Lymphocyte subsets in human immunodeficiency virus-unexposed Brazilian individuals from birth to adulthood

Ataxia-telangiectasia in Latin America: clinical features, immunodeficiency, and mortality in a multicenter study

Ataxia-telangiectasia (AT) is a rare genetic disorder leading to neurological defects, telangiectasias, and immunodeficiency. We aimed to study the clinical and immunological features of Latin American patients with AT and analyze factors associated with mortality. Referral centers from 9 Latin American countries participated in this retrospective cohort study, and 218 patients were included.  Median (IQR) ages at symptom onset and diagnosis were 1.0 (1.0-2.0)  and 5.0 (3.0-8.0) years, respectively. Most patients presented recurrent airway infections, which was significantly associated with IgA deficiency. IgA deficiency was observed in 60.8% of patients and IgG deficiency in 28.6%. T- and B-lymphopenias were also present in most cases. Mean survival was 24.2 years, and Kaplan-Meier 20-year-survival rate was 52.6%, with higher mortality associated with female gender and low IgG levels. These findings suggest that immunologic status should be investigated in all patients with AT.

Evolution of CD4 T-Cell Count With Age in a Cohort of Young People Growing Up With Perinatally Acquired Human Immunodeficiency Virus

BACKGROUND

Recent studies have shown a decrease in CD4 count during adolescence in young people with perinatally acquired human immunodeficiency virus (HIV, PHIV).

METHODS

Young people with PHIV in the United Kingdom, followed in the Collaborative HIV Paediatric Study who started antiretroviral therapy (ART) from 2000 onward were included. Changes in CD4 count over time from age 10 to 20 years were analyzed using mixed-effects models, and were compared to published CD4 data for the gerneral population. Potential predictors were examined and included demographics, age at ART start, nadir CD4 z score (age-adjusted) in childhood, and time-updated viral load.

RESULTS

Of 1258 young people with PHIV included, 669 (53%) were female, median age at ART initiation was 8.3 years, and the median nadir CD4 z score was -4.0. Mean CD4 count was higher in young people with PHIV who started ART before age 10 years and had a nadir CD4 z score ≥-4; these young people with PHIV had a decline in CD4 count after age 10 that was comparable to that of the general population. Mean CD4 count was lower in young people with PHIV who had started ART before age 10 and had a nadir CD4 z score <-4; for this group, the decline in CD4 count after age 10 was steeper over time.

CONCLUSIONS

In children, in addition to starting ART at an early age, optimizing ART to maintain a higher CD4 z score during childhood may be important to maximizing immune reconstitution later in life.

Autosomal Recessive IL-12p40 Deficiency due to a Mutation in the IL12B Gene: Report of a Brazilian Patient with Lymph Node Mycobacterial Infection

Background: Autosomal recessive interleukin (IL)-12p40 deficiency is a genetic etiology of Mendelian susceptibility to mycobacterial disease (MSMD). It has been described in ∼50 patients, usually with onset at childhood with Bacille Calmette-Guérin (BCG) and Salmonella infections. Case Presentation: A male patient born to consanguineous parents was diagnosed with presumed lymph node MSMD at the age of 13 years after ocular symptoms. A positive history of inborn error of immunity was present: BCG reaction, skin abscess, and recurrent oral candidiasis. Abnormal measurements of cytokine levels, IL-12p40 and interferon-gamma (IFN-γ), lead to the diagnosis of MSMD. Genetic analysis showed a mutation in exon 7 of the IL12B gene. Currently, the patient is alive under prophylactic antibiotics. Conclusion: We report a rare case of IL-12p40 deficiency in a Latin American patient. Medical history was crucial for immune defect suspicion, as confirmed by precision diagnostic medicine tools.

High Inborn Errors of Immunity Risk in Patients with Granuloma

OBJECTIVE

Granuloma etiology includes infections, vasculitis, chemicals, malignancies, lymphoproliferative disorders, and immunological diseases. We hypothesized that patients with granuloma have an underlying primary immunodeficiency disease (PIDD).

