Immunoglobulin A deficiency in children, an undervalued clinical issue.

Immunoglobulin A (IgA) is the principal antibody in secretions that bathe the gastrointestinal and respiratory mucosal surfaces and acts as an important first line of defense against invasion of pathogenic micro-organisms. The reported prevalence rate of complete IgA deficiency in healthy children ranges from 1:170 to 1:400, and as a solitary condition, it is often considered of limited clinical importance. However, patients with IgA deficiency can develop recurrent respiratory and gastrointestinal infections, as well as allergic and autoimmune diseases. In children referred for recurrent respiratory tract infections, the observed prevalence rate increases more than tenfold. This review discusses several aspects of IgA deficiency in children, including immunologic and microbiome changes in early childhood and the potential consequences of this condition in later life. It illustrates the importance of early identification of children with impaired IgA production who deserve appropriate clinical care and follow-up.

Primary immunodeficiencies in the Netherlands: national patient data demonstrate the increased risk of malignancy.

PURPOSE: To analyze the data of the national registry of all Dutch primary immune deficiency (PID) patients, according to the European Society for Immunodeficiencies (ESID) definitions. RESULTS: In the Netherlands, 745 patients had been registered between 2009 and 2012. An overall prevalence of 4.0 per 100,000 inhabitants was calculated. The most prevalent PID was 'predominantly antibody disorder (PAD)' (60.4%). In total, 118 transplantations were reported, mostly hematopoietic stem cell transplantations (HSCT). Almost 10% of the PID patients suffered from a malignancy, in particular 'lymphoma' and 'skin cancer'. Compared to the general Dutch population, the relative risk of developing any malignancy was 2.3-fold increased, with a >10-fold increase for some solid tumors (thymus, endocrine organs) and hematological disease (lymphoma, leukemia), varying per disease category. CONCLUSIONS: The incidence rate and characteristics of PID in the Netherlands are similar to those in other European countries. Compared to the general population, PID patients carry an increased risk to develop a malignancy.

Increased prevalence of gastrointestinal viruses and diminished secretory immunoglobulin a levels in antibody deficiencies.

PURPOSE: Gastrointestinal disease occurs frequently in antibody deficiencies. This study aims to explore the relation between gastrointestinal infections and mucosal homeostasis in patients with antibody deficiencies. METHODS: We performed an observational study including 54 pediatric antibody deficient patients (48 % CVID, 41 % CVID-like, 11 % XLA) and 66 healthy controls. Clinical symptom scores and stool samples were collected prospectively. Stool samples were evaluated for bacteria, parasites, viruses, secretory IgA- and for calprotectin levels. Results were compared between patients and controls. RESULTS: 24 % of antibody deficient patients versus 9 % of healthy controls tested positive for gastrointestinal viruses (p = 0.028). Fecal calprotectin levels were significantly higher in virus positive patients compared to virus negative patients (p = 0.002). However, in controls, fecal calprotectin levels were similar between virus positive and virus negative controls. Moreover, gastrointestinal virus positive patients had low serum IgA levels in 13/14 cases (94 %) versus 40/62 (62 %) patients in the virus negative patient group (p = 0.04). The virus positive patient group also displayed significantly lower secretory IgA levels in stool (median 13 ug/ml) than patients without gastrointestinal viruses detected or healthy controls (median 155 ug/ml) (p = 0.046). CONCLUSION: We here report an increased prevalence of gastrointestinal viruses and gastrointestinal complaints in antibody deficient patients. Patients that tested positive for gastrointestinal viruses showed diminished serum- and secretory IgA levels, and only in patients, virus positivity was associated with signs of mucosal inflammation. These findings suggest that particularly patients with low IgA are at risk for longstanding replication of gastrointestinal viruses, which may eventually result in CVID-related enteropathy.

CT screening for pulmonary pathology in common variable immunodeficiency disorders and the correlation with clinical and immunological parameters.

