Milton D. Rossman

HLA-DRB1*1101: A Significant Risk Factor for Sarcoidosis in Blacks and Whites

Sarcoidosis is a granulomatous disorder of unknown etiology, associated with an accumulation of CD4+ T cells and a TH1 immune response. Since previous studies of HLA associations with sarcoidosis were limited by serologic or low-resolution molecular identification, we performed high-resolution typing for the HLA-DPB1, HLA-DQB1, HLA-DRB1, and HLA-DRB3 loci and the presence of the DRB4 or DRB5 locus, to define HLA class II associations with sarcoidosis. A Case Control Etiologic Study of Sarcoidosis (ACCESS) enrolled biopsy-confirmed cases (736 total) from 10 centers in the United States. Seven hundred six (706) controls were case matched for age, race, sex, and geographic area. We studied the first 474 ACCESS patients and case-matched controls. The HLA-DRB1 alleles were differentially distributed between cases and controls (P<.0001). The HLA-DRB1*1101 allele was associated (P<.01) with sarcoidosis in blacks and whites and had a population attributable risk of 16% in blacks and 9% in whites. HLA-DRB1-F(47) was the amino acid residue most associated with sarcoidosis and independently associated with sarcoidosis in whites. The HLA-DPB1 locus also contributed to susceptibility for sarcoidosis and, in contrast to chronic beryllium disease, a non-E(69)-containing allele, HLA-DPB1*0101, conveyed most of the risk. Although significant differences were observed in the distribution of HLA class II alleles between blacks and whites, only HLA-DRB1*1501 was differentially associated with sarcoidosis (P<.003). In addition to being susceptibility markers, HLA class II alleles may be markers for different phenotypes of sarcoidosis (DRB1*0401 for eye in blacks and whites, DRB3 for bone marrow in blacks, and DPB1*0101 for hypercalcemia in whites). These studies confirm a genetic predisposition for sarcoidosis and present evidence for the allelic variation at the HLA-DRB1 locus as a major contributor.

Efficacy of infliximab in extrapulmonary sarcoidosis: results from a randomised trial

The aim of the present study was to investigate the efficacy of infliximab for the treatment of extrapulmonary sarcoidosis. A prospective, randomised, double-blind, placebo-controlled trial was conducted, with infliximab at 3 and 5 mg·kg−1 body weight administered over 24 weeks. Extrapulmonary organ severity was determined by a novel severity tool (extrapulmonary physician organ severity tool; ePOST) with an adjustment for the number of organs involved (ePOSTadj). In total, 138 patients enrolled in the trial of infliximab versus placebo for the treatment of chronic corticosteroid-dependent pulmonary sarcoidosis. The baseline severity of extrapulmonary organ involvement, as measured by ePOST, was similar across treatment groups. After 24 weeks of drug-therapy study, the change from baseline to week 24 in ePOST was greater for the combined infliximab group compared with the placebo group. After adjustment for the number of extrapulmonary organs involved, the improvement in ePOSTadj observed in the combined infliximab group was also greater than that observed in placebo-treated patients, after 24 weeks of therapy. The improvements in ePOST and ePOSTadj were not maintained during a subsequent 24-week washout period. Infliximab may be beneficial compared with placebo in the treatment of extrapulmonary sarcoidosis in patients already receiving corticosteroids, as assessed by the severity tool described in the present study.

Immunologic Abnormalities in Sarcoidosis

Patients with active sarcoidosis (acute and chronic) have a depression in systemic cell-mediated immunity manifested by a reduction in the number of circulating T cells and impaired responses of these cells to polyclonal mitogens and recall antigens. These abnormalities are absent in patients with resolved disease and contrast with heightened B-cell activity. The latter includes elevated serum immunoglobulins and the presence of autoantibodies and circulating immune complexes. Similarly, many humoral abnormalities (for example, immune complexes) are absent in patients with resolved disease. Studies of bronchoalveolar cells have revealed changes that are opposite to what is found in peripheral blood. The number of lymphocytes recovered by bronchoalveolar lavage is increased. This is mainly due to an increase in the number of T cells and a subpopulation of activated T cells. These findings suggest that the lung (when involved) is the site of an immune inflammatory response.

