Common Immunodeficiency Research Articles

OA01.12. A clinical study of efficacy of Vyoshadi gutika and Pippalayadi churna avapida nasya in the management of Pratishyaya

Purpose: Pratishyay basically is a Vat-kaphaj disorder arising from accumulation of vitiated Vat along with kaph-pitta-rakta in uttamang (shirh pradesh) and comparable to Rhinitis which describes a group of symptoms including runny nose, stuffiness, sneezing usually due to common cold, environmental irritants and immunodeficiency. This study aim to do 1.Evaluation of effectiveness of Vyoshadi gutika (samshaman therapy) and Pippalayadi churna Avapida nasya (samshodhan therapy) in the management of pratishyay, 2.Statistical assessment of data post treatment. Method: 60 patients of Pratishyay aged between 16-60 years of age of both sexes complaining of Rhinorrhoea/ nasal block, sneezing, heaviness of head, anosmia were selected randomly and assigned for clinical study were divided into 2 groups. Group A consisting of 30 patients had internal administration of Vyoshadi gutika in a dose of 2 tablets QID (each tab. 375 mg) with lukewarm water for 30 days. Group B- 30 patients took Vyoshadi gutika along with Pippalayadi churna Avapida nasya (6 drops in each nostril early morning) for duration of 21 days. All patients were advised to attend 15 days Intercal regularly for 3 months for assessment of disease through subjective and objective parameters. Result: 60% patients (18 no.) of Group B while 47% patients (14 no.) Group A responded satisfactorily with maximum improvement (more than 76% symptomatic improvement). Similarly, Moderate improvement (between 51-75%) was seen in 47 patients of Group A and 37% of Group B while mild improvement in 10% and 3% patients of Group A and B respectively. No untoward adverse effects were seen in any patients. Conclusion: It can be concluded that on the basis of Practical, Therapeutic and Statistical analysis, patients of both groups got satisfactory improvement. Besides, patients treated with both Samshodhan Nasya therapy and Samshaman Vyoshadi Gutika therapy comparatively got better results.

Biology and novel treatment options for XLA, the most common monogenetic immunodeficiency in man

Introduction: X-linked agammaglobulinemia (XLA) is the most common primary immunodeficiency in man, and is caused by a single genetic defect. Inactivating mutations in the Bruton's tyrosine kinase (BTK) gene are invariably the cause of XLA,. XLA is characterized by a differentiation arrest at the pre-B cell stage, the absence of immunoglobulins and recurrent bacterial infections, making it an insidious disease that gradually disables the patient, and can result in death due to chronic lung disease. Current treatment involves prophylactic antibiotics and immunoglobulin infusions, which are non-curative. This disease is a good candidate for curative hematopoietic stem cell (HSC)-based gene therapy, which could correct the B cell and myeloid deficiencies.Areas covered: This paper reviews the basic biology of BTK in B cell development, the clinical features of XLA, and the possibilities of gene therapy for XLA, covering the literature from 1995 to 2010.Expert opinion: Work from various laboratories demonstrates the feasibility of using gene-corrected HSCs to complement the immune defects of Btk-deficiency in mice. We propose that it is timely to start clinical programs to develop stem cell based therapy for XLA, using gene-corrected autologous HSC.

Lymphocyte subsets, immunoglobulin levels, complement activity CH50, and phagocytic peroxide production in 19 Iranian patients with first episode of bacterial meningitis

Despite the availability of potent antimicrobial drugs, bacterial meningitis remains a serious infection with significant morbidity and mortality. In many studies, pyogenic meningitis is reported in patients with immunoglobulin (Ig) and complement deficiencies. In the present study, a broad range of immunological tests were performed to determine the relative importance of primary immunodeficiency as a predisposing cause of first episode of pyogenic meningitis without any evidence of other major infections in past medical history. We studied 19 patients with bacterial meningitis confirmed by smear, culture, and cerebrospinal fluid parameters. Immunological tests were performed within 1 to 21 days of diagnosis. Twenty healthy adults served as controls. Serum Ig levels (IgA, IgG, IgM, IgE) and total hemolytic complement (CH5O) as screening tests were done. Lymphocytes, neutrophils, and T-cells were enumerated. Nitroblue tetrazolium test was used for the assessment of neutrophil function. Thirteen patients were male and six were female. The mean age of the patients was 27.8 ± 19 years (range 5-73 years). One patient had subnormal IgA levels; five patients had subnormal IgE levels; one patient had lymphopenia and low CD4, CD3, and CD19; and one patient had subnormal IgM and IgE levels with lymphopenia and low CD4, CD3, CD8, and CD19 counts. All patients had normal complement components (C3 and C4), CH50, and nitroblue tetrazolium test. The most common immunodeficiency in our study was Ig deficiency. Our results support the recommendation that immunological evaluation, especially Ig assay, should be used in patients with bacterial meningitis even in the first episode.

