Common variable immune deficiency in children--clinical characteristics varies depending on defect in peripheral B cell maturation

Common variable immune deficiency (CVID) is a heterogeneous disease associated with ineffective production of antibodies. It is usually diagnosed in adulthood, but a variable proportion of children develop CVID. Early identification of patients with potentially worse prognosis may help to avoid serious complications. The goal of this study was to associate the clinical phenotype of patients with early onset CVID with peripheral B-cell maturation profile. Four color flow cytometry was used to define distribution of peripheral B-cell subsets in 49 children with early-onset CVID. All clinical data were extracted from medical records. A proportion of patients demonstrated diminishing with time total B-lymphocytes pool, beyond physiological age-related changes. Irrespective from duration of the follow-up period the B-cell maturation profile in individual patients remained unchanged. We identified six different aberrant peripheral B cell maturation profiles associated with different clinical characteristics. Patients with an early B-cell maturation block earlier required replacement therapy and were at significantly greater risk of enteropathy, granuloma formation, cytopenia, and lymphoproliferation. B-cell maturation inhibited at the natural effector stage was associated with higher risk of autoimmune manifestations other than autoimmune cytopenia. Prevalence of male patients was observed among patients with B-cell maturation inhibited at naïve B-cell stage. In conclusion, the diagnostic process in patients with suspected early-onset CVID shall include routine analysis of peripheral B-cell maturation to provide surrogate markers identifying patients at greater risk of developing certain complications.

Peripheral blood T lymphocyte subsets in children with congenital asplenia

The aim of the current study was to examine whether a congenital lack of the spleen changes distribution, state of activation and function of peripheral lymphocyte T subsets. Seven children with congenital asplenia (CA) aged 1.5-17 years and seven age-matched controls were tested. By triple-color flow cytometry we examined: (1) the expression of CD3(+), CD4(+), CD8(+), CD19(+), and CD56(+) on lymphocytes; (2) the distribution of CD45RA(+) and CD45RO(+) in CD4(+) and CD8(+); (3) the expression of CD27(+) in the CD4(+) and CD8(+) T-cell-bearing CD45RA(+), CD45RO(+), or CD45RB(+). Lymphocyte proliferative responses and cytokines production (IFN-gamma, IL-6, TNF-alfa, and IL-10) in anti-CD3-induced peripheral blood mononuclear cells were tested. The results indicate (1) a normal distribution of the basic lymphocyte subsets, (2) low CD3(+)/CD8(+) percentage but expressing CD8(+high) and non-significantly elevated CD4(+)/CD8(+) ratio, (3) CD45RA(+high) and CD27(+high) in the CD4(+) and CD8(+) T cell, and (4) CD45RB(+high) in the CD4(+) and CD45RO(+high) in the CD8(+). The distribution of CD27(+) in the CD45RA(+) and CD45RO(+) CD4(+) T cells remained unchanged. However, the percentage of CD8(+)/CD45RO(+)/CD27(+) T cells tended to be elevated. Altogether, these data indicate that CA is connected with (1) the presence CD4(+) T cells expressing the "naive" phenotype (CD45RA(+high) RB(+high) and CD27(+high)), (2) high numbers of activated CD8(+) T cells shifted toward the memory phenotype (CD45RO(+high)) but still showing high CD27(+) expression, which may indicate failure in T CD8(+) cytotoxic effectors differentiation, and (3) a tendency to the rather pro-inflammatory status of cells, low IL-10 expression, and suboptimal lymphocytes responses to mitogenic stimulation.

The defect in humoral immunity in patients with Nijmegen breakage syndrome is explained by defects in peripheral B lymphocyte maturation

