Immunoglobulin and IgG subclass levels in a regional pediatric cystic fibrosis clinic

Abstract

The aim of this study was to report serum immunoglobulin (Ig) and IgG subclass levels in a large pediatric population with cystic fibrosis, and relate these to measures of disease severity. Total immunoglobulin levels were measured in 154 patients, and IgG subclass levels were measured in 136 patients and compared to age-related normal population data and to levels reported in previously published studies of children with cystic fibrosis. Clinical data were also collected: genotype; height, weight, and BMI standard deviation scores; FEV(1) (as percent predicted); Shwachmann-Kulczycki (S-K) and Northern chest X-ray scores; and Pseudomonas aeruginosa infection status. The clinical well-being of patients with hypo- or hyper-gammaglobulinemia was compared with age- and sex-matched control patients who had normal levels of gammaglobulin. IgG subclass levels were measured, and the results were compared with previous studies. Eleven patients had hypergammaglobulinemia (7.8% compared with 0-69% in the published literature). Patients with hypergammaglobulinemia had lower FEV(1) percent-predicted values, and worse S-K and Northern chest X-ray scores than controls. Three patients had hypogammaglobulinemia (1.9% compared with 0-10.8% in the published literature). There was no difference in any clinical parameter between controls and those with hypogammaglobulinemia. Nineteen patients (14%) had low levels of IgG1, and 40 patients (29%) had low levels of IgG2. The low percentage of patients with abnormally high immunoglobulin levels probably reflects the improved respiratory status of today's children with CF. The low percentage of those with low IgG probably reflects better nutritional status. The finding of worse lung function and clinical scores in patients with hypergammaglobulinemia agrees with the published literature. The high percentage of patients with low IgG2 was unexpected and was not previously reported. The clinical significance of this in patients with CF is unknown.

Comparison Between Magnetic Resonance Imaging and Computed Tomography of the Lung in Patients With Cystic Fibrosis With Regard to Clinical, Laboratory, and Pulmonary Functional Parameters

“…Hypergammaglobulinemia has been proven to predict pulmonary progression in CF 35 ; however, only few patients with CF demonstrate manifest hypergammaglobulinemia, minimizing its importance for the determination of CF disease severity. 35,36 The Spearman correlation coefficients between CT imaging and pulmonary functional parameters, published by Helbich et al, 8 were similar to our calculated coefficients. Accordingly, some imaging features showed higher correlations to pulmonary functional parameters, such as severity/extent of bronchiectasis or extent of mucus plugging, than others, such as severity of bullae/emphysema; whereas these differences were similar for CT and MRI.…”

Serum procalcitonin is not an early marker of pulmonary exacerbation in children with cystic fibrosis

“…Serum markers closely reflecting lung disease severity are being sought [9]. Serum immunoglobulin G values have some value and are known to rise in subjects with CF, but the signal is aspecific [7]. The search for other serum markers of inflammation has so far been unsuccessful.…”

Immunoglobulin E deficiency: a forgotten clue pointing to possible immunodeficiency?

“…The first (Patient 1, Table 1) had cystic fibrosis (CF). Reactive hypergammaglobulinaemia is typical in CF, but hypogammaglobulinaemia is found in a minority of children with CF, 9 although it is not necessarily a poor prognosis feature. 10,11 This child was also shown to be IgG2 deficient, as is seen in a significant minority of patients with CF.…”

“…10,11 This child was also shown to be IgG2 deficient, as is seen in a significant minority of patients with CF. 9 Since the time of the original analysis the patient's immunoglobulins, including IgE, have steadily improved. The second (Patient 2, Table 1) was under investigation for recurrent sino-pulmonary infections at the time of referral.…”