Differential impact of the HIV-1 non-nucleoside reverse transcriptase inhibitor mutations K103N and M230L on viral replication and enzyme function

We wished to study the resistance profile of etravirine, a novel non-nucleoside reverse transcriptase inhibitor (NNRTI) active against common human immunodeficiency virus type-1 (HIV-1) drug-resistant strains. We compared the effects of K103N, the most prevalent NNRTI resistance mutation, and M230L on enzyme function, virus replication and extent of biochemical inhibition by etravirine, efavirenz and nevirapine. Growth kinetics analyses in cord blood mononuclear cells (CBMCs) demonstrated that K103N-containing virus replicated as well as wild-type (WT) virus and that the M230L-containing virus was severely impaired in replication ability in the absence of NNRTIs. K103N-containing viruses replicated well in the presence of efavirenz and nevirapine, while virus containing M230L displayed substantial replication in the presence of all NNRTIs tested. RNA-dependent DNA polymerase assays using a heterogeneous HIV-1 RNA template and purified recombinant WT or mutated reverse transcriptase enzymes revealed that the fold change (FC) for etravirine was 0.7 for K103N and 8 for M230L. K103N and M230L conferred high-level resistance to both efavirenz (FC=39 and 15.3, respectively) and nevirapine (FC=43.5 and 33), confirming that M230L confers cross-resistance to both drugs while K103N-containing viruses remain susceptible to etravirine. In enzymatic assays, the K103N mutation was associated with moderate reductions in the efficiency of 3' DNA end-directed RNA template cleavage, while comparable efficiency to WT enzyme was observed with regard to minus-strand strong stop DNA synthesis and polymerase processivity. These properties help to explain differences in the evolution and prevalence of these two NNRTI mutations.

HIV Related Hodgkin's Lymphoma in the HAART Era: A Comprehensive Review and Meta-Analysis of Response and Survival Rates.

Abstract 1652Poster Board I-678 IntroductionHodgkin lymphoma (HL) is one of the most common non-acquired immunodeficiency syndrome (AIDS)-defining tumors in human immunodeficiency virus (HIV)-infected patients. Studies have shown that HIV infected individuals have approximately a 7.5-fold (Goedert et al 1998) to nearly 13-fold increased risk for HL compared with the general population (Biggar et al. 2006, Engels 2006). The outcomes for patients with HL and HIV (HIV-HL) were described as inferior to HIV-negative patients. The existing literature regarding response and survival data is mainly comprised of small and/or retrospective studies. We reviewed the literature for the purpose of examining a larger HIV HL cohort for response rates and survival in the HAART era. MethodsWe searched PUBMED, OVID & Google Scholar (1980- July 2009) and ASH (2004-2008) & ASCO (2004-2009) Annual Meeting Abstracts. Key words used were ‘Hodgkin's Lymphoma', ‘Hodgkin's Disease',' HIV/AIDS', HAART, therapeutic outcomes, concomitant chemotherapy & HAART/antiretroviral therapy, non AIDS malignancies. Criteria for inclusion of studies were: 1) Upfront treatment of HL HIV infected patients with chemotherapy, with or without radiotherapy, with or without antiretroviral drugs/ HAART. 2) Reported in English 3) Studies with outcome measures of treatment for HIV-HL patients such as complete response (CR) rates, and/or at least one type of survival statistic. We also examined references from above articles as well as review articles, studies on pathogenesis & histologic features of HIV-HL, and epidemiologic studies for additional references. Studies that did not clearly report on a comprehensive cohort were excluded given increased probability of reporting bias. Primary outcome measures were CR rates, and 1- and 2-year overall survival rates. The data extracted included pre-treatment patient characteristics such as median age, sex, histological diagnosis, clinical staging, site of involvement, median CD4 cell counts, treatment regimen used, use or not of antiretrovirals/HAART & prophylactic agents with chemotherapy, response to treatment, toxicity, opportunistic infections, median follow up time, relapse, disease progression, death from treatment or infections. Summary CR and OS estimates were calculated based on the assumption of fixed effects and using the Mantel-Haenszel method. Results12 articles met inclusion criteria for meta-analysis of CR and/or OS. The overall CR rate was 72% (95% CI 67-77%) with 1- and 2-year OS of 78% (95% CI 73-82%) and 69% (95% CI 67-77%), respectively (Figure 1). Advanced stage was present in 63%, and histology other than nodular sclerosing in 76%. Mean baseline CD4 count was 212 (3-887); 59% of subject received HAART with chemotherapy. Death during treatment occurred in 7% and relapse was reported in 14%. ConclusionsAdverse baseline characteristics including advanced disease and histology other than NS persist in the HAART era. Response and survival rates are improved compared to pre-HAART era but remain lower than rates found in the HIV-negative population. Further prospective trials need to be done to examine improvements in treatment for this patient population. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Cross-reactive antibodies induced by xenogeneic IgA can cause selective IgA deficiency