BACKGROUND: Pulmonary disease is common in patients with common variable immunodeficiency disorders (CVID) and involves infections, chronic airway disease and interstitial lung disease. Chronic pulmonary disease is associated with excess morbidity and early mortality and therefore early detection and monitoring of progression is essential. METHODS AND PURPOSE: Thin slice CT scan and pulmonary function were used to determine the prevalence and spectrum of chronic (pre-clinical) pulmonary disease in adult CVID patients regardless of symptoms. CT Scans were scored for airway abnormalities (AD) and interstitial lung disease (ILD). Other CVID related complications and B and T lymphocyte subsets were analyzed to identify patients at risk for pulmonary disease. RESULTS: Significant pulmonary abnormalities were detected in 24 of the 47 patients (51%) consisting of AD in 30% and ILD in 34% of cases. In only 7 (29%) of these 24 patients pulmonary function test proved abnormal. The presence of AD was correlated to (recurrent) lower respiratory tract infections despite IgG therapy. The presence of ILD was correlated to autoimmune disease and a reduction in the numbers of CD4 + T cells, naïve CD4 + T cells, naïve CD8 + T cells and memory B cells and lower IgG through levels over time. CONCLUSION: Preclinical signs of AD and ILD are common in CVID patients despite Ig therapy and do not correlate to pulmonary function testing. Patients at risk for ILD might be identified by the presence of autoimmunity or a deranged T cell pattern. Larger studies are needed to confirm these findings and to determine thresholds for the T lymphocyte subsets.

The spectrum of disease manifestations in patients with common variable immunodeficiency disorders and partial antibody deficiency in a university hospital.

BACKGROUND: Common variable immunodeficiency disorders (CVIDs) represents a heterogeneous disease spectrum that includes recurrent infections and complications such as autoimmunity, inflammatory organ disease and an increased risk of cancer. A diagnostic delay is common in CVIDs patients. PURPOSE: To determine the spectrum of clinical manifestations, immunological characteristics, and the time to diagnosis of 61 adult CVIDs and 18 patients with a partial antibody deficiency (SADNI and IgG subclass deficiency). METHODS: A retrospective cohort study was performed in patients who met the ESID/PAGID for CVIDs, IgG subclass deficiency and SADNI. Medical records were reviewed to obtain patient demographics, clinical and laboratory data. RESULTS: Infections were the main presentation of all antibody deficient patients and the number of patients with infections declined during IgG therapy. The development of bronchiectasis continued despite IgG therapy, as well as the development of autoinflammatory conditions. Non-infectious disease complications were present in 30% of CVIDs patients at the time of diagnosis and this increased to 51% during follow up despite IgG therapy. The most common complications were autoimmunity or lymphoproliferative disease. The median time to diagnosis was 10 years and in the patients with non-infectious complications the time to diagnosis was considerably longer when compared to the group of patients without complications (17.6 vs. 10.2 years, p = 0.026). CONCLUSION: In contrast to the partial antibody deficiencies we found a considerable delay in the diagnosis of CVIDs, especially in those patients who were dominated by non-infectious complications, and thus increased awareness would be beneficial. Pulmonary and other complications may continue despite adequate IgG replacement therapy suggesting other causes responsible for these complications.

Airway and interstitial lung disease are distinct entities in paediatric common variable immunodeficiency.

Common variable immunodeficiency (CVID) is a common primary immune deficiency, caused by undefined defects in lymphocyte function, and is treated routinely by immunoglobulin substitution. CVID complications include airway disease (AD) and interstitial lung disease (ILD). It was not known if AD and ILD in CVID have a common immunological aetiology and should be considered separate features of the same disease, or as distinct syndromes that require specialized monitoring and treatment. We used high-resolution computed tomography (CT) to diagnose AD or ILD in paediatric CVID patients. Spirometry and body plethysmography did not differentiate between ILD and AD. Patients with AD (n = 11, 20%) developed more pneumonias while children with ILD (n = 8, 15%) showed immune dysregulation characterized by autoimmune complications, more severe memory B cell reduction and expansion of non-naive cytotoxic T cells. In conclusion, ILD and AD in CVID have dissimilar clinical and immunological characteristics, suggesting distinct aetiology requiring tailored monitoring and treatment of these patient subgroups.

High-resolution computed tomography and pulmonary function in children with common variable immunodeficiency.

High-resolution computed tomography (HRCT) may be useful to monitor lung disease in children with common variable immunodeficiency disorder (CVID). We evaluated interobserver agreement and correlation with pulmonary function tests (PFTs) for automated quantification and visual scoring of air trapping and airway wall thickening on HRCT in paediatric CVID patients. In a cohort of 51 children with CVID, HRCT was analysed visually and automated for presence of air trapping and airway wall thickening. PFTs were expressed as % predicted. Disease duration, physician-diagnosed pneumonias and antibiotic prophylaxis were recorded. Interobserver agreement for automated airway wall thickening was good with an intra-class correlation coefficient of 0.88, compared with 0.51 for visual scoring. Presence of air trapping on HRCT correlated significantly with PFTs and disease duration, but was not associated with previous pneumonias. Airway wall thickening did not correlate significantly with PFTs or disease duration and was not associated with previous pneumonias or prophylactic antibiotic use. In children with CVID disorders, HRCT air trapping measurements are significantly correlated with PFTs and disease duration. Quantitative air trapping is a feasible and promising technique for small airway disease quantification that may be applied to monitor (silent) disease progression in CVID.