PATIENTS AND METHODS

We retrospectively enrolled 82 patients with immunological evaluation among 294 biopsy-proven granuloma patients (0- to 20-year-old). At the same time frame, we followed up with 1910 patients in the same age group.

RESULTS

Out of 82 patients, male/female ratio was 45/37. Median age at symptom onset was 5 years (28 days-17.4 years), age of granuloma at diagnosis was 8.6 years (36 days-19.4 years). Common symptoms at disease onset were fever (23.2%), lymphadenopathy (19.6%), abdominal pain (12.2%), and cough (12.2%). Granuloma was frequent in lymph nodes (26.8%), skin (19.5%), lung (13.4%), and bone (11%). Common infectious agents isolated were Mycobacterium spp. (23.2%) and EBV (4.9%). We document PIDD in 76.8% (63/82) of patients. 49.4% (40/81) of immunologically evaluated granuloma patients had hypogammaglobulinemia. Granuloma rate in pediatric PIDD was 3.3%(63/1910). Patients with multiple granulomas (n = 16) had a PIDD diagnosis. Lung involvement was three times more in PIDD. Brain involvement was only seen in PIDD. Fibroadipose tissue and liver involvement were more frequent in patients without documented PIDD and patients whose evaluation was not completed. The mortality rate in PIDD with granuloma was 15.9%, whereas there was no mortality in patients without PIDD.

CONCLUSION

As documented here, even in a university hospital, the immunologic evaluation ratio is about one-third. We showed high PIDD frequency in children with granuloma, and higher mortality in PIDD with granuloma. Thus, an immunologic evaluation performed meticulously by immunologists is a must for accurate diagnosis and decision of individualized therapeutic options.

SCID and Other Inborn Errors of Immunity with Low TRECs - the Brazilian Experience

Severe combined immunodeficiency, SCID, is a pediatric emergency that represents the most critical group of inborn errors of immunity (IEI). Affected infants present with early onset life-threatening infections due to absent or non-functional T cells. Without early diagnosis and curative treatment, most die in early infancy. As most affected infants appear healthy at birth, newborn screening (NBS) is essential to identify and treat patients before the onset of symptoms. Here, we report 47 Brazilian patients investigated between 2009 and 2020 for SCID due to either a positive family history and/or clinical impression and low TRECs. Based on clinical presentation, laboratory finding, and genetic information, 24 patients were diagnosed as typical SCID, 14 as leaky SCID, and 6 as Omenn syndrome; 2 patients had non-SCID IEI, and 1 remained undefined. Disease onset median age was 2 months, but at the time of diagnosis and treatment, median ages were 6.5 and 11.5 months, respectively, revealing considerable delay which affected negatively treatment success. While overall survival was 51.1%, only 66.7% (30/45) lived long enough to undergo hematopoietic stem-cell transplantation, which was successful in 70% of cases. Forty-three of 47 (91.5%) patients underwent genetic testing, with a 65.1% success rate. Even though our patients did not come from the NBS programs, the diagnosis of SCID improved in Brazil during the pilot programs, likely due to improved medical education. However, we estimate that at least 80% of SCID cases are still missed. NBS-SCID started to be universally implemented in the city of São Paulo in May 2021, and it is our hope that other cities will follow, leading to early diagnosis and higher survival of SCID patients in Brazil.

