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Of 44 children who recovered from an attack of bacterial meningitis, 3 (7%) were found to have IgG subclass deficiency, 5 (11%) had IgA deficiency and 22 (50%) had raised IgE levels. These results suggest that immunoglobulin abnormalities may be an important predisposing factor in some cases of bacterial meningitis.
Alterations in duodenal Ig-producing cells induced by two oral cholera vaccinations were studied by two-colour immunofluorescence in mucosal tissue sections from adults with selective IgA deficiency (IgAD), either with (n = 7) or without (n = 9) frequent infections, infection-prone patients with combined IgAD and IgG subclass deficiency (IgGSD) (n = 7), and normal control subjects (n = 11). The proportion of IgG-producing cells prior to immunization tended to be lower in the symptomatic IgAD subjects than in the clinically healthy ones. In the first subgroup the absolute number of IgG cells per intestinal length unit was significantly increased after immunization (P < 0.04), and this tendency was also observed in the healthy IgAD subjects (6/9) and in those with combined deficiency (5/7). Very few IgAD subjects responded with an increase of IgM-producing cells. The normal controls responded variably in all major immunocyte classes, in the order IgA > IgG > IgM. Compared with these controls, the patients with combined IgAD and IgGSD showed significantly increased IgG1 (P < 0.01) and reduced IgG2 (P < 0.006) proportions, which was in accordance with their serum subclass levels. Our study showed that oral cholera vaccination preferentially activates intestinal IgG-producing cells in IgAD subjects. This result agreed with data recently obtained by ELISPOT in the same patients with regard to antibody-forming cells specific for cholera toxin. Both methods suggested that IgG rather than IgM antibodies are elicited as compensation for a lacking IgA response. However, our overall results showed that intestinal B-cell activation is quite variable after oral cholera vaccination. Although such vaccination might be of importance for enhancing mucosal immunity also in IgAD patients, a concurrent gut disease could possibly be aggravated by IgG-mediated mucosal immunopathology in the absence of anti-inflammatory IgA antibodies.
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Patients with primary or secondary IgG subclass deficiencies suffer from infections due to encapsulated microorganisms such as H influenzae and pneumococci. In addition to relapsing infections, some patients with primary subclass deficiencies may have autoimmune disorders. The best characterized defect in IgG2 deficiency, either isolated or combined with IgG4 deficiency. It is frequently associated with IgA deficiency or with ataxia telangiectasia. IgG1 deficiency occurs mostly in combination with disturbances of other immunoglobulin isotypes, and probably represents a form of common variable immune deficiency. Decreased IgG3 levels were reported in association with lung dysfunction and viral diseases. Except in IgG1 deficiency, total IgG serum levels in primary as well as secondary IgG subclass deficiency states may be normal or even increased. It is assumed that IgG subclass deficiencies represent an indicator of more basic immunologic abnormalities. There is evidence that antibody defects correlate better with the clinical symptoms than the total serum IgG subclass concentrations. In patients with severe recurrent infections and IgG subclass deficiency, intravenous immunoglobulin treatment at dosages of 0.3 to 0.4 g/kg body weight every 3-4 weeks is indicated.
UNLABELLED: Primary immunodeficiency diseases are not common in children. The possibility of an immunological defect should be considered in any individual with repeated infections. A definite diagnosis for immodeficiency is sometimes difficult to achieve because of overlapping clinical manifestations. Immunoglobulin subclass deficiency is an immunological deficiency disease with which, one or more IgG subclasses are deficient. T cell immunity is normal. Patients may develop recurrent bacterial and respiratory infections or could remain asymptomatic. OBJECTIVE: The authors report a case of immunoglobulin G subclass deficiency presenting initially as transient hypogammaglobulinemia of infancy. CASE REPORT: A 2 month-old boy presented to Siriraj Hospital with a history of chronic protracted diarrhea, disseminated scabies and sepsis. On presentation, he had generalized scaly and maculopapular rash with no palpable lymph nodes. CBC revealed WBC 22,100 cells/cm3 with PMN 42 per cent, lymphocytes 38 per cent, Eosinophils 4 per cent, Basophil 2 per cent and platelets 254,000/cm3. The immunoglobulin levels were as follows: IgG 181 mg/dl, IgA < 6.6 mg/dl, IgM 26.3 mg/dl. Lymphocyte enumerations revealed CD4 of 2,433 cells/cm3 (N 1,460-5,160); CD8 4,682 cells/cm3 (N 650-2,450); CD19 1,588 cell/cm3 (N 500-1,500); CD16 230 cell/cm3 (N 573 +/- 264). The initial diagnosis was X-linked agammaglobulinemia vs common variable immunodeficiency disease. His diarrhea and five courses of sepsis responded well to antibiotics administration and courses of intravenous immunoglobulin (IVIG) replacement. His through IgG became normal at 2 years of age (after 12 months of IVIG). IVIG was stopped and the diagnosis was changed to transient hypogammaglobulinemia of infancy (THI). Nevertheless, during his 4 month follow-up he developed recurrent sinopulmonary infections (i.e, otitis media and pneumonia). Repeated immunoglobulin profile showed IgG 1,200 mg/dl, IgA 135 mg/dl, IgM 26 mg/dl, IgG subclass were IgG, 1,030 mg/dl (N 280-830), IgG2 30 mg/dl (N 40-2,400), IgG3 22 mg/dl (N 6-130), IgG4 3 mg/dl (N 3-120). A diagnosis of IgG2 subclass deficiency presenting early as transient hypogammaglobulinemia of infancy was then made. Treatment with monthly IVIG was reinitiated and the patient is currently doing well. CONCLUSION: The authors present a case of IgG subclass deficiency presenting as transient hypogammaglbulinemia of infancy. Follow-up of the immune profile and clinical manifestation is necessary for a definite diagnosis.
