A syndrome associating partial albinism and immunodeficiency

Unconventional myosins in cell movement, membrane traffic, and signal transduction

In the past few years genetic, biochemical, and cytolocalization data have implicated members of the myosin superfamily of actin-based molecular motors in a variety of cellular functions including membrane trafficking, cell movements, and signal transduction. The importance of myosins is illustrated by the identification of myosin genes as targets for disease-causing mutations. The task at hand is to decipher how the multitude of myosins function at both the molecular and cellular level-a task facilitated by our understanding of myosin structure and function in muscle.

Human herpesvirus-6 (HHV-6)-associated necrotizing encephalitis in Griscelli's syndrome

We report a male caucasian German pediatric patient of no Arab or Mediterranean ancestry with virus associated CNS lesions in Griscelli's syndrome (GS; McKusick No. 214450). The boy presented with recurrent infections, and meningitis with subsequent progressive signs of increased intracranial pressure leading to death at 32 weeks of age. At autopsy, various sites of the CNS revealed necroses in gray and white matter. CNS histology revealed numerous and massive predominantly perivascular CD8 positive lymphohistiocytic infiltrates. These findings were associated strictly with the presence of human herpesvirus-6 (HHV-6) genome or the HHV-6 specific late antigen H-AR 3, found in neurons, oligodendrocytes, and astrocytes. The search for HHV-6 replication dependent antigen, HHV-7 DNA, CMV, adenovirus, Coxsackie B1, B2, and B4-antigens, and mycobacteria was not successful. Detection of viruses was attempted using immunohistochemistry, in situ hybridization or nested polymerase chain reaction, respectively. Lymphocyte typing was carried out immunohistochemically. In GS, virus induced CNS damage does not seem to require necessarily active virus replication. It may also appear as a consequence of an immune reaction triggered by antigen expression.

Griscelli disease maps to chromosome 15q21 and is associated with mutations in the myosin-Va gene

Griscelli disease (OMIM 214450) is a rare autosomal recessive disorder characterized by pigmentary dilution, variable cellular immunodeficiency and onset of acute phases of uncontrolled lymphocyte and macrophage activation, leading to death in the absence of bone-marrow transplantation. The pigmentary dilution is characterized by a diffuse skin pigmentation, silvery hair, large clumps of pigments in the hair shafts (Fig. 1) and an accumulation of melanosomes in melanocytes, with abnormal transfer of the melanin granules to the keratinocytes. Immunological abnormalities are characterized by absent delayed-type cutaneous hypersensitivity and an impaired natural-killer cell function. A similar disorder has been described in the dilute lethal mouse--which, however, differs by the occurrence of a severe neurological disorder. The dilute locus encodes myosin-Va, a member of the unconventional myosin family. Myosins bind actin and produce mechanical force through ATP hydrolysis. Some members of this family are thought to participate in organelle-transport machinery. Because of the phenotype resulting in the dilute mouse and because of their potential role in intracellular transport, unconventional myosin-encoding genes were regarded as candidate genes for Griscelli disease. Here we report that the Griscelli disease locus co-localizes on chromosome 15q21 with the myosin-Va gene, MYO5a, and that mutations of this gene occur in two patients with the disease. Griscelli disease is therefore a human equivalent of dilute expression in the mouse.

Immunodeficiency as a component of recognizable syndromes

Immunodeficiency occurs in numerous genetic syndromes. While it is the dominant manifestation in primary immunodeficiencies, immune deficits may also be seen in a variety of other recognizable syndromes. Immunodeficiency has been reported in 64 such conditions, adding to the 45 recognized primary immunodeficiencies. These uncommon syndromes with immune defects can present with: (a) growth deficiency (11 syndromes with disproportionate or proportionate short stature), (b) specific organ system dysfunction (18 with gastrointestinal, dermatologic, or neurologic abnormalities), (c) inborn errors of metabolism (13), (d) miscellaneous anomalies (10), or (e) chromosome anomalies (12). In most of the disorders, only some of the affected patients have immune defects. However, in 27 syndromes, immunodeficiency is a constant finding. We briefly review the clinical manifestations of each syndrome and delineate the specific associated immune defects. In most syndromes, the connection between the immune and other defects is unknown. Recognition of these conditions involving both the immune and other organ systems may facilitate accurate diagnosis and management as well as yield information regarding genes critical for the development of the involved systems.

