## 4 Discussion
In the present study, we found that mice administered CPA were characterized by marked reductions in WBCs, RBCs, hemoglobin, hematocrit, and platelets. Moreover, we also detected reductions in the numbers of immune cells, such as lymphocytes and neutrophils, although the percentage of WBCs remained relatively constant. Collectively, these observations thus indicate that CPA therapy can be a cause of myelosuppressive nonregenerative anemia, paneleukopenia, and thrombocytopenia. These myelosuppressive changes were, nevertheless, relieved by the subsequent administration of HM, which has previously been proven to be effective against anemia [7]. Immun cells (T cells, B cells, and macrophages) release cytokines, immunomodolating compounds that contribute to the regulation of immune responses and play key roles in immune cell development and tissue healing [42]. Among these, IFN-\(\gamma\) is a pro-inflammatory cytokine produced by NK and Th1 cells that causes disease-related tissue damage. However, it is also one of the cytokines that plays a role in tissue homeostasis and protection in homeostatic circumstances by inducing host defense and immunological responses and minimizing tissue damage [43]. TNF-\(\alpha\), produced by macrophages and Th1 cells, and IL-1\(\beta\), produced by macrophages, play roles in the regulation of normal inflammatory reactions and can be utilized as biomarkers to assess inflammatory conditions [44; 45]. T regulatory cell-derived IL-10 is an important regulatory cytokine that suppresses excessive T cell responses and contributes to regulating the immune response [46]. In the present study, we established that CPA treatment causes not only myelosuppression and quantitative reductions in immune-related cells but also impairs the qualitative functioning of immune systems, including a reduction in cytokine levels. Notably, however, we found that co-administration of HM had the effect of restoring these reduced cytokine levels. We also established that CPA treatment has certain immunosuppressive effects, among which were losses in body and lymphoid organ weights, atrophic changes in lymphoid organs, and reductions in NK cell activities. The spleen and submandibular LN are essential immune organs, in the former of which the white pulp area, in particular, is involved in innate and adaptive immunity via mediation of the differentiation, development, and maturation of T and B cells, along with macrophages. Lymph nodes in the submandibular region also produce lymphocytes and filter out foreign particles that can potentially cause infections. Losses in body, spleen, and LN weights attributable to a reduction in lymphocytes and atrophy of the lymphoid organs are also used as markers of immunosuppression [44; 45]. Among the different types of lymphocytes, NK cells are considered the most potent effectors in the innate immune system, identifying and killing diseased or damaged cells to control the development of malignancies and infections. However, many of the currently used immunosuppressive drugs have the effect of reducing both the numbers and activities of NK cells [47]. We nonetheless demonstrated that the administration HM had dose-dependent innate and adaptive immunological-enhancing effects with respect to gains in body and lymphoid organ weights, reducing the atrophy of immune organs, restoring NK cell activity, and ameliorating the immunosuppression attributable to CPA. A limitation of this study is the lack of investigation into the underlying mechanisms of the effect of the herbal mixture on immunological regulation. Other polyphenols have been studied as potential immunomodulatory medicines by activating the MAPK/NF-kB signaling pathway [48]. To determine the underlying mechanism, more research is needed to determine the effect of HM on the MAPK/NF-kB signaling pathway.