Assessment of Studies Evaluating Spinal Manipulative Therapy and Infectious Disease and Immune System Outcomes: A Systematic Review

IMPORTANCE

Claims that spinal manipulative therapy (SMT) can improve immune function have increased substantially during the COVID-19 pandemic and may have contributed to the rapid spread of both accurate and inaccurate information (referred to as an infodemic by the World Health Organization).

OBJECTIVE

To identify, appraise, and synthesize the scientific literature on the efficacy and effectiveness of SMT in preventing the development of infectious disease or improving disease-specific outcomes in patients with infectious disease and to examine the association between SMT and selected immunological, endocrine, and other physiological biomarkers.

EVIDENCE REVIEW

A literature search of MEDLINE, the Cumulative Index to Nursing and Allied Health Literature, the Index to Chiropractic Literature, the Cochrane Central Register of Controlled Trials, and Embase was conducted from inception to April 15, 2020. Randomized clinical trials and cohort studies were included. Eligible studies were critically appraised, and evidence with high and acceptable quality was synthesized using the Synthesis Without Meta-Analysis guideline.

FINDINGS

A total of 2593 records were retrieved; after exclusions, 50 full-text articles were screened, and 16 articles reporting the findings of 13 studies comprising 795 participants were critically appraised. The literature search found no clinical studies that investigated the efficacy or effectiveness of SMT in preventing the development of infectious disease or improving disease-specific outcomes among patients with infectious disease. Eight articles reporting the results of 6 high- and acceptable-quality RCTs comprising 529 participants investigated the effect of SMT on biomarkers. Spinal manipulative therapy was not associated with changes in lymphocyte levels or physiological markers among patients with low back pain or participants who were asymptomatic compared with sham manipulation, a lecture series, and venipuncture control groups. Spinal manipulative therapy was associated with short-term changes in selected immunological biomarkers among asymptomatic participants compared with sham manipulation, a lecture series, and venipuncture control groups.

CONCLUSIONS AND RELEVANCE

In this systematic review of 13 studies, no clinical evidence was found to support or refute claims that SMT was efficacious or effective in changing immune system outcomes. Although there were limited preliminary data from basic scientific studies suggesting that SMT may be associated with short-term changes in immunological and endocrine biomarkers, the clinical relevance of these findings is unknown. Given the lack of evidence that SMT is associated with the prevention of infectious diseases or improvements in immune function, further studies should be completed before claims of efficacy or effectiveness are made.

Modulation of biological responses of normal human mononuclear cells by antiestrogens

The effect of three non-steroidal antiestrogens, Tamoxifen, Toremifene and ICI 164, 384, on various aspects of the immune response was studied in cultures of normal peripheral mononuclear blood cells. The drugs differ somewhat in their effect on the functions tested (pokeweed mitogen-induced immunoglobulin synthesis and cell proliferation, mixed lymphocyte reaction, Interleukin 2 (IL 2) synthesis, IL 2 receptor expression and Tumor Necrosis Factor (TNF alpha) synthesis). However, all three are immunosuppressive. On the other hand, ICI 164, 384 and Tamoxifen were stimulatory for TNF alpha production by adherent cells which may prove as an additional feature in antiestrogen treatment.

Reversal of cyclosporine-induced mortality with a synthetic polymeric immunostimulant in a murine model of fecal peritonitis

We have been investigating the effects of a synthetic immunostimulative polymer known as copovithane (Cpv). This agent appears to enhance humoral immunity in untreated and cyclosporine-immunosuppressed mice and is nontoxic in rodents and man. The purpose of this study was to determine whether cyclosporine (CsA) is deleterious to survival in a murine cecal ligation, puncture, and excision (CLPE) model of fecal peritonitis, and--if so--whether this effect could be ameliorated by Cpv without interfering with skin allograft acceptance. Cpv significantly prolongs survival in the CLPE model; the optimal dose for this effect was found to be 100 mg/kg. CsA was found to have a significant and deleterious effect on survival at several dosage levels when administrated 48 and 24 hr before cecal ligation, and immediately before and 16 hr after cecal ligation. Using a dose of CsA sufficient for skin allograft acceptance and the same schedule of administration outlined above, Cpv 100 mg/kg was administered 48 hr prior to cecal ligation. Mice treated with CsA plus Cpv had significantly longer survival than mice treated with CsA alone; furthermore, the survival of CsA-plus-Cpv-treated animals was not significantly different from that of saline-treated controls. Acceptance and survival of H-2 incompatible skin allografts in mice treated with CsA were not affected by Cpv 100 mg/kg/week. We conclude that CsA-induced mortality in the CLPE model can be abrogated by Cpv without adversely affecting skin allograft survival. It may eventually be possible to reduce the incidence of septic complications in clinical allotransplantation by prophylactically administering Cpv to patients on CsA immunosuppression.

