In one of the first publications on Adacolumn leukocytapheresis in IBD, Hanai, and colleagues reported treating 41 patients with UC in active stage. Eight of the 41 patients treated by Hanai et al. [29] were steroid naïve at entry. All eight (100 %) went into a clinical remission with the Adacolumn treatment and remained steroid naïve during the treatment and follow-up time. Subsequently, Suzuki et al. [56, 57] reported treating 20 steroid naïve patients with active UC by Adacolumn leukocytapheresis. These patients had moderate to severe UC; mean CAI was 8.8, range 5 –17. At entry, all patients were on 5-ASA (1.5–2.25 g/day). Each patient was to receive up to a maximum of ten Adacolumn sessions, at a frequency of two sessions/week. Efficacy was assessed 1 week after the last session. CAI fell to clinical remission levels (CAI < 4) in the majority of patients after six sessions, only two of the 20 patients required all ten sessions. At post treatment, the mean CAI was 3; range 0–12 (P = 0.0001) and 17 of 20 patients (85 %) were in clinical remission. There were significant changes in total peripheral white blood cell counts (WBC ×10⁹/L), 9.8 ± 1.0 (range 5.9–22.5) vs 7.0 ± 0.6 (range 3.5–15.3) for pre and post treatment, respectively (P = 0.003) together with decreases in CRP (P = 0003). During the Adacolumn leukocytapheresis therapy, two incidences of transient mild headache were reported. In both cases, the headache receded within 3 h without medication. Further text on this subgroup of UC patients is presented in the subsequent sections of this chapter.

Bjarnason and colleagues in London evaluated the efficacy of Adacolumn leukocytapheresis to suppress relapse in asymptomatic IBD patients at a high risk of experiencing a clinical relapse [58]. This approach reflects a fundamental change in the philosophy of treating IBD. Instead of treating active disease, asymptomatic patients are identified solely on the basis of a very high fecal calprotectin concentration, a neutrophil selective protein that provides quantitative measure of intestinal inflammatory activity [21–23]. The high calprotectin levels (over 250 μg/g) place them in a very high risk group for relapse of their disease [21]. This prospective, randomized controlled study, assigned patients to Adacolumn leukocytapheresis, undergoing 5, once a week leukocytapheresis treatment in an outpatient setting, or to unchanged treatment. Follow-up was monthly for 6 months for clinical relapse. Thirty-one patients who met the inclusion criteria were included from 244 potential subjects who underwent screening. In the Adacolumn group 64 % maintained their remission compared to 24 % in the control group (P = 0.03). Life table analysis demonstrated the mean survival in the Adacolumn group was 181 days vs 104 days in the control arm (P = 0.01). It would appear that 5 weekly sessions of Adacolumn in such patients will have a significant effect and potentially avoid the morbidity associated with clinical relapse and subsequent drug therapy.

The vast majority of studies with the Adacolumn have been in patients with UC. However, there is evidence to suggest that Adacolumn leukocytapheresis is effective in patients with CD as well. The first study in CD was reported by Matsui and colleagues [59]. In that study, seven patients with CD refractory to conventional medication including nutritional therapy, each received five Adacolumn sessions. Five of seven patients achieved remission. It should be relevant to state here that the only two nonresponders in Matsui’s study [60] had the CD lesions confined to the small intestine, not a common site to find infiltrated neutrophils. In the follow-up study by Fukuda et al. [61], 21 patients with severe drug and nutritional therapy refractory CD received five Adacolumn sessions each. Efficacy rate was 52.5 % in these severe patients. More recently, Domenech et al. [55] reported treating 12 steroid dependent patients with CD. The remission rate in this study was 70 %, which is higher than in the study reported by Fukuda et al. [61]. Finally, Lofberg and colleagues [62] have reported treating seven patients with CD who were refractory or had relapsed despite medication. Six had received infliximab, but without success. Adacolumn leukocytapheresis was performed at one session per week for 5 weeks. Efficacy was assessed at week 7 and 12 months. The median value of Crohn’s disease activity index (CDAI) scores decreased from 290 at week 1 to 184 at week 7 (P = 0.031). At the 12 months follow-up, CDAI had decreased further to 128.5 (P = 0.0156).