Histiocytoses

Childhood histiocytoses are a rare and diverse group of histiocytic disorders. This review will focus on clinical, pathological and immunopathological features of these syndromes. The pathogenesis of Langerhans' cell histiocytosis or class I histiocytosis, a proliferative disorder of the Langerhans' cell, remains enigmatic. Approaches to treatment are as varied as the clinical presentations, ranging from a fatal leukaemia-like disorder to solitary lytic lesions of bone. Recent findings indicate that Langerhans' cell histiocytosis is a clonal histiocytic disease. The two major class II histiocytoses are familial erythrophagocytic lymphohistiocytosis and the reactive haemophagocytic syndromes. The clinicopathological similarities between these two entities suggest that they share a common immunological feature in which uncontrolled cytokine release from activated T-cells leads macrophages to a haemophagocytosing state.

Griscelli syndrome: report of three cases

The clinical features of three children with Griscelli syndrome and autopsy findings of two are presented. The patients were 5 years, 9 months, and 3 months old, respectively. Clinical features included partial albinism, hepatosplenomegaly, and various neurological symptoms. Light and electron microscopic studies of the skin were compatible with Griscelli syndrome. Postmortem examination of the viscera and central nervous system revealed lymphohistiocytic infiltration with erythrophagocytosis. Bilateral diffuse involvement of the central nervous system, cranial nerve, and spinal cord was detected in both cases.

Partial albinism with immunodeficiency (Griscelli syndrome)

Partial albinism with immunodeficiency is a rare and fatal immunologic disorder characterized by pigmentary dilution and variable cellular immunodeficiency. To define the phenotype, therapy, and outcome, we retrospectively analyzed seven consecutive patients. Primary abnormalities included a silvery-grayish sheen to the hair, large pigment agglomerations in hair shafts, and an abundance of mature melanosomes in melanocytes, with reduced pigmentation of adjacent keratinocytes. Clinical onset occurred between the ages of 4 months and 4 years and was characterized by accelerated phases (lymphohistiocytic infiltration of multiple organs, including the brain and the meninges), triggered by viral and bacterial infections. Characteristic laboratory features included pancytopenia, hypofibrinogenemia, hypertriglyceridemia, and hypoproteinemia. Consistent immunologic abnormalities were characterized by absent delayed-type cutaneous hypersensitivity and impaired natural killer cell function. Some patients had secondary hypogammaglobulinemia, impaired major histocompatibility complex-mediated cytotoxic effects, a decreased capacity of lymphocytes to trigger a mixed lymphocyte reaction, or various functional granulocytic abnormalities. The disease seems to be invariably lethal without bone marrow transplantation; the mean age at the time of death was 5 years. Bone marrow transplantation has been performed in three cases; two patients died in the immediate posttransplantation period of infectious complications, but one patient is cured after a follow-up of 5 years. We conclude that partial albinism with immunodeficiency (Griscelli syndrome) can be differentiated from Chédiak-Higashi syndrome by pathognomonic histologic features. One of the underlying immunologic defects may be a defective function of natural killer cells, predisposing the patient to virus-associated hemophagocytic syndrome or accelerated phases. The prognosis is very poor unless early bone marrow transplantation is carried out.

Oculocutaneous albinism, immunodeficiency, hematological disorders, and minor anomalies: a new autosomal recessive syndrome?

We report on 2 related children, a boy and a girl, from a large Turkish clan. Their parents are both first cousins and have several common ancestors. Both children have tyrosinase-positive oculocutaneous albinism, recurrent bacterial infections, granulocytopenia, intermittent thrombopenia, and microcephaly, a protruding midface, rough and projecting hair, and mild mental retardation. Chromosomes are normal. Metabolic disorders were excluded. None of 14 well-known types of albinism, including Hermansky-Pudlak syndrome and Chediak-Higashi syndrome, nor any other genetic syndrome, characterizes our patients sufficiently. Thus, this combination of symptoms is considered a new autosomal recessive syndrome.

A kindred with Griscelli disease: spectrum of neurological involvement

We report four members of a highly consanguineous family with silver-grey pigmentation of hair, two of whom had skin histology compatible with Griscelli disease. Unlike previously reported patients, they did not suffer from recurrent infections. In addition, there was a spectrum of neurological involvement varying from mild cognitive delay with a convulsive disorder in one patient, to a fatal degenerative course in three others. One patient developed a prolonged febrile illness with histological evidence of florid lymphoid hyperplasia.

