A randomized, controlled phase III trial of nab-Paclitaxel versus dacarbazine in chemotherapy-naïve patients with metastatic melanoma.

BACKGROUND: The efficacy and safety of nab-paclitaxel versus dacarbazine in patients with metastatic melanoma was evaluated in a phase III randomized, controlled trial. PATIENTS AND METHODS: Chemotherapy-naïve patients with stage IV melanoma received nab-paclitaxel 150 mg/m(2) on days 1, 8, and 15 every 4 weeks or dacarbazine 1000 mg/m(2) every 3 weeks. The primary end point was progression-free survival (PFS) by independent radiologic review; the secondary end point was overall survival (OS). RESULTS: A total of 529 patients were randomized to nab-paclitaxel (n = 264) or dacarbazine (n = 265). Baseline characteristics were well balanced. The majority of patients were men (66%), had an Eastern Cooperative Oncology Group status of 0 (71%), and had M1c stage disease (65%). The median PFS (primary end point) was 4.8 months with nab-paclitaxel and 2.5 months with dacarbazine [hazard ratio (HR), 0.792; 95.1% confidence interval (CI) 0.631-0.992; P = 0.044]. The median OS was 12.6 months with nab-paclitaxel and 10.5 months with dacarbazine (HR, 0.897; 95.1% CI 0.738-1.089; P = 0.271). Independently assessed overall response rate was 15% versus 11% (P = 0.239), and disease control rate (DCR) was 39% versus 27% (P = 0.004) for nab-paclitaxel versus dacarbazine, respectively. The most common grade ≥3 treatment-related adverse events were neuropathy (nab-paclitaxel, 25% versus dacarbazine, 0%; P < 0.001), and neutropenia (nab-paclitaxel, 20% versus dacarbazine, 10%; P = 0.004). There was no correlation between secreted protein acidic and rich in cysteine (SPARC) status and PFS in either treatment arm. CONCLUSIONS: nab-Paclitaxel significantly improved PFS and DCR compared with dacarbazine, with a manageable safety profile.

L-glutaminase: suppression of lymphocyte blastogenic responses in vitro.

Continuous exposure to 0.1 international unit or more of Escherichia coli L-glutaminase inhibited responses of human lymphocytes to phytohemagglutinin, streptolysin O, and allogeneic leukocytes. Inhibition was completety reversed by removing the enzyme from the culture or adding L-glutamine but not L-asparagine. Cytoxicity did not occur. L-Glutaminase should be immunosuppressive in vivo.

Cells capable of colony formation in the peripheral blood of man.

Colony-forming cells have been found in the peripheral blood of man and have been grown in vitro by use of a soft agar gel technique. It has been possible to collect these cells with a blood-cell separator in numbers similar to those found in the peripheral circulation. Repeat leukapheresis of the same donor does not reduce the number of circulating colony-forming cells.

Antigen solubilized from human leukemia: lymphocyte stimulation.

Soluble antigen was extracted with hypertonic (3 molar) potassium chloride from the malignant cells of seven patients with acute leukemia. The antigen and leukemia cells were used to stimulate autologous patients' and allogeneic normal donors' lymphocytes in mixed lymphocyte cultures. The lymphocytes of six patients showed significant blastogenic responses to autologous antigen. In contrast, the lymphocytes of only one of seven normal donors responded to the soluble antigens. Both patients' and normal subjects' lymphocytes responded to the intact leukemia cells. The use of these antigens should facilitate the study of specific tumor immunity in human leukemia.

Blastogenic suppression and alloantibody activity of sera from renal allograft recipients.