Two patients with recurrent sinopulmonary infections and normal total serum immunoglobulin levels were found to have selective deficiencies in IgG subclasses. The serum of one patient contained abnormally low IgG2 and IgG4; and the other was deficient in IgG4. Both patients responded to the treatment with high dose intravenous immunoglobulin. The experiences on these two cases strongly suggest that IgG subclasses should be checked in patients with recurrent sinopulmonary infections in face of normal total immunoglobulins.
UNLABELLED: Systemic lupus erythematosus (SLE) was observed in a 7-year-old boy with IgG2 and IgG4 subclass deficiencies who had been treated with immunoglobulin (100-200 mg/kg/4 weeks) since 2 years of age. The mother and the half-brother displayed the same deficiency. Serum IgG mainly consisted of IgG1 (98.9%) during the acute phase of SLE due to transient IgG3 deficiency. While he had no common manifestations of SLE such as arthritis or nephropathy, he developed cardiac tamponade due to massive pericardial effusion. CONCLUSION: The clinical features of SLE in the present case such as the development of cardiac tamponade and the absence of renal involvement may result from the markedly imbalanced IgG subclass distribution among auto-antibodies.
Although the occurrence of selective deficiencies of serum IgG subclasses has been known for 20 years, the large body of data presently available was collected only recently owing to the use of performing monoclonal antibodies. IgG subclass deficiency is frequent, both as an apparently isolated defect (about one fourth of patients suffering otherwise unexplained repeated infections) and in association with a number of primary and required immunodeficiency states. This paper briefly reviews the methodological problems of serum IgG subclass measurement and data on subclass deficiency in a variety of clinical conditions.
We studied the incidence of IgG subclass deficiency in children with recurrent bronchitis. Recurrent bronchitis was defined as three or more episodes a year during at least 2 consecutive years, of bronchopulmonary infection, productive cough with or without fever and/or diffuse râles by physical examination in the absence of asthma or atopy. Fifty three children were selected, of whom 30 (57%) were deficient in one of the IgG subclasses. None had an IgG1 deficiency. Nine (17%) were deficient in IgG2, 9 (17%) in IgG3 and 20 (38%) in IgG4. Isolated IgG subclass deficiencies were most frequently seen for IgG4 (14, 26%), less for IgG3 (6, 12%) and even less for IgG2 (4, 7%). Nine (17%) children were IgA deficient and 8 (15%) IgG deficient with a combined IgG subclass deficiency in 8 and 7 of them respectively. By subdivision into different age groups most patients were encountered in the youngest group. The mean content of IgG2, IgG3 and IgG4 in 3- to 4-year-old children with recurrent bronchitis was significantly lower than in the age matched controls. The mean value for IgG4 in the 5- to 6-year-olds was significantly lower than in the control group. This study demonstrates the correlation between recurrent bronchitis in childhood and IgG subclass deficiency. IgG subclass deficiency and recurrent bronchitis are both quite prominent phenomena in young children but rare in older children, suggesting a transient immaturity of the immune system as one of the possible pathogenetic factors. An IgA or an IgG deficiency is highly suggestive for the existence of a combined 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.
