Allosensitized helper and cytotoxic T-lymphocyte clones differentially modulate endotoxin-stimulated macrophage function

Alterations in macrophage function may render the immunocompromised host more susceptible to infectious complications. Although allograft recipients are at increased risk of infection primarily because of pharmacologic immunosuppression, whether the process of allosensitization per se alters this risk is unknown. We therefore studied the effects of cloned allosensitized murine helper or cytotoxic T cells on both interleukin 1 (IL-1) and prostaglandin E2 (PGE2) production by syngeneic resident murine peritoneal macrophages. Endotoxin (lipopolysaccharide [LPS]) stimulated both IL-1 and PGE2 production in macrophages. Cloned T cells alone, with or without LPS pretreatment, produced neither IL-1 nor PGE2. After 48 hours of coculture with LPS-treated macrophages, cloned helper cells augmented IL-1 release by macrophages but inhibited PGE2 production. In contrast, cytotoxic T cells not only reduced IL-1 production by macrophages but also potentiated PGE2 release. These effects were not observed when macrophages were not first exposed to LPS. Thus, endotoxin renders macrophages more susceptible to allosensitized "help" (increases IL-1, decreases PGE2) or "suppression" (decreases IL-1, increases PGE2) by cytotoxic T cells. We hypothesize that, even in the absence of immunosuppression, the process of allosensitization itself may modulate the response to sepsis by altering host macrophage function.

Lipoxygenase pathway inhibition impairs the allograft response

The inflammatory response may play a critical role in determining the ultimate fate of the allograft. Certain inflammatory mediators derived from the arachidonic acid lipoxygenase pathway (e.g., leukotriene B4), stimulate T cell function in vitro, but their role in allograft rejection is unknown. Nordihydroguaiaretic acid (NDGA) inhibits both the lipoxygenase (LO) pathway and T cell function in vitro. In this study, we investigated the effects of systemic LO inhibition with NDGA on the in vivo generation of allospecific and natural killer (NK) effector cells and arachidonic acid metabolites from sponge matrix allografts in mice. In control animals, generation of both allospecific cytolytic and NK cells increased progressively up to 12 days after grafting. Sponge cell synthesis of both leukotriene B4 (LTB4) and the cyclooxygenase product prostaglandin E2 (PGE2) could also be detected over this period. Recipient NDGA treatment (50 mg/kg/day) impaired both the accumulation and the specific cytotoxic potential of lymphocytes in allograft. Compared with control animals (1196 +/- 30 pg/10(6) cells), cells from recipients of NDGA produced significantly less LTB4 (55 +/- 10 pg/10(6) cells, p less than 0.01) but produced normal amounts of PGE2 (340 +/- /255 +/- 22 pg/10(6) cells, p = NS), thus proving the specificity of the NDGA treatment on LO pathway function. We conclude that cells capable of metabolizing arachidonic acid by both pathways accumulate in sponge allografts, but LO activity is specifically suppressed by systemic NDGA. Furthermore, systemic LO inhibition reduces the nonspecific inflammatory component, as well as allospecific cytolytic and NK generation, without compromising animal survival. These studies suggest that suppression of specific components of the inflammatory response associated with allograft rejection by LO inhibition may be a useful approach to selective immunosuppression.

The centralized prenatal genetics screening program of New York City III: The first 7,000 cases

The Prenatal Diagnosis Laboratory of New York City (PDL) is a regional program for the prevention of genetic diseases. The administrative aspects of the establishment of the laboratory were described in papers I [Hsu, 1981] and II [Hsu and Benn, 1981] in this series. We now report our experience of the first 7,000 referrals to the laboratory. The laboratory achieved a success rate of 99.5% in obtaining a diagnosis. The frequency with which a repeat amniocentesis was required was 1.9%, usually attributable to inadequate initial amniotic fluid volume or condition. Cases were completed in an average time of 20.82 days. A total of 149 (2.13%) cytogenetic abnormalities were detected. There were 59 nonmosaic autosomal trisomies and 29 sex chromosome abnormalities. The incidence of unbalanced structural abnormalities (0.186%) was much higher than that reported in surveys of newborn infants largely because of the prenatal detection of cases with supernumerary chromosomes. The incidence of balanced structural abnormalities was also considerably higher than that found in surveys of the newborn population, in part because of the detection of subtle familial pericentric inversions of common chromosome regions (inv(Y)(p11q11), inv(2) (p11q13), and inv(1)(p11q13)). The incidence of cases with multiple independent chromosome abnormalities was no higher than expected by chance. A high incidence of mosaicism, pseudomosaicism, and maternal cell contamination was found. Screening for neural tube defects accounted for the detection of a further 16 abnormalities. Nearly all women with severely abnormal fetuses (trisomy 13, 18, 21) elected to terminate their pregnancy whereas only 62% of patients with a prenatally diagnosed sex chromosome abnormality elected to terminate their pregnancies. Full details of follow-up and confirmatory studies for unusual diagnoses are reported. Utilization of prenatal diagnosis in the New York City area has increased sharply since PDL became operational. The laboratory's success illustrates the role of a prenatal diagnosis laboratory that provides a service independent of the patient's financial status. The experience further shows the high degree of acceptance of prenatal diagnosis by individuals at high risk for a child with a genetic disorder.

Unexpected death of an infant sibling

When infants die suddenly and unexpectedly, family structures are abruptly altered. This loss and its subsequent changes affect remaining older siblings. New "big brother" and "big sister" roles are suddenly terminated, often in a catastrophic manner. Young surviving children are sometimes unable to understand the meaning of this event, its impact on the family, and their own role in what has occurred. In this study, 26 families that had sustained the sudden and unexpected death of an infant and that had surviving children were interviewed to obtain data about surviving siblings at least 10 months following the loss. Among the 26 families, there were 35 surviving siblings (ages 16 months to 6 years). The interview schedule sought information relevant to changes in patterns of sleep, toilet training, feeding habits, peer relationships, and parent-child interaction. Among these 35 surviving siblings, parents of 28 siblings (80%) perceived changes in their child's interaction with them, 24 siblings (69%) demonstrated changes in sleep patterns following the baby's death, and 13 siblings (37%) showed changes in social interaction. Regression in toilet training and changes in feeding patterns were infrequent and not areas of major concern for parents. These behavioral changes reflected both a continuum of adjustment by the child and a persistence of parental worries.

Polyagglutination due to combined T and Tk activation

The development of polyagglutination in vivo in two patients with an unusual presentation of features of both T and Tk activation is described. The problems of laboratory diagnosis of these red blood cell anomalies and the impact of these anomalies in clinical management is discussed.