Screening for primary immunodeficiencies in the clinical immunology laboratory

Normal response to vaccines in inflammatory bowel disease patients treated with thiopurines

BACKGROUND

Thiopurines are considered immunosuppressive agents and may be associated with an increased risk for infections. However, few inflammatory bowel disease (IBD) patients are appropriately vaccinated, and data on their ability to mount an immune response are vague. We evaluated the effects of the thiopurines, azathioprine (AZA) and 6-mercaptopurine (6-MP), on cellular and humoral immune responses in IBD patients.

METHODS

A prospective clinical investigation was conducted on IBD patients referred for thiopurine treatment. Immune competence was evaluated by assessing lymphocyte counts and phenotype, response to mitogen and antigen stimulation, immunoglobulin levels, and response to pneumococcal and tetanus vaccines (before treatment, week 0), and to Haemophilus influenza type b vaccine (at week 24).

RESULTS

Thirty-one Crohn's disease and 12 ulcerative colitis patients who completed at least 24 weeks of therapy were included. The posttherapy average 6-MP dose was 1.05 ± 0.30 mg/kg, and white blood cell counts had decreased significantly from baseline values (P < 0.002). The posttreatment response to mitogens and antigens and the immunoglobulin levels were unchanged. Responses to vaccines were normal both in thiopurine-naïve and thiopurine-treated patients, suggesting that these patients were immunologically intact while on thiopurine therapy and capable of generating normal immune responses in vivo.

CONCLUSIONS

There is no evidence for any intrinsic systemic immunodeficiency in IBD patients. Thiopurines at the doses used for treating IBD showed no significant suppressive effect on the systemic cellular and humoral immune responses evaluated. Thiopurine-treated IBD patients can be safely and efficiently vaccinated.

Normal response to vaccines in inflammatory bowel disease patients treated with thiopurines

BACKGROUND

Thiopurines are considered immunosuppressive agents and may be associated with an increased risk for infections. However, few inflammatory bowel disease (IBD) patients are appropriately vaccinated, and data on their ability to mount an immune response are vague. We evaluated the effects of the thiopurines, azathioprine (AZA) and 6-mercaptopurine (6-MP), on cellular and humoral immune responses in IBD patients.

METHODS

A prospective clinical investigation was conducted on IBD patients referred for thiopurine treatment. Immune competence was evaluated by assessing lymphocyte counts and phenotype, response to mitogen and antigen stimulation, immunoglobulin levels, and response to pneumococcal and tetanus vaccines (before treatment, week 0), and to Haemophilus influenza type b vaccine (at week 24).

RESULTS

Thirty-one Crohn's disease and 12 ulcerative colitis patients who completed at least 24 weeks of therapy were included. The posttherapy average 6-MP dose was 1.05 ± 0.30 mg/kg, and white blood cell counts had decreased significantly from baseline values (P < 0.002). The posttreatment response to mitogens and antigens and the immunoglobulin levels were unchanged. Responses to vaccines were normal both in thiopurine-naïve and thiopurine-treated patients, suggesting that these patients were immunologically intact while on thiopurine therapy and capable of generating normal immune responses in vivo.

CONCLUSIONS

There is no evidence for any intrinsic systemic immunodeficiency in IBD patients. Thiopurines at the doses used for treating IBD showed no significant suppressive effect on the systemic cellular and humoral immune responses evaluated. Thiopurine-treated IBD patients can be safely and efficiently vaccinated.

Dendritic cells and lymphocyte subpopulations of the adenoid in the pathogenesis of otitis media with effusion

OBJECTIVE

To assess dendritic cells and lymphocyte subpopulations of adenoid and peripheral blood in patients with adenoid hypertrophy and otitis media with effusion (OME). To explain the influence of immunological status of adenoid on the development of OME.

METHODS

The examined group covered 123 surgically treated patients due to adenoid hypertrophy (39 children with coexisting OME). Preoperative clinical examination included anamnesis and otorhinolaryngological examination with nasofiberoscopy, videootoscopy and assessment of the hearing organ. The material of the study were surgically removed adenoids and peripheral blood samples prepared and then analyzed by the means of tri-colour flow cytometry. The obtained results were statistically analyzed.

RESULTS

Significant differences between patients with adenoid hypertrophy with coexisting OME and children without OME concerning CD19+CD69+, CD3+CD69+, CD4+CD69+CD8+CD69+ and CD19+CD25+ cells were observed. No statistical differences were revealed in the blood of patients with and without OME. Several statistical differences were noted between the adenoid and peripheral blood in patients with otitis media with effusion concerning BDCA-2+/CD123+ cells, CD3+ and CD19+ lymphocytes with the markers of their activation.

