Symptomatic hypogammaglobulinemia in infancy and childhood - clinical outcome and in vitro immune responses

Transient hypogammaglobulinaemia of infancy: many patients recover in adolescence and adulthood

Transient hypogammaglobulinaemia of infancy (THI) is a relatively rare disorder where there is an exaggeration of the physiological nadir of immunoglobulin (Ig)G between loss of transplacentally acquired maternal IgG and production by the infant. Patients may be vulnerable to infections during the period of hypogammaglobulinaemia. The precise time to recovery in all infants is currently unknown. We sought to determine the clinical features and time-course of recovery for patients with THI. We reviewed our experience with THI over the last three decades in order to describe clinical and laboratory features, as well as the time-course of recovery. Forty-seven patients were identified with THI. Only thirty-seven per cent remitted by 4 years of age, while some patients did not recover until the third or fourth decade. In keeping with previous studies, the majority (25 of 47) presented with recurrent infections, nine had a family history of immunodeficiency and 13 had adverse reactions to food as their dominant clinical manifestation. Chronic tonsillitis developed in 10 patients and symptoms improved following surgery. The group with food allergies recovered sooner than those presenting with infections or with a family history immunodeficiency. Eight patients failed to respond to at least one routine childhood vaccine. Two have IgA deficiency and four individuals recovering in adolescence and adulthood continue to have borderline/low IgG levels. None have progressed to common variable immunodeficiency disorders (CVID). THI is a misnomer, as the majority do not recover in infancy. Recovery from THI can extend into adulthood. THI must be considered in the differential diagnosis of adolescents or young adults presenting with primary hypogammaglobulinemia.

B lymphocyte subsets and outcomes in patients with an initial diagnosis of transient hypogammaglobulinemia of infancy

PURPOSE

Transient hypogammaglobulinemia of infancy (THI) is a common immunodeficiency, but definitive diagnosis can only be made retrospectively. While the pathogenesis is still unknown, abnormalities have been reported in the B cell compartment. In this study, we analysed the B cell subsets of patients with an initial THI diagnosis (n = 20) and compared them with those of healthy age-matched Turkish children (n = 72).

METHODS

Flow cytometric analyses of the B subsets were performed by staining with anti-CD27-PE, anti-CD19-PerCP, anti-IgD-FITC and anti-IgM-APC antibodies.

RESULTS

During a median follow-up of 6.6 years, 13 patients whose IgG levels had normalized before they reached four years of age were diagnosed with definitive THI. The memory subsets of these patients were lower but not statistically different from the healthy controls (HC). The remaining seven patients had prolonged hypogammaglobulinemia after the age of four and had significantly lower memory B cell subsets compared to the HC. On follow-up, these patients had not experienced recurrent infections or autoimmunity. Re-evaluation of patients' B cell subsets six years later showed that the memory B cell ratios had increased to levels comparable to HC, despite the patients still having mildly low IgG levels.

CONCLUSION

Patients with prolonged hypogammaglobulinemia had lower levels of memory B cells despite having a similar clinical course to patients who had been diagnosed with definitive THI. This subgroup of putative THI patients poses a diagnostic and classification dilemma. Our results suggested that these patients' memory B cells and IgG levels may recover over time.

In vitro T lymphocyte proliferation by carboxyfluorescein diacetate succinimidyl ester method is helpful in diagnosing and managing primary immunodeficiencies

BACKGROUND

Functional studies besides routine laboratory tests for the definitive diagnosis of T lymphocyte disorders with isolated T or combined T/B-cell immunodeficiencies are important. We hereby summarized our experience with a carboxyfluorescein diacetate succinimidyl ester (CFSE)-based assay for the assessment of mitogenic T-cell proliferation responses in primary immunodeficiency (PID) patients who have not been diagnosed yet or genetically analyzed, but classified as probably having T-cell defects.

