Figure 1.
CD3 versus CD7 plots in flow cytometric analysis of patients who are asymptomatic HTLV-I carriers (ACs) and have various clinical subtypes of adult T-cell leukemia-lymphoma (ATL) suggest disease progression in HTLV-I infection.
(A) Flow cytometric profile of an AC, various clinical subtypes of ATL (smoldering, chronic, and acute), and a normal control. Representative cases of CD3 versus CD7 plots in CD4+ cells are shown. (B) A two-dimensional plot of AC cases showing the percentage of the D and L subpopulations by flow cytometry. AC cases were divided into two groups according to HTLV-I VL (greater or less than 4%). The border line (45% of D+L subpopulations) between Group 1 and 2 was set based on proviral load (VL). All AC cases with less than 4% VL were included in Group 1. All AC cases included in Group 2 had greater than 4% VL. VL<4%: n = 21; VL>4%: n = 19. All VL data in this figure were provided from the database of the Joint Study on Predisposing Factors of ATL Development (JSPFAD). (C) A two-dimensional plot of all patients showing the percentage of the D and L subpopulations. The smoldering type was divided into two categories: smoldering type with greater than 5% abnormal lymphocytes and smoldering type with less than 5% abnormal lymphocytes with skin manifestation. The two diagonal dotted lines indicate 45% and 100% of D+L subpopulations (i.e., 55% and 0% of the H subpopulation). Data were categorized into three groups.
Table 1.
Clinical profile of patients infected with HTLV-I and normal controls.
Figure 2.
HTLV-I proviral load (VL) and clonality in each subpopulation, based on the CD3 versus CD7 plot.
(A) The three subpopulations (H, D, L) based on the CD3 versus CD7 plot were subjected to fluorescence-activated cell sorting (FACS) and VL analysis. Three representative cases are shown. G1 or G2 in the dotted box indicates Group 1 or Group 2, categorized by the percentage of the D and L subpopulations, respectively. (B)–(D) Analysis of clonality in the three subpopulations based on the CD3 versus CD7 plot. Genomic DNA was extracted from FACS-sorted cells of each subpopulation and subjected to inverse long polymerase chain reaction (PCR). Representative data of two cases of AC (B), three cases of smoldering type, including one with skin manifestations (C), and cases of a chronic type and an acute type (D) are shown. PCR was performed in duplicate (black bars) in cases when a sufficient amount of DNA was obtained.
Figure 3.
Study of exceptional cases categorized by proportion of the CD3dimCD7dim (D) and CD3dimCD7low (L) subpopulations.
Left: An HTLV-I AC patient who was categorized in Group 2 in the D(%) versus L(%) plot. Middle: A patient with smoldering-type ATL who was categorized in Group 1. Right: A patient with acute-type ATL who was categorized in Group 2.
Figure 4.
Alteration in the CD3 versus CD7 profile by flow cytometry in accordance with disease progression.
(A) Change in the CD3 versus CD7 profile in representative cases. In all three cases shown, change in clinical data (e.g., abnormal lymphocyte, LDH) resulted in progression of the clinical subtype. (B) Change in the CD3 versus CD7 profile in a time course in the case of chronic-type ATL. Clinical data are shown in Table S1. (C) Flow cytometric data in (B) are summarized in the D(%) versus L(%) plot.
Figure 5.
Summary of the study: the CD3 versus CD7 profile reflects progression of disease stage in patients infected with HTLV-I.
In the percentage of D (CD3dimCD7dim) versus L (CD3dimCD7low) plot, Group 1 includes the majority of AC cases. As disease stage progresses, the CD3 versus CD7 profile then changes. With downregulation of CD3 and CD7, the D and L subpopulations increase gradually (Group 2). During this step, clones in the D and L subpopulations increase in size. Further accumulation of genetic alterations will result in rapid expansion of ATL clones—i.e., evolution to acute-type ATL. In this step, the CD3 versus CD7 profile will progress from Group 2 to 3.