We appreciate the opportunity to respond to the comment regarding our recently published article (1). Our intent in the Discussion referenced by Thiel and Kohler (2) was to point out the contrast between the relative number of perturbations in the CD31 and CD31+ naive subsets as well as the absolute deviation from clonality in both subsets indicated by our two reports. While we do acknowledge that our statement of “strongly perturbed repertoires” is evidenced more by our relative discrepancies with Kohler et al. (2), in assessing the repertoire of the CD31 subset Kohler et al. did find a larger number of perturbations in the CD31+ subset than did we. As reported in Fig. 6 of our article, we only found significant expansions in ∼8% of all measured peaks in our analysis. In contrast, in Table I of their article (3) Kohler et al. report that ∼16% of their six measured Vβ-Jβ-chain transcripts indicated oligoclonal distributions. While we appreciate that, relative to their own analysis, the amount of contraction in the CD31 subset was significantly greater than in that the CD31+ subset, we feel that in comparison to our findings both subsets as measured by Kohler indicate larger numbers of perturbations.

The authors have no financial conflict of interest.

1
Kilpatrick, R. D., T. Rickabaugh, L. E. Hultin, P. Hultin, M. A. Hausner, R. Detels, J. Phair, B. D. Jamieson.
2008
. Homeostasis of the naive CD4+ T cell compartment during aging.
J. Immunol.
180
:
1499
-1507.
2
Thiel, A., S. Kohler.
2008
. Comment on “Homeostasis of the naive CD4+ T cell compartment during aging.”.
J. Immunol.
180
:
6437
3
Kohler, S., U. Wagner, M. Pierer, S. Kimmig, B. Oppmann, B. Möwes, K. Jülke, C. Romagnani, A. Thiel.
2005
. Post-thymic in vivo proliferation of naive CD4+ T cells constrains the TCR repertoire in healthy human adults.
Eur. J. Immunol.
35
:
1987
-1994.