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To determine the pulmonary complications in HIV-1-infected patients in Dar es Salaam, Tanzania, and to evaluate the diagnostic utility of bronchoscopy and bronchoalveolar lavage, we carried out a prospective study of 237 patients with acute respiratory disease who were hospitalized at Muhimbili Medical Center (MMC). Diagnoses were made using well-defined criteria. Of the total, 127 (54%) were HIV-1-seropositive and 110 (46%) were seronegative. Tuberculosis was the most common diagnosis occurring in 95 (75%) HIV-1-seropositive and 87 (79%) seronegative patients. Bacterial pneumonia was the next most common diagnosis occurring in 18 (14%) HIV-1-seropositive and 17 (15%) seronegative patients. Pneumocystis carinii pneumonia was diagnosed in one and Kaposi's sarcoma was seen in only two HIV-1-seropositive patients. Bronchoscopy with bronchoalveolar lavage was the sole source of a diagnosis in nine (8%) seropositive and six (5%) seronegative patients. We conclude that the HIV seroprevalence rate among patients hospitalized for acute respiratory disease at MMC is extremely high. Tuberculosis was the most common cause of pulmonary disease, regardless of HIV serostatus, and other HIV-associated opportunistic pulmonary infections were unusual. Bronchoscopy with bronchoalveolar lavage added little to the diagnosis and thus should not be high-priority procedures for the routine workup in resource-poor areas where tuberculosis is endemic.

Molecular and genetic tools have been used to shed light on the genes that contribute to susceptibility to murine lupus and the mechanisms that lead to immunopathology. The MHC genes and their products have been consistently shown to contribute toward the development of disease. To understand the contribution of MHC-class II genes, our laboratory had derived two inbred strains of mice, NZB.H-2bm12 and NZB.H-2b. These new colonies of mice were studied and compared in the 10th generation backcross; inbreeding was serially followed by H-2 typing, responses to beef/porcine insulin, and the presence of the B6 Ig allotype, IgG2ab. Of great interest is the finding that NZB.H-2bm12, in contrast to NZB.H-2b or NZB (H-2d), mice develop high titer autoantibodies to dsDNA. This result is unique because NZB (H-2d) mice, unliked NZB x NZW (NZB/W F1) or NZB x SWR (SNF1) hybrids do not develop autoantibodies to dsDNA, even after immunization. NZB mice, in contrast, are characterized only by autoantibodies to ssDNA. Our observation is also striking because the gene conversion that resulted in the I-A beta bm12 mutation occurred at amino acid residues 68, 71, and 72 of I-E beta b. Recently the contribution of NZW to accelerated autoimmunity in the NZB x NZW F1 hybrid has also been linked to H-2 and a single amino acid change at amino acid 72 of I-E beta. Thus, amino acid residue 72 may be a hot spot for disorders of immune regulation when superimposed on the appropriate genetic background. NZB mice expressing the I-Abm12 mutation will allow specific dissection of the requirements for autoantibody production to dsDNA uncomplicated by heterozygosity.

The formation of B lymphocytes in young New Zealand Black (NZB) mice proceeds at an accelerated rate resulting in a deficiency of B lineage precursors in adult (greater than 15 wk old) animals. To study the characteristics of B lineage cells in young (4 wk) and old (6 mo) NZB mice, bone marrow from these animals was used to initiate long term lymphoid bone marrow cultures (LBMC) that permit the long term maintenance of B cells and their precursors. Age-matched cultures from BALB/c mice and NZB.xid marrow were established in parallel. Primary LBMC were readily established from these strains and showed similar patterns of growth for the 3-mo observation period. No significant differences in numbers of 14.8 positive cells were observed. However, NZB mice at both ages had a higher percentage of membrane IgM (mIgM)-expressing cells. Significant levels of supernatant IgM were found only in cultures of 6-mo NZB and BALB/c mice; levels were highest in NZB culture supernatants and were often more than 500 ng/ml; significant, although much lower, levels of IgG were likewise detected. Lymphoid cells from NZB.xid mice were unable to generate significant levels of IgM in supernatant fluids indicating the effects of the xid gene were displayed in vitro. Autoantibodies were not detected in any of the culture supernatants. Additional evidence for NZB hyperactivity in primary B lymphopoiesis was observed upon initiation of primary myeloid bone marrow cultures (MBMC) from these strains of mice and subsequently transferring them to LBMC conditions. This results in the cessation of myelopoiesis at the initiation of B lymphopoiesis. At the time of converting MBMC to LBMC, cultures of NZB and BALB/c mice morphologically resembled myeloid cultures and had neither B cell colony-forming units nor cells that expressed 14.8 or mIgM. However, following the switch, NZB mice had a 5-fold higher number of B cell colony-forming units. Further, MBMC established from NZB bone marrow cells had a reduced capacity to form colonies in the granulocyte-macrophage colony-forming unit assay. These studies indicate that defects of NZB hemopoietic cells are manifest in vitro and suggest the use of in vitro long term cultures as a valuable technique to further dissect the hematopoietic abnormalities of NZB mice and possible underlying microenvironmental defects.