To evaluate whether immunological enhancement plays a role in adaptation to renal allografts, we studied sera from transplant recipients to determine whether those which suppressed mixed leukocyte culture (MLC) responses in vitro contained alloantibodies reactive with donor cells. Sera from five of nine renal transplant recipients consistently and specifically suppressed autologous autologous MLC responses to donor cells without impairing the blastogenic responses to third-party leukocytes, soluble antigens, or nonspecific mitogenic agents. In three of the five cases the suppressive activity of the serum was striking; in two cases the effect was less marked but still readily demonstrable in studies designed to evaluate the dose of serum which provided optimal suppression of MLC responses. Serum from one of the recipients nonspecifically suppressed blastogenic activity both to donor cells and other stimuli. No alloantibody reactive with donor leukocytes was found in any of the sera which exhibited suppressive activity in MLC, whereas in one patient, serum which contained antibody reactive with donor cells did not suppress MLC response to that donor. These findings suggest that, if the serum factors which suppress MLC responses in vitro are enhancing antibodies, they are not detectable even with very sensitive techniques either because they are present in very low concentrations, belong to immunoglobulin classes other than IgA, IgG, or IgM, or are complexed with donor antigen in such a way that their ability to react with fresh donor cells in vitro is blocked.

Serial studies of immunocompetence of patients undergoing chemotherapy for acute leukemia.

Immunocompetence was followed serially for 1 yr from the onset of treatment in 55 adult patients with acute leukemia. The tests used were delayed hypersensitivity responses to a battery of five recall antigens (dermatophytin, dermatophytin 0, candida, streptokinase-streptodornase, and mumps) and in vitro lymphocyte blastogenic responses to phytohemagglutinin and streptolysin 0. There was a strong correlation between immunocompetence at the start of treatment and a good prognosis; 32/39 patients who subsequently entered remission were initially immunocompetent compared to 4/15 who failed to enter remission. In the complete remission group there was a decline in competence starting from 2 to 5 mo after the onset of treatment. In those who remained in remission for 1 yr, competence recovered at 6 mo and remained vigorous thereafter. In those who relapsed before 1 yr, the decline in competence occurred 1 mo before relapse and competence continued to decline progressively during the 1 yr follow-up period. These studies suggest that therapeutic approaches which restore immunocompetence or prevent its decline will improve both the remission rate and the remission duration of patients with acute leukemia.

Effect of BCG (Tice strain) on primary sensitization to 2,4-dinitrochlorobenzene and on established delayed hypersensitivity in human malignant melanoma.

Studies of primary sensitization and delayed hypersensitivity reactions to 2,4-dintrochlorobenzene (DNCB) and recall antigens were conducted in 71 patients with melanoma who were receiving BCG (Tice strain) immunotherapy by scarification. Similar studies were conducted in 32 control patients with melanoma who did not receive BCG. No significant differences were observed, in the various clinical stages, between patients receiving and those not receiving BCG, in terms of the frequency or intensity of primary sensitization to DNCB. Furthermore, there was no significant difference in delayed hypersensitivity to recall antigens between these groups of patients. The apparent discrepancy between the clinical benefit from BCG immunotherapy and its failure to stimulate certain parameters of cellular immunity in patients with melanoma is discussed.

The C1q binding test for soluble immune complexes: clinical correlations obtained in patients with cancer.

Sera from 134 selected patients with various types of cancer were tested for soluble antigen-antibody complexes by the C1q binding method. Sera from 85 healthy blood bank donors served as normal controls. C1q binding activity (C1q BA) values above the 95th percentile for healthy subjects were found in 83% of sera from patients with neoplastic diseases. The incidence of abnormal C1q BA values among patients with malignant melanoma was 83%, with breast cancer 74%, with colon cancer 75%, with lung cancer 88%, with leukemia and lymphoma 85%, and with miscellaneous tumors 94%. High C1q BA values were found most frequently in sera of patients who had been diagnosed relatively recently (within 5 mo) and who had evident residual disease after surgical treatment. Recurrence or progression of tumor growth occurred significantly more frequently in lung cancer patients with high C1q BA. DNA was not detected in cancer patients' sera and treatment with DNase did not decrease in C1q BA. C1q BA in sera could not be explained by the presence of antiglobulin antibodies. Sucrose density gradient ultracentrifugation studies of the serum C1q BA in 4 cancer patients showed that the major binding activity was found between 19S and 7S.