Proliferative Response of Bronchoalveolar Lymphocytes to Beryllium: A Test for Chronic Beryllium Disease

STUDY OBJECTIVE to ascertain whether measuring the proliferative response of bronchoalveolar lymphocytes to beryllium salts is useful for diagnosing chronic beryllium disease. DESIGN prospective case series compared to normal volunteers and patients with sarcoidosis. SETTING university referral center. PATIENTS twenty-three consecutive beryllium workers were evaluated. Fourteen had chronic beryllium disease diagnosed on the basis of histologic evidence of a progressive pulmonary granulomatosis. Four had biopsy evidence of non-beryllium disease. Three had probable chronic beryllium disease but did not have lung biopsies. Two did not have biopsies and had basilar fibrosis on chest roentgenogram suggestive of non-beryllium lung disease. These patients were compared with 6 normal volunteers and 16 patients with sarcoidosis. MEASUREMENTS AND MAIN RESULTS bronchoalveolar lavage was done and the proliferative response of the lung cells to two beryllium salts was tested. A positive proliferative test was defined as a stimulation index of more than five on two determinations. The sensitivity of this test was 100% in the 14 patients with definite chronic beryllium disease. The specificity of the test was also 100% among the normal volunteers and the 16 patients with sarcoidosis. The test was positive in none of the four patients with biopsy evidence of non-beryllium disease, none out of two patients with lower lobe fibrosis suggestive of non-beryllium disease, and all of three patients with probable chronic beryllium lung disease. CONCLUSIONS the proliferative response of bronchoalveolar lymphocytes to beryllium appears to be a useful test for chronic beryllium disease.

Genome-wide search for sarcoidosis susceptibility genes in African Americans

Sarcoidosis, a systemic granulomatous disease of unknown etiology, likely results from an environmental insult in a genetically susceptible host. In the US, African Americans are more commonly affected with sarcoidosis and suffer greater morbidity than Caucasians. We searched for sarcoidosis susceptibility loci by conducting a genome-wide, sib pair multipoint linkage analysis in 229 African-American families ascertained through two or more sibs with a history of sarcoidosis. Using the Haseman–Elston regression technique, linkage peaks with P-values less than 0.05 were identified on chromosomes 1p22, 2p25, 5p15-13, 5q11, 5q35, 9q34, 11p15 and 20q13 with the most prominent peak at D5S2500 on chromosome 5q11 (P=0.0005). We found agreement for linkage with the previously reported genome scan of a German population at chromosomes 1p and 9q. Based on the multiple suggestive regions for linkage found in our study population, it is likely that more than one gene influences sarcoidosis susceptibility in African Americans. Fine mapping of the linked regions, particularly on chromosome 5q, should help to refine linkage signals and guide further sarcoidosis candidate gene investigation.

Bronchoalveolar lavage in a patient with chronic berylliosis: evidence for hypersensitivity pneumonitis.

Because immunologic mechanisms are thought to have a role in chronic berylliosis, we studied the immunologic properties of peripheral blood and bronchoalveolar lymphocytes in a patient with this disease. Although the percent of peripheral blood T cells was slightly reduced compared with that in controls (59% versus 70%), there was a large increase in the number and proportion (94% versus 62%) of bronchoalveolar T cells. The percent of activated bronchoalveolar T cells was nearly five times the control value (64.5% versus 14%). Both peripheral blood and bronchoalveolar lymphocytes proliferated in response to BeSO4 and BeF2 exposure but the response of bronchoalveolar lymphocytes was greater than comparable numbers of peripheral blood lymphocytes. These findings are consistent with the concept that chronic berylliosis is a form of hypersensitivity pneumonitis and that bronchoalveolar lavage may be helpful in establishing the diagnosis of this disease.

Chronic beryllium disease and sensitization at a beryllium processing facility.

We conducted a medical screening for beryllium disease of 577 former workers from a beryllium processing facility. The screening included a medical and work history questionnaire, a chest radiograph, and blood lymphocyte proliferation testing for beryllium. A task exposure and a job exposure matrix were constructed to examine the association between exposure to beryllium and the development of beryllium disease. More than 90% of the cohort completed the questionnaire, and 74% completed the blood and radiograph component of the screening. Forty-four (7.6%) individuals had definite or probable chronic beryllium disease (CBD), and another 40 (7.0%) were sensitized to beryllium. The prevalence of CBD and sensitization in our cohort was greater than the prevalence reported in studies of other beryllium-exposed cohorts. Various exposure measures evaluated included duration; first decade worked; last decade worked; cumulative, mean, and highest job; and highest task exposure to beryllium (to both soluble and nonsoluble forms). Soluble cumulative and mean exposure levels were lower in individuals with CBD. Sensitized individuals had shorter duration of exposure, began work later, last worked longer ago, and had lower cumulative and peak exposures and lower nonsoluble cumulative and mean exposures. A possible explanation for the exposure–response findings of our study may be an interaction between genetic predisposition and a decreased permanence of soluble beryllium in the body. Both CBD and sensitization occurred in former workers whose mean daily working lifetime average exposures were lower than the current allowable Occupational Safety and Health Administration workplace air level of 2 μg/m3 and the Department of Energy guideline of 0.2 μg/m3.

