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. 2013;8(1):e55570.
doi: 10.1371/journal.pone.0055570. Epub 2013 Jan 30.

Altered responses to homeostatic cytokines in patients with idiopathic CD4 lymphocytopenia

Florence Bugault  1 , Daniela Benati, Luc Mouthon, Ivan Landires, Pierre Rohrlich, Vincent Pestre, Jacques Thèze, Olivier Lortholary, Lisa A Chakrabarti
Affiliations

Altered responses to homeostatic cytokines in patients with idiopathic CD4 lymphocytopenia

Florence Bugault et al. PLoS One. 2013.

Abstract

Idiopathic CD4 lymphocytopenia (ICL) is a rare immune deficiency characterized by a protracted CD4(+) T cell loss of unknown etiology and by the occurrence of opportunistic infections similar to those seen in AIDS. We investigated whether a defect in responses to cytokines that control CD4(+) T cell homeostasis could play a role in ICL. Immunophenotype and signaling responses to interleukin-7 (IL-7), IL-2, and thymic stromal lymphopoietin (TSLP) were analyzed by flow cytometry in CD4(+) T cells from 15 ICL patients and 15 healthy blood donors. The induction of phospho-STAT5 after IL-7 stimulation was decreased in memory CD4(+) T cells of some ICL patients, which correlated with a decreased expression of the IL-7Rα receptor chain (R = 0.74, p<0.005) and with lower CD4(+) T cell counts (R = 0.69, p<0.005). IL-2 responses were also impaired, both in the Treg and conventional memory subsets. Decreased IL-2 responses correlated with decreased IL-7 responses (R = 0.75, p<0.005), pointing to combined defects that may significantly perturb CD4(+) T cell homeostasis in a subset of ICL patients. Unexpectedly, responses to the IL-7-related cytokine TSLP were increased in ICL patients, while they remained barely detectable in healthy controls. TSLP responses correlated inversely with IL-7 responses (R = -0.41; p<0.05), suggesting a cross-regulation between the two cytokine systems. In conclusion, IL-7 and IL-2 signaling are impaired in ICL, which may account for the loss of CD4(+) T cell homeostasis. Increased TSLP responses point to a compensatory homeostatic mechanism that may mitigate defects in γc cytokine responses.

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Conflict of interest statement

Competing Interests: The authors have declared that no competing interests exist.