Selective immunoglobulin A deficiency (sIgAD) is the most common immunodeficiency in humans. Auto-reactive antibodies to human immunoglobulin A (IgA) are found in the serum of 20–40% of individuals with sIgAD. It is unknown whether these antibodies play a role in the pathogenesis of this immunodeficiency and although the prevailing thought is that they are secondary to the onset of sIgAD, there is very little, if any, support for this notion. Here, we propose that anti-IgA antibodies are in fact responsible for the removal of IgA from serum, and that the inducing antigen is most probably a xenogeneic IgA. This hypothesis is based on data obtained from an sIgAD patient in whom changes in dietary consumption of beef and/or bovine dairy products resulted in changes in anti-IgA levels in the serum. To test the hypothesis, the presence of anti-bovine IgA antibodies was tested by a highly specific enzyme-linked immunosorbent assay in serum samples from IgA-deficient and control individuals. All 13 sIgAD individuals with anti-IgA antibodies had a higher titer against bovine IgA than against human IgA. Of 23 control individuals, a surprisingly high proportion (65%) was also found to have IgG anti-bovine IgA antibodies. These results support the hypothesis that the anti-human IgA antibodies found in IgA-deficient individuals are originally produced against bovine IgA. These antibodies are found in many normal individuals, but only in cases where they cross react with endogenous human IgA, sIgAD may develop.

Human Immunodeficiency Virus Type 1 Recombinant Reverse Transcriptase Enzymes Containing the G190A and Y181C Resistance Mutations Remain Sensitive to Etravirine

Etravirine (ETR) is a second-generation nonnucleoside reverse transcriptase (RT) inhibitor (NNRTI) active against common human immunodeficiency virus type 1 (HIV-1) drug-resistant strains. This study was designed to determine the extent to which each of the Y181C or G190A mutations in RT might confer resistance to ETR and other members of the NNRTI family of drugs. Recombinant HIV-1 RT enzymes containing either the Y181C or the G190A mutation, or both mutations in tandem, were purified. Both RNA- and DNA-dependent DNA polymerase assays were performed in order to determine the extent to which each of these mutations might confer resistance in cell-free biochemical assays against each of ETR, efavirenz, and nevirapine. Both the biochemical and the cell-based phenotypic assays confirmed the susceptibility of G190A-containing enzymes and viruses to ETR. The results of this study indicate that the G190A mutation is not associated with resistance to ETR.

Impaired neutrophil extracellular trap (NET) formation: a novel innate immune deficiency of human neonates

AbstractNeutrophils are highly specialized innate effector cells that have evolved for killing of pathogens. Human neonates have a common multifactorial syndrome of neutrophil dysfunction that is incompletely characterized and contributes to sepsis and other severe infectious complications. We identified a novel defect in the antibacterial defenses of neonates: inability to form neutrophil extracellular traps (NETs). NETs are lattices of extracellular DNA, chromatin, and antibacterial proteins that mediate extracellular killing of microorganisms and are thought to form via a unique death pathway signaled by nicotinamide adenine dinucleotide phosphate (NADPH) oxidase–generated reactive oxygen species (ROS). We found that neutrophils from term and preterm infants fail to form NETs when activated by inflammatory agonists—in contrast to leukocytes from healthy adults. The deficiency in NET formation is paralleled by a previously unrecognized deficit in extracellular bacterial killing. Generation of ROSs did not complement the defect in NET formation by neonatal neutrophils, as it did in adult cells with inactivated NADPH oxidase, demonstrating that ROSs are necessary but not sufficient signaling intermediaries and identifying a deficiency in linked or downstream pathways in neonatal leukocytes. Impaired NET formation may be a critical facet of a common developmental immunodeficiency that predisposes newborn infants to infection.