Eight hemochromatosis probands with HFE C282Y homozygosity had frequent, severe, or unusual infections and common variable immunodeficiency (CVID) or immunoglobulin (Ig) G subclass deficiency (IgGSD). Thus, we performed serum Ig isotyping and other characterization of 43 additional unselected probands, 5 human leukocyte antigen (HLA)-identical siblings, and 240 consecutive CVID or IgGSD index patients. C282Y allele frequencies were estimated in 58 CVID or IgGSD index patients without hemochromatosis phenotypes and in 341 controls. HLA-A and -B haplotypes and frequencies were determined in all 51 probands, 186 CVID or IgGSD index patients without hemochromatosis phenotypes, and 751 controls. Thirteen unselected probands (30%) had CVID or IgGSD. Among all 21 hemochromatosis probands with CVID (n = 4) or IgGSD (n = 17), Ig subclass deficiency patterns were IgG(1) (n = 5), IgG(1) and IgG(3) (n = 6), IgG(3) (n = 9), and IgG(1), IgG(3), and IgG(4) (n = 1). IgG(2) or IgA deficiency was not detected; one proband had IgM deficiency. Mean values of total IgG, IgG(1), and IgG(3) were significantly lower in probands with CVID or IgGSD. Mean values of age, transferrin saturation, and ferritin at diagnosis and phlebotomy units required to induce iron depletion were similar in probands with or without CVID or IgGSD; phlebotomy had no apparent effect on IgG levels. C282Y frequencies were similar in CVID or IgGSD index cases without hemochromatosis phenotypes and in controls. There was concordance of Ig and hemochromatosis phenotypes in probands and respective HLA-identical siblings. Eight of 240 CVID or IgGSD index patients had hemochromatosis phenotypes and C282Y homozygosity (3 vs 0.7% and 0.2% controls; P < 0.0001, respectively). The frequency of A*03-B*07 was greater in CVID and IgGSD index cases without hemochromatosis phenotypes than in controls (0.0968 vs 0.0546, respectively; P = 0.0032). HLA-A*03-B*07 was the predominant haplotype in probands grouped by presence or absence of CVID or IgGSD. Some probands in each group were A*03-B*07 homozygotes; group A*03-B*07 frequencies were similar. We conclude that serum IgG abnormalities characteristic of CVID or IgGSD are common in hemochromatosis probands, and that the prevalence of hemochromatosis is increased in CVID and IgGSD index cases. These observations could be explained by the increased frequencies of HLA-A*03-B*07 in C282Y homozygotes and in CVID and IgGSD, and by the common occurrence of putative CVID or IgGSD allele(s) on haplotypes bearing C282Y.
Serum IgG subclasses were studied in 19 mothers of infants with serious infections caused by group B streptococci (GBS) and compared with a control group of 20 mothers of healthy infants. 13 of 19 mothers showed decreased subclass levels: 10 of 19 low IgG2, 9 of 19 low IgG1 and 4 of 19 low IgG3. The levels of IgG1, IgG2 and IgG3 were significantly lower among mothers of GBS-infected infants than among the controls. Thus, there is indirect evidence that the infants were immunodeficient at birth.
Congenital deficiencies that involve the lymphocyte system are complex and represent abnormalities in genetic control or gestational development. Only the more common prototypes of these diseases will be discussed. Diseases of the B cell system presented include X-linked agammaglobulinemia, selective IgA deficiency, IgG subclass deficiency, and common variable immunodeficiency. T cell defects discussed are Di-George syndrome and severe combined immunodeficiency. Also mentioned briefly are HIV infection and the increasing problem of AIDS. Diagnostic evaluation and general principles of treatment of these diseases are considered.
Levels of the sub-classes of immunoglobulins IgG2 and IgG4 have been established by radial diffusion with monoclonal antibodies in 150 subjects. 49 (42 adults and 7 children) showed either a low level of IgG2 (less than 0.42 g/l n = 11) or a reduced level of IgG4 (less than 0.05 g/l n = 38). A single patient had a double deficit, 38 subjects had a superinfection of which 17 had a severe form and in 77% of these cases a level of IgG4 of less than 0.05 g/l.
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Serum IgG subclass levels were determined using a competitive indirect immunoenzymatic assay with monoclonal antibodies in 16 patients with ataxia-telangiectasia. Eight children had IgA deficiency, two had IgG and IgA deficiency and six patients showed no immunoglobulin class abnormality. However, IgG4 and IgG2 levels were undetectable or low in almost every patient. An IgG3 deficiency was associated with the IgG2-IgG4 defect in three patients with undetectable IgA. IgG1 was very low in one patient with a total IgG deficiency. There was no clear correlation between subclass levels and the occurrence of infections.