Figures

Figure 1
Figure 1. Decreased IL-7 responses in ICL.
(A) Example of pSTAT5 response to IL-7 stimulation measured in whole blood from a healthy donor. The gating strategy to detect pSTAT5 induction by flow cytometry within the memory CD4+ T cell population, defined as CD3+ CD4+ CD45RA− lymphocytes, is depicted. The percentages within the histogram plots indicate the fraction of pSTAT5+ cells after high dose IL-7 stimulation. A dose dependent response is observed, with a higher pSTAT5 expression at high IL-7 dose (2 nM) than at low IL-7 dose (20 pM). (B) Example of decreased pSTAT5 response to IL-7 stimulation in memory CD4+ T cells from ICL patient P3. (C) Induction of pSTAT5 after stimulation with low dose IL-7. The inducible cytokine response (Δ%pSTAT5+) was measured by the difference in the percentage of pSTAT5+ cells before and after IL-7 stimulation in memory CD4+ T cells. (D) Induction of pSTAT5 after stimulation with high dose IL-7. HD: healthy donors; ICL: patients with idiopathic CD4 lymphocytopenia. P values obtained with the Mann-Whitney U test are reported. (E) Correlation between pSTAT5 responses to high dose IL-7 stimulation and absolute CD4+ T cells counts in the blood of ICL patients. (F) Correlation between pSTAT5 responses to high dose IL-7 stimulation and the total lymphocyte count in the blood of ICL patients. The Spearman correlation coefficient R and the corresponding P value are indicated.
Figure 2
Figure 2. Correlation between IL-7 responses and CD127 expression.
(A and B) The percentage of IL-7-induced pSTAT5+ cells within the memory CD4+ T cell population is reported as a function of CD127 expression. (A) Responses to low dose IL-7 (B) Responses to high dose IL-7. HD: healthy donors; ICL: patients with idiopathic CD4 lymphocytopenia. The Spearman rank correlation coefficient RICL computed for ICL patients is reported. (C) Concentration of IL-7 in plasma measured by ELISA assay. (D) Lack of correlation between plasma IL-7 and pSTAT5 responses to high dose IL-7 in memory CD4+ T cells of ICL patients. (E) Lack of correlation between plasma IL-7 and CD4+ T cell counts in ICL patients.
Figure 3
Figure 3. Cytokine responses in function of CD25 expression.
Examples of pSTAT5 responses to IL-7, IL-2, and TSLP stimulation are shown in the CD4+ CD45RA- T cell population for one healthy donor (HD-15) and two ICL patients (ICL-P3 and ICL-P12). The percentage of pSTAT5+ cells is reported in the upper right corner of each dot plot. Plots in the first column represent non-stimulated cells (NS). Responses to low dose IL-2 were highly dependent on the degree of CD25 expression (4th column). In contrast, IL-7 responses tended to be lower in the CD25hi population (2nd and 3rd columns), consistent with known properties of Tregs . TSLP responses did not show a dependence on CD25 expression (6th column).
Figure 4
Figure 4. Decreased IL-2 responses in ICL.
(A) Example of pSTAT5 response to IL-2 stimulation measured in whole blood from a healthy donor. The Foxp3/CD25 gating used to defined memory Tregs (MTreg) and conventional memory CD4+ T cells (Memc) within the CD3+ CD4+ CD45RA− population is reported (left plot). Histograms show pSTAT5 basal levels (light blue area) and pSTAT5 induction after stimulation with low dose IL-2 (blue line) or high dose IL-2 (orange area) within the MTreg (middle plot) and Memc (right plot) populations. The percentages within each plot indicate the fraction of pSTAT5+ cells after high dose IL-2 stimulation. Maximal response is already achieved at low IL-2 concentration in MTregs, while a dose-dependent response is observed in Memc. (B) Example, of IL-2 responses in CD4+ T cells from an ICL patient. A small fraction of MTregs fail to respond to IL-2 (middle plot), while a larger fraction of Memc cells appear unresponsive (right plot). (C to F) The inducible cytokine response (Δ%pSTAT5+) was measured by the difference in the percentage of pSTAT5+ cells before and after IL-2 stimulation. HD: healthy donors; ICL: patients with idiopathic CD4 lymphocytopenia. P values obtained with the Mann-Whitney U test are reported. (C) Low dose IL-2 response in MTreg; (D) Low dose IL-2 response in Memc; (E) High dose IL-2 response in MTreg; (F) High dose IL-2 response in Memc. (G) Correlation between pSTAT5 responses of Memc to high dose IL-2 stimulation and absolute CD4+ T cells counts in the blood of ICL patients. The Spearman correlation coefficient R and the corresponding p value are indicated.
Figure 5
Figure 5. Impairment of IL-2 responses correlate with lower CD25 expression and decreased IL-7 responses.
(A) The percentage pSTAT5+ cells induced after high dose IL-2 stimulation (2 nM) is reported as a function of CD25 expression in MTregs (left plot) and Memc (right plot) populations. The mean fluorescence intensity (MIF) of CD25 is reported on the x axis. (B) Correlation between pSTAT5 responses to high dose IL-2 and high dose IL-7 in MTregs (left plot) and Memc (right plot). HD: healthy donors; ICL: patients with idiopathic CD4 lymphocytopenia. The Spearman rank correlation coefficient RICL computed for ICL patients is reported.
Figure 6
Figure 6. Induction of a compensatory TSLP response in ICL.
(A) Examples of pSTAT5 responses to TSLP stimulation in one representative healthy donor (left plot) and ICL patients P7 and P9 (middle and right plots). Whole blood was stimulated with TSLP 10 nM and evaluated for the expression of phosphorylated STAT5 (pSTAT5) in memory CD4+ T cells. (B) pSTAT5 response after stimulation with high dose TSLP within the memory CD4+ T cell population. The inducible cytokine response (Δ%pSTAT5+) was measured by the difference in the percentage of pSTAT5+ cells before and after stimulation with 10 nM TSLP. (C) Lack of correlation between expression of the TSLPR receptor chain and TSLP responses. The inducible TSLP response (Δ%pSTAT5+) cells within the CD3+ CD4+ CD45RA− population is reported in function of TSLPR expression. Blue circles: healthy donors; red squares: ICL patients. (D) Inverse correlation between IL-7 and TSLP responses. The inducible pSTAT5 responses to high dose IL-7 (x axis) and high dose TSLP (y axis) with memory CD4+ T cells are plotted. (E) Positive correlation between HLA-DR expression and TSLP responses. The percentage of HLA-DR+ cells (x axis) and the inducible TSLP response (y axis) within the memory CD4+ T cell population are plotted. HD: healthy donors; ICL: patients with idiopathic CD4 lymphocytopenia. The Spearman rank correlation coefficient RALL computed for all study subjects is reported.
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References

    1. Smith DK, Neal JJ, Holmberg SD (1993) Unexplained opportunistic infections and CD4+ T-lymphocytopenia without HIV infection. An investigation of cases in the United States. The Centers for Disease Control Idiopathic CD4+ T-lymphocytopenia Task Force. New England Journal of Medicine 328: 373–379. - PubMed
    1. Laurence J (1993) T-cell subsets in health, infectious disease, and idiopathic CD4+ T lymphocytopenia. Annals of internal medicine 119: 55–62. - PubMed
    1. Ho DD, Cao Y, Zhu T, Farthing C, Wang N, et al. (1993) Idiopathic CD4+ T-lymphocytopenia--immunodeficiency without evidence of HIV infection. New England Journal of Medicine 328: 380–385. - PubMed
    1. Netea MG, Brouwer AE, Hoogendoorn EH, Van der Meer JW, Koolen M, et al. (2004) Two patients with cryptococcal meningitis and idiopathic CD4 lymphopenia: defective cytokine production and reversal by recombinant interferon- gamma therapy. Clinical infectious diseases 39: e83–87. - PubMed
    1. Walker UA, Warnatz K (2006) Idiopathic CD4 lymphocytopenia. Current opinion in rheumatology 18: 389–395. - PubMed

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Grants and funding

I.L. is the recipient of a fellowship from the SENACYT Research Agency from Panama. This work was supported by Assistance Publique des Hpitaux de Paris (AP-HP), Ligue contre le Cancer du Grand Est, and by the Pasteur Institute, Paris. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.