Rationale and clinical results of using leucocyte-derived immunosupportive therapies in HIV disease.

Leucocyte dialysates contain a number of substances which exert important effects on human cell-mediated immunity. In this report, we describe several properties of a designated subfraction, IMREGR-1, which is obtained by a second dialysis against a membrane having a 3500 m.w. cutoff. These include the ability to augment and accelerate reactions of delayed hypersensitivity against antigens to which the test subject has been previously sensitized, and the ability to enhance the expression in vitro on CD4 lymphocytes of the p55 subunit of the receptor for Interleukin-2. We also report our observation that in a patient with advanced HIV disease whose lymphocytes had lost there ability to properly express the IL-2 receptor, treatment with IMREGR-1 over a period of months restored the expression of the IL-2 receptor on the patient's CD4+ lymphocytes towards normal.

A novel methodology for quantitating the enhancement of cutaneous delayed-type hypersensitivity by IMREG-1: a measure of the immunopotentiation of cell-mediated immunity.

IMREG-1, a low-molecular-weight immunomodulator derived from normal human leukocyte dialysates, has been shown to enhance cutaneous delayed-type hypersensitivity (DTH) responses to recall antigens. Both IMREG-1 and the biologically active peptides (Tyr-Gly[YG] and Tyr-Gly-Gly[YGG]) identified therein are able to accelerate and enhance DTH in a concentration-dependent manner. In this study, we describe a novel methodology for analyzing and quantitating this response and demonstrate its use with data comparing drug to placebo. Subjects demonstrating prior sensitivity to a recall antigen (tetanus toxoid) received intradermal injections of tetanus toxoid alone (control) and either dilutions of IMREG-1 plus antigen, or placebo plus antigen, on the volar surface of the forearm. The response, as measured by area of erythema, was calculated and plotted as a function of time. The area under the resulting curve (AUC) was then determined by use of the trapezoidal rule, whereby the area of a trapezoid formed between each sequential pair of time points was calculated. The AUC computed for each site receiving a dilution of IMREG-1 or placebo (test) was compared with the AUC computed at the site that received antigen alone (control) by means of a test to control (T/C) ratio. The respective T/C ratios for designated dilutions of IMREG-1 or placebo provided a basis of comparison between responses to IMREG-1 and to placebo, while also controlling for individual sensitivity in response to antigen. We demonstrate in this study that the enhanced response to IMREG-1 plus antigen is statistically different from that seen with placebo plus antigen. This response, as a function to time, predominantly appears in the 12- to 24-hr period after injection, illustrating the ability of the immunomodulator to accelerate, enhance, and sustain a DTH response. We further conclude that the effect of IMREG-1 in this context is one of immunopotentiation of cell-mediated immunity.