Study populations in NLPHL and THRLBCL: The 16 NLPHL evaluated in 3 analysis groups, and 4 THRLBCL are shown (Table 1, Fig. 1). By utilizing a multiplex panel of 21 markers, tumor B-cells, TME B-cells, T-cells, and monocyte subsets, inclusive of their functional status, were defined and visualized (Fig. 2, Figure S1). Markers validated individulally and by multiplex runs were visualized as defined cell populations in every case (Fig. 2, Tables 2), and in each of the ROIs selected (Figure S3). Z-scores allowed comparison of the proportion of each cellular phenotype in relation to the overall number of cells within each ROI (Tables 2 and S4, and Fig. 2, S4-5), and spatial intractions were calculated as shown (Tables 3, 4, S5 and Figs. 3–5).
Table 3
Interaction counts between LP cells and TME components
Cell Type | NLPHL | THRLBCL |
Group 1 | Group 2 | Group 3 |
TFH | 0.094 | 0.058 | 0.079 | 0.075 |
Regulatory T-cells | 0.029 | 0.029 | 0.029 | 0.027 |
Tumor B-cells | 0.26 | 0.24 | 0.29 | 0.51 |
B-cells | 0.065 | 0.062 | 0.047 | NA |
Monocytes | 0.039 | 0.023 | 0.039 | 0.05 |
CD4/CD8 T-cells | 0.027 | 0.034 | 0.034 | NA |
Cytotoxic T-cells | 0.046 | 0.034 | 0.044 | 0.04 |
Helper T-cells | 0.056 | 0.045 | 0.047 | 0.095 |
Tumor B-cell and TME B-cell abundance vary across NLPHL and THRLBCL: THRLBCL had a relatively higher number of tumor B-cells followed by groups 3, 2 and 1 NLPHL (groups 3 vs 1, p = 0.009; and groups 3 vs 2, p = 0.05). In contrast, TME B-cells in NLPHL showed significantly higher TME B-cells in groups 1 vs 2 and 3 (p = 0.003 and < 0.0001 respectively). The TME B-cells in THRLBCL were so sparse that it could not be detected using the clustering algorithm.
T-cell abundance and composition vary across NLPHL and THRLBCL: T-helper (TH) cells were significantly more abundant in groups 1 and 2, and relatively less predominant in group 3 and THRLBCL. The helper T-cell composition was strikingly higher in groups 1 vs. 3 and THRLBCL (p = 0.04 and p = 0.025 respectively), with relatively higher number of TH cells in THRLBCL compared to group 3. No significant difference between helper T-cell counts were detected in groups 1 and 2.
Activated TH cells were notably abundant in all NLPHL groups compared to THRLBCL, and showed the highest abundance in group 3. There were also a significantly higher number of activated TH cells in group 3 vs. THRLBCL [p = 0.01]. There was an abundance of helper and activated TH cells between group 3 and THRLBCL; TH cells were more abundant in THRLBCL and their activated form was predominant in group 3.
TFH cells were more abundant in all groups of NLPHL relative to THRLBCL; however, this observation did not reach statistical significance. Interestingly, there were a number of statistically significant findings involving activated TFH cells: there was significantly lower abundance of activated TFH cells in group 1 in contrast to group 3 and THRLBCL [p = 0.001 and < 0.0001 respectively]. Similarly, there was a lower adundance of activated TFH cells in groups 2 vs 3 and THRLBCL (p = 0.03 and 0.002 respectively). Overall, activated TFH cell abundance was reverse of the abundance of TH cells across NLPHL groups and THRLBCL. T-regs were deteced in abundance in groups 2 and 3 as well as THRLBCL, but were significantly less abundant in group 1 (groups 3 vs 1, p = 0.004).
Both cytotoxic and activated cytotoxic T-cells were abundant in THRLBCL relative to all groups of NLPHL. Z-scores for cytotoxic T-cells were highest in THRLBCL, followed by group 1 and 2, and were the lowest in group 3. This observation did not show statistical significance. Activated cytotoxic T-cells were most abundant in THRLBCL, low in groups 2 and 3, and least abundant in group 1 (THRLBCL and group 1, p = 0.04).
Additionally, CD4/CD8 double positive T (DPT)-cells were detected in a substantial proportion of NLPHL and included group 1 (7 of 8, 87.5%), group 2 (4 of 5, 80%), and group 3 (2 of 3, 66.7%). Among THRLBCL, only 1 of 4 (25%) cases showed CD4/CD8 DPT-cells.
Monocytes are increased in THRLBCL compared to NLPHL: Both mature and immature monocytes were more adundant in THRLBCL compared to all NLPHL groups. In addition, THRLBCL showed a statistically significant abundance in monocyte count in comparison to group 2 (P = 0.036). There was differential abundance of immature monocytes, which were most abundant in THRLBCL, followed by groups 3, 2 and 1 in descending order of abundance (THRLBCL vs. groups 1 and 2, p = < 0.001 and 0.017 respectively). Although group 3 showed a lower abundance of immature monocytes compared to THRLBCL, the difference was not statistically significant
Tumor B-cells show differences in spatial localization in NLPHL and THRLBCL: The cells with the strongest interaction/spatial proximity to LP cells in group 1 were TFH cells followed by TME B-cells, whereas cytotoxic and TH cells were not found to interact strongly with LP cells. In group 2, a similar spatial proximity was found and included TFH cells and TME B-cells; however, TME B-cells were found to be more proximal to LP cells than TFH cells. Furthermore, there was a statistically significant stronger interaction between LP cells and TFH cells in group 1 compared to group 2 (p = 0.04). In group 3, TFH cells showed the most spatial proximity to LP cells, followed by TH cells and TME B-cells. Monocytes and cytotoxic T-cells were spatially distant from LP cells. Finally, in THRLBCL, TH cells were found to show the highest proximity to tumor B-cells, followed by TFH cells, and then monocytes and cytotoxic T-cells.