A Critical Review on the Standardization and Quality Assessment of Nonfunctional Laboratory Tests Frequently Used to Identify Inborn Errors of Immunity

Inborn errors of immunity (IEI), which were previously termed primary immunodeficiency diseases, represent a large and growing heterogeneous group of diseases that are mostly monogenic. In addition to increased susceptibility to infections, other clinical phenotypes have recently been associated with IEI, such as autoimmune disorders, severe allergies, autoinflammatory disorders, benign lymphoproliferative diseases, and malignant manifestations. The IUIS 2019 classification comprises 430 distinct defects that, although rare individually, represent a group affecting a significant number of patients, with an overall prevalence of 1:1,200-2,000 in the general population. Early IEI diagnosis is critical for appropriate therapy and genetic counseling, however, this process is deeply dependent on accurate laboratory tests. Despite the striking importance of laboratory data for clinical immunologists, several IEI-relevant immunoassays still lack standardization, including standardized protocols, reference materials, and external quality assessment programs. Moreover, well-established reference values mostly remain to be determined, especially for early ages, when the most severe conditions manifest and diagnosis is critical for patient survival. In this article, we intend to approach the issue of standardization and quality control of the nonfunctional diagnostic tests used for IEI, focusing on those frequently utilized in clinical practice. Herein, we will focus on discussing the issues of nonfunctional immunoassays (flow cytometry, enzyme-linked immunosorbent assays, and turbidimetry/nephelometry, among others), as defined by the pure quantification of proteins or cell subsets without cell activation or cell culture-based methods.

Age-stratified pediatric reference values of lymphocytes in the Moroccan population

The number of circulating lymphocytes is altered in a number of diseases including either increase (lymphocytosis) or decrease (lymphocytopenia). Therefore, the assessment of total blood lymphocyte numbers and the relative distribution of lymphocyte subsets is a critical front-line tool in the clinical diagnosis of a number of diseases, including pediatric diseases and disorders. However, the interpretation of this data requires comparison of patient's results to reliable reference values. Blood lymphocyte subpopulation numbers are also subject to genetic polymorphisms, immunogenic and environmental factors and vary greatly between populations. While the best practice reference values should be established within local representative populations of healthy subjects, to date, Caucasian reference values are used in Morocco due to the absence of indigenous reference values. Potential differences in blood lymphocyte subpopulation reference values between Caucasian versus Moroccan populations can adversely affect the diagnosis of pediatric and childhood diseases and disorders such as primary immunodeficiency (PID) in Morocco.

OBJECTIVE

The aim of this study was to establish the age-stratified normal reference values of blood lymphocyte subsets for the pediatric Moroccan population.

METHODS

We measured the concentration of lymphocyte subpopulations by flow cytometry from 83 Moroccan healthy subjects stratified into 5 age groups of 0-1, 1-2, 2-6, 6-12 and > 12-18 (adult).

RESULTS

The absolute and relative amounts of the main lymphocyte subsets of T-cells, B cells and Natural Killer (NK) cells were measured and compared to previously described reference values from Cameroonian, Turkish, American and Dutch populations. Additionally, we also observed an age-related decline in the absolute population sizes of lymphocyte subsets within our study group. Relative proportions of CD3+CD4+ helper T lymphocytes decreased with increasing age and by 12 years-adult age, both proportions of CD3+CD4+ helper T lymphocytes and CD3+CD8+ cytotoxic T lymphocytes, as well as CD3-CD19+ B lymphocytes were also decreased. Finally, we compared the median values and range of our Moroccan study group with that of published results from Cameroon, Turkey, USA and Netherlands and observed significant differences in median and mean values of absolute number and relative proportions of lymphocyte subsets especially at 0-1 years and 1-2 years age groups. Above age 12 years, the Moroccan values were lower. For NK cells, the Moroccan values are also lower.

CONCLUSIONS

The results of this study have a significant impact in improving the threshold values of the references intervals routinely used in the diagnosis of paediatric diseases such as PIDs or mother-to-child transmitted HIV within the Moroccan population.

Combined immunodeficiencies

OBJECTIVES

Inborn Errors of Immunity (IEI), also known as primary immunodeficiencies, correspond to a heterogeneous group of congenital diseases that primarily affect immune response components. The main clinical manifestations comprise increased susceptibility to infections, autoimmunity, inflammation, allergies and malignancies. The aim of this article is to review the literature on combined immunodeficiencies (CIDs) focusing on the diagnosis and treatment and the particularities of the clinical management of these patients.

