Low Baseline Pneumococcal Antibody Titers Predict Specific Antibody Deficiency, Increased Upper Respiratory Infections, and Allergy Sensitization.

BACKGROUND: Inadequate titers of pneumococcal antibody (PA) are commonly present among patients with recurrent respiratory infections. OBJECTIVE: We sought to determine the effect of the degree of inadequacy in baseline PA titers on the subsequent polysaccharide vaccine response, the incidence of sinusitis, and allergic conditions. METHODS: A total of 313 patients aged 6 to 70 years with symptoms of recurrent respiratory infections were classified by baseline-pPA (percentage of protective [≥1.3 µg/mL] PA serotypes/total tested serotypes) and postvaccination pPA (post-pPA): Group A (adequate baseline-pPA), Group B (inadequate baseline-pPA, adequate post-pPA, responders), and Group C (inadequate baseline-pPA, inadequate postpPA, nonresponders, specific antibody deficiency [SAD]). Immunity against Streptococcus pneumoniae was defined as adequate when the pPA was ≥70%. Each group and combined groups, Group AB (inadequate baseline-pPA), and Group BC (adequate post-pPA) were analyzed for demographics, history of sinusitis, recurrent sinusitis in the following year, allergic conditions, and association with inadequate individual serotype titers. RESULTS: Over 80% of patients with respiratory symptoms had inadequate baseline-pPA. Baseline-pPA and SAD prevalence are inversely related (odds ratio = 2.02, 95% CI: 1.15-3.57, P = .01). Inadequate serotype 3 antibody titer is highly associated with SAD (odds ratio = 2.02, 96% CI: 1.61-5.45, P < .01). The groups with inadequate pPA (Group B and C, or BC) had significantly higher percentage of patients with chronic rhinosinusitis (P < .001), allergic sensitization, and allergic rhinitis (P < .05). Group A contained higher percentage of patients with recurrent upper airway infections (P < .001). CONCLUSION: Low baseline-pPA and low antibody titers to serotype 3 are highly associated with SAD, increased incidence of respiratory infections including CRS and allergic conditions.

Comparison of Two Different Criteria for Specific Antibody Deficiency in Patients With Chronic and Recurrent Rhinosinusitis.

BACKGROUND: Specific antibody deficiency (SAD) is highly associated with chronic rhinosinusitis (CRS) and is defined by inadequate post-vaccination percentage of protective (≥1.3 ug/mL) pneumococcal antibody serotypes divided by total tested serotypes (post-pPA). OBJECTIVE: Although < 70% post-pPA has been used commonly as the criterion for SAD, we sought to evaluate the clinical outcome of a different definition of SAD. METHODS: 203 patients aged 6 to 70 years with CRS were classified, retrospectively by pre-vaccination pPA (pre-pPA) and post-pPA by two different criteria. Using 70% as the threshold for adequate pneumococcal antibody (PA) response, patients were classified as: Group A (adequate pre-pPA), Group B (inadequate pre-pPA, adequate post-pPA), Group C (inadequate pre-pPA, inadequate post-pPA, SAD). Using 50% as the threshold, patients were similarly classified as: Group A', B' and C'. RESULTS: The recurrence rate of sinusitis during the next one year in Group A (pre-pPA ≥70%) was significantly less than that of Group A' (pre-pPA ≥50%) (10% vs. 34%, P = .03). Group A had lower incidence of sinusitis than Group B (pre-pPA < 70%, post-pPA ≥70%) (10% vs. 34%, P = .025). Among Group B' patients, the recurrence rate of sinusitis was significantly less among those with post-pPA of ≥70% than those with 50%-69% (28% vs. 69%, P < .01). CONCLUSION: Employment of a 70% pPA threshold for SAD in comparison to a 50% threshold would decrease the incidence of sinusitis in the next one year by vaccinating patients in 51-69% pPA range. Pre-existing PAs (Group A) yielded a higher protection against sinusitis than vaccine-acquired antibodies (Group B).

The four most common pediatric immunodeficiencies.

Other than the physiologic hypogammaglobulinemia of infancy, 80% of the confirmed immunodeficiencies consist of four syndromes: transient hypogammaglobulinemia of infancy (THI), IgG subclass deficiency, partial antibody deficiency with impaired polysaccharide responsiveness (IPR), and selective IgA deficiency IgAD. None are life threatening, all can be readily managed, and many recover spontaneously. An exact incidence of these disorders is not known. A summary of immunodeficiency registries in four countries listed IgAD in 27.5% of the patients, IgG subclass deficiency in 4.8%, and THI in 2.3%. The 1999 US survey of primary immunodeficiencies conducted by the Immune Deficiency Foundation found that 17.5% of these patients had IgAD and 24% had IgG subclass deficiency, while THI and IPR were not listed. The Jeffrey Modell Foundation (2005) survey of their global centers in 2004 reported IgAD in 15.5%, subclass deficiencies in 8%, and THI in 2% of their patients.