METHODS

Unclassified patients (n=46) and controls (n=25) were evaluated for T-cell disorders with CFSE-based assay.

RESULTS

CD3⁺ blast cells after PHA-L stimulation were significantly lower in patients (31.1±28.8) than controls (67.9±8.79; P<.001). Nine patients with low and four patients with normal CD3 values had severely decreased blastic transformation. The proliferation response decreased mostly in combined immunodeficiency group. Sixteen of them had impaired proliferation responses. Appropriate molecular genetical analyses were planned after thorough evaluation of each patient.

CONCLUSIONS

In vitro lymphocyte cell proliferation analysis by CFSE method is a reliable and practical choice for the assessment of mitogenic T lymphocyte responses in yet unclassified PID patients for targeting further genetical analyses.

Does intravenous immunoglobulin therapy prolong immunodeficiency in transient hypogammaglobulinemia of infancy?

Transient hypogammaglobulinemia of infancy (THI) is characterized by recurrent infections and one or more reduced serum immunoglobulin levels. Typically, THI patients recover spontaneously, mostly within 30-40 months of age, but sometimes recovery may be delayed until 5-6 years of age. The use of intravenous immunoglobulin (IVIg) as an alternative to antibiotic prophylaxis remains contraversial also in symptomatic THI patients. In fact, some authors believe that IVIg therapy may cause a delay in the maturation of the humoral immune system because of the interference from passively transfered antibodies. The aim of this study was to investigate the effect of IVIg replacement on recovery from immunodeficiency in THI patients and determine new parameters in order to include these patients in IVIg therapy groups. In this retrospective study, 43 patients (65%) received IVIg replacement therapy while 23 patients (34.8%) showed spontaneous normalization without IVIg. The percentages of patients who had more than six times the number of febrile infections in a year decreased from 91% to 21% in the group receiving IVIg treatment. At admission, before being recruited to IVIg therapy, serum immunoglobulin G (IgG) levels and anti-hemophilus B (Hib) antibody titers were found to be significantly low in cases who were selected for IVIg replacement. The percentages of patients who did not have protective levels of anti-Hib, anti-rubella or anti-rubeola-IgG were also significantly high in IVIg cases. There was no statistically significant difference in the age at which IgG levels normalized between the IVIg and the non-IVIg group. Patients in the IVIg group and non-IVIg group reached normal IgG levels at the age of 42.9±22.0 and 40.7±19.8 months, respectively. In conclusion, IVIg infusions do not cause a delay in the maturation of the immune system in THI patients. Besides the well-established criteria, very low and non-protective specific antibody responses against previously applied vaccines are important factors to consider when selecting patients for IVIg therapy.

Transient hypogammaglobulinemia and unclassified hypogammaglobulinemia: 'similarities and differences'

Transient hypogammaglobulinemia of infancy (THI) is characterized by recurrent infections and one or more reduced serum immunoglobulin (Ig) levels. Usually, this clinical picture resolves spontaneously by 3 yr of age. However, hypogammaglobulinemia persists until adolescence in some patients. In recent years, those patients have been classified as undefined/unclassified hypogammaglobulinemia (UCH). We aimed to evaluate the clinical and immunologic features of patients with THI and UCH considering age of recovery and to assess relationships between hypogammaglobulinemia, infections, and allergic manifestations. We reviewed the medical records of children followed with a diagnosis of hypogammaglobulinemia from 2001 to 2007. Patients with decreased levels (<2 s.d.) of one or more major Ig isotypes (IgG, IgA, IgM) with normal antibody responses and lymphocyte subpopulations were included (n = 374). Those patients whose Igs normalized during the follow-up period were classified as THI and the others as UCH. The THI group consisted of 71 patients (27 females, 44 males) with a mean recovery age of 68.87 +/- 36.5 months. About 95% of patients with THI recovered before 10 yr of age. The UCH group consisted of 303 patients (105 females, 198 males) with a mean age at diagnosis of 52 +/- 42 months. The most common presenting manifestations in the THI and UCH groups were upper respiratory tract infections (URTIs), lower respiratory tract infections, and asthma (42%, 50%, and 52% in the THI group vs. 39%, 53%, and 55% in the UCH group, respectively). In the THI group, the prevalence of atopic disease was related to age and found to be increased markedly after 44 months. In all patients, the prevalence of asthma was independently and positively associated with family history of atopy and age, whereas it was negatively associated with recurrent URTIs. Patients with THI and UCH have similar clinical and immunologic features. The normalization of Igs may be delayed in a majority of the patients with hypogammaglobulinemia. This observation may be a contribution to the classical definition and diagnostic criteria for THI.