Patients with an immunodeficiency in the course of Nijmegen breakage syndrome (NBS) that is caused by mutations in the NBN/NBS1 gene are prone to recurrent infections and malignancies, due to a defective DNA double-strand breaks repair mechanism. Four-color flow cytometry was used to analyze changes in B lymphocyte subsets reflecting the most important stages of peripheral B cell maturation. It was demonstrated that the humoral immune defect observed in NBS patients was caused by reduced numbers of B lymphocytes, but also by their aberrant maturation. Reduced relative and absolute counts of naïve and memory B cells were accompanied by a significant accumulation of the natural effector B lymphocytes. The elevated proportion of IgM-only memory and reduced proportion of IgM-negative cells within the memory B cell pool suggests that there is class-switch recombination defect in this population of cells in NBS patients, resulting in inadequate production of immunoglobulins. Because of the reduced T-cell counts, the T-cell dependent antigen response is severely impaired resulting in a lower frequency of memory B-cells. The T-cell independent B-cell differentiation pathway seems less affected. The reduced IgG and IgA levels in patients with NBS are caused both by ineffective class switch, at least due to poor T cell help, and low number of memory B cells. This study illustrates that the NBN gene product nibrin plays an important role at different levels in the B-cell system.

Neutrophil phenotypic characteristics in children with congenital asplenia and splenectomized for hereditary spherocytosis

The spleen plays an important role in the granulocyte homeostasis due to such mechanisms as pooling, elimination of senescent cells and regulatory effects on granulocyte renewal in the bone marrow. The expression profile of granulocyte receptors was tested in children with congenital asplenia, and splenectomized for spherocytosis. Receptors tested included those appearing with maturation (CD16, CD11b, CD11c, TREM-1), disappearing (CD54, CD49d, CD64) and maintained during maturation (CD11a, CD45). In general, we found that the circulating granulocyte pool in the asplenic patients had phenotypical features of highly matured but not apoptotic neutrophils with a significantly elevated expression of CD16 (CD16(high)), tendency to a lower expression of CD45 (CD45(low)) and an unchanged expression of CD64 (and other markers indicating systemic inflammatory reactions). The high fluorescence intensity of CD11b,c, and TREM-1 in the congenital asplenia may indicate a potentially elevated pro-inflammatory status of granulocytes, possibly due to the low activity of vagus nerve and spleen-dependent cholinergic anti-inflammatory pathway.

Antibody response to Haemophilus influenzae type-b conjugate vaccine in children and young adults with congenital asplenia or after undergoing splenectomy

Absence of the spleen constitutes a risk of infection caused by encapsulated bacteria. The aim of our study was to determine the immune response to Haemophilus influenzae type-b (Hib) conjugate vaccine (HibCV) in asplenic individuals, considering the cause of asplenia, the age when splenectomy was carried out, and previous Hib vaccinations. Twenty asplenic patients, aged five to 25 years, were immunized with a single dose of HibCV. The specific antibody concentrations against HibCV were measured by enzyme-linked immunosorbent assay. Before vaccinations, the geometric mean antibody concentration (GMC) had an average value of 3.21 μg/ml and was comparable for all of the patients, regardless of the causes of asplenia. After vaccinations, the GMC was significantly higher, with an average of 6.78 μg/ml. Further, 4.5 years after vaccinations, the GMC was comparable to that of previously unvaccinated children. Moreover, 17/20 patients had GMC ≥ 1.0 μg/ml, which included all of the children with congenital asplenia, children splenectomized before the age of six years, and only 57% of children splenectomized after that age. HibCV gives asplenic patients long-term protection. Hence, HibCV should be administered regardless of previous vaccinations and time from splenectomy, even if antibody evaluation is not available.

B cell subsets in healthy children: reference values for evaluation of B cell maturation process in peripheral blood

BACKGROUND

The process of maturation of the immune system leads to generation of various lymphoid cell populations having the ability to react in specific way and expressing various markers on the cell surface. The study was set up to establish reference values for B lymphocyte subpopulations in peripheral blood of children and young adults to find the spectrum of their physiological age-related variation.

METHODS

Blood samples were taken from 292 children and young adults aged 0-31 years and tested for distribution of B cell subsets. Relative and absolute sizes of non-memory and memory, transitional, naïve, immature marginal zone-like/IgM-only memory, class-switched memory, double negative, activated, and plasmacytoid cell populations were determined by four-color flow cytometry, based on differential expression of CD19, IgM, IgD, CD21, CD27, and CD38. Significant variation both in relative, as well as in absolute numbers of individual cell populations in tested groups was observed.

RESULTS

The reference values for age-related B cell subsets in eleven age groups, established as result of this study, may be used in diagnostics of any pathology related to B cell maturation process, as well as in attempts of correlating laboratory results with clinical symptoms of many defects affecting antibody production in pediatric population.

