Cell-mediated and humoral immune responses or renal transplant recipients with cytomegalovirus infections

Cell-mediated and humoral immune responses were determined in immunosuppressed renal transplant recipients. A micro-phytohaemagglutinin (PHA) stimulation test utilizing whole heparinized blood and a macro-PHA test utilizing separated, washed lymphocytes were used to study cell-mediated immunity. Humoral immune status was estimated by determining quantitative immunoglobulins and complement fixing (CF) antibody titres to cytomegalovirus (CMV) infection. Micro-PHA responses were found to be markedly depressed in patients undergoing immunosuppressive therapy and in patients with chronic uraemia. Macro-PHA responses were normal, indicating that serum factors were responsible for the depressed micro-PHA responses. Antibody responses to CMV infections were found to be ten to a hundred times higher than in normal persons. An inverse relationship was demonstrated between micro-PHA responses and peak CF antibody titres to CMV infections. Humoral immune responses appeared to compensate for depressed cell-mediated immunity as measured by the micro-PHA test. Four patients had very low micro-PHA responses, did not respond to their CMV infections with CF antibody, and died of mixed bacterial and viral infections. Serum immunoglobulins of two were studied and were shown to be greater than two standard deviations below the normal mean. These patients appeared more suppressed than other patients receiving similar therapy and thus probably retained higher concentrations of suppressive drugs.

Two separate genes controlling stimulation in mixed lymphocyte reaction in man

The genetic control of strong stimulation in the mixed lymphocyte culture reaction is determined by a separate gene (MLR-S) closely linked to the FOUR-locus of the HL-A chromosomal region. Three additional examples of siblings with recombination between FOUR-locus and MLR-S locus are presented which confirms the independent genetic control of mixed lymphocyte reaction from the control of HL-A antigens. The occurrence of two recombinant children in one family with four other children representing all possible HL-A haplotype-combinations, strongly supports the genetic mapping of the MLR-S determinants outside the HL-A chromosomal region. The experiments presented show that additional genes located within the HL-A region itself contribute with a weak stimulation of allogenic mixtures. These data are discussed in relation to the marginal stimulation of the mixed lymphocyte culture reaction which can be seen between unrelated individuals. It seems that a group of relatively histocompatible individuals can be defined by identity of the MLR-S locus but with differences on the weak MLC-determinants, and that this group for the purpose of clinical transplantation behaves as histocompatible individuals.

B and T lymphocytes in primary immunodeficiency disease in man

B- and T-cell populations in 32 patients with different forms of primary immunodeficiency disease were studied. The B-cells in peripheral blood were investigated with respect to surface immunoglobulins by means of immunofluorescence. The T-cell function was studied utilizing quantitation of proliferative response to phytochemagglutinin (PHA)(1) and delayed allergy to various antigens. In 10 patients lymph node lymphocytes were also evaluated 11 male children with infantile x-linked agammaglobulinemia were divided into two subgroups. One did not show immunoglobulin spots on peripheral blood lymphocytes at all, the other contained a very low percentage of IgM- and occasionally IgA bearing lymphocytes. Eight patients with common variable immunodeficiency had moderately decreased percentages of peripheral blood and lymph node lymphocytes with surface immunoglobulins, but these patients lacked immunoglobulin secreting cells. Four cases of isolated IgA deficiency had normal or high percentages, and two cases of ataxia-telangiectasia had high percentages of lymphocytes with IgA in so called receptor distribution in both peripheral blood and lymph nodes. In three patients with infantile combined immunodeficiency that had been corrected by marrow transplantation, the percentages of Ig-bearing lymphocytes increased to normal or high levels together with establishment of functional T-cell population and ultimate secretion of serum immunoglobulins. One case of Di George syndrome reconstituted by fetal thymus transplant showed gradual decrease of B lymphocytes in circulation parallel to restoration of T-cell population.

Third party mixed-leukocyte culture test: a potential new method of histocompatibility testing

The disparity index is an expression of histocompatibility difference between two siblings with identical human leukocyte antigen (HL-A) type who are nonreactive in mixed leukocyte culture (MLC) test. This index is derived from a third-party MLC test. The disparity index was found to be correlated with the severity of graft-versus-host reaction in bone marrow transplantation between HL-A-identical siblings. The disparity index may prove to be a useful means of predicting the severity of graft-versus-host reaction and the outcome of bone marrow graft when HL-A- and MLC-matched sibling donors are studied. The third-party MLC test is offered as a new method of histocompatibility testing. It may provide a useful model for the study of immunogenetics relative to so-called weaker histocompatibility determinants in man and experimental animals.

A new micromethod for evaluating lymphocyte responses to phytohemagglutinin: quantitative analysis of the function of thymus-dependent cells

We have developed a new micromethod for testing phytohemagglutinin stimulation of human lymphocytes. 50 mul of peripheral blood is incubated at 37 degrees C directly, without cell separation, with 50 mul of tissue culture medium containing 50mug of phytohemagglutinin for 24 hr. Then, 0.5 muCi of tritiated thymidine in 50 mul of tissue culture medium is added and incubated for an additional 16 hr. After incubation, erythrocytes are selectively lysed in distilled water, and white blood cells are trapped quickly on a Millipore filter. The radioactivity of the filter is then assessed by a scintillation counter. The requirement of extremely small amounts of blood and a short incubation time are advantages. Further, this method provides a most useful evaluation of thymusdependent cell populations in man and experimental animals and, for the first time, this method provides the possibility of quantitating the deficiency of thymus-dependent cells.