Although the aim of treatment with the Adacolumn has been to remove excess and activated granulocytes and monocytes from the circulation, it has been difficult to explain why some patients continue to improve long after the treatment is concluded. Also the low relapse rate reported by Hanai et al. [29] cannot be fully explained by our current understanding of neutrophil function per se. Alternative mechanisms of actions have therefore been sought. Adacolumn is filled with cellulose acetate beads to which leukocytes that bear the FcγR and complement receptors adhere [44, 45]. The adsorbed leukocytes release an array of active substances both toxic and nontoxic, but some anti-inflammatory as well. Most of these substances are of short half-life and may not reach the patients’ circulation in appreciable amounts. Several investigators have carried out analysis on blood samples taken from the Adacolumn inflow and outflow (blood return line to patients) during leukocytapheresis. Both Hanai et al. [63] and Suzuki et al. [56] found a significant increase in blood levels of soluble TNF-α receptors I and II. Soluble TNF receptors are reported to neutralize TNF without invoking TNF-like actions [64]. Similarly, several studies report a marked decrease in the capacity of peripheral blood leukocytes to release inflammatory cytokines including TNF-α, IL-1β, IL-6, and IL-8 following Adacolumn leukocytapheresis [28, 30, 48, 65]. The procedure appears to produce a similar effect on leukocyte trafficking receptors. Thus the expression of both L selectin [30, 44, 48, 65] and the chemokine receptor, CXCR3 [44] was markedly reduced and was sustained well beyond the last leukocytapheresis session, while the expression of the leukocyte integrin, Mac-1 (CD11b/CD18) was upregulated [30, 45]. These actions should suppress leukocyte extravasation.

Recently, Ishihara et al. [66] reported novel immunomodulatory actions for the Adacolumn by using an experimental model. They established an SCID adoptive transfer model of chronic colitis. Injection of apoptotic cells (ACs) into the model in the presence of B cells led to interesting findings. The ACs-mediated effect was lost in the absence of B cells or presence of regulatory B cells (Breg)-depleted cells. Further, the Adacolumn induced neutrophil apoptosis during passage of blood through the column due to the generation of small amounts of reactive oxygen species (ROS) in the column. Finally, suppression of colitis was seen upon injection of ROS exposed neutrophils into the model. Their results suggested that the Adacolumn not only depletes elevated and activated neutrophils and monocytes (myeloid lineage) from the circulation but also indirectly promotes expansion or activation of Breg, which are involved in maintaining regulatory T cells (Treg) [67]. In clinical settings, the Adacolumn has been associated with expansion of Treg, an increase in interleukin-10 level and a decrease of anti-nuclear antibodies titer [47, 68]. Figure 49.3 summarizes the immunomodulatory actions of the Adacolumn leukocytapheresis.

The Cellsorba leukocyte removal filter column (Fig. 49.1b) is developed by Asahi Kasei Medical in Japan and has been comprehensively described by Sawada et al. [69]. This system is also a direct blood perfusion device (Fig. 49.2). Blood access is from the antecubital vein in one arm and return via the antecubital vein in the contralateral arm. Alternative access sites may be used if necessary. Cellsorba uses a filter consisting of polyester non-woven fabric that non-selectively removes approximately 13.0 × 10⁹ leukocytes from the circulating blood during one treatment session [70]. The column is capable of removing almost 100 % of neutrophils and monocytes including macrophages and 30–60 % of lymphocytes when measured between the inlet and the outlet of the column [69].

The first major application of Cellsorba for the treatment of UC was undertaken in 1995 by Sawada et al. [71]. Cellsorba leukocytapheresis was administered five times at 1 week intervals for 5 consecutive weeks during intensive therapy and 5 times, at approximately 1 month intervals for 5 months during maintenance therapy to 13 patients with IBD (eight UC and five CD patients). Improved clinical response during the intensive therapy was seen in 11 of 13 patients (84.6 %); 6 of 8 UC patients (75.0 %) and 5 of 5 CD patients (100 %). The remission was maintained in 8 of 13 patients (61.5 %) during the maintenance therapy.

A multicenter trial was carried out in Japan to assess the efficacy and safety of Cellsorba vs corticosteroid therapy in patients with active UC refractory to conventional medication [69]. This was a controlled multicenter study with randomized assignment of 76 patients with UC to two groups. The 39 patients in the Cellsorba group received weekly leukocytapheresis for 5 consecutive weeks as an intensive therapy, which was added to the on-going drug therapy, while steroids were maintained but not increased. Leukocytapheresis was gradually reduced to one session every 4 weeks as maintenance therapy. In the high dose PSL group (n = 37), PSL was added or increased to 30–40 mg/day for moderately severe and to 60–80 mg/day for severe patients and was then gradually tapered. The Cellsorba group showed a significantly higher efficacy compared with PSL (74 % vs 38 %; P = 0.005) and lower incidence of side effects (24 % vs 68 %; P < 0.001).