Prenatal diagnosis of syndromes associating albinism and immune deficiencies (Chediak-Higashi syndrome and variant)

We have successfully undertaken the prenatal diagnosis of two hereditary syndromes associating albinism and immune defects. Because the genes responsible for these diseases have not yet been mapped and the immune abnormalities are too subtle to be diagnosed in utero, the prenatal diagnosis was made using a morphological approach. In the case of Chediak-Higashi syndrome, it was based on light microscopic examination of the hair shaft and on light and electron microscopic study of polymorphonuclear cells. In the syndrome associating immune deficiency and partial albinism, the Griscelli syndrome, only examination of the hair was feasible. The diagnosis was negative in 12 fetuses at risk and positive in four.

Riyadh chromosome breakage syndrome: mental retardation with depigmentation of the skin and hair

A 20-month-old infant with "silvery-blond" hair color, widespread confettilike depigmentation of the skin, and mental retardation was found to have, in lymphocytes and fibroblast cultures, increased spontaneous chromosome breaks and breaks induced by both mitomycin and gamma-irradiation. The sister chromatid exchange frequency was normal. This child probably represents a new chromosome breakage syndrome.

Griscelli disease with cerebral involvement

A 9-month-old Turkish boy was diagnosed as having Griscelli disease (Chediak-Higashi-like syndrome). Clinical signs consisted of silver-grey hair and a relatively light skin colour, recurrent episodes of fever, with or without detectable infections, increasing hepatosplenomegaly, hypotonia and motor retardation. Laboratory studies showed pancytopenia of varying degree but neither inclusion bodies nor vacuoles were seen in his leucocytes. Serum immunoglobulin levels were normal except for a IgG2 deficiency. In the mixed lymphocyte reaction the stimulation capacity of the leucocytes was decreased. Microscopic examination of his hair and electron-microscopic examination of a skin biopsy further confirmed the diagnosis. Shortly before the diagnosis was made, the child developed cerebral symptoms with hemiparesis and convulsions. A CT scan suggested cell infiltration of the brain. A few weeks later the boy died of an infection.

Bone marrow transplantation (BMT) for the syndrome of pigmentary dilution and lymphohistiocytosis (Griscelli's syndrome)

We report the successful treatment of the syndrome of pigmentary dilution and immunodeficiency (Griscelli's syndrome) with allogeneic bone marrow transplantation. Griscelli's syndrome includes silvery hair, recurrent infections, hepatosplenomegaly, progressive neurologic deterioration, and lymphohistiocytosis and is uniformly fatal. We present a family in which four of seven children of consanguinous parents were affected. The affected children were all born with silvery hair. Microscopic examination of the hair showed large clumps of pigment in the hair shaft. Skin biopsy revealed an accumulation of melanosomes in the melanocytes. Three of the affected children were deceased before 20 months of age. Pathology of liver and lung in two of the siblings showed an infiltration of lymphocytes and histiocytes. Immunologic studies in one of these cases were notable for a decreased number of T cells and poor T-cell mitogen stimulation with concanavalin A (Con A) and pokeweed mitogen (PWM). Recently, a fourth sibling with silvery gray hair was referred to us at 3 months of age for evaluation. T-cell function studies were normal and she appeared in overall good health. Because of the expected fatal outcome, allogeneic bone marrow transplantation was performed at 4 months of age. Two years later the patient remains in excellent health. This suggests that cells of hematopoietic origin are responsible for the fatal outcome in Griscelli's syndrome and that bone marrow transplantation early in the course of the disease is an important modality for treatment of this syndrome.

Biology of hypopigmentation

A review of the basics of pigment cell biology is followed by a discussion of the characteristics of several disorders of hypopigmentation. By determining such features as inheritance pattern, time of onset (congenital, childhood, adulthood), natural history (stable vs progressive), type of pigment loss (diffuse or circumscribed), distribution of lesions (generalized vs localized), degree of pigment loss (incomplete or complete), number of melanocytes, if any, in biopsy specimens of affected areas, type of melanocytic dysfunction, and associated inflammation or infection, one can classify the disorders of hypopigmentation. The proposed pathophysiology for each disorder of hypomelanosis is presented.

