Aquagenic palmoplantar keratoderma.

Aquagenic palmoplantar keratoderma is an acquired condition characterized by burning and edema limited to the hands after brief immersion in water. The 3 patients described possess a striking similarity to those with transient reactive papulotranslucent acrokeratoderma. All 3 patients manifested the "hand-in-the-bucket" sign, having presented to a physician with a hand immersed in a bucket of water to more promptly demonstrate the physical findings. Aluminum chloride hexahydrate represents a potentially valuable therapeutic option for this unusual condition.

Production of type 2 cytokines by CD8+ lung cells is associated with greater decline in pulmonary function in patients with systemic sclerosis.

OBJECTIVE: This study addresses the hypothesis that a profibrotic pattern of cytokines is produced in the lungs of patients with systemic sclerosis (SSc) and causes fibrosis. METHODS: Using a reverse transcriptase-polymerase chain reaction technique, interleukin-4 (IL-4), IL-5, and interferon-gamma (IFNgamma) messenger RNA (mRNA) were measured in unseparated CD8+ and CD4+ bronchoalveolar lavage (BAL) cells from SSc patients and healthy controls. To confirm the results, CD8+ T cells were cloned from BAL fluids, and the pattern of cytokine mRNA made by these cells was determined. Serial pulmonary function tests were done. RESULTS: BAL cells from healthy controls made IFNgamma mRNA, with no or little IL-4 or IL-5 mRNA. In contrast, BAL cells from the majority of SSc patients made IL-4 and/or IL-5 mRNA, with or without approximately equal amounts of IFNgamma mRNA. This pattern of cytokines was made by CD8+ T cells, which were increased in the lungs of these SSc patients. Patients whose BAL cells made this type 2 pattern of cytokine mRNA had a significant decline in forced vital capacity over time after the BAL, whereas patients whose BAL cells made IFNgamma mRNA alone did not. Both wild-type and an alternative splice variant of IL-4 mRNA were increased in BAL cells from SSc patients. Both forms of IL-4 stimulated alpha2(I) collagen mRNA in human dermal and lung fibroblasts. CONCLUSION: The type 2 pattern of cytokine mRNA produced by BAL cells from SSc patients differs from unopposed IFNgamma production found in healthy BAL cells. This production of type 2 cytokine mRNA by CD8+ T cells is associated with a significant decline in lung function over time, which suggests a pathologic role for these T cells in interstitial fibrosis in SSc.

Identification and characterization of two alternative splice variants of human interleukin-2.

Our previous work showed that alternative splicing is used to make an inhibitory variant of human interleukin (IL)-4. Because of homology between IL-4 and IL-2 proteins and receptors, we tested whether alternative splicing is used to generate similar inhibitory variants of human IL-2. Messenger RNA from peripheral blood mononuclear cells was subjected to reverse transcription-polymerase chain reaction using IL-2 exon 1- and exon 4-specific primers. Two amplification products, named IL-2delta2 and IL-2delta3, were found in addition to the native IL-2 product. The IL-2delta2 cDNA sequence was identical to IL-2 cDNA throughout the entire coding region, except exon 2 was omitted by alternative splicing. In IL-2delta3 cDNA, the third exon of IL-2 was omitted by alternative splicing. Unlike IL-2, IL-2delta2 and IL-2delta3 did not stimulate T cell proliferation. However, both inhibited IL-2 costimulation of T cell proliferation, and both inhibited cellular binding of rhIL-2 to high affinity IL-2 receptors. Thus, IL-2 is the second cytokine that uses alternative splicing to generate variants that are competitive inhibitors.

Simultaneous quantitation of cytokine mRNAs by reverse transcription-polymerase chain reaction using multiple internal standard cRNAs.

Cytokines produced in abnormal amounts or patterns contribute to many immunologically mediated human diseases. We describe a competitive reverse transcription-polymerase chain reaction (RT-PCR) assay to measure interleukin (IL)1-2, IL-4, and interferon-gamma (IFN-gamma) mRNAs within the sample. Internal standard cRNAs and native cytokine mRNAs are reverse transcribed and then amplified by PCR in the same reaction tubes to control for tube-to-tube variability in these reactions. In contrast to systems that use a single multigene internal standard cRNA, this method uses separate internal standard cRNAs for IL-2, IL-4, and IFN-gamma, allowing independent dosing of the internal standards, which reduces the number of tubes processed and the amount of starting mRNA required. Internal standards are produced from cytokine cDNAs by the insertion of short segments of DNA. The same oligonucleotide primers are used to amplify internal standard and native cytokine cDNAs. Each internal standard cDNA and its matching native cytokine cDNA are amplified with equal efficiency. The RT-PCR products of the internal standards and native cytokines are distinguished by size. This technique can detect a twofold difference in mRNA levels. Examples of using this technique to measure cytokine mRNAs in peripheral blood mononuclear cells and in bronchoalveolar lavage cells are given.

Generation of a variant of human interleukin-4 by alternative splicing.

A second species of interleukin-4 (IL-4) mRNA was identified using both a reverse transcription-polymerase chain reaction and an RNase protection assay. This novel IL-4 mRNA was 48 base pairs smaller than IL-4 mRNA, which is the size of IL-4 exon 2. Sequence data of cloned cDNA demonstrated that this variant contained IL-4 exons 1,3 and 4, with exon 1 spliced directly to exon 3 in an open reading frame. The entire protein encoding region of this variant, named IL-4 delta 2, was identical to IL-4 except for the omission of exon 2. IL-4 delta 2 mRNA was detected in all human peripheral blood mononuclear cells tested and in purified CD3+ T cells. Amounts of both IL-4 and IL-4 delta 2 mRNAs increased upon T cell activation, although IL-4 mRNA increased to a greater extent than IL-4 delta 2 mRNA did. Human IL-3, IL-5, IL-13, and granulocyte macrophage-colony stimulating factor did not use alternative splicing to delete exon 2. We speculate that IL-4 delta 2 may regulate IL-4 function.