Further, Sawada and colleagues [72] investigated the efficacy of Cellsorba leukocytapheresis in a multicenter trial using active and sham devices in a double-blind study with focus on assessing the placebo effect of extracorporeal circulation. Twenty-five patients with active UC of severe or moderately severe level were assigned to the active treatment or sham treatment. Six patients who did not meet the inclusion criteria were excluded at screening and 19 (ten in the active group and nine in the sham group) were included. Cellsorba leukocytapheresis was performed once a week for 5 weeks followed by two additional sessions during the following 4 weeks, at 2 weeks intervals. Corticosteroids and other concomitant medications were continued at the same dosage for 4 weeks. CAI showed that the active group achieved a significantly greater improvement (80 %, eight of ten patients) compared with the sham apheresis group (33 %, three of nine patients; P < 0.05). Although there was a significant advantage in favor of the active treatment, the total number of patients was rather small in this study. Likewise, patients had active UC refractory to conventional drug therapy and most of them were receiving concomitant corticosteroid. A similar study with a large cohort of patients with strict control of their concomitant medications is warranted to verify the results of this study.

Sawada et al. [73] further reported the efficacy and safety of Cellsorba in treating patients with severe or fulminant UC or toxic megacolon. Six patients were included and Cellsorba leukocytapheresis was performed three times per week for 2 weeks, followed by four further sessions in the following 4 weeks. Four of six patients improved and achieved remission, and the remaining two patients had to undergo colectomy while their symptoms had been reduced by Cellsorba. Further larger studies are essential to fully assess the efficacy of Cellsorba in this clinical setting.

In earlier studies, Sawada et al. [74] and Yamaji et al. [75], reported fluctuations in the leukocyte count in the peripheral blood during Cellsorba leukocytapheresis. The count fell to 20–40 % of the baseline level at 20–30 min after the start of each session. Cellsorba itself had a sustained removal performance in excess of 90 % of the baseline value for the circulating blood leukocytes [76]. Therefore, it appears that leukocytes from the marginal pools including the bone marrow , spleen and vessel walls compensate for the lost leukocytes during a session. This finding led to the concept and investigation of Cellsorba as a therapy for UC. It is believed that activated peripheral blood leukocytes serve as “primed reserve cells” which might include leukocytes that originally have been activated in the lymph nodes. During active IBD, this pool provides a sustainable supply of activated leukocytes for infiltration into the colonic mucosa. By depleting this pool, leukocytapheresis can, in effect influence the source of activated leukocytes in the marginal pools as well. Indeed, infiltration of activated leukocytes into the intestinal mucosa has been considered as a major factor in the etiology of IBD [1, 21, 26].

Perhaps a word of caution is warranted in relation to any leukocytapheresis procedure which depletes lymphocytes. Thus, a study by King and colleagues [77] indicates that the state of lymphopenia may promote the development of autoimmunity. Likewise, it is known that human diseases of autoimmune etiology often present with lymphopenia [59]. These findings led us to say that transient lymphopenia during Cellsorba leukocytapheresis potentially may trigger homeostatic T cell expansion-associated autoimmune disease. Accordingly, if a patient with UC develops autoimmune disease following exposure to Cellsorba, the transient lymphopenia can be suspected to have predisposed to the condition. Currently, treatment of ulcerative colitis and rheumatoid arthritis by Cellsorba are covered by the Japan health insurance system. In Europe, Cellsorba has been CE-marked and approved as medical device. In Table 49.1, typical efficacy outcomes for the Adacolumn and the Cellsorba filter column are presented.