T-cell response to viral antigens in adults and children with common variable immunodeficiency and specific antibody deficiency.

Several T cell abnormalities have been described in common variable immunodeficiency (CVID), a B cell disorder of mainly unknown origin. A subset of CVID patients suffers from frequent reactivations of herpes viruses. We studied T cell function in CVID [and in a subset of paediatric patients with specific antibody deficiency (SAD)] by measuring T cell proliferation and cytokine production in response to herpes virus-antigens in paediatric CVID patients (n=9) and paediatric SAD patients (n=5), in adult CVID patients (n=14) and in healthy controls. Paediatric CVID patients, but not SAD patients, displayed moderately increased CD8+ T cell proliferation in response to cytomegalovirus, human herpes virus type 6B (HHV6-B) and herpes simplex virus compared to controls. CD8+ T cell responses in adult CVID patients tended to be increased in response to cytomegalovirus and herpes simplex virus. In response to stimulation with herpes virus antigens, the proinflammatory cytokines interleukin (IL)-1beta, IL-6, tumour necrosis factor (TNF)-alpha and interferon inducible protein (IP)-10 were produced. Overall, no major differences were detected in cytokine production upon stimulation between patients and controls, although higher IL-10 and IL-12 production was detected in paediatric patients. In conclusion, cellular immunity against herpes virus antigens appears undisturbed in CVID patients, although defects in subpopulations of CVID patients cannot be excluded.

The distribution of FSH receptor isoforms is related to basal FSH levels in subfertile women with normal menstrual cycles.

BACKGROUND: Recently a polymorphic variant of the FSH receptor in which amino acid asparagine (Asn) at position 680 is replaced by serine (Ser) was found. This is associated with higher FSH levels in the early follicular phase and an increased FSH requirement to obtain follicular response in IVF patients. The aim of our study was to test the hypothesis that this receptor isoform occurs more often in regularly menstruating subfertility patients with elevated basal FSH than in those with normal early follicular phase FSH. METHODS: A retrospective cohort study of 38 subfertility patients with a regular menstrual cycle and elevated FSH (>10 IU/l) compared to 40 patients with normal early follicular phase FSH was carried out. DNA was analysed to determine the FSH receptor genotype. RESULTS: The N680S variant on one or both alleles of the FSH receptor gene was significantly more prevalent in patients with elevated FSH (P < 0.05). The homozygous Asn/Asn variant at codon 680 was found in 45% of women with normal FSH and in 21% of women with elevated FSH. The homozygous Ser/Ser receptor variant was present in 12.5% of women with normal FSH and in 21% of patients with elevated FSH. Also the heterozygous combination of both variants Asn/Ser occurred more often in women with elevated FSH (58 versus 42.5%). CONCLUSIONS: The N680S sequence variation of the FSH receptor is found in >75% of the cases with elevated basal FSH and suggests a higher FSH threshold.

Basal FSH concentrations as a marker of ovarian ageing are not related to pregnancy outcome in a general population of women over 30 years.

BACKGROUND: Previous studies suggest that elevated basal FSH concentrations are related to aneuploid pregnancies. However, there have been no prospective studies evaluating the incidence of aneuploidies in relation to basal FSH concentrations. Since the majority of aneuploid conceptions end in early pregnancy loss or abortion of a recognized pregnancy, these determinants are appropriate intermediate end-points to study aneuploidy. METHODS: We performed a prospective study in 129 women without a history of subfertility pursuing a spontaneous pregnancy. Basal FSH concentrations were measured during three menstrual cycles. Urinary HCG levels were measured during menstruation for a maximum of six menstrual cycles, to detect early pregnancy loss. We estimated the effect of basal FSH concentrations on pregnancy outcome, taking into account possible confounders. RESULTS: We observed no significant effect of basal FSH concentrations on the incidence of early pregnancy loss or abortion of clinically recognized pregnancies. CONCLUSIONS: We conclude that in a population of women without a history of subfertility, pursuing a spontaneous pregnancy, basal FSH concentrations are not related to the incidence of early pregnancy loss or abortions. This prospective study therefore fails to confirm a relationship between signs of decreased ovarian reserve and aneuploid pregnancies.

Basal FSH, estradiol and inhibin B concentrations in women with a previous Down's syndrome affected pregnancy.