Various Expression Patterns of α1 and α2 Genes in IgA Deficiency

IgA deficiency (IgAD) is the most common immunodeficiency, however the pathogenesis in most cases of IgAD is unknown. There are 2 subclasses of IgA, IgA1 and IgA2, and its heavy chains are encoded by 2 different genes, the alpha1 and alpha2 genes. To investigate the molecular pathogenesis of IgA deficiency, it is important to evaluate each of the expressions of IgA1 and IgA2 separately.In this study, we report on the reverse transcriptase (RT)-PCR method in which alpha1 and alpha2 mRNAs can be separately evaluated. This method is based on electrophoretic separation using the difference of 39 bases between alpha1 and alpha2 mRNAs. Three selective, 5 partial and 2 secondary IgAD patients were examined.In the 3 selective IgAD patients, no alpha1 or alpha2 mRNA expression was detected. In the 5 partial IgAD patients, various alpha1 and alpha2 mRNA expression patterns were found. One of the partial IgAD patients showed only alpha2 gene expression, but not alpha1 gene expression, and was found to show an alpha1 gene deletion together with gamma 2 and epsilon gene deletions. His plasma IgA2 level was within the normal range.Patients with an alpha1 gene deletion can be considered as having partial IgAD. Using this method, we identified the second case of alpha1 gene deletion in Japan, and classified IgAD patients on the basis of alpha1 and alpha2 expression.

IgA subclass and IgA deficiency

There are two subclasses of IgA, IgA1 and IgA2, and its heavy chains are encoded by two different genes, alpha1 and alpha2 genes. These two subclasses play important roles in the first line of defense, and the amount ratio of these molecules in secretions varies. IgA deficiency (IgAD) is the most common immunodeficiency, however the pathogenesis in most cases of IgAD is unknown. The class switch disorder in IgA producing B lymphocytes is one of the important factors in IgAD patients. The decreased expression levels of Ialpha germline transcripts before a class switch may be the cause of selective IgAD. The alpha1 and alpha2 gene expression levels are low in most IgAD patients. Using RT-PCR method in which alpha1 and alpha2 mRNAs can be separately evaluated, we identified the second case of alpha1 gene deletion in Japan. Longitudinal change in the serum IgA of the patient with alpha1 gene deletion showed the pattern of the partial IgAD. Patients with alpha1 gene deletion can be considered as having partial IgAD.

Linkage of IgA deficiency to Gm allotypes; the influence of Gm allotypes on IgA-IgG subclass deficiency.

IgA deficiency (IgAD) is the most common immunodeficiency, characterized by an arrest in B cell differentiation. It has a sporadic occurrence or variable inheritance pattern, and is also linked to the HLA genes. IgA deficiency is sometimes associated with IgG subclass deficiency. In this study the Gm allotypes, as genetic characteristics of the IgG1, IgG2 and IgG3, were analysed in 83 Caucasian IgAD individuals. Half of the patients presented with IgG4 < 0.01 g/l compared with 5% (P < 0.001) in a healthy population. Three of the 83 had significantly low IgG2 and four had significantly low IgG3 levels. Gm allotype frequencies in IgAD deviated compared with a normal population. Of the 83 patients, 44 (53%) showed homozygous G2 m(",") expression on the IgG2 locus (33% in controls, P < 0.01). In IgAD the Gm(a,",g) haplotype was more frequent (43%) compared with controls (31%, P < 0.01). The Gm homozygous phenotype Gm(a,",g/a,",g) was most common, found in 20 of 83 patients (24%, P < 0.05) compared with controls (14%). On the other hand the Gm(f,n,b) haplotype of IgAD was rare (28%) compared with controls (45%, P < 0.001). The low IgG4, < 0.01 g/l, found in 50% of the patients, was even more frequent (56-69%) among the G2 m(",") phenotypes. IgG subclass levels were given for different Gm phenotypes of the IgAD group and compared with controls. Significantly low IgG4 was revealed in the Gm(a,",g/a,",g) phenotype (P < 0.01) and significantly low IgG2 in the Gm(a,",g/f,",b) phenotype (P < 0.01). The Gm(a,",g/f,",b) phenotype contained the three patients found with IgG2 levels < -2 s.d., and the four patients with IgG3 levels < -2 s.d. were present among those with the homozygous Gm(a,",g/a,",g) phenotype; both phenotypes with G2 m(",") on the IgG2 locus. The 'compensatory' increase of IgG was significant for both IgG1 and IgG3 in all Gm phenotypes, but in the Gm(a,",g/f,",b). Thus, the susceptibility of IgAD with the additional IgG antibody deficiencies, down-regulated IgG4 and IgG2/IgG3, is associated with Gm allotypes, especially the homozygous G2 m(",") expression on the IgG2 locus.