The effect of liver cytosol on hepatic regeneration and tumor growth

This report further evaluates the concept that the interaction of factors that originate within the liver can contribute, regulate or even initiate the actual development of hepatic regeneration after liver cell necrosis or partial hepatectomy. The effect of liver cytosol (100,000 g supernatant), both from intact adult rat liver (NLC) and from adult rat liver remnants that had been regenerating for 24 hours after 70% partial hepatectomy (PH) in posthepatectomy liver regeneration in the rat was studied. The specificity of the growth-controlling properties in liver cytosol was determined using tumor cells. The intraperitoneal administration of NLC after PH resulted in approximately 70-80% inhibition of the peak 3H-DNA specific activity seen in controls at 18 and 24 hours post-PH, with a significant increase in DNA synthesis at 31-40 hours post-PH. The intraperitoneal administration of RLC after PH, augmented the hepatic regenerative response normally produced. Autoradiographic determination of hepatic nuclear labeling confirmed the inhibitory and stimulatory properties of NLC and RLC respectively. Syngeneic NLC or RLC at six and 24 days after subcutaneous tumor inoculation resulted in significant inhibition of tumor growth for both a methylcholanthrene-induced bladder carcinoma (FBCa) and an HTC-hepatoma. The retardation of FBCa growth could be enhanced by administering NLC or RLC every three or seven days. Syngeneic and xenogeneic liver cytosol resulted in dose-dependent inhibition of P815 mastocytoma cell proliferation in vitro. It is apparent from these studies that both stimulatory and inhibitory factors can be extracted from liver tissue that not only influence liver cell regeneration, but also affect tumor growth. Further isolation and characterization of these factors may lead to an understanding of more fundamental problems such as the control of normal and malignant cell growth.

The effect of tranexamic acid on growth and spread of an experimental tumor model

In the spontaneously metastasizing murine P815 mastocytoma studied, exposure of the cell cultures to Tranexamic acid increased plasminogen activator activity (PAA) in the cytosol and in the primary solid tumors. These increased PAA levels were associated with an increased rate of metastasis to the liver.

Sensitization to low dose 5-fluorouracil. Subsequent enhancement of its systemic antitumor effect in the rat

This report describes a novel method of immunochemotherapy; the active immunization to the drug 5-fluorouracil (5-FU) with enhanced antitumor activity resulting from its subsequent systemic administration. Two metastasizing carcinomas in the Fischer strain (F344) rat have been used: a chemically induced bladder carcinoma (FBCa) and a spontaneous mammary adenocarcinoma (MACa). Both tumors grow rapidly and result in 100% mortality within 10 wk of implantation. Neither tumor is sensitive to systemic 5-FU alone. Intradermal sensitization to 5-FU before FBCa tumor implantation, followed by 5-FU administered systemically, resulted in significant tumor regression and improvement in survival with eradication of all tumor and cure in 20% of animals. A similar antitumor effect was observed with the MACa. A comparable drug effect was observed when methotrexate sensitization was given before FBCa implantation followed by systemic MTX. Specificity to the sensitizing drug was demonstrated by the lack of effect of sensitization with either 5-FU or MTX unless followed by systemic therapy with the requisite sensitizing agent. Sensitization to 5-FU has also been assessed after FBCa implantation followed by resection of the local tumor. Resection was performed after distant tumor metastases had occurred, and was followed by systemic 5-FU therapy. Whereas tumor resection alone failed to cure any animal, sensitization to 5-FU increased cure rate fourfold over animals receiving systemic 5-FU alone. Antibody to 5-FU in the sera of sensitized animals has been suggested by an immunoenzymatic staining technique and its specificity confirmed in a radioimmunoassay. It is postulated that a combination of the systemic agent and the antibody elicited to it by sensitization produces the significant antitumor effect observed. The antitumor effect observed with this new approach to immunochemotherapy warrants further experimental and clinical study.

Thymic hormone-induced accelerated development of antibody responsiveness to sheep red blood cells in the newborn mouse

The influence of thymic preparations on the kinetics of the development of PFC response to sheep erythrocytes was tested in mice 0 to 4 weeks old. Soluble thymic factor (STF) or thymic epithelial culture supernatant (TES) was prepared from the thymuses of C57B1/6 mice. STF was injected to gravid mice on day 13 or on day 18 of gestation. A marked acceleration in the appearance of PFC to SRBC was noted only in the offspring from those mothers having received STF on day 18. The ability to generate anti-SRBC response in vitro by splenocytes from 1- to 4-week-old mice was significantly improved in the presence of TES. The accelerated appearance of the response to a T-dependent antigen is attributed to increase in the ratio of T helper/T suppressor cells resulting from differentiation and/or clonal expansion under the influence of STF crossing of the placental barrier in the materno-fetal direction.

Detection of the circulating antibodies to teratocarcinomadefined antigens in patients with testicular tumours

Sera from twenty-three patients with primary or metastatic testicular tumours of germinal origin were tested for antibodies against teratocarcinoma-associated antigen(s), using an indirect immunofluorescence technique. Human and 129/Sv mouse sperm and mouse teratocarcinoma cell line 402 AX were used as target cells. A total of fifteen sera were identified as positive, six of them when tested against both sperm and tumour cells. Tail staining has been the most prevalent pattern of fluorescence on both human and murine spermatozoa. These observations suggest that antibody to a common teratoma-defined antigen(s) was detected in sera of patients with testicular tumours.