharing common features with this primary immunodeficiency.

Impaired Antigen-Specific Immune Response to Vaccines in Children with Antibody Production Defects.

The impaired synthesis of antigen-specific antibodies, which is indispensable for an adaptive immune response to infections, is a fundamental pathomechanism that leads to clinical manifestations in children with antibody production defects. The aim of this study was to evaluate the synthesis of antigen-specific antibodies following immunization in relation to peripheral blood B cell subsets in young children with hypogammaglobulinemia. Twenty-two children, aged from 8 to 61 months, with a deficiency in one or more major immunoglobulin classes participated in the study. Postvaccination antibodies against tetanus and diphtheria toxoids, the surface antigen of the hepatitis B virus, and the capsular Haemophilus influenzae type b polysaccharide antigen were assessed along with an immunophenotypic evaluation of peripheral blood B lymph cell maturation. A deficiency of antibodies against the tetanus toxoid was assessed in 73% of cases and that against the diphtheria toxoid was assessed in 68% of cases, whereas a deficiency of antibodies against the surface antigen of the hepatitis B virus was revealed in 59% of the children included in the study. A defective response to immunization with a conjugate vaccine with the Haemophilus influenzae type b polysaccharide antigen was demonstrated in 55% of hypogammaglobulinemic patients. Increased proportions of transitional B lymph cells and an accumulation of plasmablasts accompanied antibody deficiencies. The defective response to vaccine protein and polysaccharide antigens is a predominating disorder of humoral immunity in children with hypogammaglobulinemia and may result from a dysfunctional state of the cellular elements of the immune system.

Detection and significance of cytotoxic cell subsets in biopsies of HCV-infected human livers.

Chronic viral hepatitis C still remains the clinical challenge. Attempts of the immune system to cope with this infection are unsatisfactory. There is a conviction that the main site of interaction between virus (Hepatitis C virus, HCV) and immune system is in situ, i.e., in liver. Natural killer (NK) cells appeared relevant in the acute hepatitis. Less is known about the immune response in the chronic HCV infection. The aim of this study was to evaluate the prevalence of various cytotoxic cell subsets in chronic HCV+ liver tissue and to seek links between them and laboratory data of patients. Sections from paraffin blocks of liver biopsy tissues of HCV+ untreated patients were subjected to the reaction with antibodies vs. cytotoxic cell subsets and immunohistochemistry. Positive cells were searched in cellular infiltrates in portal areas and in liver parenchyma. They were classified on the "Yes" or "No" basis. Majority of liver biopsies exhibited cellular infiltrates in portal spaces and as single cells in liver parenchyma. Infiltrates consisted of CD8+ T cells, CD56+ NK ones, including CD158i+ and CD158b+. The latter were rarely seen. There were also granzyme B+ cells. The most abundant were NKG2D+ cells, much more common than NK CD56+ ones. It implied that NKG2D was also expressed on T cells. Prevalence of NKG2D+ cells correlated with high activity of liver enzymes such as alanine aminotransferase, aspartate aminotransferase and a greater histological severity of liver injury. NKG2D+ cells form the bulk of cells infiltrating HCV-infected human liver. Correlation of NKG2D+ cells with some laboratory parameters of patients suggests their role in hepatitis C pathogenesis.

Expression of pattern recognition receptors in liver biopsy specimens of children chronically infected with HBV and HCV.

Pattern recognition receptors (PRRs) constitute a pivotal arm of innate immunity. Their distribution is widespread and not limited to cells of the immune system. Following our previous findings concerning the expression of Toll-like receptors (TLRs) 2, 3 and 4 in chronic viral hepatitis C of children, we wished to search for other PRRs, including other TLRs, NOD-like receptors (NLRs) and RIG-1-like helicase receptors (RLR) in infected hepatocytes. Liver biopsy fragments from ten children with chronic hepatitis B and C were used and two others in which hepatotropic virus infection was excluded. Frozen sections of liver samples were subjected to ABC immunohistochemistry (IHC) following incubation with a set of antibodies. Results of IHC findings were screened for correlation with clinical/laboratory data of patients. It was found that several PRRs could be shown in affected hepatocytes, but the incidence was higher in hepatitis C than in B. In hepatitis C, TLR1, 2, 4, NALP and RIG-1 helicase showed the most marked expression. In hepatitis B, TLR1, 3, 9, NOD1 and NALP expression were the most conspicuous. Expression PRRs in liver from hepatitis of unknown origin was much lower. It was also the case in cytospins from human hepatoma cell line. Several correlations between PRRs expression and clinical findings in patients could be shown by statistical exploration. In conclusion, this data suggests some role for PRRs in the pathogenesis of chronic viral hepatitis.

Assessment of expression of toll-like receptors 2, 3 and 4 in laryngeal carcinoma.

Head and neck cancers remain a big challenge for oncology. Among them laryngeal carcinomas predominate. In spite of abundant inflammatory cell infiltrates containing several immunologically competent cells, patients with head and neck cancers show markedly suppressed anti-tumor response. In general, cancer cells use strategies to avoid recognition and destruction by the immune system. Toll-like receptors 1-13 (TLRs) are crucial for activation of innate immunity and secondarily for the induction of acquired response. TLRs are mainly expressed on cells of the immune system, but they have been demonstrated on endothelial and epithelial cells. Ligand binding to TLR leads to the activation of several genes, predominantly proinflammatory ones such as IL-1 and TNF-alpha and maturation of professional antigen presenting cells (APC) i.e., dendritic cells. It can cause better tumor antigen presentation by APC. The aim of this study was the evaluation of expression of TLR-2, TLR-3 and TLR-4 in the microenvironment of laryngeal carcinoma. Tumor specimens (n = 20, male patients aged 43-77 years, mean 57 years) from patients subjected to total laryngectomy. Immunohistochemistry and indirect immunoflourescence on frozen tissue sections. Cancer tissue: portion of cancer cells manifested membrane and/or cytoplasmic expression of TLR-2, TLR-3 and TLR-4. The most frequent expression on tumor cells was TLR-2 and the least expression of TLR-4. Inflammatory infiltrates: in all cases inflammatory cell infiltrates of various intensities were present, both in tumor mass and tumor stroma. Expression of all TLRs tested, both, membrane and cytoplasmic ones were shown on inflammatory cells, but distinct in quantitative terms. TLR-4 positive cells were the most frequent. A portion of cells expressed both, TLR and HLA-DR. It is of interest that TLRs tested were expressed not only on cells of inflammatory infiltrate, but also on tumor cells. This fact may be an important factor in tumor escape from immune surveillance. It is notable, that both, TLRs and HLA-DR were shown to be co-expressed, what may favor the role and impact of TLRs in antigen presentation. Further studies are needed to elucidate TLRs function in the course of neoplastic process.