Close association of CD8+/CD38 bright with HIV-1 replication and complex relationship with CD4+ T-cell count.

Measuring lymphocyte activation provides information in addition to CD4(+) T-cell count for immune monitoring of HIV-1 infected patients. CD38 is a well-established activation marker that is generally analyzed on the whole population of CD8(+) T-cells. Focusing specifically on CD38 high expression (CD8(+)/CD38(bright)) may be an interesting surrogate gating strategy because CD38(bright) characterizes principally activated memory cells. CD8(+)/CD38(bright) was investigated in 1,353 HIV-1 infected patients over a one-year period to establish relevant cutoff values and clarify the relationships of this marker with HIV-1 RNA viral load (VL) and CD4(+) T-cell count. The CD8(+)/CD38(bright) (>8,500 CD38 binding site per cells) is well correlated with HIV-1 VL (r = 0.87, P < 0.001) in this longitudinal follow-up of nonimmunodepressed patients that initiated antiviral therapy (ART). In aviremic patients on ART, the marker was highly predictive of VL rebound (sensitivity 93%, specificity 64% for a VL level of detection >200 copies/ml). While the CD8(+)/CD38(bright) moderately correlated with CD4(+) T-cell count independently of the VL (r = -0.37, P < 0.001), it increased dramatically in aviremic patient groups that exhibited profound CD4(+) T-cell depletion (median 39% for CD4(+) T-cell counts <50/mm(3)). This result indicates that other additional immunological and/or viral factors than readily detectable HIV-1 replication appears to be involved in T-cell activation of immunodepressed individuals. CD8(+)/CD38(bright) is an effective marker for monitoring T-cell activation, which is a central factor of HIV-1 pathogenesis. This gating strategy requires only a single additional staining in conventional four color CD4 protocols.

Tuaillon E ，Al Tabaa Y ，Baillat V ，Segondy M ，Picot MC ，Reynes J ，Vendrell JP ... -  《-》

CD38 expression on CD8 T cells has a weak association with CD4 T-cell recovery and is a poor marker of viral replication in HIV-1-infected patients on antiretroviral therapy.

Steel A ，John L ，Shamji MH ，Henderson DC ，Gotch FM ，Gazzard BG ，Kelleher P ... -  《HIV MEDICINE》

CD8/CD38 activation yields important clinical information of effective antiretroviral therapy: findings from the first year of the CIPRA-SA cohort.

The affordable, reliable, and simplified flow cytometric method on single platform with 2-color (CD45+, CD4+) Panleucogating (PLG-CD4) is used to monitor HIV+ patients on antiretroviral therapy (ART) in South Africa (SA). Viral load (VL) assays are also used to monitor response to ART but are labor-intensive with costs that, in the long run, may remain unsustainable. Cheaper and quicker alternatives to VL such as CD38 tests on CD8+ T cells may therefore play a role in securing the continuation of ART programs in high-volume resource-restricted settings. The single-tube PLG assay (CD45/CD4) was modified to use the full capacity of flow cytometers for 4-color immunofluorescence by including two more parameters: the CD38-activation marker on CD8 T-cells (CD8/CD38). This was introduced at baseline prior to the start of ART and then the changes of CD38+ mean fluorescent intensity (MFI) on CD8+ T-cells were then regularly assessed during follow-up-in comparison with the VL. A total of 103 patients received ART. By the end of their 4-, 8-, 12-, and 24-week observation periods, 29 (32.2%), 58 (64.4%), 74 (82.2%), and 83 (92.2%) had undetectable VL. This was also reflected by the gradual decrease of CD38 MFI expression on CD8+ T cells, irrespective of whether patients were "high," "moderate," or "low" CD38 responders at baseline. As expected, the CD4+ T cell counts substantially increased during the first 4 weeks from baseline 186 +/- 8.3 (SEM) to 267 +/- 12.3 cells/microl blood. But the recovery was slower over the rest of the 1-year follow-up to reach 334 +/- 18.2 cells/microl at week 48. As these CD4 increments were meager, the longitudinal follow-up of the continuously decreasing CD38 MFI values has become a particularly useful laboratory parameter to ascertain that the patients had indeed been responding well to ART. This monitoring protocol, in uneventful cases, may assist in reducing the frequency of VL testing. Conversely, a rise of CD38 MFI, if significantly higher than that seen at the previous visit even without fully reverting back to high baseline CD38-MFI values, provides an immediate indication for VL testing to judge whether or not the rebound of immune-activation is due to HIV VL-related irregularities. Therefore the CD8/CD38 test can provide the early, albeit not fully HIV-specific, warning signs about nonadherence to ART and/or developing drug resistance. This single-tube 4-color PLG-CD4 + CD8/38 activation assay (CD4/CD45/CD8/CD38), can replace the conventional 4-color CD4 protocols by substituting the redundant CD3 reagent with the informative CD38 antibody. This modification carries virtually no extra costs, while adding extra value to CD4 monitoring and enabling real-time, practical management of patients on ART. As a result, the numbers of VL tests required in patients on ART can be reduced-to save costs across our national treatment program which is already equipped with the necessary flow-cytometric screening capacity.