CONCLUSION

Determination of B cell subpopulations carried in patients with antibody deficiencies may help to understand the nature of the disease and prevent its complications.

Efficacy and safety of home-based subcutaneous immunoglobulin replacement therapy in paediatric patients with primary immunodeficiencies

Subcutaneous immunoglobulin infusions are effective, safe and well tolerated in the treatment of primary immunodeficiencies, but only limited data on the treatment of children are available. We investigated the efficacy, safety and pharmacokinetics of home therapy with a 16% liquid human immunoglobulin G preparation (Vivaglobin®) when administered subcutaneously in children with primary immunodeficiencies. Data were analysed from 22 children (2-<12 years) who participated in two prospective, open-label studies (one in Europe/Brazil, one in North America). All children had previously received intravenous immunoglobulins. They started weekly subcutaneous immunoglobulin infusions with an approximately 3-month wash-in/wash-out period, followed by a 6-month (Europe/Brazil) or 12-month (North America) efficacy evaluation period. In Europe/Brazil, subcutaneous doses generally equalled the previous weekly equivalent intravenous doses. In North America, subcutaneous doses during the efficacy evaluation period were 126% (median) of the previous weekly equivalent intravenous doses. Efficacy end-points in both studies included the occurrence of serious bacterial infections and any infections, and serum immunoglobulin G trough levels. Median serum immunoglobulin G trough levels exceeded those during previous intravenous therapy by 13% (North America) and 16% (Europe/Brazil). During the efficacy evaluation period of both studies, none of the children had a serious bacterial infection; the mean overall infection rate/patient year was 4·7 in Europe/Brazil and 5·6 in North America, concurring with previous reports in adults. The adverse event profile was comparable to previous reports in adults. Both studies confirmed the efficacy and safety of subcutaneous immunoglobulin therapy with Vivaglobin in children with primary immunodeficiencies.

A multi-centre study of efficacy and safety of Intratect®, a novel intravenous immunoglobulin preparation

We studied the efficacy, safety and pharmacokinetic profiles of Intratect®, a recently developed polyvalent intravenous immunoglobulin (IVIG) preparation. Fifty-one patients (aged 6-48 years) with primary immunodeficiencies (PID) and established replacement therapy using a licensed IVIG were enrolled and treated for 12 months with Intratect®. Retrospective patient data served as prestudy controls. The primary efficacy variable was the annual rate of acute serious bacterial infection (ASBI) per patient. Secondary parameters were annual rate of acute relevant infection (ARI), days with antibiotic use, fever, absence from school/work and hospitalization. The average IVIG dose was 0·49 g/kg, with an average infusion rate of 2·4 ml/kg/h. The annual ASBI rate/patient was 0·02 and ARIs were detected 128 times during the 630 adverse events in 40 patients, specified mainly as bronchitis, sinusitis, respiratory tract infection, rhinitis and pharyngitis. The annual rate of respiratory ARIs/patient was 2·0 and the rates/patient for days with fever >38°C, school/work absence and hospitalization were 1·81, 3·99 and 0·36, respectively. A total of 630 adverse events (AEs) were observed in 50 of 51 (98·0%) of patients. In 46 of 51 patients the AEs were not related to infusion. Pharmacokinetic studies after the first infusion revealed a mean elimination half-life of 50·8 ± 30·3 days. During this study, 19 of 649 (2·9%) IgG trough levels were below 6 g/l, better than that of reference IVIGs during the 6 months before study start (10 of 201). These data suggest that Intratect® is a well tolerated, safe and effective IgG concentrate for the treatment of patients with PID.