Induction of α1 and α2 gene expression in selective immunoglobulin A deficiency

Immunoglobulin A deficiency (IgAD) is the most common immunodeficiency, but the pathogenesis of most cases of IgAD is poorly understood. The gene and protein expression levels of members of the IgA subclasses in IgAD patients were analyzed by a reverse transcriptase (RT)-PCR method that could differentiate between α1 and α2 gene expression. Three selective, 5 partial and 2 secondary IgAD patients were examined. Peripheral blood mononuclear cells which were unstimulated or stimulated with TGF-β1 and PMA for 24 h were cultured. The IgA1/IgA2 expression ratios were measured by zone densitometry. Three bands appeared (the α1 and α2 genes and a hetero-duplex formation), owing to the difference of 39 bases between α1 and α2 mRNAs. In the controls, there were no significant differences in the IgA1/IgA2 ratios between unstimulated and stimulated cells. In selective IgAD patients, both α1 and α2 gene expression was induced following stimulation, and α1 gene expression was induced more dominantly than in the other IgAD patients following stimulation. Based on our results, suppression of α1 gene expression may be related to the pathogenesis of IgAD.

Interleukin-6 gene variation in Spanish patients with immunoglobulin-A deficiency

Selective immunoglobulin-A deficiency (IgAD) is the most common immunodeficiency in Caucasian populations. Genetic factors are important in its etiology; however human leukocyte antigen (HLA) genes, which explain 40% of the genetic risk for IgAD, are the only susceptibility factors commonly agreed upon at this time. Because interleukin-6 (IL-6) plays an important role in B-lymphocyte differentiation from plasma cells, we aimed to address the IL-6 genetic influence on IgAD susceptibility. We performed a case-control study that included 305 Caucasian Spanish IgAD patients and 529 ethnically matched healthy control subjects, as well as a familial study with 128 IgAD trios. We genotyped the functional promoter polymorphism -174G>C and nine additional single nucleotide polymorphisms. For the case-control analyses the chi(2) test or Fisher's exact test were used, and for the family study the transmission disequilibrium test was used. We observed an increased frequency of the -174C allele in IgAD patients (p = 0.005, odds ratio [OR] = 1.51, 95% confidence interval [CI] = 1.12-2.04) and a protective effect of the rs2069849_C allele (p = 0.007, odds ratio = 0.29, 95% CI = 0.09-0.76). In conclusion, we described for the first time an association between IL6 polymorphisms and IgAD. Although it is not clear which genetic variants are causing susceptibility/protection, this intriguing finding is remarkable because of the role of IL-6 in antibody production.

Human Immunodeficiency Virus–Associated Kaposi Sarcoma as an Immune Reconstitution Inflammatory Syndrome: A Literature Review and Case Report

Kaposi sarcoma (KS) is the most common human immunodeficiency virus (HIV)-associated neoplasm (HIV-KS). Highly active antiretroviral therapy (HAART) results in a decrease in the incidence and prevalence of HIV-KS as well as in clinical improvement. However, in a subset of subjects who are HIV seropositive, KS may recrudesce early following the introduction of HAART as an immune reconstitution inflammatory syndrome (IRIS). The management of a patient who is HIV seropositive with rapid clinical worsening of oral KS lesions shortly after the initiation of HAART was documented. Repeated serologic testing for CD4(+) T-cell count and microscopic examination of two biopsy specimens of the oral lesion, one taken before and the other taken after cytotoxic chemotherapy, followed by surgical excision was the treatment modality used. Microscopic examination of the incisional biopsy specimen taken from the oral lesion at the time of the initial consultation confirmed the clinical diagnosis of KS. The sequential serological tests showed a progressive increase in CD4(+) T-cell counts that paralleled the rapid clinical worsening of the KS disease. This was consistent with the diagnosis of IRIS-associated HIV-KS. Subsequent cytotoxic chemotherapy brought about resolution of the IRIS and regression of the HIV-KS lesions. Microscopic examination of a biopsy specimen obtained after cytotoxic chemotherapy did not show any of the original KS. The residual palatal exophytic mass was excised. IRIS-associated HIV-KS is not a disease, but rather a temporary paradoxical immunoinflammatory reaction brought about by improvement in immune status following HAART. IRIS-associated HIV-KS can be controlled effectively by limited systemic cytotoxic chemotherapy in the setting of HAART.