Agenesis of the corpus callosum, combined immunodeficiency, bilateral cataract, and hypopigmentation in two brothers

We describe 2 brothers with a malformation syndrome consisting of agenesis of the corpus callosum, cutaneous hypopigmentation, bilateral cataract, cleft lip and palate, and combined immunodeficiency. The clinical history of both patients was characterized by severe psychomotor retardation, seizures, recurrent severe respiratory infections, and chronic mucocutaneous candidiasis. The children died of bronchopneumonia at age 2 and 3 years, respectively. Immunological investigations showed, in one sib studied, skin anergy to recall antigens, profound depletion of T4+ lymphocytes, and serum IgG2 deficiency. Necropsy showed agenesis of the corpus callosum, hypoplasia of the cerebellar vermis, and profound hypoplasia of the thymus and of the peripheral lymphoid tissue. The distinctive features of these sibs appear to define a previously undescribed hereditary MCA/MR syndrome. The clinical and pathological findings seem to indicate, as a pathogenetic mechanism, a defect involving the embryonic organization of the central nervous system and of the immune system.

Megaloblastic anemia and immune abnormalities in a patient with methionine synthase deficiency

We report a case of methionine synthase deficiency associated with cellular immune deficiency discovered in a 14-year-old boy. Principal findings were: developmental delay, recurrent upper and lower respiratory tract infections, megaloblastic anemia, discovered at 3 months of age, unresponsive to cyanocobalamin and poorly responsive to folinic acid. Biochemical studies showed: an abnormal deoxyuridine suppression test despite normal serum folate, cobalamin and transcobalamin levels; a normal intracellular uptake of these two coenzymes; and an absolute requirement of methionine for fibroblast growth, suggestive of defective methionine synthesis. An absence of methionine synthase activity in the patient's bone marrow and a profound depression of this activity in lymphocytes and liver were found. Hypergammaglobulinemia with variable lymphopenia, depressed lymphocyte transformation after lectin or recall-antigen stimulation, defective delayed-type hypersensitivity and decreased natural killer activity were noted as well. The patient died at the age of 14.

Human immunodeficiency virus-associated vitiligo: expression of autoimmunity with immunodeficiency?

Persistent viral infections have been postulated to be trigger factors for the development of autoimmune disease. We report the development of vitiligo in four patients with human immunodeficiency virus (HIV)-related conditions and in one patient with hepatitis who later developed both psoriasis and acquired immunodeficiency syndrome (AIDS). Other common features were hepatitis and multiple other viral infections. Ribavirin was associated with repigmentation in one patient. Vitiligo may be an example of an autoimmune disease triggered by viral infection in a genetically predisposed host.

Lymphohistiocytosis: a multi-factorial syndrome of macrophagic activation clinico-pathological study of 38 cases

Lymphohistiocytosis (LH) is defined by a widespread infiltrate of non-malignant lymphocytes and macrophages, involving principally the liver, spleen and central nervous system and associated with a severe lymphoid atrophy. For this histological study, 38 juvenile cases of LH were selected and reviewed. Morphological and histochemical studies revealed that the macrophages were activated. They appeared to be OKM1, OKT9 and HLA Dr positive and showed a patent or occult erythro and thrombocytophagocytosis. Comparatively, most of the lymphoid cells did not bear any immunoglobulin and did not label with a wide panel of monoclonal antibodies including T3, T4, T6, T8, T11. The review of the clinical and biological data of these 38 cases suggests that LH does not represent a single entity but can be regarded as a non-specific response to various causes. Three different conditions associated with LH can be isolated. The first group consists of patients in whom the disease is characterized by an early onset, high familial incidence and an inevitably fatal course. This category contains the largest number of cases (29 out of 38) and corresponds to the classic description of Familial Erythrophagocytic Reticulosis by Farquhar and Claireaux. The second group includes mainly male patients and children over 2 years old. Inheritance is not a predominant feature. The course of the disease is comparatively long. A viral infection was present in three of the seven cases. This category shares many of the clinico-pathological features of the Virus Hemophagocytic Syndrome and is presumably related to a chronic and latent viral infection. A third group can be identified on the basis of the presence of pigmentation abnormalities and immunodeficiency disorders probably associated with cytoskeletal abnormalities. This group includes Chediak-Higashi disease and Griscelli's disease. The fact that some genetic factors and immunodeficiency disorders are present in these three groups is probably significant and suggests that LH is a condition brought about by multiple factors--of which the common denominator is an apparent activation of the Mononuclear Phagocytic System.