The outcome of patients with unclassified hypogammaglobulinemia in early childhood

Symptomatic hypogammaglobulinemia in childhood may be the initial finding of primary immunodeficiency (PID) or may be due to delay in maturation of immunoglobulin synthesis. The aim of this study was to review the clinical and laboratory records of patients with unclassified hypogammaglobulinemia and to evaluate whether these children experience changes in serum immunoglobulin concentrations during long-term followup and have an exact diagnosis in natural course of disease. We reviewed the data of 412 patients who were diagnosed as PID with symptomatic hypogammaglobulinemia. Thirty-seven patients with hypogammaglobulinemia [19 males (51.4%) and 18 females (48.6%), with a followup of 34.1 +/- 22.0 months] who were not classified according to European Society for Immunodeficiencies diagnostic criteria were included in this study. The mean age at the beginning of the symptoms was 21.4 +/- 20.6 months and the mean age at admission was 51.5 +/- 25.8 months. The commonest clinical presentations were recurrent upper (94.6%) and/or lower (40.5%) respiratory infections, urinary infection (27%) and gastroenteritis (10.8%). Percentage of consanguinity was 8%. Of the initial 37 patients, 18 (48.6%) spontaneously corrected their immunoglobulin abnormalities during followup. Clinical symptoms of these patients were also improved. IgG, IgA and IgM levels reached to normal levels at ages 62.5 +/- 21.8, 72.0 +/- 11.2, 55.2 +/- 7.8 months, respectively. In remaining 19 patients with undefined/unclassified hypogammaglobulinemia, three partial IgA deficiency, seven IgG subclass deficiency, two selective IgM deficiency and two common variable immunodeficiency (CVID) were diagnosed by long-term monitoring of immunoglobulin levels. Five (13.5%) of the 37 unclassified patients could not be exactly diagnosed while two of them might have a T-cell defect and three of them still had low IgG and IgA levels but adequate antibody responses against vaccine antigens. In conclusion, it is important to monitor symptomatic patients with hypogammaglobulinemia periodically. Some children may spontaneously correct their immunoglobulin abnormalities not in the first 30 months of age, but during the first decade of life and some of them may have a severe PID like CVID.

Massive empyema associated with transient hypogammaglobulinemia of infancy and IgA deficiency

Transient hypogammaglobulinemia of infancy (THI) is originally defined as a physiological maturation defect of immunoglobulin G (IgG) production that occurs at 3-6 months of age and lasts until 18 to 36 months of age. We report here on a 22-month-old child with THI and IgA deficiency, who had massive pneumococcal empyema. Her depressed IgG level returned to normal within 6 months, but IgA level was still low at 6 yr of age. Although THI is an age-dependent and self-limiting disorder, severe infection that includes an atypical presentation of an infection may occur in some patients and this requires evaluation with immunologic study.

Hypogammaglobulinaemia

This article reviews the primary immunodeficiencies that result in hypogammaglobulinemia or predominantly antibody deficiency disorders. This group makes up the largest proportion of patients with primary immunodeficiency. Significant advances have been made in understanding the molecular basis and clinical characteristics of patients with the more severe forms of antibody deficiency in the last 6 years. Recognition of these disorders remains poor with significant diagnostic delay. The milder forms of antibody deficiency disorders, especially those with normal total serum immunoglobulin G levels, remain poorly characterized and understood. Further work remains to be done in understanding and recognizing these syndromes to benefit patient care and foster further knowledge of the immune system.