Genetic characteristics of eighty-seven patients with the Wiskott-Aldrich syndrome

The Wiskott-Aldrich syndrome (WAS) is an X-linked recessive immune deficiency disorder characterized by thrombocytopenia, small platelet size, eczema, recurrent infections, and increased risk of autoimmune disorders and malignancies. WAS is caused by mutations in the WASP gene which encodes WASP, a 502-amino acid protein. WASP plays a critical role in actin cytoskeleton organization and signalling, and functions of immune cells. We present here the results of genetic analysis of patients with WAS from eleven Eastern and Central European (ECE) countries and Turkey. Clinical and haematological information of 87 affected males and 48 carrier females from 77 WAS families were collected. The WASP gene was sequenced from genomic DNA of patients with WAS, as well as their family members to identify carriers. In this large cohort, we identified 62 unique mutations including 17 novel sequence variants. The mutations were scattered throughout the WASP gene and included single base pair changes (17 missense and 11 nonsense mutations), 7 small insertions, 18 deletions, and 9 splice site defects. Genetic counselling and prenatal diagnosis were applied in four affected families. This study was part of the J Project aimed at identifying genetic basis of primary immunodeficiency disease in ECE countries. This report provides the first comprehensive overview of the molecular genetic and demographic features of WAS in ECE.

Genetic and demographic features of X-linked agammaglobulinemia in Eastern and Central Europe: a cohort study

Primary immunodeficiency disorders are a recognized public health problem worldwide. The prototype of these conditions is X-linked agammaglobulinemia (XLA) or Bruton's disease. XLA is caused by mutations in Bruton's tyrosine kinase gene (BTK), preventing B cell development and resulting in the almost total absence of serum immunoglobulins. The genetic profile and prevalence of XLA have not previously been studied in Eastern and Central European (ECE) countries. We studied the genetic and demographic features of XLA in Belarus, Croatia Hungary, Poland, Republic of Macedonia, Romania, Russia, Serbia, Slovenia, and Ukraine. We collected clinical, immunological, and genetic information for 122 patients from 109 families. The BTK gene was sequenced from the genomic DNA of patients with a high susceptibility to infection, almost no CD19(+) peripheral blood B cells, and low or undetectable levels of serum immunoglobulins M, G, and A, compatible with a clinical and immunological diagnosis of XLA. BTK sequence analysis revealed 98 different mutations, 46 of which are reported for the first time here. The mutations included single nucleotide changes in the coding exons (35 missense and 17 nonsense), 23 splicing defects, 13 small deletions, 7 large deletions, and 3 insertions. The mutations were scattered throughout the BTK gene and most frequently concerned the SH1 domain; no missense mutation was detected in the SH3 domain. The prevalence of XLA in ECE countries (total population 145,530,870) was found to be 1 per 1,399,000 individuals. This report provides the first comprehensive overview of the molecular genetic and demographic features of XLA in Eastern and Central Europe.

[Hyper-IgE syndrome with mutation in STAT3 gene - case report and literature review]

Hyper-IgE syndrome (HIES) is a primary immunodeficiency (PID) characterized by recurrent skin abscesses (S. aureus), recurrent pneumonia with pneumatocele formation, atopic dermatitis and elevated levels of serum IgE (>2000 IU/ml). HIES is a sporadic disease, however, two distinct entities - classic HIES inherited in an autosomal dominant pattern (AD HIES), and an autosomal recessive HIES (AR HIES) have been described. Some cases of AD HIES with predominant pulmonary manifestation are caused by mutation in STAT3 gene. It is important to differentiate cases of atopic dermatitis and AD HIES where it is necessary to implement antibacterial and antifungal prophylaxis. Opportunity of performing genetic analysis in suspicion of AD HIES leads to definitive diagnosis of the disease and earlier institution of appropriate treatment. We present the case of a 22-year-old patient with typical course of autosomal dominant hyper-IgE syndrome, confirmed in the Royal Free Hospital, University College London, UK, by finding mutation in STAT3 gene.

[Prevention of infections in primary and secondary antibody deficiency]

Antibody deficiency may have genetic basis or be secondary to other diseases or iatrogenic factors. Recurrent respiratory, gastrointestinal and skin infections consist on the most frequent clinical picture. Severe course of these infections, recurrences and difficulties in treatment may suggest immunodeficiency. Antibody deficiency may be associated with numerous complications. Intravenous or subcutaneous immunoglobulin substitution is the way of treating these patients. Prevention of infection in primary and secondary antibody deficiency also includes vaccinations, prophylaxis with antibiotics and education of patients, parents and caregivers.