Evaluation of BCG administered by scarification for immunotherapy of metastatic hepatocarcinoma in the guinea pig.

In inbred guinea pigs, administration of Mycobacterium bovis strain BCG by scarification at a site distant from an excised skin tumor, but in the regional lymph node drainage, was evaluated for its immunotherapeutic effect on the development of lymph node metastases. Scarification was performed after surgical excision of intradermally transplanted syngeneic (line-10) hepatocarcinoma at a time when microscopic foci of tumor cells were present in regional lymph nodes. Various strains of BCG were evaluated for their immunotherapeutic potential: fresh-frozen Phipps, Pasteur, and Tice; and lyophilized Pasteur, Tice, and Connaught. Scarification commenced 3 days after surgical removal of the tumor and continued once a week for 5 weeks. Only lymph nodes from fresh-frozen Phipps- and Pasteur-scarified animals were significantly smaller than those in the control groups. Differences in lymph node weight correlated histologically with less detectable metastases. This cytostatic effect was short lived; eventually, the metastatic tumor growth was not significantly different from that of control animals. No significant differences were observed in mean survival time: All animals died as a result of metastases 3 months after tumor inoculation. These results demonstrated that limited scarification with BCG of certain strains temporarily inhibits the growth and proliferation of metastases in regional lymph nodes after removal of the primary tumor.

Studies on the antitumor activities of pyrimidinone-interferon inducers. I. Effect against artificial and spontaneous lung metastases of murine tumors.

Since pyrimidinone compounds induce interferon production in several animal species and have potent antivirus activities, it appeared important to determine whether these compounds could also induce antitumor activities in their recipients. Pyrimidinone compounds 2-amino-5-bromo-6-methyl-4-pyrimidinone (ABMP), 2-amino-5-brome-6-phenyl-4-pyrimidinone (ABPP), and 2-amino-5-iodo-6-phenyl-4-pyrimidinone (AIPP) were studied for their activities against artificial lung metastases of the weakly immunogenic spontaneous fibrosarcoma NFSa, the moderately immunogenic spontaneous mammary carcinoma MCa-K, and the strongly immunogenic 3-methylcholanthrene-induced fibrosarcoma FSa syngeneic to inbred C3Hf/Kam mice. In addition, the therapeutic efficacy of ABPP and AIPP was also determined against spontaneous lung metastases of NFSa. ABPP and AIPP given ip at 250 mg/kg for 2 or 3 consecutive days before or after iv inoculatin of NFSa, FSa, or MCa-K cells greatly reduced the number of tumor nodules developed in the lungs. ABMP, however, was considerably less effective. ABPP and AIPP were also effective in therapy of spontaneous lung metastases of NFSa, especially when these compounds were given before surgical removal of the primary tumor. Neither ABPP nor AIPP was effective against tumor nodules growing in whole-body irradiated (WBI) mice, but both protected mice against enhancement of lung metastasis formation induced by exposure to whole-body irradiation. ABPP was more effective than AIPP in inducing production of interferon in normal mice. When treated with ABPP, WBI mice, however, were unable to produce interferon. These results show that 6-phenyl-pyrimidinone compounds induce strong antitumor activities in mice, which correlated with neither tumor immunogenicity nor the ability of these agents to induce interferon, but which depended on the immune status of the tumor host.

Antiproliferative and antitumor activity of the 2-cyanoaziridine compound imexon on tumor cell lines and fresh tumor cells in vitro.