SOURCE OF DATA

Critical integrative review, aimed to present articles related to primary immunodeficiencies combined with a searchin the PubMed and SciELO databases, with evaluation of publications from the last twenty years that were essential for the construction of knowledge on this group of diseases.

SUMMARY OF DATA

We highlight the main characteristics of CIDs, dividing them according to their pathophysiological mechanisms, such as defects in the development of T cells, TCR signaling, co-stimulatory pathways, cytokine signaling, adhesion, migration and organization of the cytoskeleton, apoptosis pathways, DNA replication and repair and metabolic pathways. In CIDs, clinical manifestations vary widely, from sinopulmonary bacterial infections and diarrhea to opportunistic infections, caused by mycobacteria and fungi. Neonatal screening makes it possible to suspect these diseases before clinical manifestations appear.

CONCLUSIONS

The CIDs or IEI constitute a complex group of genetic diseases with T-cell involvement. Neonatal screening for these diseases has improved the prognosis of these patients, especially in severe ones, known as SCIDs.

Immune system: development and acquisition of immunological competence

OBJECTIVES

To describe the ontogeny of the immune system and the adaptive mechanisms of the immune system in the neonatal period, with an emphasis on transplacental antibody transport and breastfeeding.

SOURCE OF DATA

Non-systematic literature review in the PubMed database.

SUMMARY OF THE FINDINGS

The last two decades have witnessed a great advance in the knowledge of the immune system since conception. Several investigation tools have provided insight on phenomena that were previously inadequately understood. Still expanding, the functional and molecular investigation of various aspects of the immune system will make it possible to understand how intra-uterus maternal-fetal exchanges, the maternal microbiota interacting with the fetus and newborn, and the acquisition of immunological competence occur in healthy and disease scenarios.

CONCLUSIONS

In-depth knowledge of the development of the immune system and of the adaptive mechanisms that allow a safer transition to the extrauterine environment are fundamental components of optimizing maternal and young infant vaccination, as well as the strategies associated with full postnatal development, and the early diagnosis and treatment of innate errors of immunity.

A Patient With AIRE Mutation Who Presented With Severe Diarrhea and Lung Abscess

Autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy (APECED) (polyglandular endocrinopathy type 1) is a rare autosomal recessive disorder caused by mutations in the autoimmune regulator gene (AIRE). The major clinical features of APECED are hypoparathyroidism, adrenal insufficiency (Addison disease), and chronic mucocutaneous candidiasis. This disease is also associated with multiple other and uncommon autoimmune (autoimmune hepatitis, autoimmune enteropathy, atrophic gastritis with or without pernicious anemia, gonadal failure, diabetes mellitus, hypothyroidism, functional hyposplenism), ectodermal (alopecia and vitiligo), and inflammatory (intestinal lung disease, nephritis) features. Here, we report a case of a 13-year-old Turkish boy who presented wih enteropathy and lung abscess. Molecular genetic analysis demonstrated a homozygous frameshift mutation (p.Asp70fs, c.208_209insCAGG) in exon 2, in AIRE gene. APECED may present with severe, life-threatening infections due to functional hyposplenism. Multidisciplinary approach, careful follow-up, and molecular genetic studies are needed.