CONCLUSIONS

The adenoid is involved in local immune response regardless of constitutional immunological mechanisms in patients with OME coexisting with adenoid hypertrophy. Significantly lower percentage of CD3+CD69+, CD4+CD69+, CD8+CD69+ and CD19+CD69+ cells of adenoid in patients with OME attests to reduced T-cells activation of the adenoid in relation to patients without OME.

Outcome of hypogammaglobulinemia in children: immunoglobulin levels as predictors

We evaluated 131 children (M=88, F=43) with hypogammaglobulinemia. Data was analyzed mainly for delineating predictor factors for outcome. The distance from the lower limit of normal (-2SD) for any single measurement of immunoglobulins (Ig) was calculated and transformed into Ig scores. Mean age and duration of follow-up were 5.06 ± 4.05 and 3.7 ± 3.03 years, respectively. The diagnoses were: 22 CVID, 16 IgA deficiency, 33 transient hypogammaglobulinemia of childhood (THC), 3 selective IgM deficiency and 57 unclassified hypogammaglobulinemia (UCH). Low IgA scores (<-0.124) at presentation were indicative of subsequent development of IgA deficiency or CVID, whereas low IgM score (<-0.038) pointed towards more severe and persistent phenotypes. Combination of low IgM score between 2 and 5 years, impaired antibody response and low B cell counts enabled us to predict persistence of hypogammaglobulinemia beyond 5 years (specificity=90.5% and PPV=94.9%) and chronic lung disease (sensitivity=90.4% and specificity=68.3%). The set of criteria including low IgM scores, impaired antibody response and low B cell counts provided a high predictive value in detecting those with persistent hypogammaglobulinemia.

Children with frequent infections: a proposal for a stepwise assessment and investigation of the immune system

Although many children develop frequent infections, only a few have an underlying immune disorder. Children with dysfunction of the immune system develop frequent infections and/or recurrent, persistent, severe, and rare infections. The aim of this review is to provide to the clinician a valuable tool for recognizing any 'discords' of the 'immune-system symphonic orchestra'. By following a reverse route, it will be possible to brighten up the dark and winding road of immunodeficiencies and identify the exact point of immune dysfunction. This is fundamental and crucial to perceive etiologic management and subsequently achieve the best for these young patients and their families.

Pathogenesis, diagnosis, and management of primary antibody deficiencies and infections

Primary antibody deficiencies are the most common primary immunodeficiency diseases. They are a heterogeneous group of disorders with various degrees of dysfunctional antibody production resulting from a disruption of B-cell differentiation at different stages. While there has been tremendous recent progress in the understanding of some of these disorders, the etiology remains unknown for the majority of patients. As there is a large spectrum of underlying defects, the age at presentation varies widely, and the clinical manifestations range from an almost complete absence of B cells and serum immunoglobulins to selectively impaired antibody responses to specific antigens with normal total serum immunoglobulin concentrations. However, all of these disorders share an increased susceptibility to infections, affecting predominantly the respiratory tract. A delay of appropriate treatment for some diseases can result in serious complications related to infections, while timely diagnosis and adequate therapy can significantly decrease morbidity and increase life expectancy and quality of life.

Cellular and genetic basis of primary immune deficiencies

Knowledge of the genetic mutations of primary immune deficiency syndromes has grown significantly over the last 30 years. In this article the authors present an overview of the clinical aspects, laboratory evaluation, and genetic defects of primary immunodeficiencies, with an emphasis on the pathophysiology of the known molecular defects. This article is designed to give the primary pediatrician a general knowledge of this rapidly expanding field.

Recognizing primary immune deficiency in clinical practice

Primary immunodeficiency results in recurrent infections, organ dysfunction, and autoimmunity. We studied 237 patients referred for suspicion of immunodeficiency, using a scoring system based on clinical information. The 113 patients with immunodeficiency had higher scores and more episodes of chronic illnesses and were more likely to have neutropenia, lymphopenia, or splenomegaly.