Deficiency of the adhesive protein complex lymphocyte function antigen 1, complement receptor type 3, glycoprotein p150,95 in a girl with recurrent bacterial infections. Effects on phagocytic cells and lymphocyte functions

A patient presenting delayed umbilical cord detachment, severe recurrent bacterial infections, and inability to form pus exhibited a profound defect in the expression of alpha- and beta-chains of the receptor for the C3bi fragment of C3 (CR3), lymphocyte function antigen 1 (LFA-1) molecule, and the p150,95 molecule found on neutrophils, monocytes, and lymphocyte membranes. This was shown by immunofluorescence studies using specific monoclonal antibodies, rosette formation with C3bi-coated erythrocytes, and immunoprecipitation for the LFA-1 complex. These membrane defects were responsible for abnormal phagocytic cell functions including adherence to nylon wool, cell movement, phagocytosis, and opsonized particle-induced oxidative response and for defective natural killer cell activity. In addition, lymphocyte function deficiencies previously unobserved in this disease were found. Cytolytic T lymphocyte activity was profoundly reduced; alpha- and gamma-interferon production were impaired. Finally, there was no antibody production to vaccinal antigens whereas the antibody responses to polysaccharides and to cytomegalovirus were found to be normal. The cytotoxic T cell deficiency could be expected from previous blocking experiments of this function with monoclonal antibodies to LFA-1 and is probably related to an extremely severe deficiency in LFA-1 expression in this patient. Anomalies in interferon and in antibody production suggest additional role(s) of the LFA-1 complex in monocyte/T lymphocyte/B lymphocyte cell interactions that have not yet been envisaged.

Pleiotropisms associated with alleles of the C locus in the domestic fowl

Pleiotropisms associated with the recessive white (c) and albino (ca) alleles at the C locus of the domestic fowl were investigated. Hatchability of fertile eggs was not significantly different for the colored (C+/c, C+/ca), recessive white (c/ca), and albino (ca/ca) chicks; however, late embryonic mortality was higher in ca/ca embryos P less than or equal to .005). Albinos exhibited shorter down lengths (P less than or equal to .01), higher incidences of subcutaneous hemorrhage and inflammation (P less than or equal to .01) and an increased incidence of yolk sac protrusions (P less than or equal to .01). Suppressed body weights (P less than or equal to .01) were evident at all times, except at hatching, in both male and female albinos reared in batteries. Recessive white females also exhibited smaller body weights than colored chicks at 7 and 8 weeks of age in battery trials (P less than or equal to .01). Significant suppression of body weights occurred in albinos only at 4 weeks of age in trials where floor rearing was used. Mortality in albinos was also significantly higher, particularly under floor rearing conditions (P less than or equal to .01). In addition, both feed consumption and feed utilization were reduced in albinos (P less than or equal to .01). These data suggest that melanin synthesis is an important component in the expression of a number of important physiological traits and that the C locus exerts a previously undefined regulatory influence on such traits.

Albinism

Albinism is the term applied to a heterogeneous group of genetically determined disorders characterized by hypopigmentation and affecting the eyes. After describing the clinical features of albinism in general, the authors discuss the various forms of oculocutaneous albinism, ocular albinism, and albinoidism that are of interest to the ophthalmologist. Emphasis is placed on the ocular features of each form. The visual pathway abnormalities and the clinical management of albinism are discussed.

Histiocytosis: nosology and pathobiology

The histiocytoses represent a heterogeneous group of conditions. Their common denominator is the proliferation and the activation of the mononuclear phagocyte system (MPS). On the basis of recent advances in the knowledge of the distribution, biology, and behavior of the MPS, the following classification is proposed. Reactive and secondary histiocytoses related either to a chronic parasitic intracellular infection or to a patent or latent immunodeficiency state. Some well-established conditions belong to this category--i.e., familial lympho-histiocytosis, cytophagic sinus histiocytosis, Omenn's reticulosis. The dystrophic histiocytoses associated with the storage of either exogenous or endogenous material. It is prudent to separate the storages of homogeneous and chemically defined lipid material (such as cerebroside, sphingomyelin, etc.) from those of heterogeneous lipid material. Proliferative histiocytoses: it is crucial to distinguish the malignant histiocytosis from the histiocytosis X, which seems to be associated with a nonmalignant proliferation of a subpopulation of the MPS, the Langerhans cell system.