Glencross DK ，Janossy G ，Coetzee LM ，Lawrie D ，Scott LE ，Sanne I ，McIntyre JA ，Stevens W ... -  《-》

HIV-1-infected children on HAART: immunologic features of three different levels of viral suppression.

HIV-1-infected children show changes of blood lymphocyte subpopulations. We have, therefore, investigated how highly active anti-retroviral therapy (ART) alter these subsets. Blood samples were taken from 41 HIV-1-infected children on ART who were divided into groups showing good, partial and poor responses to ART on the basis of viral load (VL) measurement in blood. The observations were compared to those seen in 20 uninfected children. The samples were studied using 4-color flow cytometry for "naïve", central memory and effector memory cells as well as for CD38 expression as the sign of activation within both the CD4+ and the CD8+ T cell populations. HIV-1 infected children were also evaluated for the presence and the titers of antibodies induced by vaccination against childhood infections in our patients while on HAART. Lymphocyte counts were lower in the "poor" viral load responding (VLR) group when compared with partial and good VLRs. Poor VLRs had lower total and naïve CD4+ T cell counts. HIV-1-infected children from all three groups had high CD8+ T cell counts. Central memory CD4+ and CD8+ T cell percentages were particularly low in the poor VLR group while in the poor VLR group the percentages of effector memory CD4+ and CD8+ T cells were higher when compared with the control group. Higher cellular activation of CD8+ T cells was observed in HIV-1-infected children, particularly when analyzed for the intensity of CD38 expression in the poor VLR group. CD5 expression on B cells was higher among all HIV-1-infected children. Antibodies to tetanus, diphtheria, measles, rubella, and hepatitis B were present in a large proportion of children but the titers were similarly low for all three groups of HIV-infected children. Children with different levels of viral response to HAART present immune phenotype characteristics that tend to place the children with partial and good virological responses into the same group. These children are still moderately deficient in their immune responses but show better recovery than seen with children in the poor VLR group. These observations indicate that the proportions of central memory cells among the CD4+ T cells and the intensity of the expression of CD38 activation antigen on CD8+ T cells provide more informative parameters for monitoring children on HAART than the absolute numbers of CD4+ and CD8+ T cells alone.

Zaccarelli-Filho CA ，Ono E ，Machado DM ，Brunialti M ，Succi RC ，Salomão R ，Kallás EG ，de Moraes-Pinto MI ... -  《CYTOMETRY PART B-CLINICAL CYTOMETRY》

HIV-1 viral replication below 50 copies/ml in patients on antiretroviral therapy is not associated with CD8+ T-cell activation.

Steel A ，Cox AE ，Shamji MH ，John L ，Nelson M ，Henderson DC ，Gotch FM ，Gazzard BG ，Kelleher P ... -  《ANTIVIRAL THERAPY》