Sáva Pešák

B-lymphocyte Subpopulations in Patients with Selective IgA Deficiency

IntroductionSelective deficiency IgA (IgAD) is the most common primary abnormality of immunoglobulin production with unknown pathophysiology. It is genetically related to common variable immunodeficiency (CVID), where besides IgA also IgG and frequently IgM serum levels are decreased. In this study we focused on determination of B-lymphocyte developmental stages and searching for similarities between CVID and IgAD.Materials and MethodsUsing flow cytometry we determined major lymphocyte subpopulations and B-lymphocyte subsets: naïve (CD27-IgD+), marginal zone cells (CD27+IgD+), class-switched memory cells (CD27+IgD-), “double-negative” B cells (CD27-IgD-), transitional cells (IgM++CD38++), plasmablasts (CD38+++IgM+ or IgM-), and CD21lowCD38low cells in 80 patients with IgAD, 48 patients with CVID, and 80 control persons.ResultsCompared to healthy controls, a decrease in the absolute number and frequency of CD4+ cells (both < 0.001) was observed in IgAD patients. A decrease in the frequency of switched memory cells (P < 0.001), transitional cells (P = 0.035) as well as plasmablasts (P < 0.001) and an increase in the CD21lowCD38low subset (P = 0.007) was observed in IgAD patients compared to control persons. No significant differences were observed in the remaining B-cell developmental subsets. A decrease in CD27+IgD- (<0.4% of peripheral blood lymphocytes), frequently observed in CVID patients and also previously reported in IgAD, was found in only five patients (6%) with IgAD, two of them being first-degree relatives of CVID patients.ConclusionOur results show a decrease of terminally differentiated B-lymphocyte subsets in patients with IgAD, similar as previously found in patients with CVID, but these results are less expressed than in CVID patients.

Isoprinosine does not protect against frequent respiratory tract infections in childhood

Abstract Isoprinosine, an in vitro immuno-enhancing agent principally acting by stimulating T-lymphocytes, is one of a number of agents sometimes used in an attempt to prevent recurrent respiratory infections in children, although there are no formal trials for this particular drug. We performed a placebo-controlled double-blind trial to assess the efficacy of isoprinosine (50 mg/kg per day) for 6 weeks followed by 50 mg/kg per day twice weekly for 6 weeks in the prevention of frequent acute respiratory tract infections in 102 children aged 4–8 years. A total of 43 children treated with isoprinosine and 41 with placebo finished the study. Despite a transient increase in the total number of CD3+, CD4+ and CD8+ T-lymphocytes after 6 weeks of daily isoprinosine treatment, there was no difference in the number and length of duration of acute respiratory infections, number of antibiotic courses and number of days with cough, pharyngitis, rhinitis and increased body temperature (≥37.0°C and ≥38.0°C). There were no changes in markers of T- or B-lymphocyte activation (CD25, HLA-DR, CD45RA/RO, CD23). Conclusion Attempts at immunomodulation using isoprinosine in the dose and for the duration used may increase the total numbers of both CD4 and CD8 T-lymphocytes but is ineffective in prevention of respiratory tract infections in childhood.

Sequence variants of the TNFRSF13B gene in Czech CVID and IgAD patients in the context of other populations.

Mutations in the TNFRSF13B gene, encoding TACI, have been found in common variable immunodeficiency (CVID) and selective IgA deficient (IgAD) patients, but only the association with CVID seems to be significant. In this study, Czech CVID, IgAD and primary hypo/dysgammaglobulinemic (HG/DG) patients were screened for all TNFRSF13B sequence variants. The TNFRSF13B gene was mutated in 4/70 CVID patients (5.7%), 9/161 IgAD patients (5.6%), 1/17 HG/DG patient (5.9%) and none of 195 controls. Eight different mutations were detected, including the most frequent p.C104R and p.A181E mutations as well as 1 novel missense mutation, p.R189K. A significant association of TNFRSF13B gene mutations was observed in both CVID (p=0.01) and IgAD (p=0.002) Czech patients. However, when combined with all published data, only the association with CVID remained significant compared with the controls (9.9% vs. 3.2%, p<10(-6)), while statistical significance disappeared for IgAD (5.7% vs. 3.2%, p=0.145). The silent mutation p.P97P was shown to be associated significantly with CVID compared with the controls in both Czech patients (allele frequency 4.3% vs. 0.2%, p=0.01) and in connection with the published data (5.1% vs. 1.8%, p=0.003). The relevance of some TNFRSF13B gene variants remains unclear and needs to be elucidated in future studies.

Change in referral diagnoses and diagnostic delay in hypogammaglobulinaemic patients during 28 years in a single referral centre.

Background: The classical clinical manifestation of untreated immunoglobulin deficiency comprises predominantly recurrent and complicated respiratory tract infections. Before the 1980s, little was known about the clinical manifestation of immunodeficiency in the general medical population, and also the availability of serum immunoglobulin laboratory determination was not sufficient, leading to a significant diagnostic delay. Methods: We have analysed the diagnostic delay and referral diagnoses in patients in whom any form of primary hypogammaglobulinaemia had been diagnosed at our department, which was established in 1981. Results: Comparing the diagnostic delay in the 1980s (19 patients, median 5.5 years), the 1990s (37 patients, median 3.5 years) and the years 2001–2008 (33 patients, median 1 year), a significant decrease was observed (p < 0.05, Spearman’s correlation coefficient). Also, the median number of pneumonia episodes during the diagnostic delay decreased from 5 in the 1980s, to 1 in the 1990s and to 0 in the period of 2001–2008 (p < 0.05, Spearman’s correlation coefficient). While in the 1980s 17 of the 19 patients had pneumonia in their past history, in the period of 2001–2008 only 13 of the 33 patients were concerned. Conclusions: Our observation documents improved awareness of immunodeficiencies among physicians. It is supposed that earlier diagnosis will prevent complications, improve the quality of life and even survival of hypogammaglobulinaemic patients.