Recurrent enterovirus encephalitis: chance or something else?

A 22-month-old boy presented with repeated enterovirus infections including two episodes of encephalitis at the age of 8 months and 16 months and two episodes of febrile illnesses at 14 and 19 months old. These episodes were associated with at least two different serotypes of enterovirus. There were no residual neurological deficits and he underwent complete recovery in between. Immunology workup showed normal circulating leucocyte differential counts and lymphocyte subsets. His serum IgG concentration was persistently low but could mount satisfactory specific antibody responses to booster vaccines. The clinical picture was compatible with transient hypogammaglobulinaemia of infancy (THI) which was traditionally believed not to be associated with serious viral infections. This is the first case report to alert physicians that repeated serious enterovirus infections can happen in a relatively benign immunodeficiency disease.

Common variable immunodeficiency in children

PURPOSE OF REVIEW

Common variable immunodeficiency is the most common primary immunodeficiency that needs medical attention. Symptoms may occur at any time, with two major peaks of onset at 5-10 and 20-30 years. We present the different clinical phenotypes of common variable immunodeficiency, review recent genetic findings and point to current treatment strategies.

RECENT FINDINGS

Five genes, ICOS, CD19, TNFRSF13B, TNFRSF13C and MSH5, have been found to be mutated in patients with common variable immunodeficiency. Additional possible genetic loci for autosomal dominant forms were detected on chromosomes 4q and 16q. These findings illustrate the heterogeneous molecular basis of common variable immunodeficiency and indicate the value of genetic linkage studies, thereby improving the genetic diagnosis.

SUMMARY

In young patients with unusually frequent bacterial infections, common variable immunodeficiency should always be considered as a differential diagnosis. The compulsory individual work-up should comprise a family history in order to document siblings and additional family members suffering from common variable immunodeficiency and/or selective IgA deficiency. Since the recently found gene defects affect a minority of patients with common variable immunodeficiency only, future genetic research is required to identify further susceptibility genes involved in the pathogenesis of this condition.

Hypogammaglobulinaemia secondary to cow-milk allergy in children under 2 years of age

Symptomatic hypogammaglobulinaemia in children younger than 2 years of age was studied to rule out a primary immunodeficiency. Thirty-four patients were referred to the Immunology Service to study the hypogammaglobulinaemia-associated clinical picture. Food allergy was documented in 10 patients by personal and familial history, presence of specific immunoglobulin E (IgE) and elevated total serum IgE levels. Coeliac disease and human immunodeficiency virus infection were also ruled out. Protein loss through stools was assessed by clearance of alpha1-antitrypsin (AAT). Serum immunoglobulin levels were determined by nephelometry and functional antibodies were studied by enzyme-linked immunosorbent assay. The cellular immune response was assessed by in vitro lymphocyte proliferation in response to mitogens and cell subsets were analysed by flow cytometry. In five patients of the 10 patients we suspected a protein loss through the mucosa. Four of these five patients showed an increased AAT and the other showed an extensive cutaneous lesion. Immunological studies revealed normal antibody function, in vitro lymphoproliferative responses and cell numbers in four of the 5 patients. One patient showed abnormally low numbers of CD4(+) T cells as well as a defective proliferative response to mitogens. After diagnosis of cow milk allergy, milk was replaced with infant milk formula containing hydrolysed proteins. Recovery of immunoglobulin values and clinical resolution were achieved. Hypogammaglobulinaemia during early childhood in some children may be secondary to cow milk allergy, and immunoglobulins and cells may leak through the inflamed mucosa. Resolution of symptoms as well as normalization of immunoglobulin values may be easily achieved by avoidance of the offending allergen.