Relationship of environmental exposures to the clinical phenotype of sarcoidosis

STUDY OBJECTIVES Sarcoidosis is a granulomatous disorder with heterogeneous clinical manifestations, which are potentially reflective of a syndrome with different etiologies leading to similar histologic findings. We examined the relationship between environmental and occupational exposures, and the clinical phenotype of sarcoidosis. DESIGN We performed a cross-sectional study of incident sarcoidosis cases that had been identified by A Case Control Etiologic Study of Sarcoidosis. Subjects were categorized into the following two groups: (1) pulmonary-only disease; and (2) systemic disease (with or without pulmonary involvement). Logistic regression was used to examine the associations of candidate exposures with clinical phenotype. SETTING Ten academic medical centers across the United States. PATIENTS The current study included 718 subjects in whom sarcoidosis had been diagnosed within 6 months of study enrollment. Patients met the following criteria prior to enrollment: (1) tissue confirmation of noncaseating granulomas on tissue biopsy on one or more organs within 6 months of study enrollment with negative stains for acid-fast bacilli and fungus; (2) clinical signs or symptoms that were consistent with sarcoidosis; (3) no other obvious explanation for the granulomatous disease; and (4) age > 18 years. MEASUREMENTS AND RESULTS Several exposures were associated with significantly less likelihood of having extrapulmonary disease in multivariate analysis, including agricultural organic dusts and wood burning. The effects of many of these exposures were significantly different in patients of different self-defined race. CONCLUSIONS The differentiation of sarcoidosis subjects on the basis of clinical phenotypes suggests that these subgroups may have unique environmental exposure associations. Self-defined race may play a role in the determination of the effect of certain exposures on disease phenotypes.

Chronic beryllium disease: diagnosis and management.

Chronic beryllium disease is predominantly a pulmonary granulomatosis that was originally described in 1946. Symptoms usually include dyspnea and cough. Fever, anorexia, and weight loss are common. Skin lesions are the most common extrathoracic manifestation. Granulomatous hepatitis, hypercalcemia, and kidney stones can also occur. Radiographic and physiologic abnormalities are similar to those in sarcoidosis. While traditionally the pathologic changes included granulomas and cellular interstitial changes, the hallmark of the disease today is the well-formed granuloma. Immunologic studies have demonstrated a cell-mediated response to beryllium that is due to an accumulation of CD4+ T cells at the site of disease activity. Diagnosis depends on the demonstration of pathologic changes (i.e., granuloma) and evidence that the granuloma was caused by a hypersensitivity to beryllium (i.e., positive lung proliferative response to beryllium). Using these criteria, the diagnosis of chronic beryllium disease can now be made before the onset of clinical symptoms. Whether, with early diagnosis, the natural course of this condition will be the same as when it was traditionally diagnosed is not known. Currently, corticosteroids are used to treat patients with significant symptoms or evidence of progressive disease.

Monocyte-derived macrophage and alveolar macrophage fibronectin production and cathepsin D activity

Alveolar macrophages are thought to play an important role in ongoing tissue breakdown and repair processes in the normal lung. The secretion and regulation of cathepsin D (important for the final breakdown of collagen) and fibronectin (involved in the healing process) in human peripheral blood monocytes (PBM) and pulmonary alveolar macrophages (PAM) were investigated. Cathepsin D enzyme activity was measured by quantitating the TCA-soluble fragments of [3H]hemoglobin. Freshly isolated PBM contained less cell-associated cathepsin D activity than did freshly isolated PAM (314 +/- 35 micrograms/10(6) cells vs 381 +/- 35 micrograms/10(6) cells, respectively). After 7-10 days in culture, cell-associated enzyme levels in both PBM and PAM were significantly increased (P less than 0.001 for PBM; P less than 0.0001 for PAM). In addition, freshly isolated PAM secreted more cathepsin D than did freshly isolated PBM (5.8 +/- 3.2 micrograms/10(6) cells vs 0.83 +/- 0.83 micrograms/10(6) cells, P less than 0.02). In the presence of LPS (10 micrograms/ml), cell-associated cathepsin D was inhibited in both PBM and PAM. With the addition of gamma-IFN (500 U/ml), both cell-associated and secreted enzyme were increased in freshly isolated and 10-day-cultured PBM and PAM. In parallel studies, fibronectin secretion (by ELISA assay) in both PBM and PAM increased over time in culture. LPS had no effect on PBM or PAM secretion of human fibronectin while gamma-IFN increased PBM and PAM fibronectin levels. Thus, both macrophage cathepsin D activity and fibronectin secretion are increased by gamma-interferon while macrophage cathepsin D activity, but not fibronectin secretion, is decreased by LPS. These studies demonstrate that human macrophage cathepsin D activity is actively modulated by inflammatory mediators and that macrophage mediators of tissue breakdown and repair are not modulated synchronously.