Managing costs in primary immunodeficiency: minimal immunophenotyping and three national references

Our aim was to evaluate the cost-effectiveness of a minimal lymphocyte subset quantification (LSQ) by flow cytometry as the first screening in children with clinically suspected primary immunodeficiency (PID). Two hundred sixty-eight Brazilian patients (0-21 years old) were studied. They were divided by clinical and phenotypical features into those fulfilling criteria for PID (PID phenotype) according to the 2017 International Union of Immunological Societies (IUIS) classification and those not fulfilling these criteria (non-PID phenotype). We evaluated how many patients had values below the 10th percentile for five lymphocyte subsets in peripheral blood, (suggestive of PID) according to reference values for Brazil, Italy and USA. Three lymphocyte subsets (T CD3/CD4, B CD19 and NK CD16/CD56) had p-value < 0.05 and Odds Ratio (OR) indicating a risk at least two times higher for the diagnosis of a PID phenotype. The application of Kappa coefficient (k) on Brazilian vs Italian and Brazilian vs US data sets resulted in k compatible with strong or excellent level of agreement between the three classification systems. The authors conclude that a number of CD3⁺ /CD4⁺ , CD19⁺ and CD16⁺ /CD56⁺ (NK) cells in peripheral blood <10th percentile represented a significant risk for the diagnosis of PID in this cohort. Natural killer (NK) deficiency is quite rare and has a very specific clinical profile. So, the analysis of these cells could be requested only in some cases, saving even more costs. The minimal immunophenotyping, with quantification of T CD4⁺ , CD19⁺ and in some cases CD16⁺ /CD56⁺ cells, may be a useful tool for the first screening of PID, saving costs, especially in developing countries.

B-cell subsets imbalance and reduced expression of CD40 in ataxia-telangiectasia patients

BACKGROUND

Ataxia-telangiectasia (AT) is a well-known primary immunodeficiency with recurrent sinopulmonary infections and variable abnormalities in both the humoral and cellular immune system. Dysfunctions in immunoglobulin production, reduced number of B cells, and B-cell receptor excision circles copies have been reported. We aimed to understand the immunological mechanisms involving the humoral compartment in AT patients by analysing peripheral blood B cells subsets, B-T lymphocyte cooperation through the expression of CD40 and CD40 ligand (CD40L), and cytokines involved in class-switch recombination production.

METHODS

We compared the proportion of B-cell subsets, the expression of CD40/CD40L, and the plasma levels of IL-6 and IFN-γ of 18 AT patients and 15 healthy age-sex-matched controls using flow cytometry.

RESULTS

We found that some steps in peripheral B cell development were altered in AT with a pronounced reduction of cell-surface CD40 expression. The proportions of transitional and naïve-mature B cells were reduced, whereas CD21-low, natural effector memory, IgM-only memory, and IgG atypical memory B cells were present in a higher proportion.

CONCLUSIONS

These findings revealed a disturbed B-cell homeostasis with unconventional maturation of B lymphocyte memory cells, which can explain the consequent impairment of humoral immunity.

NEWBORN SCREENING FOR SEVERE COMBINED IMMUNODEFICIENCIES USING TRECS AND KRECS: SECOND PILOT STUDY IN BRAZIL

OBJECTIVE

To validate the quantification of T-cell receptor excision circles (TRECs) and kappa-deleting recombination excision circles (KRECs) by real-time polymerase chain reaction (qRT-PCR) for newborn screening of primary immunodeficiencies with defects in T and/or B cells in Brazil.

METHODS

Blood samples from newborns and controls were collected on filter paper. DNA was extracted and TRECs, and KRECs were quantified by a duplex real-time PCR. The cutoff values were determined by receiver operating characteristic curve analysis using SPSS software (IBM®, Armonk, NY, USA).

RESULTS

Around 6,881 samples from newborns were collected and TRECs and KRECs were quantified. The TRECs values ranged between 1 and 1,006 TRECs/µL, with mean and median of 160 and 139 TRECs/µL, respectively. Three samples from patients with severe combined immunodeficiency (SCID) showed TRECs below 4/µL and a patient with DiGeorge syndrome showed undetectable TRECs. KRECs values ranged from 10 to 1,097 KRECs/µL, with mean and median of 130 and 108 KRECs/µL. Four patients with agammaglobulinemia had results below 4 KRECs/µL. The cutoff values were 15 TRECs/µL and 14 KRECs/µL and were established according to the receiver operating characteristic curve analysis, with 100% sensitivity for SCID and agammaglobulinemia detection, respectively.