F antigen is a 43-kDa widely conserved liver protein that has been intensively used in studies of immunogenicity and tolerance; two murine allotypes have been identified. Immunization of specific responder inbred strains with liver homogenates from the opposite allotype leads to precipitating antibody and cell-mediated immunity against F. The antibodies produced are autoantibodies as they react equally well with self. We have identified a cDNA clone from rat liver that reacts with alloantisera to F. The fused polypeptide produced by the clone was shown to correspond to F by several experiments. First, alloantisera to F antigen reacted with the cloned fused polypeptide, but not control recombinant clones. Second, mice immunized with the fused polypeptide generate an antibody response that reacts specifically with the 43-kDa protein of mouse liver homogenates and with highly purified F antigen. Finally, both anti-F allosera and sera from mice immunized with the fused polypeptide react with the same 43-kDa liver protein on two-dimensional immunoblots. The nucleotide and deduced amino acid sequence of the clone are presented and the sequence was found to have a significant homology with L28, an Escherichia coli ribosomal protein. The availability of recombinant F antigen will allow definitive questions to be addressed with respect to epitopes and specifically the identification of the T cell epitope which allows for autoimmune responses.

The formation of B lymphocytes in young New Zealand Black (NZB) mice proceeds at an accelerated rate resulting in a deficiency of B lineage precursors in adult (greater than 15 wk old) animals. To study the characteristics of B lineage cells in young (4 wk) and old (6 mo) NZB mice, bone marrow from these animals was used to initiate long term lymphoid bone marrow cultures (LBMC) that permit the long term maintenance of B cells and their precursors. Age-matched cultures from BALB/c mice and NZB.xid marrow were established in parallel. Primary LBMC were readily established from these strains and showed similar patterns of growth for the 3-mo observation period. No significant differences in numbers of 14.8 positive cells were observed. However, NZB mice at both ages had a higher percentage of membrane IgM (mIgM)-expressing cells. Significant levels of supernatant IgM were found only in cultures of 6-mo NZB and BALB/c mice; levels were highest in NZB culture supernatants and were often more than 500 ng/ml; significant, although much lower, levels of IgG were likewise detected. Lymphoid cells from NZB.xid mice were unable to generate significant levels of IgM in supernatant fluids indicating the effects of the xid gene were displayed in vitro. Autoantibodies were not detected in any of the culture supernatants. Additional evidence for NZB hyperactivity in primary B lymphopoiesis was observed upon initiation of primary myeloid bone marrow cultures (MBMC) from these strains of mice and subsequently transferring them to LBMC conditions. This results in the cessation of myelopoiesis at the initiation of B lymphopoiesis. At the time of converting MBMC to LBMC, cultures of NZB and BALB/c mice morphologically resembled myeloid cultures and had neither B cell colony-forming units nor cells that expressed 14.8 or mIgM. However, following the switch, NZB mice had a 5-fold higher number of B cell colony-forming units. Further, MBMC established from NZB bone marrow cells had a reduced capacity to form colonies in the granulocyte-macrophage colony-forming unit assay. These studies indicate that defects of NZB hemopoietic cells are manifest in vitro and suggest the use of in vitro long term cultures as a valuable technique to further dissect the hematopoietic abnormalities of NZB mice and possible underlying microenvironmental defects.

F antigen is a 43-kDa widely conserved liver protein that has been intensively used in studies of immunogenicity and tolerance; two murine allotypes have been identified. Immunization of specific responder inbred strains with liver homogenates from the opposite allotype leads to precipitating antibody and cell-mediated immunity against F. The antibodies produced are autoantibodies as they react equally well with self. We have identified a cDNA clone from rat liver that reacts with alloantisera to F. The fused polypeptide produced by the clone was shown to correspond to F by several experiments. First, alloantisera to F antigen reacted with the cloned fused polypeptide, but not control recombinant clones. Second, mice immunized with the fused polypeptide generate an antibody response that reacts specifically with the 43-kDa protein of mouse liver homogenates and with highly purified F antigen. Finally, both anti-F allosera and sera from mice immunized with the fused polypeptide react with the same 43-kDa liver protein on two-dimensional immunoblots. The nucleotide and deduced amino acid sequence of the clone are presented and the sequence was found to have a significant homology with L28, an Escherichia coli ribosomal protein. The availability of recombinant F antigen will allow definitive questions to be addressed with respect to epitopes and specifically the identification of the T cell epitope which allows for autoimmune responses.