Immune response to the 7-valent pneumococcal conjugate vaccine in 30 asplenic children

The aim of the study was to determine the concentration of pneumococcal antibodies after a dose of 7-valent pneumococcal conjugate vaccine (PCV7) in 30 asplenic children between 4 months and 19 years of age. Fifteen children had received pneumococcal polysaccharide vaccine (PPV) approximately 5 years prior to vaccination with PCV7. The antibody concentrations against serotypes 4, 6B, 9V, 14, 18C, 19F, and 23F were measured by ELISA before and after the PCV7 vaccination. Before vaccination with PCV7, the antibody concentrations were similar in children who had or had not received PPV previously. A dose of PCV7 stimulated a good immune response in asplenic patients. Prior immunization with PPV did not affect the antibody concentration after the vaccination with PCV7. In conclusion, asplenic children vaccinated with PPV may need revaccination with PPV earlier than the recommended 3-5 years after the first dose. PCV7 induces a satisfactory immune response in asplenic patients and should be considered as an alternative vaccine in that patient group.

[Haemophilus influenzae type b--active prevention]

Infection with non-encapsulated types of Haemophilus influenzae bacteria can cause such diseases as sinusitis, pharyngitis, bronchitis or otitis. Of the six capsulated types of Haemophilus influenzae, type b (Hib) is the main cause of invasive diseases in childhood, including meningitis, septicaemia, epiglottitis, pneumonia, arthritis, osteomyelitis. The article presents the data about the virulence of Haemophilus influenzae, its carrier state, invasive Hib infections in the world and in Poland as well as active prevention with usage of Hib vaccinations, with special reference to high risk groups.

[Paediatric Expert Group on the Immunization Programme. Activities focusing on effective immunization in Poland]

The Paediatric Expert Group on the Immunization Programme was established in January 2007. It is an independent advisory body to the Minister of Health. The Expert Group consists of paediatricians from various sub-specialities. Most of them are members of the Polish Society of Vaccinology (Table I). The Group started their activities informally in 2005. The first project concerned changes in immunization against tuberculosis and prophylaxis of measles, mumps and rubella. The project was fully implemented in 2006. The changes initiated three years ago, gradually implemented in the Immunization Programme are a result of wide cooperation with the Ministry of Health, Department of Health Policy Chief Sanitory Inspector, as well as the Institute of Tuberculosis and Pulmonary Diseases. The aim of the Paediatric Expert Group on the Immunization Programme is to present a unified policy in matters related to vaccination, leading to rapid changes in the prophylaxis of infective diseases which are still a threat to the life and health of children.

Gross deletions involving IGHM, BTK, or Artemis: a model for genomic lesions mediated by transposable elements

Most genetic disruptions underlying human disease are microlesions, whereas gross lesions are rare with gross deletions being most frequently found (6%). Similar observations have been made in primary immunodeficiency genes, such as BTK, but for unknown reasons the IGHM and DCLRE1C (Artemis) gene defects frequently represent gross deletions ( approximately 60%). We characterized the gross deletion breakpoints in IGHM-, BTK-, and Artemis-deficient patients. The IGHM deletion breakpoints did not show involvement of recombination signal sequences or immunoglobulin switch regions. Instead, five IGHM, eight BTK, and five unique Artemis breakpoints were located in or near sequences derived from transposable elements (TE). The breakpoints of four out of five disrupted Artemis alleles were located in highly homologous regions, similar to Ig subclass deficiencies and Vh deletion polymorphisms. Nevertheless, these observations suggest a role for TEs in mediating gross deletions. The identified gross deletion breakpoints were mostly located in TE subclasses that were specifically overrepresented in the involved gene as compared to the average in the human genome. This concerned both long (LINE1) and short (Alu, MIR) interspersed elements, as well as LTR retrotransposons (ERV). Furthermore, a high total TE content (>40%) was associated with an increased frequency of gross deletions. Both findings were further investigated and confirmed in a total set of 20 genes disrupted in human disease. Thus, to our knowledge for the first time, we provide evidence that a high TE content, irrespective of the type of element, results in the increased incidence of gross deletions as gene disruption underlying human disease.