CONCLUSIONS

Quantification of TRECs and KRECs was able to diagnose children with T- and/or B-cell lymphopenia in our study, which validated the technique in Brazil and enabled us to implement the newborn screening program for SCID and agammaglobulinemia.

A Novel Homozygous JAK3 Mutation Leading to T-B+NK- SCID in Two Brazilian Patients

We report a novel homozygous JAK3 mutation in two female Brazilian SCID infants from two unrelated kindreds. Patient 1 was referred at 2 months of age due to a family history of immunodeficiency and the appearance of a facial rash. The infant was screened for TRECs (T-cell receptor excision circles) and KRECs (kappa-deleting recombination excision circles) for the assessment of newly formed naïve T and B cells respectively, which showed undetectable TRECs and normal numbers of KRECs. Lymphocyte immunophenotyping by flow cytometry confirmed the screening results, revealing a T-B+NK- SCID. The patient underwent successful HSCT. Patient 2 was admitted to an intensive care unit at 8 months of age with severe pneumonia, BCGosis, and oral moniliasis; she also had a positive family history for SCID but newborn screening was not performed at birth. At 10 months of age she was diagnosed as a T-B+NK- SCID and underwent successful HSCT. JAK3 sequencing revealed the same homozygous missense mutation (c.2350G>A) in both patients. This mutation affects the last nucleotide of exon 17 and it is predicted to disrupt the donor splice site. cDNA sequencing revealed skipping of exon 17 missing in both patients, confirming the predicted effect on mRNA splicing. Skipping of exon 17 leads to an out of frame deletion of 151 nucleotides, frameshift and creation of a new stop codon 60 amino acids downstream of the mutation resulting in a truncated protein which is likely nonfunctional.

Hypogammaglobulinemia in children: a warning sign to look deeply?

This study investigated phenotypic and functional characteristics of lymphocytes in children with common variable immunodeficiency (CVID) and unclassified hypogammaglobulinemia (UH), as well as B-cell subsets in non-consanguineous parents. Blood samples of 30 children, CVID (n = 9), UH (n = 9), healthy donors HD (n = 12), and 19 adults (parents and controls) were labeled by a combination of surface markers to identify CD4, CD8 T-cell and B-cell subpopulations. T-cell cytokine production in children was analyzed in vitro after stimulation with phytohemagglutinin (PHA) and tetanus toxoid. We observed low percentages of switched memory B cells in children with CVID, increase in total CD4⁺ T-cell counts, and high percentages of transitional B cells only in UH group. Analysis of T-cell immunity showed that CVID children had decreased percentages of CD8⁺ IFN-γ-producing cells after stimulation with PHA and tetanus toxoid. Parent of children with CVID had low percentages of naive B cell and increased percentages of memory B cells in comparison with controls. These results suggest that (i) early combined immune defect in children with CVID and (ii) a possible familial B-cell disturbance in pediatric CVID.

Reference values for B-cell surface markers and co-receptors associated with primary immune deficiencies in healthy Turkish children

In order to evaluate B-lymphocyte subsets of patients with primary immunodeficiencies, the normal values for national healthy children have to be used as a reference. Recently, B-cell co-receptor markers (CD19, CD21, and CD81) and CD20, CD22, and CD27 deficiencies have been reported in relation with different primary immunodeficiency diseases. The objective of this study was to establish national reference values for B-lymphocyte co-receptors and some surface markers, CD20, CD22, CD27, as well as classic lymphocyte subsets in the peripheral blood of healthy children. A total of 90 healthy children were included in this study. Complete blood counts were performed and cells with CD3, CD4, CD8, CD19, CD16/56, CD20, CD21, CD22, CD27, and CD81 surface markers were simultaneously detected by flow cytometry. The children were evaluated in three age subgroups, 0–1, 1–6, and >6 years, and minimum, maximum, mean, mean minus standard deviation, and 2.5–97.5 percentile values were all determined. By establishing reliable reference ranges for these surface markers, we hoped to help identifying and classifying some primary immunodeficiency patients, especially those defined as unclassified hypogammaglobulinemia and those without definite diagnosis.