Isolation of new lymphotropic retrovirus from two siblings with haemophilia B, one with AIDS

A human T-lymphotropic retrovirus was isolated from cultured T lymphocytes from two siblings with haemophilia B. Patient 2 was healthy, but patient 1 had acquired immunodeficiency syndrome. The retrovirus differed from human T-cell leukaemia virus (HTLV) but it was similar to the lymphadenopathy-associated retrovirus (LAV) in its morphology and its major core protein (P25). Both patients had antibodies against LAV and patient 1's retrovirus, detected by an enzyme-linked immunosorbent assay or a radioimmunoprecipitation assay. Seroepidemiological data indicated the transmission of this retrovirus by plasma products.

Impaired natural killer activity in lymphohistiocytosis syndrome

In six patients with well-documented lymphohistiocytosis syndrome, natural killer activity was found to be profoundly impaired and could not be increased by incubation in vitro with interferon. This abnormality was not found in parents of the affected children. A clear correlation with the activity of the disease was observed, although a delay of a few weeks (possibly reflecting the life span of NK cells in blood) was seen in the disappearance of NK activity after the onset of the disease and its reappearance after remission. No absolute correlation was observed between NK activity and percentage of leukocytes detected by the Leu-7 monoclonal antibody. Our findings indicate that testing NK activity is useful for the diagnosis of lymphohistiocytosis syndrome and can be used as an index of activity of the disease, among other major clinical and biologic signs of this syndrome. Reversal of the NK activity defect (rather than detection of Leu-7 positive cells) appears to be a good criterion of complete remission.

T-cell subset analysis by monoclonal antibodies in primary immunodeficiencies

T-cell subsets have been analysed in 23 cases of primary immunodeficiency with monoclonal antibodies. Functional assays investigating T-cell function--proliferative response to mitogens, antigens, and allogeneic cells, cytotoxicity generated against allogeneic target cells and helper function to pokeweek mitogen-induced immunoglobulin synthesis--were performed in parallel in the same patients. The results enabled us to delineate four groups of patients. The first group consisted of patients in whom marker and function studies show concordant data, with either normal or strongly decreased T-cell number and function. The second group consisted of patients in whom various degrees of functional abnormality coexist with subnormal T-cell number and increased suppressor T-cell proportion. In the third group, we collected all patients who showed functional deficiencies without marker abnormalities. Finally, there was a small group composed of patients whose T-cell pattern was strongly suggestive of abnormal differentiation.

Dysfunctions of pokeweed mitogen-stimulated T and B lymphocyte responses induced by gammaglobulin therapy

Lymphocytes obtained from nonimmuno deficient children treated with commercially available preparations of gammaglobulin failed to proliferate and to mature into plasma cells in vitro after stimulation with pokeweed mitogen. The influence of the treatment on lymphocyte functions varied according to the cell population considered. A T helper cell activity was detected in these patients but only in the cell subset bearing receptors for IgG after irradiation. T lymphocytes exerted a suppressive effect that disappeared after irradiation or incubation at 37 degrees C. The suppressive cells were found among E rosette-forming cells depleted of leukocytes bearing receptors for IgG. Their suppressive effect was expressed only in the presence of normal radioresistant T lymphocytes that did not bear Fc receptors for IgG. Similar dysfunctions could be induced in vitro by incubation of normal T and B lymphocytes with gammaglobulin preparations. Because F(ab)'2 fragments or deaggregated preparations of gammaglobulin failed to activate T suppressor lymphocytes, this activation was likely triggered by attachment of Fc portion of denatured IgG to the corresponding membrane receptor. This activation step was prostaglandin E(2)-dependent, suggesting that activated monocytes were involved in the activation process. B lymphocyte responses appeared directly inhibited by attachment of denatured gammaglobulin on membrane Fc receptor. Our observations suggest that immunological effects of gammaglobulin therapy are not limited to antibody transfer, since it also induces subtle modifications of in vitro pokeweed mitogen-stimulated T and B cell responses. These modifications must be considered in interpreting results obtained in immunodeficient patients investigated under gamma-globulin therapy.

Langerhans' cell-free regions in orthokeratinizing sole-of-foot epidermis of the adult mouse

The distribution of ATPase-positive Langerhans' cells was investigated in whole sheets of the glabrous sole-of-foot epidermis of the mouse. This completely orthokeratinizing tissue shows distinct morphological differences mainly with regard to the dermo-epidermal junction. Whereas the sharply outlined nodular prominences in the center of each footpad have a heavily undulated dermo-epidermal junction, the epidermal baseline in the surrounding tissue and the region just proximal to the footpad is flat. A dense population of evenly distributed ATPase-positive Langerhans' cells is found in the epidermis which surrounds the nodular structures. A slightly reduced population of Langerhans' cells is located in the epidermis of 80% of the nodules, occasionally showing a concentration in the pronounced epidermal ridges. Twenty percent of the nodules possess an epidermis which is completely free of Langerhans' cells. The results are discussed in view of the current hypothesis on the biological function of Langerhans' cells.