Mannose-binding lectin variant associated with severe malaria in young African children

Mannose-binding lectin (MBL) is a serum protein which initiates innate immune responses to microbial pathogens by binding to non-self surface oligosaccharides. MBL deficiency is the most common congenital immunodeficiency of human and has been shown to predispose to infections, particularly in children and immune compromised. In a matched case-control study among 870 Ghanaian children, we examined the influence of six polymorphisms of the MBL2 gene on Plasmodium falciparum infection and severe malaria. A missense mutation resulting in low MBL activity ( MBL2*C) was found in 35% of healthy controls, but in 42% of asymptomatically infected children ( P = 0.01), and in 46% of patients with severe malaria ( P = 0.007). Heterozygosity for MBL2*C was associated with increased odds of infection (odds ratio (OR), 1.6; 95% confidence interval (CI), 1.1–2.1), severe malaria (OR, 1.7; 95% CI, 1.2–2.4), and of severe anemia in particular (OR, 2.3; 95% CI, 1.4–3.8). The population attributable fraction of severe malaria cases attributable to MBL2*C heterozygosity was 17%. Our results suggest that the MBL pathway of the complement system is a critical determinant of both, susceptibility to P. falciparum infection and manifestation of severe malaria, particularly in young children in whom specific immune responses are weak or absent.

Diversity of the MBL2 Gene in Various Brazilian Populations and the Case of Selection at the Mannose-Binding Lectin Locus

The mannose binding lectin ( MBL2) polymorphism is responsible for a common immunodeficiency in the human species. There were suggestions that the MBL2 polymorphism has been under balancing selection, based on the high global frequency of alleles generating MBL deficiency and on the worldwide distribution of diseases negatively associated with them. To describe the distribution of MBL2 allelic haplotypes in Brazilian populations and to discuss the evolution of this polymorphism, we analyzed six South Brazilian populations (152 Guarani Amerindian, 239 Kaingang Amerindian, 107 admixed, Brazilian 32 Afro-Brazilian, 202 Euro-Brazilian and 16 Oriental-Brazilian). Eight haplotypes were observed: MBL2*HYPA, LYQA, LYPA, LXPA, LYPB, LYQC, HYPD, and LYPD. In addition, through sequencing of the promoter and exon 1 from Amerindian and Oriental individuals, three new single-nucleotide polymorphisms (SNPs) were found in the MBL2 promoter region in the Kaingang. Analysis of the sequencing data by neutrality tests (Tajima’s D and Fu and Li’s D* and F*) revealed no deviation from selective neutrality equilibrium in the Guarani and Kaingang. Significant Fay and Wu’s H results are explained by the recent gene flow in these populations. Contrarily to previous thoughts, stochastic evolutionary factors seem therefore to have had a predominant role in shaping the MBL2 polymorphism, at least in the Amerindians.

Class switch recombination in selective IgA-deficient subjects.