Neonatal screening for severe combined immunodeficiency in Brazil

OBJECTIVE

To apply, in Brazil, the T-cell receptor excision circles (TRECs) quantification technique using real-time polymerase chain reaction in newborn screening for severe combined immunodeficiency and assess the feasibility of implementing it on a large scale in Brazil.

METHODS

8715 newborn blood samples were collected on filter paper and, after DNA elution, TRECs were quantified by real-time polymerase chain reaction. The cutoff value to determine whether a sample was abnormal was determined by ROC curve analysis, using SSPS.

RESULTS

The concentration of TRECs in 8,682 samples ranged from 2 to 2,181TRECs/μL of blood, with mean and median of 324 and 259TRECs/μL, respectively. Forty-nine (0.56%) samples were below the cutoff (30TRECs/μL) and were reanalyzed. Four (0.05%) samples had abnormal results (between 16 and 29TRECs/μL). Samples from patients previously identified as having severe combined immunodeficiency or DiGeorge syndrome were used to validate the assay and all of them showed TRECs below the cutoff. Preterm infants had lower levels of TRECs than full-term neonates. The ROC curve showed a cutoff of 26TRECs/μL, with 100% sensitivity for detecting severe combined immunodeficiency. Using this value, retest and referral rates were 0.43% (37 samples) and 0.03% (3 samples), respectively.

CONCLUSION

The technique is reliable and can be applied on a large scale after the training of technical teams throughout Brazil.

Response to immunization in children born to renal transplant recipients using immunosuppressive drugs during gestation

The use of immunosuppressive drugs can impair vaccination responses. When used during pregnancy, they may interfere with the development of the fetus's immune system. However, little is known regarding their influence on infant's response to vaccinations. Twenty-seven children born to renal transplant mothers (Tx) taking immunosuppressive drugs and 31 healthy children had the humoral immune response and reactogenicity to tetanus, Haemophilus influenzae type b (Hib) and 7 pneumococcal serotypes evaluated. The evolution of BCG vaccine scar was also registered. Antibodies were measured by ELISA. Lymphocyte immunophenotyping was performed on cord blood and at 7-8 months of age. Among Tx neonates, 82.4% had low B lymphocyte numbers at birth, and 29.4% had also low numbers of other lymphocyte subpopulations. Nevertheless, all children developed protective antibodies with similar antibody concentrations to the control group. Vaccine reactogenicity was similar in both groups and BCG healing was uneventful.

Immunophenotypic profile and increased risk of hospital admission for infection in infants born to female kidney transplant recipients

Children born to female kidney recipients are exposed to immunosuppressive drugs during gestation. Little is known about their immune system at birth or in the long term. Twenty-eight children born to female kidney recipients and 40 full-term children born to healthy mothers were evaluated. T, B, NK, NKT, γδT cells were assessed by flow cytometry and functional evaluation of T and dendritic cells after in vitro activation was performed at birth and at 8 months of age. At birth, infants born to female kidney recipients showed lower numbers of CD4+ T, NKT and intense reduction of B cells (median cells/mm(3) , transplant: 153.7 X control: 512.4; p < 0.001). There was also a reduced percentage of activated CD8+ T and of CD4+ regulatory T cells. Activated memory and exhausted memory B cells showed higher percentages among children exposed to immunosuppressors when compared to control group. At 8 months, most immune alterations were no longer observed, but four children still had low numbers of some lymphocyte subsets at this age. Children born to female kidney recipients had 4.351 (95% CI: 1.026-15.225; p = 0.046) higher risk of hospital admission in the first months of life-some, with severe clinical manifestations-than those born to healthy women.