BACKGROUND: Imexon, a 2-cyanoaziridine, is therapeutic and reverses lymphadenopathy and splenomegaly in the LP-BM5 murine retrovirus-induced immunodeficiency disease (murine AIDS). It can restore chemotherapy-induced immunosuppression. Imexon reduced the incidence of lymphoma in severe combined immune deficient mice inoculated with human lymphocytes. PURPOSE: To determine its antitumor activity, we screened imexon against fresh human tumor cells and tumor cell lines. To determine the time-concentration relationships of its cytotoxicity, we studied the effects of imexon on macromolecular synthesis and on the cell cycle. METHODS: Imexon was incubated at 1-200 micrograms/mL with various tumor cell lines, mitogen-stimulated peripheral blood lymphocytes, and fresh tumor cells. Cell survival, macromolecular synthesis, and cell cycle progression were studied. RESULTS: The concentration of imexon that caused 50% inhibition of growth was under 10 micrograms/mL for lymphocytes stimulated with mitogens. It was about 3-10 micrograms/mL for B-cell lymphomas and both multi-drug-resistant and -sensitive myeloma cell lines. Imexon inhibited four of seven fresh lymphoma and 11 of 16 fresh myeloma biopsy specimens to less than 40% of the control. A 1-hour exposure of lymphoma cells to 50-100 microgram/mL followed by removal of drug by washing the cells and continuing culture resulted in greater than 95% inhibition during the next 48-72 hours. Imexon selectively inhibited protein synthesis during the first 24-48 hours of exposure of lymphoma and myeloma cells. Cells exposed to inhibitory concentrations of imexon were blocked in cell cycle progression. CONCLUSION: Imexon may be a potentially useful agent in the treatment of malignant disease, particularly lymphoid malignancies, and should be explored further.

Analysis of natural killer cell cytotoxicity of cancer patients treated with recombinant interferon.

Peripheral blood natural killer (NK) cell cytotoxicity of 24 cancer patients was studied prior to and after single and multiple injections of various doses of human leukocyte recombinant interferon-alpha clone A (IFN-alpha rA). The NK cell cytotoxicity of all cancer patients declined consistently 4 and 8 hours after a single injection of IFN-alpha rA. Twenty-four hours after the injection of IFN-alpha rA, NK cell cytotoxicity of patients with low NK cell phenotype (NK-LR) was significantly augmented, whereas that of patients with medium (NK-MR) or high (NK-HR) NK phenotype was depressed. After multiple injections of IFN-alpha rA, depression of NK cell cytotoxicity was observed in a number of NK-MR and NK-HR patients, but in some patients with NK-LR phenotype, further potentiation was observed. No direct correlation between the NK cell augmentation and serum IFN levels was detected. In in vitro studies, IFN-alpha rA, when added to cultures of target and effector cells of normal individuals in a dose of 10(3) U/ml, was efficient in augmenting NK cell cytotoxicity. NK cell cytotoxicity of cancer patients could also be augmented by the IFN-alpha rA preparation; however, this augmentation occurred only prior to in vivo IFN-alpha rA therapy. After IFN-alpha rA in vivo therapy, their NK cells became refractory to further in vitro IFN-alpha rA treatment.

Effect of immunotherapy with Corynebacterium parvum and methanol extraction residue of BCG administered intravenously on host defense function in cancer patients.

The effects of active nonspecific immunotherapy were studied in 42 patients receiving daily iv Corynebacterium parvum at 2 mg/m2 in 14-day courses and in 14 patients receiving iv methanol extraction residue of BCG (MER) at 0.5 mg/m2 weekly. The host defense evaluations included measurement of the number of adherent macrophage precursors per milliliter of blood (monocyte adherence), serum lysozyme, and antibody-dependent cell-mediated cytotoxicity (ADCC) of peripheral blood mononuclear cells to chicken red blood cells (CRBC) or human red blood cells (HRBC). During a single course of C. parvum, monocyte adherence did not rise significantly, whereas ADCC of peripheral blood mononuclear cells to CRBC and HRBC rose significantly (15.7-49.9% and 34.8-53.5% lysis of target cells, respectively). However, after a mean of 4.5 months on therapy, monocyte adherence increased an average of 7.5-fold. During weekly MER therapy, monocyte adherence, serum lysozyme, and ADCC of peripheral blood mononuclear cells to CRBC rose significantly within 4-7 days after the first dose (3.8-8.7 adherent cells/ml blood x 10(4), 7.6-10.8 microgram, and 34.4-41.4% target cell lysis, respectively). The host defense parameter, which was subnormal in the cancer patients (monocyte adherence), was boosted into the normal range in all the deficient patients by iv MER. The host defense parameters, which were normal or slightly elevated in the patients before therapy (serum lysozyme and ADCC of peripheral blood mononuclear cells to CRBC and HRBC), were hyperactivated above the upper limit of the normal range in 71.4, 71.4, and 50% of the patients, respectively, by iv MER. These methods can quantitatively reflect activation of monocytes and killer cells by C. parvum and MER and may be useful for evaluation and quantitation of both active nonspecific and immunorestorative immunotherapy in general.