Selective IgA deficiency is a common immunodeficiency in Caucasians, but the molecular basis of the disorder remains elusive. To address this issue we examined the molecular events leading to IgA production. Naive IgD positive B cells were purified from four donors with IgA deficiency and four control donors, all Caucasians. Stimulation of B cells from IgA-deficient donors with the cytokines transforming growth factor (TGF)-beta, interferon (IFN)-gamma or interleukin (IL)-10 in the presence of anti-CD40 antibodies showed reduced expression of both activation-induced cytidine deaminase (AID) and alpha germline transcripts (GLT) compared to controls. It was possible, however, to induce AID and alpha GLT when stimulating the cells with anti-CD40 antibody and TGF-beta in the combination with IL-10. Moreover, in anti-CD40 antibody-stimulated cultures, addition of IL-10 or IL-10 + TGF-beta in combination, induced IgA production, albeit lower than found in B cells from controls. The B cells from the IgA-deficient subjects were less effective in differentiating into CD138(+) X-box binding protein 1 (XBP-1)(+) plasma cells when stimulated with TGF-beta, IFN-gamma or IL-10. Interestingly, when adding IL-4 to TGF-beta alone or in combination with IL-10, the immunoglobulin production in B cells from IgA-deficient donors was comparable with those of normal controls. These data show that in healthy subjects in vitro IgA production can be up-regulated by addition of IL-10 to CD40-stimulated B cells, whereas a similar B cell differentiation does not occur in IgA-deficient subjects. Addition of IL-4, however, reverts this abnormality.

Uncovering a Pediatric Immunodeficiency Part 2

In Part I of this series the diagnosis of a pediatric immunodeficiency was discussed. In that article key history and exam findings were discussed to help alert the clinician to a problem. Part II will further the knowledge of immunodeficiencies by describing some of the common immunodeficiencies. Diseases affecting neutrophil granule function, specific B-cell or T-cell function, combined T and B cell function and newer syndromes that have multi-system involvement, their diagnosis, and treatment are presented here. The genetic links for many of these diseases are known, and described in this article. Today most large medical centers are able to perform the appropriate diagnostic testing to assure early diagnosis and rapid treatment with aggressive antibiotic regimens and intravenous immunoglobulin. In many cases early bone marrow transplantation is curative or vital to survival. The diagnosis of an immunodeficiency in a child can be overwhelming to the family as well as the primary care clinician. A well armed clinician, knowledgable in the principles of immunodeficiencies, their diagnosis, and treatment can be an active and vital member of the multi-disciplinary team that will care for these challenging children.

Mannan-binding-lectin-associated serine proteases, characteristics and disease associations

Mannan-binding lectin (MBL)-associated serine proteases (MASPs) circulate in plasma as zymogens in complexes with MBL and with L- and H-ficolin. Upon binding of MBL or ficolin to pathogen-associated molecular patterns, the MASPs are activated. MASP-2 can now cleave C4 and C2 to generate the C3 convertase, C4bC2b. The functions of the other two MASPs, MASP-1 and MASP-3 have not been elucidated. MASP-1 can cleave C2, and with low efficiency also C3, and may serve a function through direct C3 activation. No natural substrate for MASP-3 has been identified. MBL deficiency, occurring at a frequency of about 10%, is the most common congenital immunodeficiency and is associated with susceptibility to infections and autoimmune disorders. Inherited MASP-2 deficiency has been described as the result of a mutation causing the exchange of aspartic acid with a glycine at position 105, a position in the first domain, CUB1, involved in calcium binding. This mutation abolishes the binding to MBL and ficolins, and deprives MASP-2 of functional activity. The index case suffered from recurrent severe infections and autoimmune reactions. The gene frequency of the mutation among Caucasians is 3.6%. It is not found in Chinese, who present a different mutation also associated with MASP-2 deficiency.

Mannose-binding lectin enhances phagocytosis and killing ofNeisseria meningitidisby human macrophages

Deficiency of mannose-binding lectin (MBL) is probably the most common human immunodeficiency and is associated with an increased risk of mucosally acquired infections including meningococcal disease. Tissue macrophages are an important component of mucosal defense, and so we determined the effect of MBL on uptake of meningococci by human monocyte-derived macrophages. Opsonization with MBL significantly increased the capture and doubled the amount of internalization of Neisseria meningitidis. Inhibition of f-actin polymerization indicated that MBL exerted this effect by a dose-dependent acceleration of uptake into phagosomes, which was maximal within the normal physiological concentration of MBL (1.5 microg/ml) and was independent of scavenger receptors. MBL accelerated the acquisition and subsequent loss of the early endosome marker, early endosomal antigen-1, and enhanced the acquisition of the late endosomal marker, lysosome-associated membrane protein-1. MBL reduced the survival of meningococci within macrophages by more than half, despite the increased uptake of organisms, and significantly reduced the number of viable extracellular bacteria by 80%. We conclude that MBL is a dependent opsonin able to accelerate microbial uptake and killing. These results suggest that MBL could modify disease susceptibility by modulating macrophage interactions with mucosal organisms at the site of initial acquisition.