In the first major study by Sawada et al. [71] in patients with IBD, flow cytometry revealed that patients who improved had a higher percentage of HLA-DR⁺, HLA-DR⁺CD3⁺, and HLA-DR⁺CD8⁺ cells (pro-inflammatory) at entry. The levels of these cells, CRP and erythrocyte sedimentation rate (ESR) decreased to within the normal range by the end of therapy. In contrast, patients who showed poor response to leukocytapheresis, CRP and ESR did not change. Cellsorba leukocytapheresis also affected the cytokine production [74, 75]. The levels of pro-inflammatory cytokines, TNF-α, IL-1β, IL-2, IL-8, and IFN-α were high in responders at entry and were significantly reduced by leukocytapheresis [85]. These cytokines are mainly secreted by activated peripheral blood leukocytes [86, 87]. Additionally, the level of IL-4, an immunoregulatory cytokine increased after leukocytapheresis [88]. These observations indicate that Cellsorba leukocytapheresis is associated with changes in cytokine profile in the disease state, returning to normality via inhibition of several pro-inflammatory cytokines and by stimulation of an immunoregulatory cytokine.

Andoh et al. [89] evaluated the alterations in circulating T cell subsets after Cellsorba leukocytapheresis therapy in 18 patients with UC. Peripheral blood was obtained within 5 min before and 5 min after leukocytapheresis therapy. The average number of lymphocytes, T and B cells were significantly decreased after Cellsorba (P < 0.01). The number of CD4⁺ and CD8⁺ T cells were also significantly decreased (P < 0.01), but the CD4⁺/CD8⁺ ratio did not change. Also, the number of CD45RO⁺CD4⁺ memory T cells significantly decreased. Using intracellular cytokine staining method, they showed that IFN-γ expressing (Th1) cells had significantly decreased after leukocytapheresis while there was no significant change in the number of IL-4-expressing (Th2) cells. The Th1/Th2 ratio was significantly decreased after Cellsorba.

IBD may be viewed as the consequence of an exuberant immune profile triggered and maintained by inflammatory cytokines including TNF-α, IL-6, IL-12, IFN-γ, IL-17, and others [19, 20]. This might be a major factor for IBD showing poor response to conventional drug therapy [1, 29, 90, 91]. Indeed, administrations of these agents, often at high doses over long periods of time can produce additional complications [1, 50, 73, 92, 93]. Further, it is true to say that for decades, drug therapy of IBD has been empirical rather than based on sound understanding of the disease mechanisms (poorly understood etiology). The current view is that treatment interventions targeted at inflammatory mediators (like biologicals) should be more effective and produce minimal side effects. Accordingly, the present era of antibody based therapy targeting specific cytokines, chemokines, and adhesion molecules represent some progress, albeit truly effective in a minority of treated patients [91, 94, 95]. Cytokines in particular represent the best validated therapeutic targets and it is logical to view cytokines as major causes of persistent intestinal inflammation. However, major sources of inflammatory cytokines include leukocytes of the myeloid lineage [86, 87], which in IBD are elevated [29, 30] with activation behavior [26], prolonged survival time [33] and are found in vast numbers within the inflamed intestinal mucosa [1, 21]. Granulocyte infiltration into the mucosal tissue indeed can predict relapse of both UC and CD [21, 58]. This indicates that during quiescent IBD, activated leukocytes infiltrate the intestinal mucosa and have a major role in mucosal inflammation, injury and IBD relapse [1, 21, 26, 58]. Indeed, leukocyte activation and prolonged survival is a feature of persistent inflammation and neutrophil mediated mucosal damage has been shown to be associated with the development of IBD [21, 26, 31, 32]. Accordingly, selective depletion of activated peripheral blood leukocytes by centrifugation, the Adacolumn or Cellsorba has been associated with dramatic efficacy and a marked reduction of inflammatory cytokines produced by leukocytes [28, 29, 45, 74, 75].

Naïve T cells preferentially recirculate between blood and secondary lymphoid tissues, entering lymph nodes from the blood by crossing high endothelial venules. After encountering the activated dendritic cells undergoing antigen presentation in the mesenteric lymph nodes, the naïve T cells become activated, proliferate and differentiate into activated effector T cells. These effector T cells then acquire the gut-homing receptors, integrin αβ₄β₇. Thus, colitogenic effector T cells, unlike naïve T cells can migrate efficiently to sites of inflammation [96], subsequently entering afferent lymphatic vessels and travel to local lymph nodes [93, 96–99]. In parabiotic mouse models, endogenous memory T cells in most peripheral tissues react in equilibrium with migrating blood-borne donor T cells within a week [100], suggesting that there is rapid recirculation of T cells in peripheral tissues. These recent understandings suggest that selective removal of these colitogenic activated effector T cells by leukocytapheresis should reduce the cellular components of IBD.