Therapy of artificial and spontaneous metastases of murine tumors with maleic anhydride-divinyl ether-2.

A 15,500 molecular-weight fraction of a pyran copolymer, (MVE-2) was investigated for its therapeutic efficacy against artificial lung metastases of a weakly immunogenic spontaneous fibrosarcoma (NFSa), a relatively strongly immunogenic fibrosarcoma (FSa), a moderately immunogenic spontaneous mammary carcinoma (MCa-K-, and a weakly immunogenic spontaneous mammary carcinoma (MDAH-MCa-4) syngeneic to C3Hf/Kam mice. In addition, the therapeutic efficacy of this polyanionic compound against spontaneous lung metastases of NFSa was also determined. Systemic i.v. or i.p. application of MVE-2 in doses ranging from 10 to 50 mg/kg body weight greatly reduced the number of artificial NFSa lung metastases and prolonged the survival of the mice. Multiple injections of MVE-2 given at weekly intervals were more effective than were single treatments. Although various treatment schedules with MVE-2 were capable of reducing the number of metastases and prolonging survival of tumor-bearing mice, no cures were observed. A therapeutic effect was also evident against spontaneous lung metastases of NFSa. The effect, however, was more profound when MVE-2 was given before rather than after surgical removal of the primary tumor. MVE-2 was not effective in mice exposed previously to whole-body or local thoracic irradiation. In contrast, MVE-2 protected mice against enhancement of lung metastases induced by exposure of the mice to these irradiations. NFSa growing i.m. promoted the formation of lung metastases from tumor cells given i.v. This concomitant enhancement of metastases was abolished by treatment of the mice with MVE-2. MVE-2 was also effective against tumor deposits in the other three tumors. The extent of its therapeutic efficacy was independent of tumor immunogenicity. These results suggest several approaches to the clinical application of MVE-2 and provide additional data on the therapeutic activity of the pyran copolymer derivatives in different animal models.

Radiosensitive, thymic hormone-sensitive peripheral blood suppressor cell activity in cancer patients.

Suppressor cell activity which was radiosensitive in most subjects and thymic hormone sensitive in some was identified in patients with cancer, and compared to simultaneously studied normal controls. Suppressor cell activity was measured in cocultures of normal lymphocytes with patient lymphocytes added in microwells using the blastogenic response to phytohemagglutinin and concanavalin A as the measure of activity. Thirty-five patients (lung cancer, 21; leukemia in remission, seven; and various solid tumors, seven) and an equal number of controls were studied. Suppressor cell activity was identified in 71% of the patients. In approximately 75% of these, the suppressor cell activity was radiosensitive (4000 to 6000 rads). For the phytohemagglutinin response, suppressor cell activity was thymic hormone sensitive in approximately 40% (Thymosin Fraction 5 or thymic humoral factor), and for the concanavalin A response, it was thymic hormone sensitive in about 25% of the cases. There was a significant correlation between the presence of immunodeficiency (defined as a phytohemagglutinin response < 35,000 or a concanavalin A response < 12,000 cpm) and the presence of the suppressor cell activity. The suppressor cell activity was heterogenous relative to its radiosensitivity and thymic hormone sensitivity. Suppressor cell activity was observed in all the patient categories. These results indicate that certain available therapeutic manipulations may have significant effects on suppressor cell activity and should be an important subject for further investigation.