TME B-cells are spatially proximal to helper and regulatory T-cells in typical NLPHL: A higher level of spatial interaction was found between TME B-cells and both helper T-cell and T-regs in group 1 NLPHL. The helper T-cell interaction with TME B-cells in group 1 was significantly stronger compared to groups 2 and 3 (p = 0.002, 0.035 respectively). Similarly, T-regs interacted strongly with TME B-cells in group 1 compared to groups 2 and 3 (p = 0.002, 0.013 respectively). In group 1 =, although TME B-cells follow TFH cells in their interaction with LP cells, TME B-cells also interact significantly with TH cells and T-regs.
Helper T-cell interactions show spatial variation in NLPHL and THRLBCL: TH and cytotoxic T cell interactions showed significant differences in nodular versus diffuse configurations across NLPHL and THRLBCL. There was a notable, significantly stronger interaction between helper and cytotoxic T-cells in group 1 compared to group 3 and THRLBCL (p = 0.002, and 0.017 respectively). Similarly, the interaction between both helper and cytotoxic T-cells was more pronounced in group 2 compared to group 3 and THRLBCL (p = 0.012 and 0.03 respectively). TH cells showed strongest likelihood of interaction with monocytes in THRLBCL and group 1. There was no significant difference between both groups regarding this interaction, however, helper T-cell and monocyte interaction was significantly higher in group 1 compared to groups 2 and 3 (p = 0.06, < 0.0001 respectively), and between group 2 and group 3 NLPHL (p = 0.012).
CD4/CD8 DPT-cells are spatially removed from LP cells: CD4/CD8 DPT-cells were spatially distant from the vicinity of LP cells and TFH-rosettes where most TME B-cell interactions with LP cells were detected. The DPT-cells showed stronger interaction with cytotoxic T-cells in groups 1 vs 2 (p = 0.047). These DPT-cells also interacted more with monocytes and T-regs in group 1 compared to group 3 (p = 0.02, 0.03 respectively). Overall, cytotoxic T-cells, T-regs, CD4/CD8 DPT-cells and monocytes were spatially distant from LP cells when compared with TME B-cells and TFH cells.
Cytotoxic T-cell interactions with T-regs and monocytes show spatial variation: Cytotoxic T-cells
exhibit closer proximity to monocytes in THRLBCL in comparison to groups 1, 2, and 3 (p > 0.05,
0.019, 0.002, respectively). Furthermore, cytotoxic T-cells and TFH cells were found to have the
strongest spatial relationship in groups 2 and 3 as well as THRLBCL compared to group 1
(p = 0.013, > 0.05, and 0.019, respectively). This relationship was strongest in group 2 NLPHL compared to all other cases and was least consequential in THRLBCL. Moreover, cytotoxic T-cells and T-regs showed a significant spatial proximity in groups 1 and 2 compared to THRLBCL (p = 0.0006, 0.006 respectively).
Monocyte interactions in group 1 NLPHL and THRLBCL: Spatial proximity between monocytes and T-regs was prominent in group 1 NLPHL compared to group 3 and THRLBCL (p = 0.003, 0.048 respectively). In contrast, the proximity between monocytes and TFH cells was the highest in THRLBCL. TFH-monocyte interaction was highest in THRLBCL compared to groups 1, 2 and 3 NLPHL (p = < 0.0001, 0.0001, 0.001 respectively). Monocyte interactions with LP cells were less prominent in group 2 compared to groups 1 and 3 NLPHL [p = 0.04, 0.035 respectively].
T-reg interactions are unique to group 1 NLPHL: T-regs showed strong interactions with TME B-cells, monocytes, cytotoxic T-cells, and CD4/CD8 DPT-cells in group 1 NLPHL. In contrast, T-reg and TFH populations showed stronger interactions that were statistically significant in groups 2 and 3, as well as THRLBCL in comparison to group 1 NLPHL (p = 0.004, 0.002, and 0.02 respectively). The overall abundance of T-regs was, however, the lowest in group 1 among all cases evaluated. Our spatial analysis data takes into consideration the number of interactions between populations in relation to the number of cells in each of the studied groups.
NLPHL and THRLBCL tumor cell size measurements: Tumor cell nuclear area and perimeter showed a gradual increase from group 1 to 2 to 3 NLPHL. These findings were statistically significant (p < 0.001 for group 3 vs 2, group 3 vs 1 and group 2 vs 1, p < 0.001 with regard to nuclear area. Similar statistical significances were noted with nuclear perimeter (p < 0.001 for group 3 vs 1 and group 3 vs 1 NLPHL; and p = 0.018 for group 3 vs 2 NLPHL). Both nuclear size and perimeter were smaller in THRLBCL cases compared to group 3 NLPHL (p < 0.001 for THRLBCL vs group 3 for both nuclear area and perimeter). However, nuclear size of THRLBCL remained higher than both groups 1 and 2 NLPHL (p < 0.001 for THRLBCL vs groups 1 and 2 NLPHL for both nuclear area and perimeter) (Figure S6).