INFLUENCE OF IRON DEFICIENCY ON SERUM IgG SUBCLASS AND PNEUMOCOCCAL POLYSACCHARIDES SPECIFIC IgG SUBCLASS ANTIBODIES

The serum IgG subclass concentrations in 47 cases and specific IgG subclass antibodies against pneumococcal polysaccharides (PnPs) were measured in 18 cases with iron deficiency. IgG subclass deficiencies were found in 28 (59.6%) cases with the frequency in order as IgG4 (27.7%, 13 / 47), IgGl (21.3%, 10/47), IgG3 (14.9%, 7/47), and IgG2 (2.1%, 1 / 47). Compared with age-atched healthy children, the mean concentration of serum IgG4 and IgGl, and PnPs specific IgGl, IgG2 antibodies were decreased in children with iron deficiency. Decreased CD4 cells and CD4 / CD8 ratio in peripheral blood, low interleukin? (IL-6) activity, reduced lymphocyte proliferative responsiveness and increased recurrent respiratory tract infections (RRTI) were found in iron deticiency children. These results suggested that serum IgG subclass and PnPs specific IgG subclass antibody deficiencies caused by dysfunction of the regulation of T lymphocyte on B lymphocyte may be related to the susceptibility to RRTI in children with iron deficiency.

STUDIES ON DYNAMIC CHANGES AND COMPARISONS OF SERUM SPECIFIC IGM AND IGG ANTIBODIES IN PATIENTS WITH HEMORRHAGIC FEVER WITH RENAL SYNDROME

The speciric IgM and IgG antibodies in serum samples from patients with hemorrhagic fever with renal syndrome (HFRS) were sequentially and simultaneously determined during the course of the disease. The results showed that the detectable days and the days reaching 100% positive rate after onset of illness in specific IgM antibodies were earlier than those in specific IgG antibodies. No significant differences were observed between the titers of specific IgM antibodies on different days after onset of the disease while the titers of specific IgG antibodies differed, significantly on different days after onset of illness (F'= 11. 72,P< 0. 01 ). The titers of specific IgM antibodies in different clinical types were not significantly different at the same illness day but the titers of specific IgG antibodies in various clinical types were significantly different from day 7 to day 8 after onset of disease (F' = 4. 004, P< 0. 05). The levels of specific IgM and IgG antibodies were more stable and the crossings of the IgM and IgG antibody curves presented later in patients with mild and middle clinical types than those in patients with severe and gravis types. These results suggest that the detection of specific IgM antibodies may be useful for the early laboratory diagnosis of HFRS,the excess Production of specific IgG antibodies may play a role in the formation of immune complexes and the exacerbation of pathologic damage in patients with severe and gravis types and the observations of the dynamic changes of specific IgM and IgG antibody curves may have some implications in evaluating the seventies of the disease and the prognosis of the patients with HFRS.

Immune Profile of COVID-19 Survivors and Contacts During 9 Months:A Cohort Study

Background:Severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)causes a multi-organ systemic damage that can lead to long-term consequences.Little is known about the possible long-term effects of COVID-19 on circulating leukocyte kinetics and functional T-cell activity after recovery.To investigate immune system changes,we designed a cohort study.Methods:Volunteer screening and sample collectionwere performed at the Irkutsk Research Anti-Plague Institute of Rospotrebnadzor.Sixty-four volunteers who have had COVID-19(recovered volunteers(RVs))betweenMay 2020 andMay 2021,33 volunteers who had been in contact with COVID-19 patients(contact volunteers(CVs))within the family setting but had not become ill,and 47 healthy volunteers(HVs)participated in the study.We performed immunophenotyping of peripheral blood cells using flow cytometry.Serum was tested for SARS-CoV-2 anti-nucleocapsid immunoglobulin G antibodies by enzyme-linked immunosorbent assay(Ab(+),people with specific anti-N antibodies to SARS-CoV-2;Ab(−),people without specific antibodies).Results:There were no serious disturbances in the internal environment of the body in RVs and CVs.In the evaluation of the general state of the immune system,the most informative indicator was the index of the ratio of neutrophils to bloodmonocytes–decreased on the 1st terms of observation(1 and 3 months post-symptom onset(PSO)/post-contact onset(PCO)),on average,1.3 times compared with HVs(8.6%(7.5%–10.5%),P<0.05),which recovered by the 6th month of observation.Redistribution of the cells responsible for the development of the adaptive immune response was noted only in RVs–increased B-lymphocyte content(HVs,9.1%(6.4%–10.2%))and immunoregulatory index ratio(HVs,1.6%(1.2%–2.1%))due to redistribution of T-helper and cytotoxic T cells throughout the follow-up period by an average of 1.2-fold compared with HVs(P<0.05).However,CVs with specific antibodies to SARS-CoV-2 N-protein also had an increased proportion of CD3−CD19+cells after 1 month PCO(Ab(+),11.4%(10.2%–15.1%);Ab(−),8.6%(5.7%–9.7%);P=0.006).A significant difference between RVs and CVs is that the RVs showed significant activation of circulating T cells,which persisted up to the 6th month of the study,whereas in CVs,it persisted for 3 months PCO.The highest proportion ofHLA-DR+T-lymphocyteswas recorded after 1month PSO/PCOin Ab(+)RVs andCVs:Ab(+)volunteers,8.1%(6.0%–11.2%)and 4.4%(2.7%–6.4%),respectively;Ab(−)volunteers,4.2%(2.6%–5.4%)and 5.1%(3.7%–5.6%);and HVs,3.5%(2.5%–4.7%)(P<0.01).In CVs,natural killer cells also played a major role in preventing manifest infection(CVs,10.8%±4.3%;HVs,15.9%±7.6%;P<0.05).Conclusion:In this study,we demonstrated the dynamics of returning to the initial state of health in RVs and CVs.In CVs,we observed changes in the studied immunological parameters similar to those of RVs,butwhich are less intense and prolonged.Complete recovery of the studied immunological parameters occurs within 6 months.