Antibody development to viral and allogeneic tumor cell-associated antigens in patients with malignant melanoma and ovarian carcinoma treated with lysates of virus-infected tumor cells.

Pre- and postimmunization sera from six malignant melanoma and six ovarian carcinoma patients were used to investigate the humoral immune response to antigens expressed in extracts of allogeneic tumor cells and lysates of these same cells infected with virus. Nitrocellulose paper replicas of cell extracts, fractionated by polyacrylamide gel electrophoresis, were used as antigenic targets. Antibodies that bound to tumor cell antigens of defined molecular weight were identified with enzyme-linked probes specific for human immunoglobulins G, A, and M. Prior to therapy, all sera reacted with one or more antigens expressed by the unmodified tumor cells. Postimmunization sera from two malignant melanoma patients and one ovarian carcinoma patient reacted with antigens in extracts of uninfected tumor cells. These same antigens were not detected by preimmunization sera. Most postimmunization antibody responses were directed against antigens associated with the infecting virus itself and antigens found in extracts of virus-infected but not in extracts of uninfected tumor cells. These results suggest that treatment with lysates of virus-infected allogeneic human tumor cells elicits humoral immune responses against: (a) tumor cell-associated antigens; (b) antigens that are specifically virus associated; and (c) antigens that may be virus induced or virus modified cytoplasmic or nuclear antigens.

A human monoclonal antimelanoma single-chain Fv antibody derived from tumor-infiltrating lymphocytes.

With the development of recombinant DNA technology, it has become feasible to clone, construct, and express fully human immunoglobulin molecules. Here we report a novel methodology to make human antitumor single-chain Fv (scFv) antibodies from tumor-infiltrating B lymphocytes. We isolated and expanded tumor-infiltrating B lymphocytes from melanomas in the presence of Epstein-Barr virus. The transformed B cells secreting tumor-specific antibodies were identified and cloned by limiting dilution. From one B cell clone with specific melanoma reactivity, we captured the immunoglobulin variable region genes VH and Vk by PCR, sequenced the genes, and linked them together by PCR assembly with the use of a (Gly4Ser)3 linker. The scFv gene was then cloned into the pET21d vector and expressed. The obtained scFv protein with a M(r), of 29,000 was purified and biotinylated for further characterization. The scFv demonstrated specific tumor reactivity to 21 of 24 different melanoma cell lines and not to 14 nonmelanoma tumor cell lines, such as breast, ovarian, and colon cancer cells lines; normal human melanocytes as well as normal human leukocytes. These results were obtained in (a) a tumor cell ELISA, (b) fixed cell immunofluorescence, and (c) live cell flow cytometry. The immunoprecipitation results indicated that a protein antigen of M(r) 45,000 was recognized by the scFv. Since we reported previously that about 70% of human tumors of different histological types contain tumor-infiltrating B lymphocytes producing specific antitumor antibodies, this approach offers a rapid, effective method by combining in vitro B-cell expansion and PCR gene cloning to elucidate the repertoire of the human antitumor immune response and to make human monoclonal antitumor antibody molecules.

Immunomorphological features of prognostic significance in Dukes' Class B colorectal carcinoma.

Histological slides of primary tumors and regional lymph nodes from 134 unselected patients operated on for colorectal carcinoma of Dukes' Class B were assessed semiquantitatively for the presence of perivascular lymphocyte cuffing in the muscular layers and pericolic/subserosal fat immediately subjacent to the tumors and for paracortical hyperplasia in the regional lymph nodes. These two immunomorphological features related significantly to each other (p less than 0.05), and their combined presence related signifcantly to favorable disease-free interval (p = 0.02) and to survival (p = 0.04), making possible the identification of a subgroup of approximately one-third of Dukes' B class patients with an estimated better than 85% chance for 5-year recurrence-free survival.

