Lymphocyte immunological function and 24 T cell receptor V beta subfamilies expression in convalescent patients with severe acute respiratory syndrome

Xing ZENG; Cui CAI; Yu HUANG; Aihua OU; Xian ZHANG

ABSTRACT

BACKGROUND:

Severe acute respiratory syndrome (SARS) is caused by a genetically novel coronavirus that is caused by acute infectious disease. It is not yet clear for the immunology function of SARS patients in their convalescent stage.

OBJECTIVE:

To study the effects on T lymphocyte, and the titer profiling of 24 T cell receptor (TCR) V β subfamilies expressions in SARS convalescent patients.

DESIGN:

A self-control observation.

SETTING:

Central Laboratory, Guangdong Provincial Hospital of Traditional Chinese Medicine.

PARTICIPANTS:

Seventy-six cured SARS patients who received treatment in the Second Hospital Affiliated to Guangzhou University of Traditional Chinese Medicine between January and April 2003. All the patients corresponded to "clinical diagnostic criteria of atypical pneumonia", " diagnostic criteria of severe atypical pneumonia and discharge criteria" and "clinical diagnostic criteria and discharge criteria of severe acute respiratory syndrome". The involved patients, 30 male and 46 female, averaged (32±11 (years old. Another 10 subjects who simultaneously received health examination in the same hospital, 5 male and 5 female, aged (32±7(years, were involved in the study. Informed consents of detected items were obtained from all the subjects.METHODS：①Detecting the expression of 24 T cell receptor(TCR)V β subfamilies in SARS convalescent patients：Peripheral blood(2 mL) was collected from the healthy convalescent subjects,and EDTA-K2 was used as anticoagulant．In the flow cytometry delection tubes．10 μL various fluorescein-labeled mAb，such as anti-CD3,anti-CD4，anti-CD8,anti-CD25，anti-CD28，anti-HLA-DR，anti-CD3mAb conjugated with PC5，TCR Vβ1(PE+FITC)．Vβ2(PE+FITC)。Vβ3 (FITC)，Vβ4(PE+FITC)，Vβ5．1(PE+FITC),Vβ5．2(PE),Vβ5．3(PE)，Vβ7．1(PE+FITC)，Vβ7．2(FITC),Vβ8(FITC),Vβ9 (PE)，Vβ11(PE)，Vβ12(FITC)，Vβ13．1(PE),Vβ13．2(PE),Vβ13．6(PE+FITC)，Vβ14(FITC),Vβ16(FITC),Vβ17 (PE+FITC)，Vβ18(PE)，Vβ20(FITC)，Vβ21．3(FITC),Vβ22(PE+FITC)and Vβ23(PE)，was added in special flow tubes,and then 50 μL whole blood was added．The mixed solution was incubated away from light for 15 minutes．After erythrocytolysin being added，mixed solution was washed．Finally．cell deposit was dissolved in 300 μl phosphate buffer solution (PBS)．Coulter ESP flow cytometer was used for detection．For the analysis of TCR expression,an electronic gate was set on these cells and at least 5000 events per sample were collected．Three-color cytofluodmetric analysis was performed using a Coulter ESP flow cytometer．②Detecting the T cell subset,activated T and B cells,and the percentage of Ts and Tc cells：5000 cells were collected and used to calculate the expression of T cells (CD3,CD4 and CD8),the activated T and B cells(CD3+／CD25+,CD3+/HLA-DR+ and CD3-／HLA-DR+),as well as the percentage of Ts and Tc cells by Coulter ESP flow cytometer and its software．MAIN OUTCOME MEASURES：①The change of T cell subset(CD3，CD4，and CD8)from SARS convalescent patients．②The change of activated T and B cells(CD3+／CD25+，CD3+／HLA-DR+ and CD3-／HLA-DR+)．③The percentage of Ts and Tc cells(CD8+／CD28+，CD8+/CD28-)in convalescent patients．④Analysis of the 24 TCR V β subfamilies from SARS patients in convalescence．RESULTS：All data were explored to analyze the expression profiling of 24 TCR Vβ subfamilies,the data from 74 SARSpatients and 10 healthy controls were explored to other result analysis．①The detecting results of T celI subset：The percentage of CD4+T cell mean value was lower than the reference value[(33．33±6．64)％ vs．(43±9)％，P＜0．01]．The percentage of CD8+T cell mean value was higher than the refefence value[(34．07±6．40)％ vs．(30±9)％,P＜0．01]．② The expression of activated T and B cells：Percentage of HLA-DR+ T and B cell was Increased while the percentage of CD25+ T-cell was decreased compared with reference values．In 53 out of 74 patients,the percentage of CD25+ T cells was lower than the reference value,and 64 patients had a lower percentage in CD3+/CD25+ T cells．The percentages of CD3+/HLA-DR+ and CD3-／HLA-DR+ cells were higher than the normal reference value．T cells expressing higher CD3+／HLA-DR+ were found in 36 patients，and T cells expressing higher CD3-/HLA-DR+ were found in 30 patients．③The ratios of Ts and Tc cells：The percentage of Ts cells which expressed CD8+／CD28- was increased compared with reference value [(28．75±7．31)％ vs．(15．99±5．1)％，P＜0．01],while the percentage of Tc cells which expressed CD8+／CD28+ was decreased [(5．99±3．60)％ vs．(13．2±4．1)％，P＜0．01]．Thirty-nine patients were found to possess the lower Tc cells and forty-eight patients were found to possess the higher Ts cells．The ratios of both CD4+ and CD8+ T cells were in the normal reference value．④24 TCR Vβ subfamilies expressions in T cells：It was noteworthy that Vβ14 had a highest percentage in all 24 Subfamilies,and followed by Vβ 5．3,and Vβ 23 in the convalescent patients．The percentage of Vβ 14 was the highest in the normal controls,which was consistent with the results of SARS patients．But the other subfamilies expression patterns were different．There were significant differences between Vβ1,Vβ5．2,Vβ5．3,Vβ7．2，Vβ9，Vβ11,Vβ13．1,Vv13．2，Vβ17,Vβ18，Vβ22 and Vβ23．In the convalescent period，each TCR Vβ expression of SARS patients was higher than that of controls(P＜0．05-0．01)．

CONCLUSION:

In SARS convalescent patients,the increased CD8+CD28- T cell may elevate CD8+ T cell number;Meanwhile.the reduced CD3+ and CD4+ T cell number may be corresponding to the increased Ts cell number．For some inhibiting factor secreted by Ts cell was also increased．The usage pattern of 24 TCR Vβ subfamilies in SARS patients is different from that of control group．The increase of percentage of CD3+／HLA-DR+ and CD3-／HLA-DR+ T cell may be related to the late response of activated T and B cells.