BACKGROUND: Two recent studies reported elevated basal FSH concentrations in women with a history of aneuploid conceptions. However, it is not known whether these elevated basal FSH concentrations reflect depletion of the primordial follicle pool, or were caused by an increased secretory drive for FSH. METHODS: Inhibin B and estradiol concentrations were measured as indicators for depletion of the primordial follicle pool in women with a history of a Down's syndrome pregnancy and in controls. RESULTS: In the women with a history of a Down's syndrome pregnancy, there was a significant inverse correlation between basal FSH and inhibin B concentrations (P < 0.0001, 95% CI -0.26 to -0.56). In the control group, this correlation did not reach statistical significance. CONCLUSIONS: Our data indicate that the elevated basal FSH concentrations observed in women with a history of a Down's syndrome pregnancy are likely to reflect early depletion of the primordial follicle pool. Therefore, further research into the ovarian ageing process could provide more insight in the origination of chromosomal abnormalities during pregnancy.

Are elevated FSH concentrations in the pre-conceptional period a risk factor for Down's syndrome pregnancies?

Recent publications have reported a relation between a decreased ovarian reserve and Down's syndrome pregnancies. Using the data of a case-control study into risk factors for a Down's syndrome pregnancy, we estimated the usefulness of pre-conceptional basal follicle stimulating hormone (FSH) screening (detection rate, false positive rate, positive and negative likelihood ratio, as well as the loss rate of unaffected pregnancies) to identify Down's syndrome pregnancies. The optimal detection rate of pre-conceptional basal FSH screening for Down's syndrome pregnancies was 14%, corresponding to a false positive rate of 5% and a positive likelihood ratio of 2.8. Incorporation of basal FSH screening into the regimen of first trimester serum screening followed by nuchal translucency measurement would increase the detection rate from 85 to 87%. However, basal FSH screening alone or in combination with other screening methods would cause an unacceptably high loss rate of unaffected pregnancies compared with current screening protocols, indicating that routine pre-conception basal FSH screening would not be useful to identify women at risk for a Down's syndrome pregnancy. However, when elevated basal FSH concentrations are diagnosed during subfertility evaluation, an elevated risk for a Down's syndrome pregnancy could be discussed with women who become pregnant.

Birth weight corrected for gestational age is related to the incidence of Down's syndrome pregnancies.

Three recent studies reported that early depletion of the primordial follicle pool is likely to be an independent risk factor for Down's syndrome pregnancies. The size of the primordial follicle pool at birth is determined by oogenesis and by the rate of follicle atresia during the intra uterine period. Since intra uterine growth retardation was reported to be associated with a significantly reduced primordial follicle pool at birth, we investigated the possibility of a relation between low birth weight for gestational age and the risk of a Down's syndrome pregnancy. In a case control study, 95 women with a history of a Down's syndrome pregnancy and 85 controls provided information on their own birth weight and length of gestation. Birth weight standard deviation scores, indicating the difference in birth weight from a reference group, were significantly lower in Down's syndrome mothers than in controls. These findings illustrate that the risk of a Down's syndrome pregnancy is related to a low birth weight corrected for gestational age, possibly by a causal relation between intra uterine growth retardation and the size of the primordial follicle pool.

Predictive value of basal follicle-stimulating hormone concentrations in a general subfertility population.

OBJECTIVE: To assess the predictive value of elevated basal FSH concentrations during the initial subfertility workup with respect to fecundity in a general subfertility population with ovulatory menstrual cycles. DESIGN: Nested case-control study. SETTING: Fertility center of a university hospital. PATIENT(S): Fifty subfertile women with basal FSH levels >10.0 IU/L and 50 age-matched controls. INTERVENTION(S): Long-term follow-up (3-7 years). MAIN OUTCOME MEASURE(S): Pregnancies, deliveries, and time to pregnancy. RESULT(S): Patients with elevated basal FSH levels and controls were comparable with regard to basic characteristics, clinical diagnoses, and subfertility treatment. Long-term follow-up showed that 52% of the women with elevated basal FSH concentrations became pregnant (positive predictive value 48%) versus 62% of the controls, and 42% versus 46% eventually delivered a child, respectively. The mean time to pregnancy was 3.0 years in the elevated-FSH group and 3.4 years in controls. Most of the pregnancies in both groups occurred after spontaneous conceptions. CONCLUSION(S): The results of this study suggest that screening for elevated basal FSH concentrations is of no additional value in a general subfertility population with ovulatory menstrual cycles.