Phytohemagglutinin skin tests in cancer patients

Mitogen immunotherapy for HIV infections exemplified by phytohemagglutinin and pokeweed mitogen

The ideal treatment for HIV infections would supplement highly active antiretroviral therapy (HAART) started at the time of initial diagnosis with an agent that can facilitate cure in the briefest time possible to avoid adverse effects of extended HAART such as drug toxicity, noncompliance, and shortened telomere-induced replicative senescence of CD8 cells. As a crucial part of the regimen, the agent must be able to initiate killer reactions against the HIV, replenish CD4 cells, rejuvenate CD8 cells, block HIV invasion of CD4 cells, activate latent HIV-sequestering host cells, stimulate effective immune reactions against malignancies, generate effective immune responses against conventional and opportunistic infections, circumvent the treatment- and immune response-evading capacities of HIV mutations, and reconstitute immune and hematopoietic competences. Over the past decade, the L4 isolectin of PHA has been presented as a mitogen capable of meeting these goals as they have become defined, but its potential has not been recognized sufficiently to expedite its evaluation. Pokeweed mitogen (PWM) offers the major advantage of being up to 500 times more potent than PHA and has much smaller molecular weight (22,500 to 38,000 daltons versus approximately 125,000 daltons). Given by injection, it has demonstrated curative effects for metastatic malignancies in dogs and cats unassisted by ancillary therapy. Unlike PHA, PWM does not block the attachment of HIV gp 120 to CD4 membrane receptors, but it can obstruct CD4 cell invasion by binding with the CD4 receptors themselves. An expeditious manner of applying PWM would be to give minute doses of an ultra potent root extract capable of inducing a benign plasmacytoid lymphoblastic leukemoid reaction that reverses spontaneously after about 10 weeks. This might prove curative given in conjunction with HAART or possibly even without it. The preferred route of administration for the mitogens in humans would be intravenous although oral administration might prove more advantageous, particularly with PWM. These mitogens might be used singly or, if necessary, in combination after the toxicities have been carefully delineated in humans. Economic forces might restrict treatment availability solely to orally administered PWM therapy in poverty-stricken undeveloped countries if this were shown to be curative. These proposals originating from the authors long concerned with mitogen management of various disorders including HIV infections but only peripherally involved with their clinical applications, are offered for consideration by investigators perceptive enough to see the wisdom of exploring the curative possibilities.

The immunopharmacology of head and neck cancer: an update

Patients with head and neck squamous cell cancer have cell-mediated immune defects and anergy, which progress with disease. T-lymphocytopenia and dysfunction, monocyte dysfunction, prostaglandins, antigen-antibody complexes, serum and cell suppressive factors, radiation therapy and poor nutrition with zinc deficiency all contribute. Nevertheless, cell-mediated immunoreactivity to tumor is manifest in the majority of the patient's blood and regional nodes, and in the tumor itself by tumor-infiltrating lymphocytes. Lymphocytes from these sources cloned in the presence of interleukin-2 +/- tumor extracts show relatively specific cytotoxicity against squamous cell cancer. Humoral immunity is intact, and increased IgA and IgE levels and antibodies reactive to tumor antigens are common. Tumor-associated antigens detected in serum and tumor include carcinoembryonic antigen, tumor polypeptide antigen, squamous cell cancer antigens, tumor antigen-4 and various mucin antigens. The mucin antigens, in particular, can elicit T-cell responses. Humoral reactivity to such antigens is manifest in circulating immune complexes and immunoglobulin coating of tumor surfaces. Immunotherapeutic efforts in head and neck squamous cell cancer should logically employ T-cell adjuvants, contrasuppression and immunorestoration. Non-specific stimulation with bacille Calmette-Guerin (BCG), levamisole and other agents has not been successful. Encouraging results have been observed in limited trials with indomethacin and plasmapheresis. Early trials with local administration of low dosages of interferon-alpha, natural interleukin-2 and a natural interleukin mixture have produced partial and complete regressions with no toxicity and with intense leukocyte infiltration indicating cellular immunity. Efforts are needed to define the mechanisms and the antigens involved in these reactions. On the contrary, treatments with high dosages of recombinant interferon-alpha and interleukin-2 have yielded few responses and considerable toxicity. Combination strategies are discussed which may improve upon these initial immunotherapeutic effects of these low dose trials.