Biomarkers to assess potential developmental immunotoxicity in children

Clinical tests are readily available for assessing severe loss of immune function in children with diseases such as AIDS or primary immunodeficiency. However tests that could reliably identify subtle immune changes, as might be expected to result from exposure to developmental immunotoxic agents, are not readily available. A number of tests are described which we believe have potential applicability for epidemiological studies involving developmental immunotoxicity. Several of the tests, such as T cell receptor rearrangement excision circles (TRECs) and cytokine measurements, while highly relevant from a biological standpoint, may be precluded from use at the current time, for either technical issues or insufficient validation. Immunophenotyping and measurement of serum immunoglobulin levels, on the other hand, are well validated. Yet they may require extraordinary care in experimental design and technical performance in order to obtain data that would consistently detect subtle changes, as these tests are not generally considered highly sensitive. Quantification of the immune response to childhood vaccine, while up to the present used sparingly, may represent an excellent indicator for developmental immunotoxicity when conducted under appropriate conditions.

Identifying undiagnosed primary immunodeficiency diseases in minority subjects by using computer sorting of diagnosis codes

BACKGROUND

Primary immunodeficiency diseases occur in all populations, but these diagnoses are rarely made in minority subjects in the United States.

OBJECTIVE

We sought to develop and validate a method to identify patients without diagnoses but with immunodeficiency in an urban hospital with a substantial minority patient population.

METHODS

We developed a scoring algorithm on the basis of International Classification of Disease, Ninth Revision (ICD-9) codes to identify all hospitalized patients age 60 years or less who had been given a diagnosis of 2 or more of 174 ICD-9-coded complications associated with immunodeficiency. Codes were weighted for severity and expressed as a sum for all admissions between October 1, 1995, and December 31, 2002. Patients with, for example, cancer or HIV or those after transplantation or major surgery were excluded. Demographic features of subjects with aggregated ICD-9 codes suggestive of immunodeficiency were compared with those of other inpatients; 59 computer-selected subjects were then tested for immune defects.

RESULTS

The computer-identified group contained 533 patients (0.4% of all inpatients), who had been hospitalized 2683 times. The median age was 6.6 years. Sixty-five percent were African American or Hispanic, and 61% were insured by Medicaid, which is significantly more than other inpatients younger than 60 years of age (median age, 32.6 years; 37% minority, 27% insured by Medicaid; P<.0001). Primary immunodeficiency was found in 17 (29%) of the 59 subjects tested. Thirteen other patients had secondary immune defects, and 86% of immunodeficient subjects were Hispanic or African American.

CONCLUSIONS

An ICD-9-based scoring algorithm identifies patients demographically different from other hospitalized subjects who have multiple illnesses suggestive of immunodeficiency. This group contains undiagnosed minority patients with immunodeficiency.

Immunoglobulin A (IgA) deficiency and alternative celiac disease-associated antibodies in sera submitted to a reference laboratory for endomysial IgA testing

Immunoglobulin A (IgA) deficiency occurs more frequently in patients with celiac disease (CD) than in the general population and can lead to false-negative results in the best serologic test for CD, endomysial IgA (EMA). To evaluate the impact of IgA deficiency on serologic detection of CD in a reference laboratory setting, IgA levels were measured in 510 consecutive serum specimens submitted for testing for EMA; 510 consecutive serum specimens submitted for Helicobacter pylori IgG testing served as a gastrointestinal symptom control group. The frequency of IgA deficiency was significantly higher among the specimens submitted for testing for EMA (5.1%) than among the specimens from the symptom control group (1.4%). Three subsets of sera from the group of specimens submitted for testing for EMA were then tested by additional serologic assays for CD; these subsets were EMA-positive sera (n = 25), EMA-negative, IgA-deficient sera (n = 26), and control sera (from EMA-negative, IgA-nondeficient patients age matched to IgA-deficient patients; n = 26). The proportions of EMA-positive sera positive by other assays for CD were 92% for transglutaminase IgA (TG-IgA), 80% for gliadin IgA, 84% for gliadin IgG, 60% for endomysial IgG (EMG), and 32% for transglutaminase IgG (TG-IgG). Very low proportions (0 to 8%) of IgA-deficient sera and control sera were positive for TG-IgA, gliadin IgA, EMG, and TG-IgG. Eight of 26 (31%) IgA-deficient serum samples were positive for gliadin IgG, whereas 3 of 26 (12%) control serum samples were positive for gliadin IgG, but this difference was not statistically significant. Physicians supplied clinical data for 18 of 26 patients with IgA deficiency; only 4 patients had undergone small-bowel biopsy, and 0 of 4 patients showed villous atrophy. These findings show that IgA deficiency is found more frequently among sera submitted for testing for EMA in a reference laboratory setting, but there was no clear-cut serologic or clinical evidence of CD in EMA-negative, IgA-deficient patients.