Branched cells in the epidermis: an overview

Current knowledge concerning the nature, lineage, and function of the Langerhans cell, Merkel cell, and, to a lesser extent, the melanocyte, are reviewed under headings that emphasize the confederate constitution of the epidermis as a compound tissue composed of a variety of cellular elements; the role of the lymphocyte as a component of normal epidermis is also considered. It appears that the function of the Langerhans cell has finally been established, i.e., it serves as a front-line element in immune reactions of the skin. Developmentally, it is of mesenchymal origin. The Merkel cell still presents a number of problems centering around questions of its lineage, the nature of its characteristic granules, and the "synaptic" relationship between it and the associated neurite. The melanocyte continues to hold the attention of investigators, mainly from the point of view of the chemistry of melanin and the rational treatment of pigmentary disorders based upon findings derived from fundamental research into all aspects of its biology.

Inappropriate use of albino animals as models in research

Sensory-neural, biochemical-metabolic, and physiological anomalies occur in albino mammals. There are ontogenic and biochemical parallels between the senses, peripheral nervous system, endocrine glands, metabolism, and melanin pigmentation. All albino mammals examined have abnormal optic systems. Many drugs cannot be adequately evaluated in an albino model because of melanin's ability to bind and interact with some chemicals. There is evidence that a general reduction in melanin pigment is correlated with a paucity of amino acids necessary for normal chemical function of the brain. There is a high probability that enzyme levels indicative of metabolic performance are deficient in the liver and kidneys oif albinos. Congenital defects are associated with hypopigmentation in animal models and human syndromes. Melanin is found in abundance in the eye, inner ear, and midbrain where neural impulses are initiated indicating a possible role as an electrophysiologic mechanism. Microwave irradiation differentially affects albino and pigmented animals. Implications of these observations and other reports of anomalies associated with hypopigmentation suggest caution in the use of albino and other hypomelanotic animals as normal models in biological research.

[The Buckley syndrome: recurring, severe staphylococcal infections, eczema and hyperimmunoglobulinemia E. (author's transl)]

Fifteen patients aged between three and 27 years were examined clinically and immunologically. Common to all patients were severe recurring cutaneous and pulmonary staphyloccal infections, chronic eczema, eosinophilia and an extremely elevated serum IgE level. Eight of the patients had in addition facial dysplasia characterised by coarse features, prognathism and poorly formed external ears. Marked osteoporosis, particularly of the vertebral bodies, was observed in eight patients. A constant defect of granulocyte chemotaxis was found in only three patients; fluctuating or constantly normal chemotaxis occurred in six patients. Polycloncal hypergammaglobulinemia was detected in 14 patients, elevated IgD in two patients, a partial T-cell defect in two patients and a history of lack of antibody response in one patient. Therapeutic trails anti-H2 receptor-antihistamines did not produce lasting or satisfactory clinical or immunological results in the pathogenetically unidentified disease.

Natural killer and killer cell activities in patients with primary immunodeficiencies or defects in immune interferon production

Natural cell-mediated cytotoxicity (NCMC) against K-562 target cells was explored in patients with various primary immunodeficiencies. (a) NCMC was present in 2 patients lacking detectable B cells. Conversely, NCMC was depressed in 2 patients with severe combined immunodeficiency presenting a normal number of circulating B cells. These data exclude a major role for B cells in NCMC. (b) NCMC was depressed mainly in patients with severe combined immunodeficiency or with defects affecting cellular immunity, which suggests a major role in NCMC for cells of T lineage. (c) Four patients with various clinical features associated with a lack of immune interferon production exhibited a strikingly depressed NCMC. Interferon thus appears as a major in vivo activator of natural killer (NK) cell activity. (d) Eight patients exhibiting a depressed NK cell activity had a normal killer (K) cell activity against L1210 cells in the presence of rabbit anti-L1210 antiserum. These data are consistent with the assumption that NK and K cell activity are mediated through two distinct cellular mechanisms.