[Chronic granulomatous disease recognised in 42-years-old patient]

Chronic granulomatous disease (CGD) comprises a heterogeneous group of diseases that are caused by defect in the superoxide-producing NADPH oxidase of neutrophils. This defect impairs the intracellular killing of microorganisms. Typical manifestations are recurrent bacterial or mycotic infections affecting the lungs, skin, lymph nodes and gastrointestinal tract (liver). Chronic granulomatous disease could be diagnosed on the basis of the anamnesis, clinical picture and results of granulocyte function tests showing impaired phagocytic activity (NBT tests, RDH test and a deficit of superoxide production). Typically symptoms of disease occur in the first years of live, leading often to death in the 2. or 3. decade. Below we present a patient, in whom diagnosis of the CGD was established at the age of 42.

[Difficulties in diagnostics and therapy of infectious complications in primary immunodeficient patients]

Primary immunodeficiencies (PIDs) are group of more than 200 different genetic disorders. Reccurrent, severe infections are major clinical manifestation of these disorders. Ethiology and course of infections in PIDs are different, depending on type of immunodeficiency. We present short characteristics of infections in PIDs, as well as difficulties in diagnostics and treatment of infectious complications.

Chronic Granulomatous Disease Recognised in 42-Years-Old Patient

Przewlekła choroba ziarniniakowa (PChZ) jest heterogenną grupą chorób związanych z defektem enzymu oksydazy NADPH odpowiedzialnej za produkcję nadtlenków przez granulocyty obojętnochłonne, których brak lub niedobór uniemożliwia zabijanie sfagocytowanych przez nie drobnoustrojów. Typowymi objawami PChZ są bakteryjne lub grzybicze nawracające ciężkie, często zagrażające życiu infekcje głównie płuc, skóry, węzłów chłonnych oraz przewodu pokarmowego (wątroby). Rozpoznanie jest ustalane na podstawie wywiadów, objawów oraz testów wykazujących upośledzoną funkcję fagocytozy granulocytów (testy NBT, RDH czy bezpośrednie testy, których wynik wskazuje na deficyt produkcji nadtlenków). Objawy występują zwykle w pierwszych latach życia, prowadzą często do zgonu w 2. lub 3. dekadzie. Poniżej przedstawiono przypadek chorej, u której rozpoznanie PChZ ustalono dopiero w 42. roku życia.

[Chronic neutropenia - experience from the Department of Immunology, Children's Memorial Health Institute]

Chronic neutropenia (CN) is defined by an absolute neutrophil count (ANC) below 1500/ul, lasting at least 6 months.

AIM

clinical course and treatment of children afflicted with CN was analysed.

MATERIAL AND METHODS

we present 60 children treated in our department due to CN. The diagnosis was based on: bone marrow smears, ANC, immunologic investigation.

RESULTS

we established the diagnosis of: Kostmann disease (KD), cyclic neutropenia (CyN), hyperIgM syndrome (HIGM), Shwachman-Diamond syndrome (SDS), severe chronic neutropenia (SCN) and chronic benign neutropenia (CBN) in: 4, 2, 2, 1, 21 and 20 children respectively. Due to positive results of tests: MAIGA, GIFT or GAT autoimmune neutropenia of infancy (AIN) was confirmed in 7 children. In 3 infants neutropenia was connected with HCMV- infection and Gancyclovir therapy. RHuG-CSF treatment was implemented in 14 and effective in 13 patients. A girl, suffering from KD, during rHuG-CSF therapy, developed chronic myeloblasts leucaemia and died. A boy, with the same diagnosis, underwent bone marrow transplantation from related donor but died from invasive pulmonary aspergillosis. Antibacterial prophylaxis was necessary in 29 children. We used Amoxicillin or Trimethoprim/Sulfametoxazole, obtaining decrease of frequency and severity of infections. During observation period all children suffered from upper respiratory tract infections, 19 had chronic gingivitis. Severe infections- bacterial pneumonia, sepsis, severe varicella and measles were observed in 30, 5, 2 and 1 patient respectively. A teenager, affected with SCN, died due to fulminant Clostridium perfringens infection.

CONCLUSIONS

1. RHuG-CSF therapy is essential in children with KD and SCN (when accompanied by severe infections). 2. AIN proved to be a mild condition, although ANC decreased below 500. In this entity rHuG-CSF is recommended during severe infections and before surgery. 3. Antibiotic prophylaxis is recommended for children with: KD, CyN, GSD1b, CN in 1st year of life, HIGM; in other cases it is considered individually.