Theoretical benefits of mitogen applications for HIV-1 infections

Ideal treatment of HIV-1 infections should include an agent that can reverse the capacity of the virus to evade destruction by hiding in sanctuaries and by frequently mutating the epitopes it displays. The rapid proliferation of virions during the years of symptomatic quiescence obligates rapid replacement of CD4+ lymphocytes that leads to a gradual attrition of the T lymphocytes needed to control infections. In vitro evidences suggest that, given systematically, certain mitogenic lectins would interfere with HIV-1 invasion of CD4+ cells by blocking gp120 molecules on the viral membrane before activating T lymphocytes subsequent to binding with their Ti/CD3 molecules. The nonspecific nature of antiviral effector cells generated by this activation should circumvent HIV-1 mutations at the same time it reconstitutes depleted T lymphocytes, stimulates myelopoiesis, and reinforces resistance to malignancies and infections prevalent with the immunodeficiency state. Properly coordinating these effects with appropriate combinations of reverse transcriptase and protease inhibitors could theoretically expedite complete elimination of HIV in a timely fashion that shorten the required treatment duration and excludes the detrimental effects of virus mutations. The proper sequence of this treatment should be maximum reduction of the HIV-1 load with drug combinations, control of complicating infection by other means to reduce mitogen-induced tissue necrosis, and addition of systemic PHA-L4 administration regulated to maintain a 5-10 micrograms/mL serum concentration. The antiviral regimen should be continued an undetermined time beyond when HIV-1 is no longer detectable, and systemic L4 administration until satisfactory immunologic and hematologic competences are re-established. Partially-matched mitogen-activated adoptive leukocyte therapy might be additionally helpful.

Putative effects of mitogenic lectin therapy corroborated by alloactivation data

A firm theoretical case for PHA and other plant mitogens as superior immunomodulators has previously been presented, but direct confirmatory evidences have been compromised by experimental studies involving excessive dosages of erythroagglutinating PHA that often compromised the circulation in smaller animals, while inadequate amounts were applied in humans because this mitogen's availability in nonagglutinating form was restricted. The resulting underestimation of efficacy has failed to inspire the production of industrial quantities of mitogens required for reliable clinical trials. As a means of circumventing this dilemma, past favorable results from the immuno-stimulating activities of allocativation have been extrapolated to forecast the effects to be anticipated from mitogenic modulation. Such an extrapolation would underrate the latter's impact, which would neither be confined to stimulation nor dependent on the uncertainties of engraftment. This review cites clear examples showing that all recognized immune system pathways have been stimulated by alloactivation except perhaps the ADCC, and an example of this pathway's activation has been shown to have occurred with PHA therapy itself. Of the mitogenic lectins currently available, PHA, Con A, and PWM have each shown rare instances of hypersensitization that hopefully might be eliminated by exclusion of contaminants with recombinant DNA methods of production.

Nutritional status in advanced upper gastrointestinal cancer

Fifty-four patients with advanced upper gastrointestinal cancer were assessed for their nutritional status prior to any form of therapy. Anthropometric parameters--weight loss, arm muscle circumference, skin-fold thickness--and biochemical parameters--serum albumin and delayed cutaneous hypersensitivity reactions to purified protein derivative (PPD) and phytohemagglutinin (PHA)--were used for nutritional assessment. Using standard values for comparison, about 80% of all patients were found to be nutritionally depleted. Immunocompetence did not show significant correlation with other nutritional parameters.

An analysis of skin tests and their relationship to recurrence and survival in stage III and stage IV melanoma patients

One-hundred-two patients with Stage III and IV malignant melanoma were analyzed to determine whether immunologic status in terms of skin testing along with sex and age played a role in recurrence and survival. Before treatment, patients had skin tests with five recall antigens (monilia, mumps, PPD, SK-SD, trichophyton) along with phytohemagglutinin (PHA). Univariate statistical analysis revealed sex as the major significant variable with respect to survival for Stage IVB patients, with female patients surviving longer than males. Patients with resected disease and greater SK-SD skin test reactivity tended to survive longer than those with impaired reactivity. Similarly, reactivity to trichophyton was associated with improved survival among patients with metastases. A multivariate analysis of the patients shows improved remission duration with mumps positivity in Stage III and Stage IVA patients. It appears that certain skin tets analyzed in this fashion have prognostic importance in these patients and should be analyzed with other variables of disease status.