Purification and characterization of high-affinity cyclic adenosine 5'-monophosphate phosphodiesterases from human acute myelogenous leukemic cells.

Soluble, high-affinity cyclic adenosine 3':5'-monophosphate (cyclic AMP) phosphodiesterases extracted from blast cells of patients with acute myelogenous leukemia have been characterized by physical, kinetic, and immunological criteria and fractionated to a high degree of purity. Procedures used in this study were similar to those used to purify the high-affinity enzyme from dog kidney. Two forms of high-affinity enzyme were found in blast cells. Form A was similar to the known type IV phosphodiesterases, including those of normal lymphocytes and monocytes. It showed a molecular weight near 60,000, a rate of hydrolysis of cyclic AMP 7 to 10 times that of cyclic guanosine 3':5'-monophosphate (cyclic GMP), competitive inhibition by cyclic GMP for cyclic AMP hydrolysis, and identical immunoreactivity by Western transfer analysis. This enzyme form was purified to apparent homogeneity by physical criteria but showed a low maximum velocity relative to other phosphodiesterase forms. A second, different form of high-affinity phosphodiesterase (Form B) was also resolved and partially purified. By comparison with Form A, this enzyme eluted from diethylaminoethyl cellulose at slightly lower ionic strength, had a lower molecular weight, appeared specific for cyclic AMP as substrate, showed no inhibition of cyclic AMP hydrolysis by cyclic GMP, and displayed no immunological cross-reactivity to the Mr 60,000 enzyme. Neither enzyme form was activated by calmodulin or proteolysis, whereas both showed comparable inhibition by 6,7-dimethoxy-1-veratrylisoquinoline, 1-methyl-3-isobutylxanthine, and 1,3-dimethylxanthine.

Immunological characterizations of patients with acquired immune deficiency syndrome, acquired immune deficiency syndrome-related symptom complex, and a related life-style.

Immunological, hematological, and biochemical studies were done at the time of referral in 135 homosexual subjects, 28 of whom were symptom free (SF), 74 of whom had the acquired immune deficiency syndrome (AIDS)-related symptom complex (ARC), and 33 of whom had AIDS with Kaposi's sarcoma, opportunistic infection, or both. Of 38 laboratory parameters, 11 were significantly different than controls in the SF patients, 19 in the ARC patients, and 20 in the AIDS patients. In SF patients, delayed hypersensitivity was significantly suppressed for 6 of 12 recall antigens. In addition, the percentage of circulating lymphocytes, the percentage of T3+ cells, the percentage and absolute number of T4+ cells, the T4/T8 ratio, the blastogenic responses to phytohemagglutinin, pokeweed mitogen, and concanavalin A were depressed significantly in this group. In contrast, the percentage and absolute granulocyte count, the serum lysozyme, and the serum thymosin alpha 1 were significantly elevated in these patients. In patients with more advanced disease (ARC and AIDS), immunological and hematological parameters tended to worsen. Thus, in the AIDS patients the white blood cell count, percentage, and absolute T11+ cells, absolute T3+ cells, percentage of T4+ cells and absolute level of B-cells, as well as the monocyte adherence and delayed hypersensitivity responses to 12 of 12 recall antigens were depressed. Serum levels of thymosin alpha 1 were equally elevated in all three groups. Serum interferon was found in 15 of 18 opportunistic infection patients with or without Kaposi's sarcoma, in 3 of 9 Kaposi's sarcoma patients without opportunistic infection, but in none of the ARC or SF patients. This study has demonstrated that SF sexually active homosexuals have a characteristic pattern of immune deficiency and that immunodeficiency worsens as one compares SF to ARC to AIDS patients. The study has provided a data base for the development of prognostic criteria and for characterization and evaluation of immunorestorative and immunomodulatory therapy.